The prevalence and immunological features of anti-glomerular basement membrane antibody in patients with HIV

Abstract

Background: Anti-glomerular basement membrane disease (GBM) is a kind of chronic autoimmune disease caused by the deposition of circulating anti-GBM antibodies. Non-collagen region of α3 chain of type IV collagen (α3(IV)NC1) is one of the main target antigens. And on α3, EA and EB are the most classical antigen epitopes. It has been reported that anti-GBM antibodies can be detected in HIV patients, but its immunological characteristics are still unclear. In this study, the immunological characteristics of the target antigens were clarified. Methods: Total 93 HIV patients and 20 healthy volunteers were selected in Beijing Youan Hospital from 2017 to 2018. Recombinant human α1-α5(IV)NC1, chimeric protein EA and EB were used as solid phase antigens. Enzyme-linked immunosorbent assay was employed to measure concentrations and subtypes of serum IgG autoantibodies specifically against GBM.Results: Five out of the 93 patients with HIV had low to moderate levels of anti-GBM antibodies. However, these patients presented with no clinical manifestation of any kidney injury or pulmonary hemorrhages. Compared with HIV patients with negative antibodies, there were no significant differences in gender, age, CD4+T cell count and HIV viral load. All sera of five patients recognized non-collagenous domain1 (NC1) of alpha 3 chain of type IV collagen [(α3(IV)NC1] as classic anti-GBM patients, followed by α5(IV)NC1. The antibodies against α3(IV)NC1 were IgG3 predominant, but did not react with either of the classic epitopes on α3 (EA and EB).Conclusion: These data suggest a distinct immunological profile of anti-GBM antibodies in patients with HIV, and might explain the non-pathogenic features of HIV associated anti-GBM antibodies.