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CD20 Expression (cd20 + expression)
Selected AbstractsModulation of antigen expression in B-cell precursor acute lymphoblastic leukemia during induction therapy is partly transient: Evidence for a drug-induced regulatory phenomenon.CYTOMETRY, Issue 3 2010Results of the AIEOP-BFM-ALL-FLOW-MRD-Study Group Abstract Background: Changes of antigen expression on residual blast cells of acute lymphoblastic leukemia (ALL) occur during induction treatment. Many markers used for phenotyping and minimal residual disease (MRD) monitoring are affected. Glucocorticoid (GC)-induced expression modulation has been causally suspected, however, subclone selection may also cause the phenomenon. Methods: We investigated this by following the phenotypic evolution of leukemic cells with flow cytometry from diagnosis to four time points during and after GC containing chemotherapy in the 20 (of 360 consecutive) B-cell precursor patients with ALL who had persistent MRD throughout. Results: The early expression changes of CD10 and CD34 were reversible after stop of GC containing chemotherapy. Modulation of CD20 and CD45 occurred mostly during the GC phase, whereas CD11a also changed later on. Blast cells at diagnosis falling into gates designed according to "shifted" phenotypes from follow-up did not form clusters and were frequently less numerous than later on. Conclusions: Our data support the idea that drug-induced modulation rather than selection causes the phenomenon. The good message for MRD assessment is that modulation is transient in at least two (CD10 and CD34) of the five prominent antigens investigated and reverts to initial aberrant patterns after stop of GC therapy, whereas CD20 expression gains new aberrations exploitable for MRD detection. © 2010 Clinical Cytometry Society [source] Loss of CD20 expression in relapsed lymphomas after rituximab therapyEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2003Joud H. Haidar Abstract: The response rate at relapse to rituximab in prior responders B-cell non-Hodgkin's lymphoma (NHL) patients is below 50%. Loss of CD20 expression after rituximab therapy may explain this secondary resistance. However, the frequency of CD20 negative relapses cannot be assessed since most patients that relapsed after rituximab therapy have not been re-biopsied. Here, we present two patients with CD20 positive low grade B-cell NHL that lost the cell surface and cytoplasmic expression at relapse after rituximab therapy. Our findings suggest that confirmation of CD20 expression on the malignant B cells is required whenever rituximab therapy is considered. [source] CD5-Negative, CD10-Negative small B-cell leukemia: Variant of chronic lymphocytic leukemia or a distinct entity?,AMERICAN JOURNAL OF HEMATOLOGY, Issue 4 2002Salwa S. Sheikh Abstract CD5- and CD10-negative chronic lymphocytic leukemias are quite uncommon as compared to the CD5-positive CLL. We reviewed 250 sequential cases of peripheral blood lymphocytosis to characterize cases of small B-cell lymphoproliferative disorders, submitted with a clinical diagnosis of chronic lymphocytic leukemia exhibiting a non-classic immunophenotypic profile. Six cases of CD5-, CD10-negative chronic lymphocytic leukemias and no tissue involvement were identified that revealed high-density surface-membrane immunoglobulin and CD20 expression, with variable expression of CD11c, CD23, and CD25. Most had a profound leukocytosis (mean WBC 180 × 109/L) with proliferation of mature-appearing lymphocytes. Subsequent bone marrow biopsies showed diffuse infiltration by neoplastic cells in all evaluated patients. The clinical course appeared indolent, with follow-up revealing three patients alive (survival time 38,68 months), while two died of unrelated causes and one was lost to follow-up soon after diagnosis. These cases may represent somewhat unusual chronic lymphoproliferative disorders, with morphologic features and immunophenotypic profile not readily classifiable, but which are certainly atypical for classic chronic lymphocytic leukemia. Some of these features are reminiscent of those seen in marginal-zone lymphoma. However, it is most unusual for this known to be tissue-based disease to present primarily as leukemia rather than lymphoma. Am. J. Hematol. 71:306,310, 2002. © 2002 Wiley-Liss, Inc. [source] Prognostic significance of CD38 and CD20 expression as assessed by quantitative flow cytometry in chronic lymphocytic leukaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2003Eric D. Hsi Summary. CD38 expression on chronic lymphocytic leukaemia (CLL) cells is a poor prognostic factor, however, methods for measuring this vary. The QuantiBRITETM flow cytometry (FC) system yields an absolute antigen expression value (antibodies bound/cell, ABC) and may be useful in standardizing CD38 expression analysis. We evaluated cryopreserved pretreatment CLL cells for CD20 ABC, CD38 ABC, and percentage of CD38+ B cells from 131 patients requiring therapy. The 92 patients (70%) with , 100 CD38 ABC had worse overall survival (OS; 34% at 5 years) compared with those with <,100 CD38 ABC (70% at 5 years, mortality hazard ratio 2·30, 95% confidence interval 1·28,4·12; two-tailed P = 0·003). Among the 64 patients with <,30% CD38+ cells, OS of the 25 with , 100 ABC was worse than that of the 39 with <,100 ABC (P = 0·018). OS of patients with <,30% CD38+ cells and , 100 ABC was actually similar to that of patients with , 30% CD38+ cells. BrightCD20 expression (, 20 000 ABC) was not associated with a worse OS (P = 0·10). The presence of , 100 CD38 ABC in CLL patients requiring therapy is an unfavourable prognostic factor for OS and quantitative FC may be superior to percentage CD38+ cell assessment. Prospective trials are required to determine more precisely the prognostic significance of absolute expression levels in fresh CLL cells. [source] | ||||||||||