Platelet antibodies detection: A limitation for Indian population.

Sir,

The blood group system H is determined by α-(1, 2) - fucosyltransferase genes FUT1 and FUT2[1-3] and it is widely expressed on the human tissues and cells. The H antigen is the precursor of the A and B blood group antigens. Despite the Bombay blood group[4] is characterized by devoid of the A, B and H antigens on the red blood cells (RBCs) and IgM anti-H; however, the presence of a strong IgG anti-H antibody[5] is also well documented. The frequency of the Bombay phenotype is about 1 in 10,000 individuals in India; and 1 in 1,000,000 individuals in Europe.[6] In 1954, Moreaux and Andre[7] provided the first evidence of the ABH antigens expression on the platelets. Later in 1991, Santoso and his associates[8] localized the ABH antigens, which non-covalently bound to the glycoproteins (GP) Ib, IIb and IIIa. All platelet antibodies detection techniques available hitherto including the two cornerstones monoclonal antibody specific immobilization of platelet antigens (MAIPA) and platelet immunoflourescence test (PIFT) use group O platelet panel. In other words and according to Santoso et al findings,[8] the O platelets have H antigen, which should be also expressed on the GP IIb/IIIa. To avoid the false positive reaction by IgG anti-H using O platelets, I would like to suggest few solutions in such cases:

Care should be taken in case of blood grouping of neonatal alloimmune thrombocytopenia patients and attention also to ethnic origin should be kept in mind.

Adsorption of anti-H antibodies to O RBCs.

Using of soluble peptides β3[9] and soluble GP IIb/IIIa.[10]