DETECTION OF CLONAL CD34(-MARROW OF BCL2-IGH-POSITIVE FOLLICULAR LYMPHOMA PATIENTS()19(+) PROGENITORS IN BONE)

The frequent occurrence of BCL2-IgH rearrangements in follicular lymph oma (FL) makes detection of low numbers of tumor cells possible by pol ymerase chain reaction (PCR). The presence of BCL2-IgH in the bone mar row (BM) and peripheral blood of many FL patients at the time of autog rafting has led to the suggestion that selection of the CD34-enriched fraction may lead to reinfusion of lower numbers of tumor cells. To ad dress this issue, we PCR-amplified BCL2-IgH from fluorescence-activate d cell sorting (FACS)-purified BM CD34(+) and CD34(-) fractions in sev en FL patients showing a PCR-detectable translocation in the major bre akpoint region of BCL2, five of which showed morphological BM involvem ent. The total CD34(+) fraction showed diminished but residual positiv ity in the first two cases tested. Therefore, BM cells from the remain ing five patients were sorted for the CD34(+)19(-) immature population , the CD34(+)19(+) B-cell precursors, and the CD34(-)19(+) mature B-ce ll fraction. The CD34(+)19(-) subpopulation was negative in four of fi ve, despite evident BM infiltration in three cases. In contrast, the C D34(+)19(+) fraction was positive in all three cases tested. These cel ls represented 0% to 50% (mean. 18%) of the total CD34(+) population, suggesting that, a reinfusion of BCL2-IgH-positive cells plays a role in postautograft relapse in FL, therapeutic CD34 selection procedures should include additional purging of the CD34(+)19(+) B-cell precursor s or, at least, assessment of the proportion of CD19(+) cells in the C D34(+) fraction and its correlation with clinical outcome postreinfusi on. (C) 1995 by The American Society of Hematology.