Blood Bank Guy Essentials Podcast 063CE: Anti-CD47 Testing Interference with Connie Westhoff
Feb 6, 2019
Connie Westhoff, researcher studying anti-CD47, discusses the interference this drug causes in blood bank testing. They explore the challenges in removing CD-47, the interference in ABO and antibody screening, and the use of polyethylene glycol absorption to remove interference. The importance of pretreatment ABO and RH typing, genotyping, and antigen match units are highlighted. The effects of anti-CD38 and potential interfering antibodies are also discussed.
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CD38 Versus CD47: A Key Difference
- Anti-CD38 (daratumumab) interference was solved by treating test red cells with DTT to remove CD38 from cells.
- Anti-CD47 is different because CD47 does not shed and is highly expressed on red cells, making interference harder to fix.
CD47 Is The 'Do Not Eat Me' Signal
- CD47 is a widely expressed 'do not eat me' signal that tells macrophages to spare cells.
- Blocking CD47 with therapeutic antibodies converts that signal into an 'eat me' cue to promote tumor clearance.
High Expression Makes CD47 A Bigger Problem
- CD47 is highly expressed on red cells and often on platelets, so anti-CD47 therapy can cause anemia and thrombocytopenia.
- Those side effects bring patients into transfusion medicine and create major serologic interference.