Lymphocyte Subsets (lymphocyte + subset)

Distribution by Scientific Domains
Distribution within Medical Sciences


Selected Abstracts


CLINICAL STUDY: FULL ARTICLE: Immunomodulating properties of gamma-hydroxybutyrate (GHB), flunitrazepam and ethanol in ,club drugs' users

ADDICTION BIOLOGY, Issue 3 2010
Simona Pichini
ABSTRACT Despite the increasing concern about gamma-hydroxybutyrate (GHB) toxicity in users, no studies have addressed GHB and other club drugs effects on the immune system under controlled administration. Lymphocyte subsets and functional responsiveness of lymphocytes to mitogenic stimulation were measured in 10 healthy male recreational users of GHB who participated in five experimental sessions within the framework of a clinical trial. The study was randomized, double blind, double dummy and cross-over. Drug conditions were: a single oral dose of GHB (40 mg/kg or 60 mg/kg), ethanol (0.7 g/kg), flunitrazepam (1.25 mg) and placebo. Acute GHB produced a time-dependent immune impairment in the first 4 hours after drug administration associated with an increase in cortisol secretion. Although total leukocyte count remained unchanged, there was a significant decrease in the CD4 T/CD8 T-cell ratio, as well as in the percentage of mature T lymphocytes, probably because of a decrease in both the percentage and absolute number of T helper cells. A significant decrease was also observed in natural killer cells and in functional responsiveness of lymphocytes to mitogenic stimulation. Flunitrazepam administration did not produce any change in the immune system, while ethanol intake produced a decrease in B lymphocytes and in lymphocyte proliferative response to mitogens. These results provide the first evidence that GHB intake under a controlled environmental setting impairs the immunological status and confirms the alterations in the immune function caused by ethanol. [source]


Analysis of peripheral blood T-cell subsets, natural killer cells and serum levels of cytokines in children with Down syndrome

INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 4 2010
S. Cetiner
Summary The objective of this study was to evaluate the relationship between humoral and cell-mediated immune response parameters and impairment of immune functions in children with Down syndrome (DS). The patient group was consisted of cytogenetically documented 32 children with DS. Lymphocyte subsets and natural killer cells were counted by flow-cytometry system. Levels of interleukin (IL)-1,, IL-2, IL-4, IL-6, IL-8, IL-10 and tumour necrosis factor-alpha (TNF-,) were detected by enzyme-linked immunosorbent assay method. Serum IgG, IgM, IgA levels were measured by turbidimetric methods. The percentage of CD8+ lymphocytes and CD56+ cells of patients with DS were significantly higher, whereas CD20+ lymphocytes were lower than that of controls (P < 0.05). The percentage of CD2 and CD4 levels and CD4/CD8 ratio of patients with DS and normal controls were similar (P > 0.05). Levels of IL-4 and IL-10 were significantly increased, but IL-6 and TNF-, levels were decreased in children with DS (P < 0.05). Levels of other studied cytokines between patients with DS and controls were not statistically different (P > 0.05, for all). Serum IgG, IgM and IgA levels were found to be similar between the groups (P > 0.05). It has been known that IL-4 and IL-10 are anti-inflammatory molecules which inhibit the synthesis of proinflammatory cytokines such as IL-6 and TNF-,. In this study, levels of IL-4 and IL-10 were significantly increased, but IL-6 and TNF-, levels were decreased in children with DS. These results may suggest that continuing anti-inflammatory state in DS and this process may explain the cause of recurrent infection of the disease. On the other hand, in contrast to the low percentage of CD20+ cells, high percentage of CD8+ and CD56+ cells were found. Our findings may demonstrate that the cell-mediated and humoral immune system parameters in children with DS were altered according to healthy children. [source]


Elevated NK Cell Cytotoxicity, CD158a Expression in NK Cells and Activated T Lymphocytes in Peripheral Blood of Women with IVF Failures

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010
Viktor P. Chernyshov
Citation Chernyshov VP, Sudoma IO, Dons'koi BV, Kostyuchyk AA, Masliy YV. Elevated NK cell cytotoxicity, CD158a expression in NK cells and activated T lymphocytes in peripheral blood of women with IVF failures. Am J Reprod Immunol 2010; 64: 58,67 Problem, The aim of this study was to evaluate the role of elevated natural killer cytotoxicity (NKc) in women with multiple implantation failures (IF) in vitro fertilization,embryo transfer (IVF,ET) cycles. Methods of study, Seventy-nine antiphospholipid antibodies-negative women with IF including 33 women with elevated NKc were selected for investigation. K-562 cell line was used to evaluate NKc. Lymphocyte subsets, intracellular cytokines [interferon (IFN)-,, interleukin (IL)-4, tumour necrosis factor, IL-10], expression of activating markers [CD69, human leukocyte antigen (HLA)-DR], CD8, KIR (CD158a), CD95, and chemokine receptors (CXCR3, CCR4) were estimated by flow cytometry. Results, In women with IF, levels of NKc were higher than in IVF successful women. IF was associated with higher expression of CD8, CD158a, and HLA-DR in NK cells, activating markers in T lymphocytes, and lower levels of CCR4+ and IL-4+ T lymphocyte subsets. Predictive value of single elevated NKc for IVF success was 0.85, but addition of two other abnormal parameters resulted in its decrease to <0.39. Conclusions, Elevated NKc is negative factor, though not critical for implantation in IVF cycles. Immune mechanism of IVF failure includes not only elevated NKc but also some other factors, such as elevated expression of CD8 and CD158a on NK cells, T lymphocyte activation, and diminished T helper 2 parameters. [source]


Maternal and Neonatal Lymphocyte Subpopulations at Delivery and 3 Days Postpartum: Increased Coexpression of CD45 Isoforms

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2004
Emilia Juretic
Problem:, Huge physiologic changes during parturition involve immune cells. Alterations in maternal and neonatal lymphocytes postpartum might ascertain the subpopulations that are most affected and may possibly be of importance in the process. Method of study:, Peripheral blood was taken from 20 healthy women at vaginal delivery and 3 days later, concomitantly with cord and peripheral blood from their newborns. Lymphocyte immunophenotyping was done by three-color flow-cytometry. Results:, Maternal T helper cells were decreased and natural killer (NK) cells were significantly increased during labor. Percentage of CD4+ and percentage and absolute count of CD8+ cells coexpressing CD45RA and CD45RO antigens were higher than 3 days later. In cord blood NK cells were considerably increased and more CD4+ cells expressed CD45RO antigen. Conclusion:, Coexpression of CD45RA and CD45RO molecules indicates activation of maternal CD4+ and CD8+ lymphocytes. NK cells increase suggests their possible association with parturition processes. Lymphocyte subsets in cord blood correspond to maternal subsets to some extent. [source]


