Blood neutrophils (PMN) and B and T lymphocytes (B cells and T cells, respectively) were separated by flow cytometry cell sorting and mRNA extracted as described in Materials and Methods. Allelic Xkrx and BTK expression levels, normalized for 18S RNA in B cells (A and B), T cells (C and D), and neutrophils (E and F), were determined. Mean ± sem; n = 4. *Statistically significant difference, as indicated by connecting line.