Background: Platelet CD36 (glycoprotein [GP] IV) deficiency occurs in 3 to 5 percent of persons of Asian or African ancestry. A subset of these individuals is at risk for immunization against CD36, but the magnitude of this problem and its significance in transfusion medicine have not yet been clarified.
Study design and methods: Clinical and laboratory aspects of neonatal thrombocytopenia involving five infants born to four CD36- mothers were characterized. The CD36 gene was sequenced in three mothers. The literature concerning isoimmunization against CD36 was reviewed and summarized.
Results: Isoantibodies reactive with CD36 on normal platelets and platelets from the fathers were identified in each of the four mothers. Two African-American mothers were homozygous for a 1264TG mutation in the CD36 gene. A mother of Italian ancestry was homozygous for a previously unidentified deletion of exons 1 through 3. Previously reported cases of isoimmunization against CD36 were reviewed and summarized.
Conclusion: Isoimmunization against CD36 can cause neonatal isoimmune thrombocytopenia (NITP), refractoriness to platelet transfusions, and post-transfusion purpura. Immunization against this glycoprotein (GP) should be considered in patients with apparent alloimmune platelet disorders not explained by immunization against recognized platelet-specific alloantigens, especially in persons of African, Asian, and, possibly, Mediterranean ancestry.