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Systemic Immunosuppression (systemic + immunosuppression)
Selected AbstractsApparent Reactivation of a Fibrohistiocytic Proliferation with Features of Dermatofibroma and Dermatomyofibroma Following Systemic ImmunosuppressionJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005W.A. High A 41 year-old man presented with an atrophic, hyperpigmented plaque on the right lower abdomen present since"birth". He denied any prior activity at the site, and had been told it was a "scar" from a prenatal insult. Six months earlier, he developed idiopathic focal sclerosing glomerulonephritis and was placed on 70 mg prednisone per day. He had not demonstrated evidence of lupus eythematosus. Shortly after beginning this regimen, erythematous and tender papules developed around the quiescent plaque. He had tapered his prednisone dose to 60 mg per day, but additional papules continued to erupt. An ellipse biopsy was performed which included a portion of the atrophic plaque and several surrounding papules. Histological examination revealed a proliferation of fibrohistiocytes between and amongst collagen bundles. In some areas, fibrohistiocytes entrapped collagen in a fashion reminiscent of a dermatofibroma. In other areas, particularly that of the atrophic plaque, the fibrohistiocytes were less numerous and more delicate in appearance. Scattered rudimentary fascicles were demonstrated. Adnexal structures were preserved. Immunohistochemical staining revealed the fibrohistiocytes to be positive for factor XIIIa and actin, but negative for desmin, CD34, S-100, procollagen I, and CD68. This lesion demonstrated unique clinical/histiological aspects not well characterized in the literature. [source] Molecular determinants of UV-induced immunosuppressionEXPERIMENTAL DERMATOLOGY, Issue 2002Agatha Schwarz Abstract: It is almost three decades ago that it was discovered that ultraviolet radiation (UV) can compromise the immune system. UV suppresses immune responses in several ways. It inhibits the function of antigen-presenting cells, induces T cells with suppressor activity and induces the release of immunosuppressive cytokines. The latter phenomenon is mainly responsible for systemic immunosuppression. Although UV can also target cytoplasmic and cell membrane components, UV-induced DNA damage has been recognized as the most important molecular structure in mediating UV-induced immunosuppression. Recently, it was observed that interleukin-12 (IL-12), which antagonizes UV-induced immunosuppression, can accelerate the removal of UV-induced DNA lesions, probably via inducing DNA repair. Hence, it is tempting to speculate that the activity of IL-12 to reduce UV-induced immunosuppression may be due at least partially to this new biological activity of IL-12. [source] Immunosuppression using the mTOR inhibition mechanism affects replacement of rat liver with transplanted cells,HEPATOLOGY, Issue 2 2006Yao-Ming Wu Successful grafting of tissues or cells from mismatched donors requires systemic immunosuppression. It is yet to be determined whether immunosuppressive manipulations perturb transplanted cell engraftment or proliferation. We used syngeneic and allogeneic cell transplantation assays based on F344 recipient rats lacking dipeptidyl peptidase IV enzyme activity to identify transplanted hepatocytes. Immunosuppressive drugs used were tacrolimus (a calcineurin inhibitor) and its synergistic partners, rapamycin (a regulator of the mammalian target of rapamycin [mTOR]) and mycophenolate mofetil (an inosine monophosphate dehydrogenase inhibitor). First, suitable drug doses capable of inducing long-term survival of allografted hepatocytes were identified. In pharmacologically effective doses, rapamycin enhanced cell engraftment by downregulating hepatic expression of selected inflammatory cytokines but profoundly impaired proliferation of transplanted cells, which was necessary for liver repopulation. In contrast, tacrolimus and/or mycophenolate mofetil perturbed neither transplanted cell engraftment nor their proliferation. Therefore, mTOR-dependent extracellular and intracellular mechanisms affected liver replacement with transplanted cells. In conclusion, insights into the biological effects of specific drugs on transplanted cells are critical in identifying suitable immunosuppressive strategies for cell therapy. (HEPATOLOGY 2006;44:410,419.) [source] Effect of nondepleting anti-CD4 monoclonal antibody (Rib 5/2) plus donor antigen pretreatment in peripheral nerve allotransplantationMICROSURGERY, Issue 8 2002Vaishali B. Doolabh M.D. Peripheral nerve allotransplantation allows the reconstruction of injuries with long nerve gaps that