Retroviral infection in peripheral mononuclear cells in patients with IgA nephropathy

An etiologic agent directly linked to the development of IgA nephropathy (IgAN) has not been identified, despite the fact that various causes, including viral infections, have been implicated in the pathogenesis of this disease. Human immunodeficiency virus (HIV) infection has been linked with the development of IgAN in several clinical studies, and retroviral infection may be associated with the pathogenesis of IgAN in some patients. The incidence of IgAN has been found to possess distinct geographical distributions, and familial genetic clustering. To determine if retroviral infection is associated with IgAN in a large population of patients, genomic DNA from peripheral blood mononuclear cells from 90 patients seronegative for HIV and human T-cell leukemia virus type 1 (HTLV-1) (37 IgAN, 33 other glomerulonephritis, and 20 healthy controls) was evaluated by nested PCR using a pan-lentivirus-specific primer set (PLSPS), targeting the consensus sequence of the lentiviral pol gene. In 37.8% (14 of 37) of the patients with IgAN, the PCR products migrated in parallel with bands produced by PCR of simian immunodeficiency virus (SIV) infected cells. No products of the expected size were detected in the other patient groups (p < 0.0001, Chi-square). These results suggest that exposure to retroviral infection is more common in patients with IgAN, compared with patients with other proliferative glomerulonephritides, or patients without renal disease. These data demonstrate a possible association of IgAN with infection with non-HIV, non-HTLV-1 retrovirus.