Pretreatment with Daudi cells eliminates anti-CD47 monoclonal antibody interference in immunohematology testing

Abstract

Background - Anti-CD47 monoclonal antibodies have clinical application prospects for treating cancer. However, anti-CD47 monoclonal antibodies interfere with immunohematology testing in patients who require blood transfusion. The current approaches to removing any interferences still have technical problems. Therefore, the need to resolve anti-CD47 interference in immunohematology testing is urgent.

Materials and Methods - We approved a novel cell line, Daudi, to facilitate immunohematology testing in anti-CD47 monoclonal antibody-treated patients for the adsorption of free anti-CD47 monoclonal antibodies from patient plasma. CD47 expression was identified in Daudi cells using flow cytometry and confocal microscopy. Next, we tested the ability of intact Daudi cells mixed with simulating plasma to achieve efficient removal of interfering anti-CD47 monoclonal antibodies. The indirect antiglobulin test was used to verify whether interference was eliminated from anti-CD47 monoclonal antibodies in plasma and whether the detection of other irregular antibodies was affected. The interference elimination effect was investigated in relation to the preservation time after the cells were fixed with paraformaldehyde.

Results - CD47 expression was higher in Daudi cells than in red blood cells. The indirect antiglobulin test analysis revealed that incubating plasma absorbed from the Daudi cell line of anti-CD47 monoclonal antibody-treated patients for 15 min at 37℃ could completely prevent the interference of anti-CD47 monoclonal antibodies in immunohematology testing while the detection of other irregular antibodies such as anti-D and anti-K was unaffected.

Discussion - By decreasing the incubation time, we discovered that interferences in samples with agglutination strengths below 2+ could be eliminated after incubation for only 5 min. Of importance, Daudi cells can be preserved with 4% paraformaldehyde for 14 days. This is the first study in which Daudi cells were used to effectively resolve the interference of anti-CD47 monoclonal antibodies in pretransfusion tests. Daudi cells can also be used as short-term storage reagents.