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Updated: May 23, 2026
In Vitro Methods for Comparing Target Binding and CDC Induction Between Therapeutic Antibodies: Applications in Biosimilarity Analysis
Published on: May 4, 2017
Comparison of CD20 expression in B-cell lymphoma between newly diagnosed, untreated cases and those after rituximab
Hiroaki Miyoshi1, Fumiko Arakawa, Kensaku Sato
1Department of Pathology, School of Medicine, Kurume University, Kurume, Japan. miyoshi_hiroaki@med.kurume-u.ac.jp
Abstract:
Few studies have statistically investigated reduced CD20 expression in B-cell lymphoma after rituximab therapy and genomic mutation of CD20 associated with reduction. We examined CD20-positive rate in follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) by flow cytometry (FCM) and immunohistochemical staining (IHS), comparing 138 cases after rituximab therapy with 360 initial, not yet treated cases. Sequence analysis of exons 3 to 8 of CD20 was performed on 22 cases with low CD20-positive rate after rituximab treatment. The results showed a statistical correlation between CD20-positive rate in FCM and IHS. By FCM, the CD20-positive rate among post-rituximab cases was significantly lower than among initial cases in DLBCL, non-germinal center origin B-cell type (average values [avg] 57.8 and 87.9, respectively) (P < 0.0001), FL2 (avg, 93.9; 103.2) (P = 0.0083), and FL3A (avg, 90.6; 100.7) (P = 0.033). Stratified analyses of post-rituximab cases showed significantly lower CD20-positive rate in cases that were resistant at the start of the treatment and cases with progressive disease during rituximab therapy before biopsy. Sequence analysis showed silent mutation of exon 4 (632 C/T) in seven cases, although this number was not statistically significant. These results suggest the influence of B-lymphoma subtype and a therapeutic effect before biopsy on CD20 expression at relapse and contribute to a better therapeutic approach for relapse cases after rituximab therapy.
