Multiple bcl‐2/Ig gene rearrangements in persistent polyclonal B‐cell lymphocytosis

Persistent polyclonal B-cell lymphocytosis is a benign lymphoproliferative disorder of unknown aetiology occurring exclusively in women, characterized by typical binucleated lymphocytes, polyclonal expansion of cells and elevated serum IgM. Owing to the role of B.1-2 oncogene in inhibition of apoptosis, we have investigated the presence of the bcl-2/lg gene rearrangement. B.l-2/lg gene rearrangement was determined by polymerase chain reaction targeting the usual breakpoint regions of the t(14;18). Bcl-2/lg gene rearrangement was identified in all six patients and, more importantly, multiple rearrangements were present in five patients. The frequency of the b.1-2/lg gene rearrangement is estimated to be of one translocation in 1 x lU 2 to 1 x x 10 3 peripheral blood mononuclear cells. We conclude that persistent polyclonal B-cell lymphocytosis is associated with bcl-2/lg gene rearrangement. These findings are of clinical importance because these patients may be misdiagnosed as having a leukaemic expression of non-Hodgkin's lymphoma.