HLA immunogenetic heterogeneity in black American patients with Graves' disease

Seventy-three American black patients with Graves' disease were typed for HLA-A, HLA-B, and HLA-DR antigens. There was a slight increase in HLA-DRw6 antigen frequency compared with 238 normal American black controls, but this was not significant after correction for the number of antigens tested. A significant increase in HLA-DR4 and HLA-DRw6 frequency was found in a subgroup of patients with exophthalmos (22.9% and 29.2% compared with 7.6% and 10.1% of normal black controls). There was a significant increase in HLA-DRw6 in a subgroup of patients who were thyroid antibody-positive (26.0%). The increment in HLA-DRw6 was higher in 32 patients who had both exophthalmos and who were antibody positive (37.5%). A significant increase in HLA-DR5 was found in a subgroup of patients who did not have exophthalmos and who were antibody-negative (83.3%). Our findings support previous evidence for immunogenetic heterogeneity in patients with toxic Graves' disease. In American blacks HLA-DRw6 is in some way associated with the disease in contrast to the well-recognized HLA-DR3 association in whites.