HLA-A, -B and -DR gene frequency distributions in populations of Australia, Melanesia, Micronesia and Polynesia are examined in relationship to known HLA and disease associations in other populations. With the exception of a correlation between Reiter's syndrome and B27, other HLA and disease associations are markedly absent. Recombinant DNA and cellular subtyping analyses suggest that the HLA-DR subtypes predominating in susceptibility to several autoimmune disorders in Caucasoids are rare in Oceania. The high frequency of serum complement component C4A deficiency in Australian Aborigines may explain the high prevalence of systemic lupus erythematosus in this group.
