CD5(+) persistent polyclonal B-cell lymphocytosis in a male

Persistent polyclonal B-cell lymphocytosis with binucleate lymphocytes is a rare lymphoproliferative syndrome of uncertain cause that is strongly asso ciated with HLA-DR7 positivity, cigarette smoking, and female sex. As yet, there is no explanation for the strong sex predilection. We report the thir d case of persistent polyclonal B-cell lymphocytosis in a male. Other notab le findings in this case are lack of HLA-DR7 and strong positive CD5 marker s in the polyclonal B-cell population. To our knowledge, CD5 expression has not been mentioned or reported in association with this syndrome.