It's always been suspected that infection may be the trigger or driver of many autoimmune diseases that emerge in adulthood, such as Rheumatoid Arthritis. However, proof has not been forthcoming.
There are clues, however.
Apart from anecdotal patient accounts of how their joint pains started after an apparent infective episode, or that their RA flared after such an infective bout, there are the cases of Chikungunya arthritis persisting and morphing to a chronic arthritis clinically indistinguishable from RA.
Then there is an increasing body of evidence drawing the association of dysbiosis with active RA.
And there is the autoantibody against citrullinated proteins, which is pathognomonic of RA. Citrullination is catalysed by enzymes called PADs, produced by both chordates and certain bacteria (eg P gingivalis in gum disease) to regulate normal DNA function. Perhaps the bacterial PAD triggers an appropriate immune response flagged by citrullinated gingival proteins, but an inappropriate immune response to human PAD generated citrullinated synovial proteins results in RA.