IgA nephropathy in systemic lupus erythematosus.

Renal involvement in systemic lupus erythematosus (SLE) is a typical manifestation of the disease. The occurrence of non-lupus nephritis in SLE patients has rarely been reported; we describe the case of a woman suffering from SLE and IgA nephropathy (IgAN). Although IgAN and lupus nephritis share some common physiopathological characteristics, their laboratory and histopathologic findings and the extra-renal clinical manifestations are different and support a different pathogenesis. Our case highlights the importance of renal biopsy in lupus patients with urinary alterations since a correct diagnosis would permit the most appropriate treatment to be started, thus avoiding unnecessary immunosuppressive treatments.