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Journal: Cytometry. Part B, Clinical cytometry

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BACKGROUND: B-cell lymphomas with concurrent translocations of MYC and BCL2 or BCL6, also known as “double-hit” lymphomas (DHL), are rare malignancies characterized by aggressive clinical behavior and poor prognosis. Previous reports suggest that decreased CD20 and/or CD19 expression by flow cytometry is relatively common in DHL and may help to identify cases requiring additional cytogenetic analysis. METHODS: We conducted a retrospective analysis of 26 cases of DHL, and compared their flow cytometric characteristics to cases of Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). Cases were analyzed by four-color flow cytometry, and bivariate dot-plots were reviewed for light scatter characteristics, CD19, CD20, CD45, and surface light chain. RESULTS: Relatively few DHL cases showed dim expression of CD19 or CD20, and statistically significant differences were found only in the frequency of dim CD19 expression between DHL and BL or DLBCL. Although concomitant dim CD19 and CD20 expression was exclusive to DHL, it was present in only a minority of cases. CONCLUSIONS: We conclude that although a subset of DHL expresses aberrant levels of CD19 and/or CD20 by flow cytometry, these findings are of limited utility in identifying cases requiring cytogenetic analysis due to their low frequency. Until more sensitive pathologic parameters can be identified and validated, the decision to perform cytogenetic analysis should rest on a combination of clinical, morphologic, and immunophenotypic features suggestive of high-grade, aggressive disease. © 2013 International Clinical Cytometry Society.

Concepts: AIDS, Cancer, B cell, Types of cancer, Lymphoma, Flow cytometry, Diffuse large B cell lymphoma, B-cell lymphoma

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In drug development, in vivo assessment of target engagement provides confidence when testing the drug’s mechanism of action and improves the likelihood of clinical success. For biologics, receptor occupancy (RO) determined from circulating cells can provide evidence of target engagement. Integrating this information with mathematical modeling can further enhance the understanding of drug-target interactions and the biological factors that are critical to the successful modulation of the target and ultimately the disease state.

Concepts: DNA, Pharmacology, Gene expression, Epidemiology, Cell biology, Operations research, The Target, Success

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The aberrant expression of CD5 in both HCL and HCL-v is a very rare event. Although a number of CD5 positive HCL and HCL-v cases have been reported, but these are far and few in between. We aimed to review the reported cases of CD5 positive HCL and its variant.

Concepts: Leukemia, Hairy cell leukemia

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CD157, encoded by BST-1, has been described as a useful flow cytometric marker for the analysis of paroxysmal nocturnal hemoglobinuria (PNH) as it is a glycosylphosphatidylinositol (GPI)-linked molecule highly expressed on normal monocytes and neutrophils. We and others observed isolated CD157 signal dropouts during intended PNH analysis. We hypothesize that these negative populations occur due to an antibody failure. To investigate the reason for this finding, we compared two different anti-CD157 antibody clones for PNH analysis.

Concepts: White blood cell, Monocyte, Scientific method, Cell biology, Flow cytometry, Clone, Paroxysmal nocturnal hemoglobinuria

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Flow cytometric intracellular myeloperoxidase (MPO) staining of leukemic blasts is a useful tool in diagnosis of leukemia subtype. Interpretation of high MPO-positivity can be a diagnostic challenge in B-lineage acute lymphoblastic leukemia (B-ALL). While very few such cases have been reported, high MPO positive B-ALL cases without additional myeloid antigen positivity are suspect and require further investigation.

Concepts: Medical terms, Diagnosis, Hematology, Leukemia, Flow cytometry, Acute myeloid leukemia, Acute lymphoblastic leukemia, Vincristine

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The data on the clinical utility of the quantitative assessment of immunophenotypes in distinguishing mature CD5-positive B-cell neoplasms is limited. The study aim was to assess the diagnostic value of the quantitative assessment of a panel of 18 markers and to identify the most informative ones.

Concepts: Psychology, Evaluation methods, Sociology, Psychological testing

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We performed a retrospective analysis of 88 adult patients with B-ALL diagnosed in our center by a flow-cytometric assessment. Immunophenotypic expression of leukemic cells was explored by simultaneous evaluation of positivity, percentage of expressing cells and median fluorescence intensity (MFI). Presence of BCR/ABL1 fusion transcripts were assessed by RT-PCR analysis and were identified in 36 patients (40.9%). CD10 and CD34 were positive in the totality of BCR/ABL1-positive cases. Patients with gene rearrangement had a greater frequency of CD66c, CD13 and CD33 positivity compared with BCR/ABL1-negative cases. Moreover, BCR/ABL1-positive cases exhibited a greater median percentage and MFI values of CD13, CD33, CD66c, CD10, CD34 and CD25 expressions, but a lower median percentage and MFI values of CD38 and CD22 expressions than patients without gene rearrangement. Multivariate logistic regression analysis showed that CD10, CD38 and CD13 expressions were independent predictors for the presence of BCR/ABL1 rearrangement. Predictive probabilities of molecular occurrence based on these markers are proposed. This article is protected by copyright. All rights reserved.

Concepts: Regression analysis, Logistic regression, Gene expression, Prediction, Leukemia, Acute lymphoblastic leukemia, Expression, Copyright

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Accumulation of classical monocytes CD14(++) CD16(-) (also called MO1) ≥94% can accurately distinguish chronic myelomonocytic leukemia (CMML) from reactive monocytosis. The HematoFlow™ solution, able to quantify CD16 negative monocytes, could be a useful tool to manage monocytosis which remains a common issue in routine laboratories.

Concepts: Monocyte

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Hematological cytometers with a biological fluid module could potentially correct the limitations of the manual chamber method. This study evaluates the agreement between the manual technique and the Sysmex XN-1000 analyzer for white blood cell (WBC) and red blood cell (RBC) counts, as well as for leukocyte differentiation in different types of fluids. This study also evaluates the advantages of incorporating the technique in routine laboratory work.

Concepts: White blood cell, Blood, Red blood cell, Bone marrow, Hematology, Leukemia, Spleen, Blood transfusion

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Current flow-cytometric plasma cell (PC) gating is based on CD138, CD38 and CD45 expression. CD138 is known for variable expression and loss during storage and processing. Introduction of anti-CD38 and anti-CD138 monoclonal-antibody therapies has limited the use of these markers during follow-up. Hence, additional reliable PC-gating markers are required. Recently, CD229 has been claimed as an alternative PC-gating marker. However, these studies are limited to a small cohort of samples. We evaluated the utility of CD229 as a new PC-gating marker in routine laboratory practice.

Concepts: DNA, Medicine, Flow cytometry, Marker, Expression, Marker pen