In 2015, the U.S. FDA approved the multiple myeloma drug daratumumab, a monoclonal antibody that targets the CD38 antigen on plasma cells. Unfortunately, mature RBCs also carry CD38, so patients taking this drug (and another anti-CD38 drug approved more recently) will appear to be incompatible with pretty much all screening red cells; we call the pattern of reacting against every test red cell “panagglutination.” DTT can be used in this setting to treat the screening red cells and remove CD38 from their surface. Then when you run the screening tests with the DTT-treated cells, the reactions due to anti-CD38 go away (yay!). This allows us to screen accurately for alloantibodies. There is one caution, though: Since DTT eliminates Kell system antigens as noted above, the patient should receive K- blood unless the patient is K+). For more info on DARA and DTT, see episode 010 of the BBGuy Essentials Podcast.
Updated October 2023 by Joe Chaffin, MD.
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