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CD20 (pan-B cell antigen) expression on bone marrow-derived T cells
K M Algino1, R W Thomason, D E King
1Department of Pathology, University of Texas Health Science Center, San Antonio 78284, USA.
American Journal of Clinical Pathology
|July 1, 1996
Summary
CD20 antibodies, typically used for B lymphocytes, also identify CD20-positive T cells in bone marrow. This finding is common in normal and abnormal samples, requiring caution when interpreting CD20 expression in T-cell lymphomas.
Area of Science:
- Immunology
- Hematology
- Oncology
Background:
- Antibodies targeting CD20 are standard for identifying B lymphocytes.
- Recent studies reveal CD20 expression on T cells in peripheral blood and some T-cell cancers.
- The presence and significance of CD20-positive T cells in bone marrow remain less understood.
Purpose of the Study:
- To investigate the prevalence and characteristics of CD20-positive T cells within bone marrow aspirate specimens.
- To assess potential correlations between CD20-positive T cells and clinical parameters or diagnoses.
- To clarify the implications of CD20 expression on T-lymphoid cells in bone marrow analysis.
Main Methods:
- Flow cytometry was employed to analyze 34 bone marrow aspirate specimens.
- Specimens included normal controls and various hematologic malignancies (ALL, AML, CML, CLL, multiple myeloma) and HIV-positive cases.
- Cells were analyzed for coexpression of CD3 (T-cell marker) and CD20 (B-cell marker).
Main Results:
- A CD3+/CD20dim population was detected in 94% of bone marrow specimens.
- This population represented a small percentage of total mononuclear cells (mean 1.77%) and lymphoid cells (mean 6.54%).
- No significant correlation was found between CD20-positive T cells and CD4:CD8 ratio, age, gender, or specific diagnosis.
Conclusions:
- CD20-positive T cells are frequently present in bone marrow, including in normal individuals.
- The CD20dim population includes both immature B cells and T cells.
- Interpretation of CD20 expression in bone marrow T-lymphoid cells requires caution, as it can occur in normal, reactive, or neoplastic conditions.