Ninety-four children with idiopathic nephrotic syndrome (17 steroid-resistant with a histological diagnosis of a focal segmental glomerulosclerosis) were typed for HLA-A, B and DR antigens. The patients showed a significant increase of DR7 (58% vs 18%, p less than 0.0001) and of B8-DR3 (27% vs 5%, p less than 0.05). Combination of both markers (DR7 and B8-DR3) was observed in 14 per cent of patients but in none of the controls (relative risk 15.2). Patients with B8-DR3 and DR7 had a more severe course of INS.