Bone marrow lymphoid cells differentially express the CD164(103B2/9E10) epitope. Representative dot plots from one of two separate experiments showing CD34⁺ bone marrow cells and Ficoll separated bone marrow mononuclear cells labeled with the 103B2/9E10 MoAb or with an IgG₃ negative control MoAb plus CD34-PerCP and with the PE-conjugated MoAbs indicated before counterstaining with FITC anti-mouse IgG₃ and analysis on the FACSCalibur. In contrast to the more mature CD34⁻CD19⁺ and CD34⁻CD20⁺ B cells, the immature CD34⁺CD19⁺ B-cell subset failed to express the CD164(103B2/9E10) epitope. The median fluorescence intensity for CD164(103B2/9E10) staining of the CD34⁻CD3⁺cells was 9.08 after subtraction of the isotype-matched negative control value, indicating that the CD34⁻CD3⁺ T-cell subset was weakly reactive with the 103B2/9E10 MoAb.