Using two complementary antibody tests together improved detection of anti-CD36 antibodies, a rare but serious cause of platelet transfusion failure and fetal and neonatal alloimmune thrombocytopenia (FNAIT), leading to safer transfusions and better outcomes for patients and newborns, according to a preprint of a study published recently in ResearchSquare.
CD36 is a recently recognized blood group protein found on platelets and other cells, and when a person lacks this protein, their immune system may attack transfused platelets or, in pregnancy, the baby’s platelets.
“CD36 deficiency complicates transfusion outcomes by forming an often overlooked immune barrier,” the authors wrote. “If left unrecognized, it results in refractory thrombocytopenia, despite adequate platelet doses.”
Researchers reviewed 2,333 patients tested over 6.5 years at a tertiary care center to understand how often anti-CD36 antibodies were missed and which tests worked best. Anti-CD36 antibodies are often overlooked but can cause platelet transfusion refractoriness, meaning platelet counts do not rise despite transfusion, as well as FNAIT, where maternal antibodies destroy fetal or neonatal platelets. These conditions can lead to bruising, internal bleeding, organ failure or life-threatening hemorrhage.
Read more about testing and diagnosis for FNAIT
Two commonly used screening tests were compared: ELISA and the solid phase red cell adherence assay, known as SPRCA. ELISA detected antiplatelet antibodies in 33.6% of samples, while SPRCA detected them in 18.7%.
The tests agreed in 78.2% of cases, with moderate overall agreement. Importantly, ELISA identified additional antibodies in 18.4% of patients who tested negative by SPRCA alone, while SPRCA alone identified only 3.4%. When both tests were positive, the antibodies were more likely to be clinically significant and responsible for platelet failure or FNAIT.
Several patient cases showed how this matters in real life. In one severe adult case, uncontrolled bleeding and organ failure improved only after transfusion with CD36-negative platelets. In a pregnancy-related case of FNAIT, the mother lacked CD36 while the father was positive, leading to antibody formation. The newborn had severe thrombocytopenia with platelet counts as low as 40 × 10³/μL, causing petechiae, but recovered as maternal antibodies cleared, a typical FNAIT pattern.
For patients, this research could mean faster answers when platelet transfusions do not work and clearer explanations for unexpected bleeding. For families affected by FNAIT, accurate testing can guide monitoring, delivery planning and treatment to reduce bleeding risk in newborns. Using both ELISA and SPRCA together, followed by confirmatory tests, may help doctors choose compatible CD36-negative platelets and avoid ineffective transfusions.
These results also highlight the importance of rare donor registries so patients with CD36 deficiency or FNAIT risk can receive matched platelets quickly. Overall, broader testing improves safety, reduces complications and gives patients and families clearer paths forward when facing rare but dangerous bleeding disorders.
Sign up here to get the latest news, perspectives, and information about FNAIT sent directly to your inbox. Registration is free and only takes a minute.
