In Vitro Studies to Explain High Renal Allograft Survival in Iga Nephropathy Patients

The pretransplant sera of 27 IgA nephropathy (N) kidney transplant patients were investigated for antibodies to the HLA molecule, together with 104 sera from non-IgA N patients and 60 controls. IgA antibodies to HLA were found in 61% of IgA N patients and 2% of non-IgA N patients. IgA N patients with IgA antibodies to HLA had a 100% 2-year cadaver donor graft survival rate compared with 70% in those without IgA antibodies. Patients with IgG antibodies to HLA without accompanying IgA antibodies had the worst graft survival rates. We propose that IgA anti-HLA contributes to the high kidney graft survival in IgA N patients by blocking IgG antibodies or inhibiting cellular immune response.