Diffuse mesangial IgA glomerulonephritis in a patient with rheumatoid arthritis: a possible extra-articular manifestation in rheumatoid arthritis.

Rheumatoid arthritis (RA) is an inflammatory joint disease, in which, unlike systemic lupus erythematosus (SLE), renal involvement is uncommon. The major causes of renal disease in RA are usually linked to amyloid or secondary effects of drugs. Nevertheless the relation between IgA, IgA-rheumatoid factor (RF) and renal disease in patients with RA is not clear, but the affinity of IgA for mesangium, skin and synovium might explain clinical presentation of RA with mesangial IgA glomerulonephritis. The case of a 42-year-old Caucasian man with RA and diffuse mesangial IgA glomerulonephritis proven by renal biopsy is presented. The patient was treated with boluses of methylprednisolone 1000 mg and cyclophosphamide 1000 mg monthly for 13 months. Between boluses there was a supported therapy with methylprednisolone 8 mg/day. After a year of treatment full clinical and laboratory remission of RA and IgA glomerulonephritis was achieved. Pathogenic therapy will be stopped and the patient followed-up.