Amount of t(14;18)⁺ cells at diagnosis, at the end of CHOP, and after rituximab. The amount of BCL2/IgH⁺ cells are expressed as the number of neoplastic cells per million normal cells. The black bold line indicates the median value observed. The box refers to the range defined by the 25th and 75th percentiles. The bars extend from the 5th to 95th percentile. The minus symbol indicates the extremes. Neoplastic cells were evaluated at diagnosis (□), at the end of CHOP chemotherapy (▦), and after rituximab (▨). Small squares inside boxes represent the mean value. Statistical analyses and P values were calculated by Wilcoxon test on paired samples.