Morbidity and mortality in rheumatoid arthritis patients with prolonged therapy-induced lymphopenia: Twelve-year outcomes

ARTHRITIS & RHEUMATISM, Issue 2 2008
Alice R. Lorenzi
Objective To assess immunologically relevant outcomes in a cohort of rheumatoid arthritis (RA) patients with prolonged therapy-induced lymphopenia. Methods Morbidity (infection or malignancy) and mortality were assessed in 53 RA patients who were treated with the lymphocytotoxic monoclonal antibody alemtuzumab between 1991 and 1994. Data were obtained by interview, medical record review, and Office for National Statistics mortality monitoring. Lymphocyte subsets were enumerated by flow cytometry. A retrospective, matched-cohort study of mortality was performed with 102 control subjects selected from the European League Against Rheumatism database of patients with rheumatic disorders. Results Lymphopenia persisted in the patients: median CD3+CD4+, CD3+CD8+, CD19+, and CD56+ lymphocyte counts measured at a median followup of 11.8 years from the first administration of alemtuzumab were 0.50 × 109/liter, 0.26 × 109/liter, 0.11 × 109/liter, and 0.09 × 109/liter, respectively. Twenty-seven of 51 cases and 46 of 101 controls with available data had died, yielding a mortality rate ratio of 1.20 (95% confidence interval 0.72,1.98). Causes of death were similar to those that would be expected in a hospital-based RA cohort. No opportunistic infections were noted, and only 3 infections were documented following 36 elective orthopedic procedures. Conclusion Despite continued lymphopenia 11.8 years after therapy, our patient cohort did not exhibit excess mortality or unusual infection-related morbidity, and surgery was well tolerated. These data should be reassuring for clinicians and patients who are considering lymphocytotoxic or other immunomodulatory therapy for RA. [source]


T lymphopaenia in relation to body mass index and TNF-, in human obesity: adequate weight reduction can be corrective

CLINICAL ENDOCRINOLOGY, Issue 3 2001
S.-I. Tanaka
OBJECTIVE Although individuals with obesity are susceptible to infection, the underlying causes have not been fully identified. To investigate whether obesity affects immunity, we studied subjects with isolated obesity. DESIGN AND SUBJECTS Thirty-four obese persons from our outpatient obesity clinic and 50 nonobese healthy control subjects were studied. The effects of weight reduction were evaluated in obese subjects on a very-low-energy diet. We examined blastogenic response, lymphocyte subsets, circulatory TNF-,, soluble TNF-, receptor 1, soluble TNF-, receptor 2, and in vitro TNF-, production in obesity. MEASUREMENTS Lymphocyte subsets were analysed with flowcytometry. TNF-, and soluble TNF receptors levels were assayed using commercially available enzyme-linked immunosorbent assay kits. RESULTS Blastogenic responses to phytohemagglutinin or concanavalin A of T cells, CD3+, CD4+, CD8+, CD4+CD45RO+, and TCR ,, T cells were significantly diminished in obese subjects. Strong negative correlations were observed between TCR ,, and body weight and BMI in obese subjects. Circulatory levels of TNF-,, soluble TNF-, receptors, and in vitro TNF-, production were significantly increased compared to nonobese subjects. In obese subjects, there were significant positive correlations between serum levels of TNF-, and waist-hip ratio, serum levels of soluble TNF-, receptor 1 and body weight, soluble TNF-, receptor 2 and BMI, and soluble TNF-, receptor 2 and waist-hip ratio. The T cell responses and previously reduced non-CD8 T cell subsets were increased significantly following weight reduction. CONCLUSIONS Our results suggest that subsets of T cell populations and their function may be reduced in human obesity, and that this may be related, at least in part, to the elevated TNF-, production. Furthermore, this T cell dysfunction can be recovered by adequate weight reduction. [source]


Decrease in intrahepatic CD56+ lymphocytes in gastric and colorectal cancer patients with liver metastases

APMIS, Issue 12 2009
MAYA GULUBOVA
The aim of the study was to examine the main intrahepatic lymphocyte subpopulations, namely CD3+ lymphocytes, natural killer (NK)-like T lymphocytes (NKT) expressing the CD3+ CD56+ phenotype, CD56+ NK cells, CD4+, and CD8+ T cells in livers of patients with gastric and colorectal cancer with and without hepatic metastases. The proportion of each lymphocyte subset was determined in 34 patients with gastric or colorectal cancer (18 with and 16 without liver metastasis) by two-color flow cytometry after extraction of hepatic mononuclear cell fraction. The distribution of lymphocyte subpopulations in selected areas of liver metastases and adjacent liver tissue was evaluated using immunohistochemistry for CD4, CD8, and CD56. Flow cytometry analysis revealed a significant decrease in the proportion of CD3+ CD56+ cells in metastatic livers, but not in nonmetastatic livers (11.9 ± 10.3 vs 24.2 ± 13.6%, p = 0.02). The percentage of intrahepatic CD3,CD56+ cells was also decreased in patients with metastases compared to those without (10.1 ± 11.6 vs 16.6 ± 8.9%, p = 0.039). Immunohistochemically, three types of lymphocytes (CD4+, CD8+, and CD56+) were present in the metastatic tissue, although the number of CD56+ cells was almost twice lower. We found a low prevalence of tumor-infiltrating CD4+, CD8+, and CD56+ cells in livers with multiple metastases, whereas in cases with solitary metastasis a higher degree of lymphocyte infiltration was observed. The number of CD3,CD56+ and CD3+ CD56+ cells was decreased in metastatic livers compared to those unaffected by metastases. Therefore the prevalence of tumor-infiltrating lymphocytes seems to be related to the progression of metastatic liver disease. Depletion of hepatic innate lymphocytes may reveal susceptibility to metastatic liver disease and could be a reason for the escape of metastatic cells from the mechanisms of liver immune control. [source]


