SIR, We read with interest the study of O'Dell et all showing a high incidence of mesangial changes in renal biopsies from patients with systemic lupus erythematosus (SLE) without clinical renal abnormalities. They found no cases of focal or diffuse proliferative glomerulonephritis. These results are different from those previously reported by other authors2 3 and question the relevance of renal biopsy in these patients...