are otherwise unsalvageable. In this study, the efficacy of anti-CD4 monoclonal antibody (mAb) combined with donor antigen pretreatment in prolonging the survival of short peripheral nerve allografts was investigated in a rodent model. Such an approach could potentially avoid the need for systemic immunosuppression and its concomitant morbidities. Buffalo rats received either nerve isografts or nerve allografts from Lewis rats. Untreated isograft and allograft groups were used as controls. Allograft recipients received either a single dose of RIB 5/2, a nondepleting anti-CD4 mAb, a single dose of Lewis splenocytes, or both antigen and RIB 5/2, 7 days prior to transplantation. Flow cytometric analysis verified that the T-lymphocyte population was maintained, while CD4 expression was downregulated by RIB 5/2. Histologic evaluation demonstrated better regeneration in the allograft recipients receiving both donor antigen and antibody, compared to recipients of untreated allografts or treatment with antigen or antibody alone. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:329,334 2002 [source] Treponema denticola immunoinhibitory protein induces irreversible G1 arrest in activated human lymphocytesMOLECULAR ORAL MICROBIOLOGY, Issue 3 2004W. Lee Oral spirochetes may contribute to the pathogenesis of a number of disorders including periodontal and periradicular diseases; however, the mechanism (s) by which these organisms act to cause disease is unknown. We have previously shown that extracts of the oral spirochete, Treponema denticola, contain an immunosuppressive protein (Sip) which impairs human lymphocyte proliferation. The objective of this study was to determine the mechanism by which Sip alters the proliferative response of lymphocytes. Human T-cells were activated by PHA in the presence or absence of Sip and cell cycle progression was assessed by flow cytometry. Cell cycle distribution was based upon DNA, RNA and protein content as well as expression of the activation markers; CD69 and IL-2R. Seventy-two hours following activation with PHA, cells were found in the G0, G1, S and G2/M phases of the cell cycle. In contrast, pretreatment with Sip resulted in a significant reduction of cells in the S and G2/M phases and a concomitant increase in the G1 phase. Sip did not alter the expression of the early activation markers CD69 and CD25R. To determine if G1 arrest resulted in activation of the checkpoint and cell death, we also monitored Sip-treated cells for apoptosis. Indeed, treatment with Sip resulted in both DNA fragmentation and caspase activation after 96 h. Our results indicate that Sip induces G1 arrest in human T-cells and, furthermore, that the arrest is irreversible, culminating in activation of the apoptotic cascade. We propose that if cell cycle arrest occurs in vivo, it may result in local and/or systemic immunosuppression and thereby enhance the pathogenicity of spirochetes and/or that of other opportunistic organisms. [source] Number II Pemphigus vulgarisORAL DISEASES, Issue 3 2005M Black Pemphigus is a group of potentially life-threatening autoimmune diseases characterized by cutaneous and/or mucosal blistering. Pemphigus vulgaris (PV), the most common variant, is characterized by circulating IgG antibodies directed against desmoglein 3 (Dsg3), with about half the patients also having Dsg1 autoantibodies. There is a fairly strong genetic background to pemphigus with linkage to HLA class II alleles and ethnic groups such as Ashkenazi Jews and those of Mediterranean and Indian origin, are especially liable. Oral lesions are initially vesiculobullous but readily rupture, new bullae developing as the older ones rupture and ulcerate. Biopsy of perilesional tissue, with histological and immunostaining examination are essential to the diagnosis. Serum autoantibodies to either Dsg1 or Dsg3 are best detected using both normal human skin and monkey oesophagus or by enzyme-linked immunosorbent assay. Before the introduction of corticosteroids, PV was typically fatal mainly from dehydration or secondary systemic infections. Current treatment is largely based on systemic immunosuppression using corticosteroids, with azathioprine or other adjuvants or alternatives but newer therapies with potentially fewer adverse effects, also appear promising. [source] Ultraviolet B Radiation of Human Skin Generates Platelet-activating Factor Receptor AgonistsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2010Jared B. Travers Ultraviolet B radiation (UVB) is a potent stimulator of epidermal cytokine production. In addition to cytokines, such as tumor necrosis factor-alpha (TNF-,), UVB generates bioactive lipids including platelet-activating factor (PAF). Our