Treatment scheme and flow chart of the study.

One hundred twenty-eight newly diagnosed patients with FL with a PCR-proved rearrangement in the BM and PB at diagnosis were treated with CHOP chemotherapy. A PCR analysis was repeated on BM (▪) and PB (●) after the third cycle, as well as 4 and 6 weeks after the sixth cycle of chemotherapy (baseline). In case of discrepancies between the molecular results at baseline, a third assay was performed (8 weeks) after CHOP and this result conclusively established the positivity or negativity of the molecular marker. Only clinically responsive but persistently PCR-positive patients were eligible for rituximab treatment.