Age-matched lymphocyte subpopulation reference values in childhood and adolescence: application of exponential regression analysis

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2008
Sabine Huenecke
Abstract Background:, Normal values of lymphocyte subpopulations for healthy children and adults have been published in defined age groups exclusively, which results in difficult data interpretation for patients close to the limit of contiguous age group ranges. In addition, normal values for a number of lymphocyte subpopulations have not been established to date. Objective:, The aim of this study was to develop a model which provides continuous age-dependent reference values. This model was applied for lymphocyte subpopulations such as naïve and memory T cells as well as their activation profile with diagnostic relevance in children and adults. Study design:, A total of 100 blood samples, obtained from 80 healthy children and 20 adults were analysed by means of four colour-flow cytometry. Continuous age-dependent reference values were computed based on the residual values in an exponential regression model. Results:, We calculated a continuous age-related regression model for both, absolute cell counts and percentages of CD3+CD4+ T helper (TH) cells, CD3+CD8+ cytotoxic T cells, CD56+CD3, natural killer (NK) cells, CD56+CD3+ T cells, CD3+CD4+CD45RA+ naïve TH cells, CD3+CD4+CD45RO+ memory TH cells, CD3+CD8+CD45RA+CD28+ naïve cytotoxic T cells, CD3+CD8+CD45RO+ memory cytotoxic T cells, CD3+CD8+CD69+ early activated cytotoxic T cells and CD3+CD8+HLA-DR+ late activated cytotoxic T cells, respectively, to obtain reference values. Conclusion:, Based on an exponential regression model, the obtained reference values reflect the continuous maturation of lymphocyte subsets during childhood. [source]


The antiapoptotic effects of blood constituents in patients with chronic lymphocytic leukemia

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2003
Yonit Bomstein
Abstract: Objective: Clonal B-lymphocytes of chronic lymphocytic leukemia (B-CLL) are characterized by decreased sensitivity to programmed cell death and, therefore, they accumulate in vivo. However, these malignant cells die rapidly in vitro. In the current study we concentrated on the contribution of autologous serum (AS) and lymphocyte subsets to the survival of the malignant cells in vitro. Methods: Mononuclear cells from the peripheral blood of 26 CLL patients and 24 controls were incubated overnight in the presence or absence of AS and heat-inactivated AS (HI-AS) or fetal calf serum (FCS). Also, isolated B cells were incubated at different concentrations in the presence of AS and/or isolated T cells. The level of apoptosis of CD19+ cells was measured by flow cytometry. Results: Spontaneous apoptosis of unfractionated B-CLL cells incubated with AS, FCS or without serum was significantly lower than the rate of B-cell death in the control group, in similar culture conditions. AS had an antiapoptotic effect on unfractionated B-CLL cells when compared with FCS. The rate of apoptosis of B-CLL cells was directly associated with stage. HI of AS had a variable effect, which was related to the stage of the disease. High concentrations of B cells and the addition of autologous T cells reduced the rate of apoptosis when incubated without serum. The antiapoptotic effect of T cells was most prominent in progressive stages. Conclusions: B-CLL cells exhibit decreased spontaneous apoptosis, which is partially prevented by humoral (AS) and cellular (T cells and B-CLL cells) factors. The equilibrium between apoptotic and antiapoptotic factors changes with disease progression. [source]


Assessment of peripheral blood lymphocyte subsets in idiopathic myelofibrosis

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 2 2000
Francisco Cervantes
Abstract: The objective of this study was to contribute to a better characterization of the immunological profile of idiopathic myelofibrosis (IM) at presentation by analysing the blood lymphocyte subsets and their possible correlations with other disease features. Absolute blood lymphocytes and lymphocyte subsets were assessed in 31 IM patients, compared with those from 34 healthy individuals, and correlated with the patients' main clinical, hematological and bone marrow histologic features. The mean lymphocyte count of the IM patients was 1.1 (SD 0.6)×109/L, versus 1.6 (SD 0.49)×109/L in controls (p=0.0006), with 24 of the 31 patients (77.4%) showing lymphocytopenia (<1.5×109/L). IM patients had significantly lower counts of CD3, CD4, CD8, and CD3,/CD56+ cells, and significantly higher CD3+/CD56+ lymphocyte counts. Although no significant differences were found between patients and controls with regard to CD19+/CD5+ cell counts, increased CD5+ B-cell lymphocytes were observed in three IM patients. In one of the latter patients, Ig gene rearrangement analysis of the heavy chain gene demonstrated such a subpopulation to be clonal, but the patient did not develop features of chronic lymphoid leukemia during a 5-yr follow-up. No correlation was found between the patients' blood lymphocyte counts and other disease features. We conclude that most IM patients have absolute lymphopenia, decreased T cells and increased cytotoxic T cells at diagnosis, and 10% of them show an increased CD5+ B-cell subpopulation. [source]


Natural killer cell proliferation and circulating cytokines in patients with bilateral basal ganglia calcification

EUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2002
T. Morishima
Ten adult patients with symmetrical calcifications in the bilateral basal ganglia (diagnosed as physiological calcifications) were analyzed for lymphocyte subsets and cytokines. Increased number of natural killer (NK) cells were identified in the peripheral blood of seven patients by lymphocyte subset analysis. Tumor necrosis factor- , was detected in the sera of five patients and interferon- , was detected in one patient. In summary, NK cell propagation and circulating cytokines, particularly tumor necrosis factor- ,, may be involved in the etiology of basal ganglia calcification. [source]


The amazing universe of hepatic microstructure,

HEPATOLOGY, Issue 2 2009
Valeer J. Desmet
An informal review is presented by the author of his 50 years of involvement in practice and research in hepatopathology. Some background for the author's attitude and meandering pathway into his professional career serves as introduction to a short discussion of the main topics of his interest and expertise. Histogenesis of liver cancer was the theme of early work for a Ph.D. thesis, the results of which were lost into oblivion due to local rules and circumstances, but were rescued three decades later. His conclusions about the cells of origin of liver cancer remain concordant with the newer concepts in the field after nearly half a century. Studies in the field of chronic hepatitis became a long saga, involving the first classification of this syndrome by "the Gnomes" in 1968, histochemical investigations of viral antigens, lymphocyte subsets and adhesion molecules, and a quarter century later, the creation of a new classification presently in use. Cholestasis was a broadening field in diagnostic entities and involved the study of liver lesions, comprising pathways of bile regurgitation (including reversed secretory polarity of hepatocytes) and so-called ductular reaction. The latter topic has a high importance for the various roles it plays in modulating liver tissue of chronic cholestasis into biliary cirrhosis, and as the territory of hepatic progenitor cells, crucial for liver regeneration in adverse conditions and in development of liver cancer. Study of the embryology of intrahepatic bile ducts helped to clarify the strange appearance of the ducts in "ductal plate configuration" in several conditions, including some forms of biliary atresia with poor prognosis and all varieties of fibrocystic bile duct diseases with "ductal plate malformation" as the basic morphologic lesion. (HEPATOLOGY 2009;50:333,344.) [source]


