A recent preliminary study highlighted the potential role of rare platelet alloantibodies in conditions such as fetal and neonatal alloimmune thrombocytopenia (FNAIT), underscoring the need for more precise diagnostic approaches beyond standard antigen matching.
FNAIT is most often linked to differences in well-known platelet markers, known as human platelet antigens (HPAs). But the new study, published as a preprint on Research Square, suggests that rare and often overlooked platelet proteins may also trigger harmful immune responses, and may be missed by routine testing.
Researchers analyzed data from more than 2,400 patients tested for platelet antibodies over nearly seven years. They compared different laboratory methods used to detect these antibodies. The results showed substantial variability in antibody detection depending on the testing platform used.
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The study authors found that no single test was able to identify all clinically important antibodies. Some antibodies were detected by one test but not another, meaning that relying on a single screening method could lead to missed diagnoses. When multiple tests yielded positive results, patients were more likely to have meaningful immune reactions that caused platelet destruction.
One particularly important finding involved CD36, a protein found on platelets that was only recently recognized as part of a formal blood group system. Antibodies against CD36 are rare and not considered a routine part of screening, but the researcher found that they can cause severe immune reactions affecting platelet survival. In the context of pregnancy, such antibodies could potentially contribute to unexplained or severe cases of FNAIT.
The authors emphasize that combining different antibody tests with genetic and cell-based analyses can provide a more complete picture of platelet incompatibility. For newborns at risk of bleeding, this approach could improve diagnosis, guide treatment decisions and help doctors select safer, compatible platelet transfusions when needed.
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