Major histocompatibility complex antigens in steroid-responsive nephrotic syndrome.

An increased frequency of specific major histocompatibility complex (MHC) class I, II and III antigens in children with steroid-responsive nephrotic syndrome (SRNS) has been reported. This frequency distortion, in some cases, is thought to affect the outcome of the disorder. We studied the phenotypic frequency of HLA antigens -A, -B, and -DR, as well as complement proteins Bf and C4 in an unrelated population of 25 SRNS children. Complete MHC haplotypes were also derived for four families in which 8 individuals developed SRNS. HLA-DR8, with a relative risk of 4.8, showed the strongest association with SRNS. Nonetheless, the 95% confidence intervals of this and the relative risks for all other antigens fell below 1.0. No common haplotype was found in SRNS patients in whom complete family studies were available, and disease and inheritance of the MHC were discordant in two of these families. In this study of well-characterized SRNS patients we were unable to discover a clear association between this disorder and the MHC.