Molecular negativization rates. Results were obtained by nested PCR in (A) BM and (B) PB and by RQ-PCR in (C) BM and (D) PB. NEG, negative; PNQ, positive not quantifiable; POS, positive; R-CTX, rituximab-cyclophosphamide; R-HD-ARA-C, rituximab-high dose cytarabine.