Better Resolving of Anti-CD38 Antibody Interference with Blood Compatibility Testing by Using Manual Polybrene Method compared with Dithiothreitol-pretreatment Indirect Antiglobulin Test

Background: It is advised to pretreat the reagent erythrocytes with Dithiothreitol (DTT) to denature the surface CD38 to prevent anti-CD38 monoclonal antibodies (MoAb) from interfering with the blood compatibility test. Anti-CD38 has little impact on the Polybrene test, but it is still unknown how sensitive it is to detect irregular antibodies and how effective it is when compared to the standard DTT-based method.

Methods: Twenty-one patients receiving daratumumab (N = 13) and isatuximab (N = 8) had their serum collected. Standard anti-sera (anti-c, D, E, Fy , Jk , M, Mi ) with serial dilution were added to patients' serum. Antibody screening tests were performed simultaneously using the manual polybrene method (MP) and DTT-pretreated, automatic indirect antiglobulin test (DTT-IAT) to compare the detection sensitivity. These two methods' operating times and costs were also analyzed.

Results: Both MP and DTT-IAT can overcome the interference caused by anti-CD38 MoAb. However, MP is more sensitive in detecting anti-M and anti-Mi and is comparable to DTT-IAT in detecting other antibodies. In terms of cost and operating time, MP is also far superior to DTT-IAT.

Conclusion: MP is a cost-effective alternative to DTT-IAT in resolving anti-CD38 interference and is especially suitable for populations with a high prevalence of anti-M and anti-Mi . However, both methods have a well-known drawback of low detection sensitivity for anti-K, and K-units should be provided to patients to prevent hemolytic transfusion reactions.