Original article

Ahead-of-Print

Multicenter evaluation of soluble CD38: neutralizing anti-CD38 pan-reactivity to enable alloantibody detection

Authors

Key words: pre-transfusion testing, CD38, neutralization, antibody, multiple myeloma
Publication Date: 2025-09-19

Abstract

Background - Anti-CD38 is a monoclonal antibody treatment for multiple myeloma, B-cell malignancies, and autoimmune diseases that targets CD38 antigens on the cell surface. Red blood cells are CD38+, therefore anti-CD38 causes panagglutination, hindering immunohematology testing such as antibody screen, antibody identification, and crossmatch. This interference masks detection of clinically significant alloantibodies in pre-transfusion testing.

Materials and methods - To assess the effectiveness of soluble CD38 (sCD38) in neutralizing anti-CD38 in the clinical setting and user satisfaction, plasma samples from patients receiving anti-CD38 therapy were collected between 0 and 150 days after the last infusion and tested according to routine laboratory procedures with an established sCD38 neutralization method (15 minutes incubation at 37°C with up to 6 µL of sCD38 per 25 µL of plasma). Neutralization was evaluated using antibody screening or crossmatching, by tube or gel card. Some samples were spiked with irregular antibodies to evaluate the impact of sCD38 on antibody detection. A survey assessed user satisfaction.

Results - In total, 273 patient samples were evaluated (263 patients treated with daratumumab and 10 with isatuximab). sCD38 completely neutralized anti-CD38 present in 79.8% of samples tested using either 2 or 4 µL of sCD38. When either 2-4 or 6 µL of sCD38 was used, 98.5% of samples were neutralized. Except for anti-Fya and anti-Fyb, all spiked alloantibodies (anti-D, -c, -E, -K, -Jka, -Kpa, -Lua, -S) were detected. The mean score for general satisfaction with sCD38 was 4.44 (with 5 [very satisfied] the highest score).

Discussion - sCD38 has demonstrated strong potential in neutralizing anti-CD38 drugs in the clinical setting. While tested against isatuximab and daratumumab, it could be a potentially universal solution. By mimicking CD38 antigen on red blood cells, sCD38 is likely to interact with a broad range of anti-CD38 antibodies, suggesting its possible applicability across various settings.

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Authors

Charlotte Engström - Swiss Red Cross, Blood Donation Zurich, Zurich, Switzerland

Eliane Scherrer - Swiss Red Cross, Blood Donation Zurich, Zurich, Switzerland

Jonathan Falconer - NHS Lothian, Western General Hospital, Edinburgh, United Kingdom https://orcid.org/0009-0000-2334-2001

Donatella Londero - Department of Transfusion Medicine, ASUFC-Udine, Italy https://orcid.org/0000-0002-0583-4958

Carlos Penatejera - Blood Bank and Hemotherapy Service, University Hospital Araba, Vitoria-Gasteiz, Spain https://orcid.org/0009-0006-3851-9352

Isabelle Legoff - GCS Biology of the Ariège Territory, Intercommunal Hospital Center of the Ariège Valleys, Foix, France

Nadine Dubosc Marchenay - Medical Biology Laboratory, Libourne Hospital Center, Libourne, France

Marine Le Bouar - Medical Biology Laboratory, Libourne Hospital Center, Libourne, France https://orcid.org/0009-0006-0707-3490

Cosimo Nocera - U.O.C. Transfusion Medicine, "Ospedale del Mare" Hospital Facility, Naples, Italy

Luigi Paesano - U.O.C. Transfusion Medicine, "Ospedale del Mare" Hospital Facility, Naples, Italy

Salvatore De Martino - U.O.C. Transfusion Medicine, "Ospedale del Mare" Hospital Facility, Naples, Italy

Marie-Edith Pettinelli - Joint Medical Biology Laboratory, Angoulême Hospital Center, Angoulême, France

Ariane Caesar - Medion Grifols Diagnostics AG, Düdingen, Switzerland

Thomas Bise - Medion Grifols Diagnostics AG, Düdingen, Switzerland

Laziza Amniai - Diagnostic Grifols SA, Parets del Vallès, Spain

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