IMMUNOPATHOLOGICAL CHARACTERISTICS OF IN-SITU T-CELL SUBPOPULATIONS IN HUMAN IMMUNODEFICIENCY VIRUS-ASSOCIATED NEPHROPATHY

Human immunodeficiency virus-associated nephropathy (HIVAN) is a commo n form of nephropathy present in HIV-infected individuals that clinica lly presents with proteinuria that is frequently in the nephrotic rang e, less often with hematuria and with a course that may evolve to irre versible azotemia ultimately resulting in renal failure. Pediatric and adult HIV-positive patients both experience HIVAN morphologically aft er displaying focal segmental glomerulo-sclerosis, diffuse mesangial h yperplasia, microcystic tubular dilatation, interstitial inflammation, edema, and fibrosis. There is minimal information regarding the inter stitial inflammatory cell infiltrate, despite the possibility that the se cells may play an important role in the etiology of HIVAN. This stu dy was designed to characterize and compare several morphological and immunopathological features of clearly established HIVAN, particularly the hematopoietic cell markers present on the interstitial inflammato ry cells and the state of T-lymphocyte activation tie, class II expres sion). Quantitative grading of HIVAN kidneys showed that CD4-positive and CD8-positive T cells comprised the major cell populations in the i nterstitium, often with CD4-positive T cells exceeding or being equiva lent in number to CD8-positive T cells. B cells and macrophages were n egligible components of the infiltrate. Human leukocyte antigen-DR cla ss II molecules were found to be increased on the interstitial T cells as well as on all glomerular cells and endothelial cells. There was n o significant relationship established between the immunophenotype of the interstitial inflammatory cells and other morphological, ultrastru ctural, immunofluorescent, or clinical features. These data imply that the inflammatory infiltrate in HIVAN is largely composed of activated T cells. At this point the role of these interstitial T cells in HIVA N is undetermined, although it can be speculated that they may be part icipating as antiviral or autoreactive immune effector cells imparting renal injury in this entity. HUM PATHOL 26:408-415. Copyright (C) 199 5 by W.B. Saunders Company