Place et intérêt de la détection des anticorps anti-hla de classe I lors de la recherche des anticorps anti-plaquettes

In platelet antibody testing, detection of Class I HLA antibody is possible. Presence of HLA antibody was screened by introducing a monoclonal anti-β2 microglobulin antibody in a « Monoclonal Antibody-specific Immobilization of Platelet Antigen(MAIPA) assay. When a positive result was obtained, the sample was tested with a specific ELISA screening test and confirmed by a lymphocytotoxicity assay. Among 263 patients positive with the anti-β2 microglobulin antibody, 223 (84,8 %) are positive on the HLA antibody screening test and 159 (71,3 %) are confirmed by the lymphocytotoxicity assay. Among the 159 samples positive on the lymphocytoxicity assay, 6 have a low optical density, 3 between 0,100 and 0,149 and 3 between 0,150 and 0,199. All the 60 samples with an optical density at 1 500 or more are positive on the HLA antibody specific screening test and 54 (90,0 %) are confirmed by the lymphocytotoxicity assay. Among 50 subjects MAIPA negative, 4 (8,0 %) have HLA specific antibody on the lymphocytotoxicity assay. In several diseases, detection of anti-HLA antibody is informative for diagnosis and treatment. Specific testing of HLA antibody is recommanded even when a weak (< 0,150) optical density is observed on the MAIPA assay.