EXPERIENCE WITH THE NEUTRALIZING AGENT DARAEX® IN BLOOD COMPATIBILITY TESTS IN PATIENTS TREATED WITH DARATUMUMAB
Author(s): ,
Estefanía Morente Constantin
Affiliations:
Servicio de Hematología y Hemoterapia,Hospital Universitario Virgen de las Nieves,Granada,Spain
,
Pablo Romero Garcia
Affiliations:
Unidad De Cuidados Intensivos,Complejo Asistencial de Soria,Soria,Spain
,
Maria Pilar Garrido Collado
Affiliations:
Servicio de Hematología y Hemoterapia,Hospital Universitario Virgen de las Nieves,Granada,Spain
,
Almudena Garcia Ruiz
Affiliations:
Servicio de Hematología y Hemoterapia,Hospital Universitario Virgen de las Nieves,Granada,Spain
,
Rafael Rios Tamayo
Affiliations:
Servicio de Hematología y Hemoterapia,Hospital Universitario Virgen de las Nieves,Granada,Spain
Manuel Jurado Chacón
Affiliations:
Servicio de Hematología y Hemoterapia,Hospital Universitario Virgen de las Nieves,Granada,Spain
EHA Library. Garcia Ruiz A. Jun 15, 2019; 267211; PS1594
Almudena Garcia Ruiz
Almudena Garcia Ruiz
Contributions
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Abstract

Abstract: PS1594

Type: Poster Presentation

Presentation during EHA24: On Saturday, June 15, 2019 from 17:30 - 19:00

Location: Poster area

Background

Daratumumab is a human monoclonal antibody used for the treatment of multiple myeloma, which binds to CD38, a protein that is expressed on red blood cells (RBCs). Therefore, the plasma of these patients reacts with the RBCs producing a panreactivity and interfering in the transfusion compatibility testing. Panagglutination may persist for up to 6 months after the last infusion of daratumumab. An anti-CD38 antibody for treatment of multiple myeloma shows a strong interference in the indirect antiglobulin test (IAT) where most of the reactions turn to unspecifically (wrong) positive. The time consuming standard technique using Dithiothreitol (DTT) counteracts the interference but has major drawbacks like destruction of Kel antigens or hemolysis. The DaraEx® compound inhibits the agglutination effect of anti-CD38 in IAT without side effects. DaraEx® is a neutralizing agent for the inhibition of the agglutination effect of the anti-CD38 antibody daratumumab in IAT.

Aims

To validate the procedure to resolve the interference of daratumumab in transfusion compatibility testing using red cells treated with DaraEx® for the inhibition of the agglutination effect of the anti-CD38 antibody daratumumab in IAT. Daratumumab can interfere with crossmatching and antibody screening in the IAT, which will allow us to identify a clinically significant antibody that has been initially masked by the presence of daratumumab.

Methods

The study has been conducted in 25 plasma samples of patients diagnosed with multiple myeloma who have been treated with daratumumab. Irregular antibody screening tests and Cross­Matching were performed on all of them, being positive in all cases. We performed the technique to eliminate reactivity by treating the red cells used in compatibility tests with DaraEx®, which neutralizes CD38 on the surface of the erythrocyte, thereby preventing Daratumumab from binding and inducing agglutination. The material used was DaraEx®, 0.9% NaCl LISS/Coombs ID-Cards and Test cell reagents for the ID-System; We performed the method in Biovue Column Agglutination Technology and gel card systems.

Results

After performing the technique, we were able to eliminate panreactivity in both Irregular antibody screening tests and Cross­Matching.

Conclusion

Daratumumab causes panreactivity in vitro by binding to CD38 on reagent RBCs. It is necessary to do a baseline antibody screen (type and screen) before starting the treatment with daratumumab. Treating reagent RBCs with DaraEx® is a useful easy and quick method to mitigate the interference created by anti­CD38 mAbs in pre­transfusion testing. DaraEx is a quick and simple procedure; it doesn’t affect other antigens or alloantibody reactions. It doesn’t have side effects like destruction of blood group antigens or hemolysis as described for the standard DTT treatment. Therefore, we consider it a very useful technique to resolve interferences produced by daratumumb with blood compatibility testing. We believe that it is essential to have a validated technique to resolve these discrepancies. If an emergency transfusion is required, noncrossmatched, ABO/RhD-compatible RBCs can be given, per local blood bank practices.

Session topic: 31. Transfusion medicine

Keyword(s): Antibody, Myeloma, Transfusion

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