Looking into the past and future of human immunodeficiency virus nephropathy

A 20-year history of childhood HIV-associated nephropathy

In 1984, physicians in New York and Miami reported HIV-infected adult patients with heavy proteinuria and rapid progression to end-stage renal disease. These patients showed large edematous kidneys with a combination of focal segmental glomerulosclerosis (FSGS) and tubulointerstitial lesions. This renal syndrome, named HIV-associated nephropathy (HIVAN), was found predominantly in African Americans. Subsequent studies confirmed the presence of HIVAN in children, who frequently develop nephrotic syndrome in association with FSGS and/or mesangial hyperplasia with microcystic tubular dilatation. Since then, substantial progress has been made in our understanding of the etiology and pathogenesis of HIVAN. This article reviews 20 years of research into the pathogenesis of HIVAN and discusses how these concepts could be applied to the treatment of children with HIVAN. HIV-1 infection plays a direct role in the pathogenesis of childhood HIVAN, at least partially by affecting the growth and differentiation of glomerular and tubular epithelial cells and enhancing the renal recruitment of infiltrating mononuclear cells and cytokines. An up-regulation of renal heparan sulfate proteoglycans seems to play a relevant role in this process, by increasing the recruitment of heparin-binding growth factors (i.e., FGF-2), chemokines, HIV-infected cells, and viral proteins (i.e., gp120, Tat). These changes enhance the infectivity of HIV-1 in the kidney and induce injury and proliferation of intrinsic renal cells. Highly active anti-retroviral therapy (HAART) appears to be the most promising treatment to prevent the progression of childhood HIVAN. Hopefully, in the near future, better education, prevention, and treatment programs will lead to the eradication of this fatal childhood disease.

Molecular identification of SV40 infection in human subjects and possible association with kidney disease

Simian virus 40 (SV40), a monkey polyomavirus that is believed to have entered the human population through contaminated vaccines, is known to be renotropic in simians. If indeed SV40 is endemic within the human population, the route of transmission is unknown. It was therefore hypothesized that SV40 might be renotropic in humans and be detected more frequently in samples obtained from patients with kidney diseases. This study found that typical polyomavirus cytopathic effects (CPE) were present and SV40 T antigen was detected in CV-1 cells cultured with peripheral blood mononuclear cells (PBMC) or urinary cells obtained from patients with kidney disease and healthy volunteers. DNA sequences homologous to the SV40 viral regulatory genome were detected by PCR in urinary cells from 15 (41%) of 36 patients with focal segmental glomerulosclerosis (FSGS), 2 (10%) of 20 patients with other kidney diseases, and 1 (4%) of 22 healthy volunteers (FSGS compared with other glomerular disease, P < 0.02; FSGS compared with healthy volunteers, P = 0.003). SV40 viral regulatory region genome was detected from PBMC at similar frequencies in patients with FSGS (35%), other glomerular diseases (20%), and healthy volunteers (22%). SV40 genome was detected by PCR in kidney tissues from 17 (56%) of 30 of patients with FSGS and 4 (20%) of 20 patients with minimal change disease and membranous nephropathy (P < 0.01). Considerable genetic heterogeneity of the viral regulatory region was detected, which argues against laboratory contamination. SV40 genome was localized to renal tubular epithelial cell nuclei in renal biopsies of patients with FSGS by in situ hybridization. This study demonstrates for the first time that human kidney can serve as a reservoir for SV40 replication and that SV40 may contribute to the pathogenesis of kidney disease, particularly FSGS.