Activation of hepatic stellate cells after phagocytosis of lymphocytes: A novel pathway of fibrogenesis,

HEPATOLOGY, Issue 3 2008
Nidal Muhanna
Increased CD8-T lymphocytes and reduced natural killer (NK) cells contribute to hepatic fibrosis. We have characterized pathways regulating the interactions of human hepatic stellate cells (HSCs) with specific lymphocyte subsets in vivo and in vitro. Fluorescence-activated cell sorting (FACS) was used to characterize human peripheral blood lymphocytes (PBLs) and intrahepatic lymphocytes (IHLs) obtained from healthy controls and from patients with either hepatitis B virus (HBV) or hepatitis C virus (HCV) with advanced fibrosis. Liver sections were analyzed by immunohistochemistry and confocal microscopy. To investigate in vitro interactions, PBLs from healthy controls or patients with HCV cirrhosis were co-cultured with an immortalized human HSC line (LX2 cells) or with primary HSCs. Significant alterations in lymphocyte distribution were identified in IHLs but not PBLs. The hepatic CD4/CD8 ratio and NK cells were significantly reduced in HBV/HCV patients. Expression of alpha-smooth muscle actin and infiltration of CD4, CD8, and NK cells were readily apparent in liver sections from patients with cirrhosis but not in healthy controls. Lymphocytes from each subset were in proximity to HSCs primarily within the periportal regions, and some were directly attached or engulfed. In culture, HSC activation was stimulated by HCV-derived CD8-subsets but attenuated by NK cells. Confocal microscopy identified lymphocyte phagocytosis within HSCs that was completely prevented by blocking intracellular adhesion molecule 1 (ICAM-1) and integrin molecules, or by irradiation of HSCs. LX2 knockdown of either Cdc42 or Rac1 [members of the Rho-guanosine triphosphatase (GTPase) family] prevented both phagocytosis and the activation of HSC by HCV-derived lymphocytes. Conclusion: The CD4/CD8 ratio and NK cells are significantly decreased in livers with advanced human fibrosis. Moreover, disease-associated but not healthy lymphocytes are engulfed by cultured HSCs, which is mediated by the Rac1 and Cdc42 pathways. Ingestion of lymphocytes by HSCs in hepatic fibrosis is a novel and potentially important pathway regulating the impact of lymphocytes on the course of hepatic fibrosis. (HEPATOLOGY 2008.) [source]


Mast cells and eicosanoid mediators: a system of reciprocal paracrine and autocrine regulation

IMMUNOLOGICAL REVIEWS, Issue 1 2007
Joshua A. Boyce
Summary:, When activated by specific antigen, complement, or other transmembrane stimuli, mast cells (MCs) generate three eicosanoids: prostaglandin (PG)D2, leukotriene (LT)B4, and LTC4, the parent molecule of the cysteinyl leukotrienes (cysLTs). These diverse lipid mediators, which are generated from a single cell membrane-associated precursor, arachidonic acid, can initiate, amplify, or dampen inflammatory responses and influence the magnitude, duration, and nature of subsequent immune responses. PGD2 and cysLTs, which were originally recognized for their bronchoconstricting and vasoactive properties, also serve diverse and pivotal functions in effector cell trafficking, antigen presentation, leukocyte activation, matrix deposition, and fibrosis. LTB4 is a powerful chemoattractant for neutrophils and certain lymphocyte subsets. Thus, MCs can contribute to each of these processes through eicosanoid generation. Additionally, MCs express G-protein-coupled receptors specific for cysLTs, LTB4, and another eicosanoid, PGE2. Each of these receptors can regulate MC functions in vivo by autocrine and paracrine mechanisms. This review focuses on the biologic functions for MC-associated eicosanoids, the regulation of their production, and the mechanisms by which eicosanoids may regulate MC function in host defense and disease. [source]


Age-dependent variation in the proportion and number of intestinal lymphocyte subsets, especially natural killer T cells, double-positive CD4+ CD8+ cells and B220+ T cells, in mice

IMMUNOLOGY, Issue 3 2004
Yuiko Ishimoto
Summary The age-dependent variation in the proportion and number of lymphocyte subsets was examined at various extrathymic sites, including the liver, small intestine, colon and appendix in mice. In comparison with young mice (4 weeks of age), the number of total lymphocytes yielded by all tested organs was greater in adult (9 weeks) and old (40 weeks) mice. The major lymphocyte subset that expanded with age was interleukin-2 receptor (IL-2R) ,+ CD3int cells (50% of them expressed NK1.1) in the liver, whereas it was CD3+ IL-2R,, NK1.1, cells at all intraepithelial sites in the intestine. Although NK1.1+ CD3+ cells were present at intraepithelial sites in the intestine, the proportion of this subset was rather low. The ratio of CD4 to CD8 tended to decrease among natural killer T (NKT) cells and T cells at all intraepithelial sites in the intestine with age. A unique population of double-positive CD4+ CD8+ cells in the small intestine increased in old mice. B220+ T cells were found mainly in the appendix and colon, and the proportion of these T cells decreased in old mice. Conventional NKT cells were very few in J,281,/, and CD1d,/, mice in the liver, while NKT cells which existed in the appendix remained unchanged even in these mice. This was because unconventional CD8+ NKT cells were present in the intestine. The present results suggest that despite the fact that both the liver and intraepithelial sites in the intestine carry many extrathymic T cells, the distribution of lymphocyte subsets and their age-associated variation are site-specific. [source]


