2023 Volume 72 Issue 4 Pages 492-498
The administration of rituximab to an organ transplantation recipient has the effects of depleting a part of B cells and temporarily suppressing their differentiation into antibody-producing cells. Therefore, rituximab has been used as a therapeutic drug to suppress the production of nascent antibodies that could develop into donor-specific alloantibodies (DSA) and treat antibody-mediated rejection. However, rituximab is known to cause a false positive result in the complement-dependent cytotoxicity crossmatch (CDC-XM) test using B cells, which is performed to detect DSA. In this study, to avoid the interference of rituximab, we investigated the protective effects against rituximab of a serum treatment method using magnetic beads and anti-idiotypic antibodies and a CD20 antigen treatment method using proteolytic enzymes on B cells. The serum treatment method enabled the prevention of false positives in patients administered with rituximab up to 600 mg/kg body weight. However, stable results could not be obtained with the B cell treatment method using proteolytic enzymes. The CDC-XM test is still the gold standard method for detecting only the complement-dependent antibodies that show reactivity with the rabbit complement. It is speculated that this serum treatment method will be a useful preconditioning method in the CDC-XM test for rituximab-administered cases.
