[Persistent polyclonal B-cell lymphocytosis]

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare and recently described entity. PPBL is diagnosed predominantly but not exclusively in women, usually smokers and is characterized by a moderate, chronic and absolute lymphocytosis (> 4 x 109/L). Peripheral blood examination show in all cases atypical binucleated lymphocytes. A polyclonal serum IgM is also associated and HLA-DR7 expression is present in most cases. The B cells are polyclonal with kappa and lambda light-chain expression. No clonal rearrangement of immunoglobulin heavy chain genes is observed. Finally, +i(3q) is a recurrent chromosomal abnormality and detected in 77% of cases with premature chromosome condensation in 50% and both abnormalities in 41% of cases. The benign clinical course of PPBL and lack of biological evolution in the majority of cases suggest that recognition is so important that aggressive therapy could be avoided.