CD79a (MB1) is a B-cell marker with a wider range of positivity in the B-cell development spectrum compared to CD20 (mature B-cell phenotype). CD79a may be expressed on malignant precursor B-cells and terminally differentiated B-cells (PAX-5 is not expressed in terminally differentiated B-cells). Please note that in the setting of ALL, CD79a is not lineage specific, and up to 50% of T-ALL cases express CD79a. AML cases with t(8;21) may also show CD79a expression (along with CD19, CD20, and TdT).
Tag Archives: CD19
CD19
CD19 is a B-cell marker. Until recently this antibody has only been available for use in flow cytometry. Now CD19 is available as an immunohistochemistry (IHC) marker, with similar sensitivity for B-cells to CD20. The IHC expression pattern is cytoplasmic and membranous. It is normally expressed on both Precursor B-cells and B-cells. CD19 combined with TdT would be specific to detect precursor B-cells. CD20 is not expressed on precursor B-cells, but mature B-cell with surface light chain expression (usually).