Frequency of CD36 deficiency in Thais analyzed by quantification of CD36 on cell surfaces and in plasma.

BACKGROUND Anti-CD36s, developing after transfusion or during pregnancy, play an important role in immune-mediated bleeding disorders among Asian populations. Currently, little is known about the clinical relevance of anti-CD36. Here, we aimed to determine the frequency of CD36 deficiency in Thais by analyzing CD36 expression on cell surfaces and in plasma. STUDY DESIGN AND METHODS The expression and deficiency of CD36 on platelets and monocytes were determined by flow cytometry. Mutations in the CD36 gene were analyzed by nucleotide sequencing. Soluble CD36 (sCD36) in plasma was quantified with enzyme-linked immunosorbent assay. RESULTS Fifteen of 700 blood donors (2.14%) were identified as CD36 deficient. The frequencies of Type I and II CD36 deficiency were 0.43% and 1.71%, respectively. Type I individuals exhibited c.1163A > T, c.429 + 4insG, and c.1156C > T. Type II individuals exhibited c.879 T > C, c.329-330delAC, c.818 + 108delAACT, c.1125 + 13C > A, and c.1163A > T. CD36 on donor platelets (n = 685) showed a wide distribution of expression levels (mean fluorescence intensity, 16.71 +/- 8.68). In the normal phenotype (n = 14), sCD36 concentration was 58.84 +/- 11.68 ng/mL, which was significantly correlated with platelet CD36 expression (r(2) = 0.8551). In Type II-deficient individuals (n = 6), a similar sCD36 concentration was detected (53.67 +/- 8.17 ng/mL). However, sCD36 could not be detected in Type I individuals (n = 3). CONCLUSION CD36 Type I deficiency was found, indicating the potential for immune-mediated platelet disorders in Thais. However, the underlying mutations differed from those reported in Japan and China. Interestingly, sCD36 could not be detected in plasma of Type I-deficient individuals. This finding may lead to the use of plasma to identify individuals at risk and to allow screening of large cohorts.