Aberrant CD79b gene expression in T cells, HPCs, and monocytes in the absence of cell-surface expression. (A) PBMCs were stained with CD79b-specific antibody (αCD79b) or isotype control (Isotype) in combination with lineage-specific markers as indicated. Histograms show CD79b expression after gating on B cells (CD19⁺), T cells (CD3⁺), and monocytes (CD14⁺). CD34⁺ HPCs were isolated from granulocyte colony-stimulating factor–mobilized blood. Activated CD4⁺ T cells were stimulated with PHA and irradiated autologous feeders and cultured for 10 days. (B) CD79b mRNA expression was determined for indicated cell subsets by qRT-PCR. Expression was normalized to average CD79b expression in primary CD19⁺ B cells, which was set to 100. Dots indicate individual samples.