Therapeutic benefit of pentostatin in severe IL-10,/, Colitis

INFLAMMATORY BOWEL DISEASES, Issue 7 2008
Jeffrey B. Brown MD
Abstract Background: Pentostatin, an adenosine deaminase (ADA) inhibitor, is a purine antimetabolite used for the treatment of leukemias. ADA inhibition blunts expansion of proliferating lymphocytes and increases adenosine release, a potent anti-inflammatory molecule. Human inflammatory bowel disease (IBD) is driven by expansion of effector T cells (Teff) that overwhelm reulatory T cells (Treg) and propagate innate immune reponses. Here we study the therapeutic benefits of ADA inhibition to impair Teff cell expansion and reduce inflammatory cytokine release in IL-10-deficient (IL-10 -/- ) mice. Methods: Colitis was induced in IL-10 -/- mice by administering piroxicam for two weeks. Mice were treated with daily pentostatin or phosphate-buffered saline for 1 week and effects on tissue inflammation, lymphocyte numbers and cytokine production examined. Results: Pentostatin reduced inflammation by >50% and nearly normalized serum amyloid A levels. Lymphocyte expansions in the colon and mesenteric lymph node (MLN) (3.5-fold and >5-fold respectively) dropped by >50-90%. Pro-inflammatory factors in the colon and MLN (IL-1,, IFN-,, IL-6, CXCL10, TNF) dropped whereas FoxP3 and TGF-, were unchanged. Reductions in cytokine production from equivalent numbers of T cells from pentostatin-treated mice after in vitro (36h) or in vivo (3h) activation suggested anti-inflammatory effects of pentostatin independent of lymphodepletion contributed to its therapeutic benefit. Analysis of mucosal lymphocyte subsets suggested pentostatin reduced numbers of effector CD4+ CD69+ T cells, while sparing CD4+ CD62L+ T cells. Conclusions: Pentostatin dosages that avoid severe lymphocyte depletion effectively treat colitis by impairing Teff cell expansion and reducing pro-inflammatory cytokine production while preserving regulatory Treg populations and function. (Inflamm Bowel Dis 2008) [source]


Immunosuppression with FK506 Increases Bone Induction in Demineralized Isogeneic and Xenogeneic Bone Matrix in the Rat

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2000
Dr. Gregor Voggenreiter
Abstract The aim of the present study was to investigate a systemic induction of bone formation in rats by immunosuppression with FK506 (1 mg/kg body weight intraperitoneally [ip]) in a model of osteoinduction of isogeneic and xenogeneic demineralized bone matrix (DBM) for a period of 28 days. In particular, alterations of in vitro cytokine synthesis and changes of lymphocyte subsets were studied. DBM was implanted intramuscularly in the abdominal wall of Lewis rats (seven per group). Blood was sampled on days ,7, 0, 7, and 28 for determination of in vitro tumor necrosis factor , (TNF-,) synthesis and lymphocyte subsets by flow cytometry (CD3+, CD4+, CD8+, CD45+, ED9+, and Ia+ antibodies). Ossicles of de novo formed bone and the tibias were removed on day 28 after double tetracycline labeling for histomorphometric analysis. Immunosuppression with FK506 significantly decreased lipopolysaccharide (LPS)-stimulated in vitro cytokine synthesis after 7 days and 28 days (p < 0.05). Compared with control animals FK506 treatment significantly increased the volume of induced bone in isogeneic (2.1 ± 0.3 mm3 vs. 10.8 ± 0.9 mm3) and xenogeneic (0 mm3 vs. 4.7 ± 0.8 mm3) DBM. Bone histomorphometry of the tibias revealed that immunosuppression increased both bone formation and bone resorption, accompanied by a significant reduction in the relative trabecular area (Tb.Ar). FK506 caused a decrease in the counts of CD8+ T cells probably because of destruction or dislocation of these cells. This suggests that the amount of CD8+ cells and the degree of T cell activation in terms of mean fluorescence intensity (MFI) may be associated with bone metabolism. In support of this, statistical analysis revealed a significant positive correlation between parameters of bone formation as well as bone resorption and the CD4+/CD8+ ratio. There was a significant negative correlation between parameters of remodeling of the metaphysis of the tibia and induced bone volume (BV), respectively, and MFI values of CD3+/Ia+ cells. These findings suggest an important role of T lymphocytes in bone formation and bone resorption in vivo. FK506 caused a marked increase of bone formation in DBM. However, the conclusion that immunosuppression increases fracture healing warrants further investigation. [source]


Effect of First Treatment with Aminobisphosphonates Pamidronate and Ibandronate on Circulating Lymphocyte Subpopulations

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2000
Martin Pecherstorfer
Abstract Up to 60% of patients receiving their first infusion of the bisphosphonate pamidronate experience an acute-phase reaction. In this study, we used flow cytometry to determine the effects of pamidronate treatment on circulating lymphocyte subpopulations, and we investigated whether pamidronate and ibandronate treatment affect lymphocyte subpopulations differently. Twenty patients received a pamidronate infusion, 20 patients received intravenously injected ibandronate, and 10 controls received a clodronate infusion. Pamidronate treatment was followed by a significant increase in median body temperature at the 10-hour measurement and a significant decrease in counts of circulating lymphocytes, natural killer cells, T cells, and CD4+ and CD8+ T-cell subsets. Ibandronate treatment did not affect median body temperature, and it was associated at the 10-hour measurement with maximum increases in total lymphocyte count, B cells, T cells, and CD4+ and CD8+ T-cell subsets. Thus, there is a substantial difference in the hematologic response to initial treatments with pamidronate and ibandronate. Clodronate treatment did not induce changes in body temperature or significantly affect the number of circulating T cells and NK cells. The reduction in lymphocyte subsets after initial pamidronate therapy might be mediated by the release of tumor necrosis factor ,, whose source in the acute-phase reaction could be T cells. [source]


The changes in T lymphocyte subsets following periodontal treatment in patients with chronic periodontitis

