HLA-C expression on platelets: studies with an HLA-Cw1-specific human monoclonal antibody

Abstract

Background and objectives: The expression of HLA-C on the surface of platelets is rarely studied due to the lack of proper alloantisera. We addressed this question using an IgM human monoclonal antibody directed against HLA-Cw1 (VP6G3).

Material and methods: Both flow cytometry and complement dependent cytotoxicity studies were used in the current analysis.

Results: The expression of the HLA-Cw1 antigen on platelets is lower than on peripheral blood lymphocytes as shown by flow cytometry. Variation in expression levels between individuals is also observed. Using this antibody in a complement-dependent cytotoxicity assay, we did not observe lysis using platelets as targets, whereas peripheral blood lymphocytes of the same blood donors were adequately lysed.

Conclusions: These results confirm that platelets indeed express HLA-C. Furthermore, the results support the insignificant role of HLA-C in immunological platelet refractoriness.