The pathogenetic role of TNFalpha in inflammatory diseases has been known for a long time and has modified the therapeutic approach towards this pathology. All over the word, about 400.000 patients have been treated with biological anti-TNF alpha drugs. Particular attention has been taken for the safety of their use. We describe a case of 60 year old man affected by rheumatoid arthritis who has developed nephrotic syndrome with histological pattern typical of systemic lupus erythematosus-like syndrome, without autoantibodies.