JOURNAL OF PERIODONTAL RESEARCH, Issue 3 2006
Kamile Erciyas
Objective:, The aim of this study was to determine whether there was any change in T-lymphocyte subsets in patients with chronic periodontitis after applying different periodontal treatment methods. Patients and methods:, Twenty-four patients with chronic periodontitis were included in the study. In every phase of the treatment (pretreatment, initial treatment, curettage and flap operations) the biopsy samples were taken from the gingival tissues at sites of chronic periodontitis. Then CD4+ and CD8+ lymphocyte and CD4+/CD8+ ratio values were determined using flow cytometry in the biopsy samples. At the same time, gingival pocket depth, Löe,Silness gingival index, and Silness,Löe plaque index scores were recorded to assess the periodontal status in patients. To determine the correlation between the clinical measurements and the laboratory results obtained before the treatment, after initial treatment, after curettage and after flap operations, we conducted an analysis using a paired t -test. Results:, Flow cytometry findings in the patients with chronic periodontitis showed that CD4+ and CD8+ lymphocyte values before treatment were under the normal value and the CD4+/CD8+ ratio was within the normal distribution interval. The CD4+/CD8+ ratio decreased postcurettage and postflap operation. This decrease was statistically significant (p < 0.001). The CD4+ and CD8+ lymphocyte values were increased postcurettage and postflap operation. This increase was also statistically significant (p < 0.001). Conclusions:, These findings suggest that local immune response was poor in the patients with chronic periodontitis. CD4+ and CD8+ T-lymphocytes could play a significant role in chronic periodontitis pathobiology. [source]


Correlation between radiculalgia and counts of T lymphocyte subsets in the peripheral blood of patients with lumbar disc herniation

ORTHOPAEDIC SURGERY, Issue 4 2009
Peng Tian MD
Objective:, To determine the correlation between the degree of radiculalgia and counts of T lymphocyte subsets in the peripheral blood of patients with lumbar disc herniation. Methods:, Forty-nine patients with lumbar disc herniation (group A) were divided into three subgroups according to Visual Analogue Scale (VAS) pain scores (group A1: n= 12, VAS 0,4.0; A2: n= 24, VAS 4.1,7.0; A3: n= 13, VAS 7.1,10.0. Twenty health blood donors who volunteered to be involved in the study comprised the control group (group B). Peripheral blood counts of various T lymphocyte subsets were measured in each group. Results:, (i) The counts of CD4+ T and CD4+/CD8+ lymphocytes were higher in group A than in group B, and the difference between the two groups was statistically significant (P < 0.05). There were also statistically significant differences between group A and group B in the counts of CD3+ and CD8+ T lymphocytes (P < 0.05); (ii) There was no correlation between the VAS scores and the counts of CD3+ T lymphocytes (r= 0.194, P > 0.05). A strong significant correlation was observed between the VAS scores and counts of CD4+ T lymphocytes (r= 0.542, P < 0.05), CD4+/CD8+ (r= 0.468, P < 0.05), which increased with increasing VAS scores in the three subgroups of group A (P < 0.05). However there was a significant negative linear correlation between CD8+ T lymphocyte counts and pain scores (r=,0.462, P < 0.05). Conclusion:, Our results suggest that changes in T lymphocyte subsets in peripheral blood take place after prolapse of lumbar intervertebral discs. The current results may provide support for involvement of immunologic mechanisms in low back pain secondary to herniation of the lumbar disc. T lymphocytes may play an important role in the development of symptoms in patients with lumbar intervertebral disc herniation. [source]


The effects of phototherapy on the numbers of circulating natural killer cells and T lymphocytes in psoriasis

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2009
A. M. Tobin
The innate immune system is believed to be important in the pathogenesis of psoriasis and natural killer (NK) have been found in increased numbers in psoriatic plaques. Alterations in the numbers of NK cells in peripheral blood have been reported. We investigated the effect of phototherapy on levels of peripheral NK cells and lymphocytes in patients with psoriasis. In nine patients whom we followed before, during and after narrowband ultraviolet B (UVB) treatment there were no differences in the numbers of circulating lymphocytes, lymphocyte subsets or cells expressing NK markers and controls. Treatment with narrowband UVB did, however, significantly lower circulating CD4 counts which gradually recovered posttreatment. [source]


Blood Lymphocyte Subpopulations, Neutrophil Phagocytosis and Proteinogram During Late Pregnancy and Postpartum in Mares

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2008
R Agrícola
Contents The aim of this study was to evaluate peripheral blood lymphocyte subpopulations, neutrophil phagocytic capacity and proteinogram characteristics in mares, during the last trimester of pregnancy and in postpartum. Measurement of phagocytosis and quantification of T-lymphocyte subsets were done by flow cytometry. Quantification of T-lymphocyte subsets was performed with monoclonal antibodies specific for CD2, CD3, CD4 and CD8 cell markers. Natural killer and B-cell counts were estimated mathematically. Serum proteinogram was obtained by electrophoresis. No significant differences were observed between gestation and postpartum on CD4+, CD8+ and NK+ lymphocyte subsets, CD4 : CD8 ratio and phagocytosis. The percentage of cells expressing CD3 (64.2 ± 1.8) and CD2 (68.4 ± 1.7) (Mean ± SEM) was reduced during gestation vs postpartum (69.7 ± 1.5 and 73.8 ± 1.4 respectively) (p < 0.05). During pregnancy, CD19+ (31.6 ± 1.7) was higher than in postpartum (26.2 ± 1.4) (p < 0.05). Total T cells (2911 ± 227 cells/,l), T helper cells (2144 ± 169 cells/,l) and T-cytotoxic cells (767 ± 68 cells/,l) were depressed in pregnancy, when compared with postpartum (4093 ± 337 cells/,l; 3004 ± 276 cells/,l; 1089 ± 94 cells/,l respectively) (p < 0.01). Total white blood cell count was reduced during pregnancy (8815 ± 427 cells/,l) with respect to postpartum (10742 ± 446 cells/,l) (p < 0.01), while neutrophil count did not change. Total proteins, albumin, ,1,,2,,1, ,2, , globulins and albumin : globulin did not differ. Our results suggest that the physiological immune depression occurring in mares, during gestation might be due to T-helper and T-cytotoxic lymphocytes reduction. [source]


Elevated NK Cell Cytotoxicity, CD158a Expression in NK Cells and Activated T Lymphocytes in Peripheral Blood of Women with IVF Failures

