Mitigation of therapeutic anti-CD38 antibody interference with fab fragments: How well does it perform?

Is drug interference still an issue for pretransfusion testing of patients on anti CD38 and other monoclonal antibody therapies?

Certain therapies that target CD markers on some blood cells can affect pretransfusion testing. Key examples are anti-CD38, CD47 monoclonal antibody (mAb) therapies such as daratumumab (DARA) and magrolimab, which have presented a challenge for transfusion medicine laboratories around the globe. Scientists have been faced with not only introducing a protocol to provide safe blood to patients but also investigating the most effective method to remove the pretransfusion pan-agglutinating interference caused. A number of papers in the last 5 years have reported on various methods to remove pretransfusion interference; however, most of these studies have been conducted only in a few countries. Most recent reviews on this topic have focused on techniques and reagents to remove pretransfusion interference, and dithiothreitol is currently the gold standard for removing DARA interference. However, it was clear from this review that while many laboratories have developed processes for addressing interference in pretransfusion testing, and DARA interference may not be a major issue, there are still laboratories around the world, that may not have adequately addressed this issue. In addition, the impact of mAb interference on widely used techniques such as flow cytometry is unclear.

Risk of new alloimmunization in patients on anti-CD38 treatment using tube LISS-IAT method

BACKGROUND

Daratumumab is a monoclonal antibody that targets CD38, a transmembrane protein expressed on many cells including RBCs and to a greater extent on myeloma cells. It has been used for treatment of multiple myeloma and autoimmune diseases. Transfusion management of patients on such therapy can be challenging as these drugs cross-react with RBC surface antigens and cause panreactivity.

MATERIAL AND METHODS

A retrospective study of the 68 patients treated with anti-CD38 from 2018-2023 was carried out. Data regarding transfusion history and antibody screens were analyzed. Depending whether they had immunohematological work-up before or during the treatment- DAT, antibody screen (CAT and tube), RBC pheno/genotyping and serologic cross-matches (CAT and tube) were performed for each patient. All cases with positive CAT IAT were retested in LISS-tube and cross-matches were performed with phenotypically matched units in LISS-tube.

RESULTS

Antibody screen has shown panagglutination with all panel cells with low and variable agglutination intensity (weak to 2 +). Panagglutination remained positive for 1 - 6 months after drug cessation. Positive DAT was seen in 60,6% patients, while autocontrol was negative. Ficin treated panel-cells eliminated nonspecific reactivity. LISS-tube antibody screen and cross-matches were negative for all patients, apart from 3 patients who had preexisting antibodies. No new antibodies were detected during the course of the study.

CONCLUSION

Among study group there were no newly identified alloantibodies, meaning that the policy of transfusing them with matched RBCs and performing IAT/cross-matches in tube is a safe and effective policy according to the findings of this study.