A further case of persistent polyclonal B-cell lymphocytosis is reported. This recently identified distinct clinicopathologic entity is frequently associated with the presence of the HLA-DR7 antigen. It follows a benign course and has so far been reported only in women smokers. The disorder is characterized by mild chronic peripheral lymphocytosis, the presence of characteristic binucleate lymphocytes on peripheral blood smears, and a polyclonal increase in serum IgM. In some cases, lymphadenopathies and/or splenomegaly are observed. Surface marker studies of peripheral lymphocytes demonstrate the polyclonal B-cell nature of this entity.