Correlation of thymic pathology with HLA in myasthenia gravis

The aim of this study was to investigate associations between thymic pathol ogy and HLA in myasthenia gravis. HLA typing was performed in 95 of 125 Cau casian patients who underwent transsternal thymectomy for myasthenia gravis between 1976 and 1995. Multiple comparison procedures applied within each HLA locus demonstrated significant correlations between the ancestral supra haplotype A1 B8 DRB1*0301 DRB3*0101 DQA1*0501 and thymic hyperplasia and be tween HLA-A24 and thymoma. A weaker association was Pound between A3 and th ymic atrophy and thymolipoma. On logistic discriminant analysis, HLA-B8 (P = 0.001) and HLA-A3 (P = 0.028) were identified as the only significant cla ssifiers to jointly provide a good discriminator between the thymic patholo gies. When the suitability of BLA. for detection of thymoma was examined in a second logistic regression analysis, both HLA-A24 (OR 9.7; 95% CI [1.6, 73.7]) and HLA-B8 (OR 0.1; 95% CI [0.0, 0.5]) were significant predictive f actors. The above correlations between thymic pathology and HLA-A3, HLA-A24 , and HLA-B8 (but not MHC class II alleles) suggest an involvement of MHC c lass I restricted T cells in myasthenic autoimmunity that may partially be reflected by thymic pathology. (C) 1999 Academic Press.