Persistent polyclonal B-cell lymphocytosis: further evidence for a genetic disorder associated with B-cell abnormalities

Persistent polyclonal B-cell lymphocytosis (PPBL) is an intriguing disorder diagnosed predominantly in women, usually cigarette smokers, characterized by an increase in the number of polyclonal B lymphocytes. Abnormality of the B-cell population is also evidenced by the presence of multiple bcl-2/Ig gene rearrangements and the finding of an additional long arm chromosome 3q+ (i3)(q10) within a significant proportion of B cells. The physiopathology of PPBL is unknown but its association with the HLA DR7 phenotype suggests a possible genetic disorder. To further determine whether PPBL has a genetic predisposition, we have undertaken an extensive study in a large family of a patient diagnosed with PPBL. Three individuals among the first-degree relatives presented all the criteria for a diagnosis of PPBL. A slight increase in serum IgM without evidence of B-cell proliferation was shown in two additional siblings. Multiple bcl-2/Ig gene rearrangements, a typical feature of PPBL, were identified in 8/10 individuals among first-degree relatives. A statistically significant association was found between the presence of these rearrangements and of a paternal HLA haplotype. We conclude that PPBL has a familial occurrence suggesting an underlying genetic defect. The development of the complete syndrome probably relies on unidentified additional co-factors.