CD20 and CD19 expression in DLBCL by flow cytometry. (A) Distribution of MFI in CD20 expression in the DLBCL samples from 2004 to 2007. (B) Distribution of MFI in CD19 expression in the DLBCL samples from 2004 to 2007. (C) Heterogeneity in CD20 expression in DLBCL and normal peripheral blood lymphocytes from 2004 to 2007. From 2002 to 2004: dim CD20, mean MFI: 2.1; STD: 0.8; range: 0.55-3.91; bright CD20 mean, MFI: 17.6; STD: 19.4; range: 4.13-103. From 1997 to 2002: dim CD20, mean MFI: 1.1; STD: 0.4; range: 0.69-1.92; bright CD20, mean MFI: 14.1; STD: 18.5; range: 2.4-85.1. (D) Heterogeneity in CD19 expression in DLBCL and normal peripheral blood lymphocytes from 2004 to 2007. From 2002 to 2004: dim CD19, mean MFI: 0.44; STD: 0.11; range: 0.27-0.57; bright CD19, mean MFI: 4.79; STD: 4.28; range: 0.6-17.5. From 1997 to 2002: dim CD19, mean MFI: 0.52; STD: 0.22; range: 0.15-0.85; bright CD19, mean MFI: 6.71; STD: 6.70; range: 1.79-36.5. MFI indicates mean fluorescence intensity; DLBCL, diffuse large B-cell lymphoma; STD, standard deviation; PB, peripheral blood.