HIV-related nephropathy: a South African perspective

Racial differences in end-stage renal disease rates in HIV infection versus diabetes

Few studies have compared the incidence of end-stage renal disease (ESRD) among individuals with the human immunodeficiency virus (HIV) and diabetes. We followed a national sample of 2,015,891 US veterans over a median peroid of 3.7 years for progression to ESRD. The age- and sex-adjusted incidence of ESRD (per 1000 person-years) among HIV-infected black patients was nearly an order of magnitude higher than among HIV-positive white patients, almost twice that of diabetic whites, and similar to that among diabetic blacks. In multivariate Cox proportional hazards analysis, diabetes was associated with an increased risk of ESRD among white patients, but HIV was not. Among black individuals, however, both HIV and diabetes conferred a similar increase in the risk of ESRD (4- to 5-fold increase compared to white individuals without HIV or diabetes). HIV and diabetes carry a similar risk of ESRD among black patients, highlighting the importance of developing strategies to prevent and treat renal disease among HIV-infected black individuals.

Genetic susceptibility, HIV infection, and the kidney

In recent years, the sequencing of mammalian and microbial genomes has provided the opportunity to study how genetic variation in the host and pathogen influence the course of infectious disease. In the case of HIV-1 infection, such studies have led to identification of key viral proteins that determine pathogenicity, immune evasion, or drug resistance. In addition, candidate gene association studies have uncovered a large number of host genetic variants that influence the outcome of infection and some organ-specific complications. HIV-associated nephropathy (HIVAN) is a pathologically distinct complication of HIV infection. Interindividual variability in incidence, skewed ethnic distribution, and familial aggregation of HIVAN with other forms of ESRD have suggested genetic susceptibility as a major contributing factor. This article reviews the host genetic factors that influence the course of HIV-1 infection and discusses murine models that have increased the understanding of HIVAN pathogenesis and demonstrated the role of genetic background on determination of disease.

HIV-1 and HIV-Associated Nephropathy 25 Years Later

Twenty-five years after the first published description of AIDS, HIV-associated nephropathy (HIVAN) remains an important cause of kidney disease in HIV-infected patients. The pathogenesis of HIVAN involves direct HIV infection of the kidney, with both viral and host genetic factors playing an important role. The widespread use of antiretroviral therapy has influenced the epidemiology of HIV-related kidney disease, and the nephrology community should support efforts to improve access to therapy and limit HIV transmission in susceptible minority populations. This article reviews the history of HIV and HIVAN, focusing on advances in the understanding of pathogenesis, epidemiology, and treatment.

Infection and glomerulonephritis

Glomerular injury, occurring either as primary glomerular disease or as part of a systemic disease process, is usually a result of immune-mediated mechanisms. The morphologic reaction pattern has a diverse spectrum of appearance, ranging from normal by light microscopy in minimal change disease to crescentic forms of glomerulonephritis, with conspicuous disruption of the normal glomerular morphology. The mechanisms of glomerular immune deposit formation include trapping of circulating antigen-antibody complexes and the in situ formation of immune complexes within the glomerulus. While the majority of postinfectious immune-complex-mediated glomerulonephritides are believed to result from the deposition of circulating antigen-antibody complexes, preformed outside of the kidney and secondarily deposited in the kidney, the notion of forming in situ antigen-antibody complexes to either planted antigens or to integral structural components of the glomerulus, through "cross-reacting" autoimmune reactions, is gaining popularity in a variety of forms of glomerulonephritides. Patients with HIV infection may develop a spectrum of renal pathology, the glomerular manifestations of which include both antigen-antibody complex and nonimmune-complex-mediated pathogenetic mechanisms. Similarly, patients with Streptococcal infections, Hepatitis B virus, or Hepatitis C virus infection may develop a spectrum of glomerulonephritides, which are predominantly immune-complex-mediated. Therapy for glomerular diseases due to HIV, hepatitis B, or C virus infections remains a challenge.

HIV-1 infection and the kidney: an evolving challenge in HIV medicine

With the advent of highly active antiretroviral therapy (HAART), the incidence of opportunistic infections has declined substantially, and cardiovascular, liver, and renal diseases have emerged as major causes of morbidity and mortality in individuals with human immunodeficiency virus (HIV). Acute renal failure is common in HIV-infected patients and is associated with acute infection and medication-related nephrotoxicity. HIV-associated nephropathy is the most common cause of chronic kidney disease in HIV-positive African American populations and may respond to HAART. Other important HIV-associated renal diseases include HIV immune complex kidney diseases and thrombotic microangiopathy. The increasing importance of non-HIV-associated diseases, such as diabetes mellitus, hypertension, and vascular disease, to the burden of chronic kidney disease has been recognized, focusing attention on prevention and control of these diseases in HIV-positive individuals. HIV-positive individuals who experience progression to end-stage renal disease and who have undetectable HIV-1 viral loads while receiving HAART should be evaluated for renal transplant. Emerging evidence suggests that HIV-positive individuals may have graft and patient survival comparable to HIV-negative individuals. Several studies suggest that HIV-1 can potentially infect renal cells, and HIV transgenic mice have clarified the roles of a number of HIV proteins in the pathogenesis of HIV-associated renal disease. Host factors may modify disease expression at the level of cytokine networks and the renal microvasculature and contribute to the pathogenic effects of HIV-1 infection on the kidney.

Renal complications in HIV

Highly Active Antiretroviral Therapy has revolutionised the care of individuals living with HIV-1. As the prognosis for this population has improved, there is an increased risk of other major causes of morbidity and mortality, including renal disease. This review discusses the frequency and causes of renal pathology, how to make the diagnosis and monitor for renal disease in HIV-infected individuals. The review was conducted having examined the key evidence focussing upon HIV and renal complications obtained from peer-reviewed journals (level of evidence I-IV). As the population of individuals living with HIV increases, so too does the prevalence of renal disease. Physicians should be vigilant and recognise individuals at risk of renal complications, and be aware of how to monitor, investigate and treat those affected.