[HLA haplotypes associated with IgA nephropathy].

Forty-four Japanese patients with IgA nephropathy and their relatives were typed for HLA-A, B, C, DR and DQ antigens and their HLA haplotypes were determined. The frequency of DQ4 increased significantly in the patients as compared with that in 100 healthy control persons (Pc < 0.01). DR4 frequency was higher than in the control subjects but revealed no significant difference (p < 0.05, Pc > 0.05). The incidence of DR4-DQ4 haplotype was increased in the patients (54.5%) and A24Cw-B52DR2DQ1 haplotype which is very common in the Japanese population was decreased as compared with controls of general Japanese population. Thirty-nine cases of 44 (88.6%) had DR4 or DR9 and HLA genotypes of DR4/DR 5, 6, 8 and DR9/DR5, 6, 8 were significantly increased as compared with those in the control subjects (P < 0.001). The incidence of DR4 was significantly higher in the patients with macroscopic hematuria as compared with those without (P < 0.01). No specific HLA antigens or HLA haplotypes were related to the prognosis of IgA nephropathy. These findings suggested that HLA haplotypes associated with DR4-DQ4, DR4-DQ3 and DR9-DQ3 as well as those associated with DR5, 6, 8 might be involved in susceptibility to IgA nephropathy, while A24Cw-B52DR2DQ1 haplotype might be resistant to the disease development.