Serological analysis of anti-K and anti-Wra detected in patient treated with daratumumab:a case report
Objective To investigate the reasonable serological detection method by analyzing the characteristics of an-ti-K and anti-Wra from a patient who received treatment with daratumumab.Methods Unexpected antibody screening and identification were performed by saline method,polybrene,cardioagglutinin,dithiothreitol(DTT)treatment,trypsin treat-ment and papain treatment in the patient's plasma and acid elution solution.Heat elution test was detected after absorbing patient serum with K antigen negative red blood cells.The characteristics of antibodies were analyzed and their titer was con-tinuously detected.Cross matching was performed after excluding interference of daratumumab.Results Anti-K and anti-Wra were detected in saline and polybrene in the patient's plasma.The patient's elution solution contained daratumumab.DTT or trypsin treatment excluded interference of daratumumab but papain treatment did not.DTT treatment destroyed K an-tigen and missed the detection of IgG antibodies in the Kell system.Trypsin treatment did not affect K antigen and can detect IgG antibodies of Kell system(anti-k)in the serum of the patient treated with daratumumab.Anti K was IgM and the titer was 4 by saline method and it decreased to no agglutination in room temperature after 39 days.Anti-Wra was IgG and the titer by polybrene method was 4,and it decreased to 1 after 39 days.After 76 days,neither anti-K nor anti-Wra could be detected.Transfusions of K and Wra antigen negative red blood cells were safe and effective.Conclusion DTT treatment can exclude interference of daratumumab,but attention should be paid to missed detection of anti-K.To avoid interference of daratumum-ab and identify unexpected antibody,multiple methods such as DTT treatment,polybrene and trypsin treatment in combina-tion are recommended.