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010
Viktor P. Chernyshov
Citation Chernyshov VP, Sudoma IO, Dons'koi BV, Kostyuchyk AA, Masliy YV. Elevated NK cell cytotoxicity, CD158a expression in NK cells and activated T lymphocytes in peripheral blood of women with IVF failures. Am J Reprod Immunol 2010; 64: 58,67 Problem, The aim of this study was to evaluate the role of elevated natural killer cytotoxicity (NKc) in women with multiple implantation failures (IF) in vitro fertilization,embryo transfer (IVF,ET) cycles. Methods of study, Seventy-nine antiphospholipid antibodies-negative women with IF including 33 women with elevated NKc were selected for investigation. K-562 cell line was used to evaluate NKc. Lymphocyte subsets, intracellular cytokines [interferon (IFN)-,, interleukin (IL)-4, tumour necrosis factor, IL-10], expression of activating markers [CD69, human leukocyte antigen (HLA)-DR], CD8, KIR (CD158a), CD95, and chemokine receptors (CXCR3, CCR4) were estimated by flow cytometry. Results, In women with IF, levels of NKc were higher than in IVF successful women. IF was associated with higher expression of CD8, CD158a, and HLA-DR in NK cells, activating markers in T lymphocytes, and lower levels of CCR4+ and IL-4+ T lymphocyte subsets. Predictive value of single elevated NKc for IVF success was 0.85, but addition of two other abnormal parameters resulted in its decrease to <0.39. Conclusions, Elevated NKc is negative factor, though not critical for implantation in IVF cycles. Immune mechanism of IVF failure includes not only elevated NKc but also some other factors, such as elevated expression of CD8 and CD158a on NK cells, T lymphocyte activation, and diminished T helper 2 parameters. [source]


ORIGINAL ARTICLE: The Effect of High Gravidity on the Carcinogenesis of Mammary Gland in TA2 Mice

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2010
Xuan Wang
Citation Wang X, Huang C, Sun B, Gu Y, Cui Y, Zhao X, Li Y, Zhang S. The effect of high gravidity on the carcinogenesis of mammary gland in TA2 mice. Am J Reprod Immunol 2010 Problem Spontaneous breast cancer in Tientsin Albinao 2 (TA2) mice, like human pregnancy-associated breast cancer (PABC), often occurs in pregnancy and puerperium, especially in mice with high gravidity. We hypothesized that the dysfunction of cellular immunity caused by the increase of 17,-estradiol (E2) and progesterone (P) might be one of the reasons for carcinogenesis of mammary gland. Method of study We investigated the T lymphocyte subsets and the concentration of serum hormone and cytokines in cancer-bearing, pregnant or postpartum TA2 mice using flow cytometry, chemiluminescent immunoassay, and enzyme-linked immunosorbent assay (ELISA), respectively. Results The number of T lymphocytes and the concentration of E2, P, interleukin-2 (IL-2), IL-4, and interferon-gamma (IFN-,) changed with the increase of pregnancy and puerperium. During four pregnancies, elevated E2 and P resulted in a decrease in the number of CD3+, CD4+ T lymphocytes, CD4+/CD8+ ratio, and the concentration of IL-2, IL-4, and IFN-,. Data in the fourth pregnancy were the closest to those of cancer-bearing mice. Conclusion T lymphocyte subsets and concentration of IL-2, IL-4, and IFN-, are affected by E2 and P during multiple pregnancy and delivery to some degree, which may contribute to the genesis of spontaneous breast cancer in TA2 mice. [source]


ORIGINAL ARTICLE: Abnormal Pattern of Lymphocyte Subpopulations in the Endometrium of Infertile Women with Chronic Endometritis

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2009
Maria Matteo
Problem, Endometrial lymphocytes play a critical role in endometrial receptivity. This study aimed at evaluating the variations induced by chronic endometritis (CE) on endometrial lymphocyte subsets. We compared the results in infertile women diagnosed with CE with those in unexplained infertile women without any sign of CE. Method of study, Twenty-three women referring for unexplained infertility had hysteroscopy and endometrial biopsy in the follicular phase; in nine women, CE was diagnosed (group CE+), while in 14 it was not (group CE,). All patients in the late secretory phase of the subsequent cycle underwent endometrial biopsy. By flow cytometry, the percentage and phenotype of the endometrial lymphocyte subpopulations were analyzed. Results, The secretory endometrium of patients with CE displayed significantly lower percentage of CD56+ CD16, and of CD56bright CD16, cells (47.8% ± 18.6 and 30.1% ± 20.5 versus 79.5% ± 3.9 and 67.3% ± 8.1, respectively; P < 0.01) as compared with group CE(,), while the percentage of CD3+ cells was significantly higher (25% ± 12.2 versus 10.5 ± 5; P < 0.01). Conclusion, Infertile women with CE showed an abnormal percentage of endometrial lymphocyte subsets compared with unexplained infertile women suggesting that different mechanisms underlie the adverse pregnancy outcome of the two groups of patients. [source]


Phase 1 Dose-Escalation Study of CP-690 550 in Stable Renal Allograft Recipients: Preliminary Findings of Safety, Tolerability, Effects on Lymphocyte Subsets and Pharmacokinetics

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2008
E. Van Gurp
CP-690 550 inhibits Janus kinase 3 with nanomolar potency. In this dose-escalation study, we assessed the safety, tolerability, effects on lymphocyte subsets, and pharmacokinetics of CP-690 550 when coadministered with mycophenolate mofetil in stable renal allograft recipients for 28 days. Twenty-eight patients were enrolled. Six patients received CP-690 550 5 mg twice daily (BID), 6 patients received 15 mg BID, 10 patients received 30 mg BID, and 6 patients received placebo. The most frequent adverse events were infections and gastrointestinal (abdominal pain, diarrhea, dyspepsia, and vomiting). CP-690 550 15 mg BID and 30 mg BID were associated with a mean decrease in hemoglobin from baseline of 11% and a mean decrease in absolute natural killer cell counts of 50%. CP-690 550 30 mg BID was also associated with a mean increase in absolute CD19+ B-lymphocytes of 130%. There were no changes in the number of neutrophils, total lymphocytes, platelets, or CD4+ or CD8+ T cells; clinical chemistry; vital signs; or electrocardiograms from the pretreatment baseline. Administration of CP-690 550 without a concomitant calcineurin inhibitor resulted in CP-690 550 exposures consistent with previous studies in nontransplant subjects. Additional dose-ranging studies are warranted to evaluate the safety and efficacy of CP-690 550 in renal transplant recipients over longer treatment duration. [source]


