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 associated with HLA-DR7 positivity, cigarette smoking, and female sex. As yet, there is no explanation for the strong sex predilection. We report the third case of persistent polyclonal B-cell lymphocytosis in a male. Other notable findings in this case are lack of HLA-DR7 and strong positive CD5 markers in the polyclonal B-cell population. To our knowledge, CD5 expression has not been mentioned or reported in association with this syndrome.