Anti-dsDNA negative and anti-Ro positive lupus nephritis: a report of a rare case.

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease, characterized by an autoantibody response to various nuclear and cytoplasmic antigens. Renal disease in SLE occurs in 40-75% of patients, most often within five years of onset of disease, and is one of the strongest predictors of a poor outcome. A hallmark of glomerular involvement in lupus nephritis is the presence of autoantibodies against double-stranded DNA (dsDNA). Its level usually correlates with disease activity. Our patient presented with a rash resembling malar rash and features of nephrotic syndrome. On investigating, patient was found to have pancytopenia, raised erythrocyte sedimentation rate and depressed serum C3 levels with positivity of antinuclear antibodies and anti- Ro antibodies. However, most of the markers of lupus nephritis including anti dsDNA antibody were negative. Renal biopsy showed features of lupus nephritis (class-IV). Differential item functioning studies showed a full house immunoflourescence staining pattern characteristic of lupus nephritis. Association of Anti-Ro antibody alone with lupus nephritis is less known in literature. Negativity of anti-dsDNA antibody, which is usually considered to be diagnostic of lupus nephritis, poses a diagnostic dilemma short of renal biopsy. Till date only very few cases of non-drug induced lupus nephritis with negative dsDNA antibodies have been reported. In this report we wish to highlight a case of lupus nephritis which was negative for its specific anti dsDNA antibodies and with possible role of anti-Ro antibodies in the pathogenesis of lupus nephritis although the underlying mechanism is incompletely understood.