Rheumatoid arthritis in smokers could be linked to Proteus urinary tract infections.

There is an interplay between genetic and environmental factors in the induction and development of rheumatoid arthritis (RA). The RA-associated HLA-DRB1 alleles which contain the shared epitope moiety as well as microbial triggers such as Proteus are involved in the aetiopathogenesis of this disease. Increased association between Proteus urinary tract infections (UTIs) and RA on one hand and the link between smoking and UTIs on the other hand could explain the increased frequency of RA among smokers. Novel therapeutic and prophylactic measures are proposed, which might help to treat and/or prevent the disease process in individuals who are susceptible to develop RA.