previous in vitro studies in keratinocytes or epithelial cell lines have demonstrated that UVB-mediated production of PAF agonists is due primarily to the pro-oxidative effects of this stimulant, resulting in the nonenzymatic production of modified phosphocholines (oxidized glycerophosphocholines). The current studies use human skin to assess whether UVB irradiation generates PAF-receptor agonists, and the role of oxidative stress in their production. These studies demonstrate that UVB irradiation of human skin results in PAF agonists, which are blocked by the antioxidant vitamin C and the epidermal growth factor receptor inhibitor PD168393. Inasmuch as UVB-generated PAF agonists have been implicated in animal model systems as being involved in photobiologic processes including systemic immunosuppression and cytokine (TNF-,) production, these studies indicate that this novel activity could be involved in human disease. [source] Radiation Sources Providing Increased UVNUVB Ratios Induce Photoprotection Dependent on the UVA Dose in Hairless MicePHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2006Vivienne E. Reeve ABSTRACT In studies involving mice in which doses of UVA (320,400 nm) and UVB (290,320 nm) radiation were administered alone or combined sequentially, we observed a protective effect of UVA against UVB-induced erythemdedema and systemic suppression of contact hypersensitivity. The UVA immunoprotection was mediated by the induction of the stress enzyme heme oxygenase-1 (HO-1) in the skin, protection of the cutaneous Th1 cytokines interferon-gM (IFN-,) and IL-12 and inhibition of the UVB-induced expression of the Th2 cytokine IL-10. In this study, we seek evidence for an immunological waveband interaction when UVA and UVB are administered concurrently to hairless mice as occurs during sunlight exposure in humans. A series of spectra providing varying ratios of UVA/UVB were developed, with the UVA ratio increased to approximately 3.5 times the UVA component in solar simulated UV (SSUV). We report that progressively increasing the UVA component of the radiation while maintaining a constant UVB dose resulted in a reduction of both the erythemdedema reaction and the degree of systemic immunosuppression, as measured as contact hypersensitivity. The UVA-enhanced immunoprotection was abrogated in mice treated with a specific HO enzyme inhibitor. UVA-enhanced radiation also upregulated the expression of cutaneous IFN-, and IL-12 and inhibited expression of both IL-6 and IL-10, compared with the activity of SSUV. The results were consistent with the previously characterized mechanisms of photoprotection by the UVA waveband alone and suggest that the UVA component of solar UV may have beneficial properties for humans. [source] Gene expression profiles of TNF-,, TACE, furin, IL-1, and matrilysin in UVA- and UVB-irradiated HaCat cellsPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2005Beata Skiba Background/Purpose: It is known that solar ultraviolet (UV) irradiation exerts multiple effects on mammalian skin tissues, one of which is the induction of local and systemic immunosuppression as well as inflammation. Tumor necrosis factor-, (TNF-,) and other cytokines are suggested to play a role in these responses. Quantitative real-time polymerase chain reaction (TaqMan RTPCR) was used to elucidate the effect of UVA and UVB irradiation on the expression of genes coding for TNF-,, IL-1,, IL-10, FasL, matrilysin, TACE and furin in HaCaT cells over a 48 h period (IL-1,, interleukin-1,; FasL, Fas ligand). Methods: Cultured HaCaT cells were either sham irradiated (control) or exposed to UVA (2000 and 8000 J/m2) or UVB (200 and 2000 J/m2) radiation. RNA was extracted from cells at 0, 4, 8, 12, 16, 24, 48 h post-irradiation and reverse transcribed to generate cDNA for subsequent real-time PCR amplification. Results: Significant increases in the mRNA levels for all genes tested were detected in both UVA- and UVB-irradiated HaCaT cells compared with control (sham-irradiated) cells. TNF-, mRNA levels were immediately up-regulated (0 h) after irradiation, with maximal induction at 8 h post 2000 J/m2 UVA and 200 J/m2 UVB irradiation, at 4 h post 8000 J UVA irradiation and at 48 h post 2000 J/m2 UVB irradiation. No correlation was observed between TNF-,, TACE and furin mRNA induction in the different irradiated cohorts. Conclusion: Results suggest that time-distinct gene induction of TNF-,, furin, IL-1, and matrilysin may be involved in UV-induced cellular responses, but not for TACE. In general, mRNA induction was dose dependent at some time points post-irradiation, but not throughout the whole time course tested. Our results show that quantitative real-time