As targeted drugs to B-cell malignancies, anti-CD20 monoclonal antibodies have been proved to be important in therapeutic antibody field. With three generations in more than ten years' development, the structures of these drugs have been improved, and many new indications have been found. Nowadays, these kinds of antibodies are not only used in the treatment of lymphoid malignancies, but also been proved to be useful in some autoimmune diseases treatment, and their new indications are still being expanded. With the optimization of their clinical dosage regimens, drug reaction has been increased, thus, therapeutic and side effects of anti-CD20 monoclonal antibody have been further improved as well. However, the exact mechanism of action of their combination therapy with other chemical drugs is still unclear, which remains to be further studied. This article reviewed new development of anti-CD20 therapeutic monoclonal antibodies research in recent years.

An enzyme linked immunosorbent assay ( ELISA ) and a flow cytometry assay ( FCA ) based on Wil2-S cells were developed and systematically compared for quantification of recombinant anti-CD20 humanized monoclonal antibody ( rh-anti-CD20zumab) in biological matrix. The specificity, precision and accuracy of each method at correspondingly different linear range showed good results. For ELISA, the precisions of intra-day and inter-day were both <19 . 5%, the relative error was from-18 . 2% to 17 . 6%;For FCA, the precisions of intra-day and inter-day were both <19. 0%, the relative error was from -18. 9% to 18. 4%. The sensitivity of ELISA was significantly higher than that of FCA. The quantitative ranges of ELISA and FCA methods were 0. 04-5. 0 mg/L and 3. 1-200 mg/L, respectively. The concentrations in serum samples and pharmacokinetics analysis were determined by both of two methods after vein drip administration of rh-anti-CD20zumab in rhesus monkeys. Pharmacokinetics data showed that there was excellent consistency between results obtained by two methods at the given dose. We believe that the novel FCA with high speed and high sensitivity can be used to perform PK and PD study of cell surface antigen-targeted antibody derivatives.