Impact of splenectomy on circulating T-lymphocyte subsets in stage III gastric cancer

ANZ JOURNAL OF SURGERY, Issue 6 2002
Min Young Cho
Background: The role of splenectomy remains unclear in patients with gastric cancer who undergo total gastrectomy. The aim of this study was to prospectively evaluate the impact of splenectomy on circulating T-lymphocyte subsets and survival in advanced gastric cancer. Methods: Analysis of lymphocyte subsets was performed in 40 patients with American Joint Committee on Cancer (AJCC) stage III gastric adenocarcinoma located on the upper one-third of the stomach, who underwent a curative total gastrectomy with or without splenectomy. Circulating T-lymphocyte subsets were measured on venous blood by using flow cytometry and monoclonal antibodies at preoperative day 1, and postoperative months 1, 3, 6, 12 and 18. Results: The proportion of lymphocytes and the values of CD3, CD8, CD16 and CD25 subsets were higher in the splenectomy group of patients at postoperative month 3. In the spleen preservation group at the same point of treatment, the proportion of granulocytes and the values of CD4 and CD4 : CD8 ratio were higher. Except for CD16 levels, all T-lymphocyte subsets showed no sig­nificant difference between splenectomy and spleen preservation groups after postoperative month 3. Increased CD16 levels in the splenectomy group were not associated with improvement in patients' 5-year survival rates. Conclusion: These results suggest that the long-term impact of splenectomy does not play an important role in postoperative quantitative changes of circulating T-lymphocyte subsets of patients with stage III gastric cancer who have undergone total gastrectomy. Furthermore, splenectomy does not give a prognostic benefit, based on tumour recurrence and survival of patients with proximal one-third gastric cancer who undergo total gastrectomy. [source]


Protein phosphorylation and kinome profiling reveal altered regulation of multiple signaling pathways in B lymphocytes from patients with systemic lupus erythematosus

ARTHRITIS & RHEUMATISM, Issue 8 2010
Taher E. Taher
Objective The cause of B lymphocyte hyperactivity and autoantibody production in systemic lupus erythematosus (SLE) remains unclear. Previously, we identified abnormalities in the level and translocation of signaling molecules in B cells in SLE patients. The present study was undertaken to examine the extent of signaling abnormalities that relate to altered B cell responses in SLE. Methods B lymphocytes from 88 SLE patients and 72 healthy controls were isolated from blood by negative selection. Protein tyrosine phosphorylation and cellular kinase levels were analyzed by Western blotting, flow cytometry, and a kinome array protocol. Changes in protein phosphorylation were determined in ex vivo B cells and following B cell receptor engagement. Results Differences in tyrosine phosphorylation in B cells from patients with SLE, compared with matched controls, were demonstrated. Further, the kinome array analysis identified changes in the activation of key kinases, i.e., the activity of phosphatidylinositol 3-kinase, which regulates survival and differentiation, was up-regulated and the activity of Rac and Rho kinases, which regulate the cytoskeleton and migration, was increased. In contrast, the activity of ATR, which regulates the cell cycle, was down-regulated in SLE patients compared with controls. Differences in signaling pathways were seen in all SLE B lymphocyte subsets that manifested phenotypic features of immature, mature, and memory cells. Conclusion This study revealed dysregulation in multiple signaling pathways that control key responses in B cells of SLE patients. Data generated in this study provide a molecular basis for further analysis of the altered B lymphocyte responses in SLE. [source]


CD4/CD8 T-Cell Ratio in Peritoneal Dialysis Effluents Predicts the Outcome of Peritonitis in Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

ARTIFICIAL ORGANS, Issue 12 2009
Ioannis Griveas
Abstract This study aimed to clarify the role of peritoneal T-lymphocytes in peritoneal immune defense mechanisms. This study was designed to examine the changes in T-cell subpopulations during peritonitis in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Our observations were correlated to responses to treatment and with outcomes. The present study was carried out in 20 patients (8 males, 12 females) under CAPD. Peritonitis was diagnosed according to the criteria defined by the Ad Hoc Advisory Committee on Peritonitis Management. Peritoneal dialysate effluent (PDE) samples were collected from our patients, and lymphocyte subsets (CD2+, CD3+, CD3+/4+, CD3+/8+, CD3,/16+56+, CD4/CD8 ratio) were quantitated by using monoclonal antibodies. CD4/CD8 ratio was measured every day during peritonitis until the patients had completely recovered. The serial measurements of the CD4/CD8 ratio made in the PDE during peritonitis followed two patterns: the first pattern was characterized by a progressive increase in the CD4/CD8 ratio. The CD4/CD8 ratios on days 5, 6, and 7 were significantly higher than those on day 1 (P < 0.05). Overall, the patients who exhibited pattern 1 had favorable clinical courses. The second pattern was characterized by high initial CD4/CD8 ratios, which progressively decreased significantly (P < 0.05). This second pattern was associated with a delayed clinical response to treatment. Symptoms and signs of peritonitis persisted beyond 72 h. The pattern of the CD4/CD8 ratio in PDE may determine the outcome of peritonitis in CAPD patients. [source]


Delayed-onset neutropenia associated with rituximab therapy

BRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2003
Kritika Chaiwatanatorn
Summary. The characteristics of severe neutropenia with a delayed onset following administration of rituximab have been evaluated in 53 consecutively treated patients. All but one patient received rituximab for the treatment of non-Hodgkin's lymphoma. Eight episodes of grade 4 neutropenia were detected between 1 and 5 months after rituximab, when administered alone on five occasions, and on three occasions in combination with chemotherapy, where neutrophil counts had recovered prior to the development of neutropenia. In three episodes, the patients presented with sepsis. Development of neutropenia did not correlate with either the presence of detectable disease or the administration of further treatment. Neutropenia was associated with selective depletion of neutrophil precursors in all but one episode, where it was associated with generalized bone marrow hypoplasia. All episodes developed after a period of either normal or mildly depressed neutrophil counts following treatment with rituximab, and persisted for between several days and several months, before undergoing spontaneous recovery in four instances, and after administration of filgrastim in the remainder. Episodes of neutropenia were associated with disordered immune status manifested by lymphopenia and hypogammaglobulinaemia, raising the possibility that either disturbance of the balance of lymphocyte subsets or an immune dyscrasia induced by rituximab resulted in the development of this type of neutropenia. [source]