摘要
Nowadays, resistance to rituximab has become a major issue in clinical practice. And loss of CD20 may contribute to it. Here we presented a case of loss of CD20 expression in relapsed diffuse large B cell lymphoma treated with rituximab and discuss the incidence, mechanism, influence factors, specific markers, prognosis and treatment of this disease. These results suggested that a post-relapse biopsy after rituximab treatment shguld be performed. CD79a and Pax-5 should be used as the first-line B lineage-specific markers for these patients. Though mechanisms of CD20 decrement are not fully elucidated, the down-regulation of CD20 mRNA is the most probable hypothesis. Recently various new agents are developed, but the prognosis is still poor. Further studies for new treatments are needed.
