De novo seropositive rheumatoid arthritis during immunosuppressive treatment after kidney transplantation.

We detected de novo seropositive erosive rheumatoid arthritis (RA) in a patient seven years after successful cadaveric kidney transplantation (RTx). RA developed in spite of treatment with cyclosporine A (CyA), methylprednisolon (MP) and azathioprine (Aza), compounds often also used for treatment of active RA. Renal failure was due to diabetes mellitus (DM) nephropathy. Besides a slight increase in C-reactive protein (CRP) concentration two years after RTx, the clinical symptoms of RA were observed seven years after RTx. RA was confirmed by X-ray examination, isotopic skeletal scan and positive serum RA factor. After switching Aza to methotrexate (Mtx) treatment, his symptoms disappeared and CRP concentration returned to normal. Our patient had HLA DRB1 *0101, *0401 alleles and DQB1 *0501, *0302 alleles which have strong genetic association with both DM and RA. To our best knowledge, this is the first case in which de novo seropositive erosive RA developed while on treatment with triple immunosuppression after RTx. The immunosuppressive treatment probably masked the inflammation and symptoms of RA.