An Unusual Case of Anti-GBM Antibody Elevation in HIV-Associated Nephropathy

A Descriptive Analysis of Nasal Polyposis in HIV Positive Versus HIV Negative Patients

Nasal polyposis (NP) represents a benign proliferation of soft tissue tumors within the nasal cavity and paranasal sinuses, characterized by chronic inflammation of the sinonasal mucosa. This phenomenon, attributed to various environmental and physiological factors, presents clinically as semi-transparent masses with variable morphology, often obstructing nasal passages and causing respiratory compromise, olfactory dysfunction, and recurrent infections. Predominantly associated with chronic rhinosinusitis (CRS), NP poses significant challenges in diagnosis and management, particularly in the context of comorbid conditions such as human immunodeficiency virus (HIV) infection. HIV infection, known for its debilitating effects on the immune system, is theorized to exacerbate NP development and manifestation through mechanisms involving CD4 cell depletion and dysregulation of immune responses. Despite extensive research, elucidating potential pathways linking HIV infection to NP, comprehensive understanding remains elusive. This study aims to address this knowledge gap by conducting a retrospective chart review of patients presenting with NP at Charlotte Maxeke Johannesburg Academic Hospital between January 2016 and December 2020. The primary objective is to investigate the influence of HIV status on the clinical, radiological, and histological features of NP. Data collection, encompassing patient demographics, HIV status, clinical presentations, radiological findings, and histopathological characteristics, will be conducted between March 2021 and August 2022. Preliminary analysis of collected data reveals a cohort of 41 patients meeting inclusion criteria, with notable exclusions based on undisclosed HIV status and incomplete documentation. Initial findings suggest a nuanced interplay between genetic predisposition, environmental factors, and HIV status in NP pathogenesis, underscoring the need for further research to validate these observations. In conclusion, this study underscores the importance of elucidating the complex relationship between HIV infection and NP to optimize diagnostic and therapeutic approaches, particularly in regions with a high HIV prevalence such as South Africa. By comprehensively assessing the clinical, radiological, and histological features of NP in HIV-positive and HIV-negative populations, this research endeavours to enhance our understanding of NP pathophysiology and improve patient outcomes.

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

Background

Anti-glomerular basement membrane disease (GBM) is an 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, in which E_A and E_B are the most classical antigen epitopes. It has been reported that anti-GBM antibodies can be detected in HIV patients; however, its immunological characteristics are still unclear.

Objectives

In this study, the positive rate of the anti-GBM antibodies in HIV and the immunological characteristics of the target antigens were clarified.

Methods

A total of 93 HIV patients diagnosed in Beijing Youan Hospital from November 2017 to January 2018 were included. Enzyme-linked immunosorbent assay was used to measure the serum IgG autoantibodies specifically against GBM in these patients, as well as their subtypes and antigen spectra.

Results

It was found that 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, while these antibodies did not react with either of the classic epitopes on α3 (E_A and E_B).

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.