Loss of CD20 expression following treatment with rituximab (chimaeric monoclonal anti-CD20): a retrospective cohort analysis.
A retrospective analysis of CD20 expression following rituximab for B-cell non-Hodgkin's lymphoma demonstrated a significant change in immunophenotype in 6/25 (24%) patients with persistent bone marrow (BM) infiltration. In three out of six patients, the B cells were uniformly CD20-/CD79alpha+, consistent with frank loss of CD20 expression. In the remaining three cases, the BM infiltrate was predominantly (> 80%) CD20-/CD79alpha+. Two of the former but none of the latter three cases achieved a clinical response. In three further cases, the post-treatment BM infiltrate was composed entirely of benign or reactive CD3+ T cells. Frank loss of CD20 was not seen in 25 post-treatment lymph node biopsies. Immunophenotyping is therefore an important adjunct in the diagnosis of BM infiltration following rituximab.
Foran
J M
JM
Imperial Cancer Research Fund Medical Oncology Unit, St. Bartholomew's Hospital, London, UK. jforan@unmc.edu
Norton
A J
AJ
Micallef
I N
IN
Taussig
D C
DC
Amess
J A
JA
Rohatiner
A Z
AZ
Lister
T A
TA
D000911:Antibodies, Monoclonal / Q000009:adverse effects*; D058846:Antibodies, Monoclonal, Murine-Derived; D015703:Antigens, CD / Q000276:immunology; D018951:Antigens, CD20 / Q000276:immunology*; D000970:Antineoplastic Agents / Q000009:adverse effects*; D001402:B-Lymphocytes / Q000276:immunology; D001854:Bone Marrow Cells / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D051925:CD79 Antigens; D006801:Humans; D016130:Immunophenotyping; D007167:Immunotherapy; D017254:Leukemic Infiltration; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000628:therapy; D011947:Receptors, Antigen, B-Cell / Q000276:immunology; D012189:Retrospective Studies; D000069283:Rituximab; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D015703:Antigens, CD; D018951:Antigens, CD20; D000970:Antineoplastic Agents; D017252:CD3 Complex; D051925:CD79 Antigens; C497881:CD79A protein, human; D011947:Receptors, Antigen, B-Cell; D000069283:Rituximab