Compound heterozygosity for five different CD36 mutations induces CD36 type I deficiency in three members of a family of Arabian origin

Background

CD36 type 1 deficiency is characterized by missing CD36 expression on both, platelets and monocytes and enables iso-immunization. A broad variety of mutations has been identified as underlying molecular reason. We describe the molecular basis of compound heterozygosity that silence CD36 expression in a family of Arabian origin with three affected members. Additionally, we analyzed the CD36 type 1 deficiency in an unrelated donor whose platelet concentrate was transfused to the index patient.

Methods

CD36 expression on platelets and monocytes was tested by flow cytometry using anti-CD36 FITC (FA6-152, Stem Cell Technologies, Vancouver, CAN), anti-CD42b PE (HIP1, Biolegend, San Diego, CA, USA), and anti-CD14 PE (M5E2, Biolegend). The presence of CD36 isoantibody in individuals with type 1 deficiency was tested by Luminex PAK Lx (Immucor Lifecodes, Dreieich, D) and crossmatch between the patient"s serum donor platelets was performed by the MASPAT assay (Sanquin, Amsterdam, NL). Sanger sequencing on an ABI Prism 310 (Applied Biosystems, Weiterstadt, D) was applied for further molecular analysis. Custom primers specific for CD36 were used for amplification and sequencing reactions of CD36 exons 2-14 including short flanking intron regions.

Results

The 15 years old patient with a glioma and severe thrombocytopenia, his mother and his paternal grandmother had CD36 type 1 deficiency combined with isoantibody formation in the patient and his mother. Compound heterozygosity for 5 variations on 4 different alleles caused the deficiencies (Genbank OQ909049-..56; fig.1)

­ CD36*c.451insTCAA (p.164X), *c.824T>G (p.I275S) ­ CD36*c.1202_1205del à fs (p.404X) ­ CD36*c.1200-7_1208dup à fs (p.422X) ­ CD36*c.1156C>T (p.R386W)

An unrelated CD36 negative donor was identified earlier with a homozygous CD36*c.649G>A (p.G217R) exchange. He and the patient"s grandmother showed a negative MASPAT crossmatch. The patient could benefit from their platelet concentrates with platelet rises from 1 to 30x10⁹/L.

Conclusion

A broad variety of mutations is responsible for CD36 deficiency on platelets and monocytes, thus aggravating rapid identification by SNP specific PCR-methods. Instead, search for CD36 negative platelet donors is most promising by flow cytometric screening amongst individuals from African, Arabian or eastern Asian descent. Sanger sequencing or NGS can add further information on the molecular background. This strategy can help to supply immunized patients with CD36 isoantibodies.

Offenlegung Interessenkonflikt:

The authors have no conflicts of interest do declare.