PCR is a useful tool in the analysis of quantitative changes of mRNA levels in cultured HaCaT cells after UV exposure. [source] Whole-body UVB (TL-01) or UVA-1 irradiation does not alter the levels of immunomodulatory cytokines in the serum of human volunteersPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2004P. Mcloone Background/Purpose: Ultraviolet (UV) exposure of mammalian skin induces local and systemic immunosuppression. In mice it has been proposed that systemic immunosuppression is mediated by an UV-induced cytokine cascade involving systemic interleukin (IL)-4 and IL-10 and a reduction in IL-12 activity. To investigate whether there was a parallel mechanism in humans we examined the effect of whole-body narrowband ultraviolet B (UVB) (311,313 nm; TL-01) and ultraviolet A (UVA)-1 (340,400 nm) on serum cytokine levels. Methods/Results: In a first study, five male psoriatic subjects were whole-body irradiated with three sessions of a standard UVB (TL-01) phototherapy regimen previously shown to cause downregulation of natural killer cell activity and T helper 1 (Th1) and Th2 cytokine production by peripheral blood mononuclear cells. Enzyme-linked immunoabsorbent assay (ELISA) of sera taken before and after the third session showed no effect of phototherapy on IL-10 and tumour necrosis factor-, (TNF-,). In a second study, five healthy subjects received three whole-body exposures of UVB (TL-01) and five other healthy subjects received three exposures of UVA-1 on alternate days (total 22 J/cm2). Blood samples were taken before the first irradiation and at 0, 4, 8, 12, 14, 24 and 48 h after the third irradiation. The sera were subsequently analysed for IL-10, IL-12, IL-8, IL-1, and TNF-,, by ELISA. The levels of IL-1, and TNF-, were below detection limits (<5 pg/ml), while no significant change in the levels of IL-10, IL-12 or IL-8 was detected as a result of either TL-01 or UVA-1. Conclusion: It seems unlikely that a modulation in these circulating cytokines assessed in this study accounts for systemic UV-induced immunosuppression in human subjects. [source] Erythrodermic chronic actinic dermatitis responding only to topical tacrolimusPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 1 2004A. V. Evans Chronic actinic dermatitis (CAD) is a disorder characterized by an often severe persistent eczematous eruption induced by exposure to ultraviolet radiation. Treatment involves photoprotective measures and topical corticosteroid therapy and in more severe cases, systemic immunosuppression. Occasionally, however, the condition can prove very resistant to all therapy and be severely disabling. We report a patient with CAD who resisted standard topical and systemic treatments, but responded to topical tacrolimus ointment 0.1% (Protopic®). [source] Decay Accelerating Factor is Essential for Successful Corneal EngraftmentAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2010A. Esposito In contrast to immune restrictions that pertain for solid organ transplants, the tolerogenic milieu of the eye permits successful corneal transplantation without systemic immunosuppression, even across a fully MHC disparate barrier. Here we show that recipient and donor expression of decay accelerating factor (DAF or CD55), a cell surface C3/C5 convertase regulator recently shown to modulate T-cell responses, is essential to sustain successful corneal engraftment. Whereas wild-type (WT) corneas transplanted into multiple minor histocompatibility antigen (mH), or HY disparate WT recipients were accepted, DAF's absence on either the donor cornea or in the recipient bed induced rapid rejection. Donor or recipient DAF deficiency led to expansion of donor-reactive IFN-, producing CD4+ and CD8+ T cells, as well as inhibited antigen-induced IL-10 and TGF-,, together demonstrating that DAF deficiency precludes immune tolerance. In addition to demonstrating a requisite role for DAF in conferring ocular immune privilege, these results raise the possibility that augmenting DAF levels on donor corneal endothelium and/or the recipient bed could have therapeutic value for transplants that clinically are at high risk for rejection. [source] Dendritic cells in cytomegalovirus infection: viral evasion and host countermeasuresAPMIS, Issue 5-6 2009ALEXANDER RÖLLE Human cytomegalovirus (HCMV) is a ,-herpesvirus that infects the majority of the population during early childhood and thereafter establishes life-long latency. Primary infection as well as spontaneous reactivation usually remains asymptomatic in healthy hosts but can, in the context of systemic immunosuppression, result in substantial morbidity and mortality. HCMV counteracts the host immune response by interfering with