Systemic autoimmune joint diseases, rheumatoid arthritis (RA), psoriatic arthritis/spondyloarthropathy (PsA/SpA), may follow Lyme disease, according to a recent study. Researchers reviewed records of all adult patients referred to a Lyme arthritis (LA) clinic over a 13-year period. For comparison, records of patients enrolled in a Lyme arthritis (LA) cohort over the most recent 2-year period were analyzed; IgG antibodies to Borrelia burgdorferi and to 3 Lyme disease-associated autoantigens were measured. They found:

• 30 patients who developed a new-onset systemic autoimmune joint disorder a median of 4 months after Lyme disease, usually erythema migrans (EM), were identified.
• 15 had RA, 13 had PsA, and 2 had SpA.
• In the comparison group of 43 LA patients, monoarticular knee arthritis, without prior EM, was the usual clinical picture.
• Most systemic autoimmune patients had positive tests for B. burgdorferi IgG antibodies by ELISA, but they had significantly lower titers and lower frequencies of Lyme-associated autoantibodies than LA patients.