Lack of influence of non-inherited maternal HLA-DR alleles on susceptibility to rheumatoid arthritis

Non-inherited maternal HLA-DR alleles may not increase susceptibility to rheumatoid arthritis (RA). The HLA-DR bands on human chromosomes have been associated in some studies to be related to maternal transfer as well as paternal transfer of a genetic risk factor for RA. In a study of families from a registry of RA patients, non-inherited maternal antigens (NIMA) from DR genes and non-inherited paternal antigens (NIPA) from DR genes were compared on DNA from 74 rheumatoid factor positive individuals from 39 families with more than one member with RA and their first-degree relatives. There was no increase in frequency of NIMA DR varieties of genes when compared with NIPA DR gene varieties. Since there are plausible arguments for these findings which do not exclude the hypotheses concerning both parents contribution to RA susceptibility, further research needs to be done.