Parkes AB, Darke C, Othman S, Thomas M, Young N, Richards CJ, Hall R, Lazarus JH. Major histocompatibility complex class II and complement polymorphisms in postpartum thyroiditis. Eur J Endocrinol 1996;134:449–53. ISSN 0804–4643
The objective was to re-evaluate the association between class II HLA-DR and DQ MHC antigens and postpartum thyroiditis (PPT) and to determine the prevalence of the class III complement allotypes of Properdin factor B (Bf), C4A and C4B in this condition. Two hundred and sixty-five (of 2897) pregnant women screened positive for thyroid autoantibody activity took part. Further blood samples were obtained for HLA class II (185) and complement (193) typing. The severity of the ensuing PPT was assessed by measuring thyroid function during the postpartum year. The HLA-DR and DQ phenotypes were assigned from restriction fragment length polymorphism analysis, and Bf, C4A and C4B allotypes were determined by immunofixation with anti-Bf or anti-C4 antibodies after electrophoresis. A weak association between the HLA class II antigens and PPT, as indicated by a reduced frequency of DR15 and DQ6 together with an increased frequency of DR5 and DQ7. was confirmed. However, only the change in DR5 frequency remained significant after correction (corrected p < 0.05). Postpartum thyroiditis was also associated with frequency disturbances in Bf and C4A allotypes but not C4B allotypes. Whilst this study has not provided evidence of a strong marker gene for PPT, it does not preclude the involvement of the MHC in this condition. These data show disturbances in complement allotype frequencies, suggesting that the class III region may provide a useful focus for further study of this pathology.
AB Parkes, Autoimmunology Research Unit, Section of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, UK