Because anti-CD22 mAbs can target and suppress matured B cells, their indications have been further expanded for the treatment of rheumatoid arthritis (RA), systemic lupus erythematous (SLE), etc. Therefore, it is urgently necessary to develop consistent and reliable protocols for quality control (QC) analysis of anti-CD22 mAbs and derivatives during antibody production or clinical studies [12,20]. The gene discussed is CD22; the disease is rheumatoid arthritis.