the recognition of infected cells. A growing body of literature has also suggested that the virus evades the immune system by paralyzing the initiators of antiviral immune responses , the dendritic cells (DCs). In the current review, we discuss the effects of CMV (HCMV and murine CMV) on various DC subsets and the ensuing innate and adaptive immune responses. The impact of HCMV on DCs has mainly been investigated using monocyte-derived DCs, which are rendered functionally impaired by infection. In mouse models, DCs are targets of viral evasion as well, but the complex cross-talk between DCs and natural killer cells has, however, demonstrated an instrumental role for DCs in the control and clearance of viral infection. Fewer studies address the role of peripheral blood DC subsets, plasmacytoid DCs and CD11c+ myeloid DCs in the response against HCMV. These DCs, rather than being paralyzed by HCMV, are largely resistant to infection, mount a vigorous first-line defense and induce T-cell responses to the virus. This possibly provides a partial explanation for an intriguing conundrum: the highly efficient control of viral infection and reactivation in immunocompetent hosts in spite of multi-layered viral evasion mechanisms. [source] MLN3897 plus methotrexate in patients with rheumatoid arthritis: Safety, efficacy, pharmacokinetics, and pharmacodynamics of an oral CCR1 antagonist in a phase IIa, double-blind, placebo-controlled, randomized, proof-of-concept study,ARTHRITIS & RHEUMATISM, Issue 12 2009Clarissa E. Vergunst Objective To assess the efficacy, safety, pharmacokinetics, and pharmacodynamics of the CC chemokine receptor CCR1 antagonist MLN3897 in patients with rheumatoid arthritis (RA) receiving methotrexate (MTX). Methods In this phase IIa, proof-of-concept study, patients meeting the American College of Rheumatology (ACR) criteria for RA who had been taking MTX for ,6 months with evidence of active disease were randomly assigned to receive either 10 mg oral MLN3897 or matching placebo once daily for 12 weeks (days 1,83) while continuing to receive MTX once a week. Clinical assessments, safety monitoring, and sampling for pharmacokinetic and pharmacodynamic analyses were performed throughout the study. The primary efficacy end point was the difference in the percentage of patients meeting the ACR 20% improvement criteria (achieving an ACR20 response) on day 84 in the MLN3897-treated group compared with that in the placebo-treated group. Results MLN3897 was well tolerated, with no evidence of systemic immunosuppression. In the intent-to-treat population, there was no significant difference in day 84 ACR20 response rates between MLN3897-treated patients and placebo-treated patients (35% versus 33%, respectively; P = 0.72). Results were similar for the per-protocol population. Pharmacokinetic analyses demonstrated no interactions between MLN3897 and MTX. MLN3897 was associated with a high degree of CCR1 occupancy (,90% on days 28, 56, and 84 in 82% of patients, by macrophage inflammatory protein 1, internalization assay). Conclusion MLN3897 at a concentration of 10 mg once daily had no discernible activity in patients with RA who were also receiving MTX. The results suggest that CCR1 antagonism is unlikely to be a viable strategy for the treatment of RA when used in isolation at the receptor occupancy levels reached in this study. [source] Susac syndrome: Microangiopathy of the retina, cochlea and brainCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 5 2000Valerie PJ Saw MBBS ABSTRACT Background: Susac syndrome is characterized by the triad of branch retinal arterial occlusions, encephalopathy and cochlear microangiopathy. The underlying process is believed to be a small vessel vasculitis causing microinfarcts in the retina, brain and cochlea. Methods: Analysis of two male and two female cases of Susac syndrome recognized in Australia. Results: In this series the epidemiology, mode of presentation, ophthalmologic features, neurologic and cochleovestibular features, radiologic characteristics, cerebrospinal fluid findings, therapeutic interventions, clinical course and outcome of Susac syndrome is examined. Key ophthalmologic differential diagnoses include systemic lupus erythematosis (SLE), Behçet's syndrome and other vasculitides such as sarcoidosis, tuberculosis, syphilis and lymphoma. Neuro-otologic features are most frequently misdiagnosed as multiple sclerosis. Conclusion: Susac syndrome, first described in 1979, is becoming an increasingly recognized condition. Early recognition of the syndrome is important because treatment with systemic immunosuppression may minimize permanent cognitive, audiologic and visual sequelae. [source] | ||||||||||