CXCR5 expression on subpopulations of B cells. An acquisition forward/side scatter dot plot was used to gate live lymphocytes, and CXCR5 expression was analyzed on different subpopulations of B cells based on the expression of CD19, CD27, and CD38. (A) CXCR5 expression on naive (CD27⁻CD19⁺) B cells in HIV-1⁺ and control samples. CXCR5 expression on memory (CD27⁺CD19⁺) B cells (B) and early pre-plasma B cells (CD38⁺⁺CD19⁺) (C) is also shown. CXCR5 expression was significantly lower in all B-cell subpopulations in HIV-1 subjects compared with controls.