Glomerular lesions in HIV-positive patients : a 20-year biopsy experience from Northern Italy

Aim: Glomerular involvement in HIV-positive patients is quite heterogeneous. In the present paper we reviewed 73 renal biopsies performed during a period of more than 20 years in a single Nephrology Unit, Milan, Northern Italy, in order to evaluate the aspects of single types of glomerular lesions (including HIV associated nephropathy- HIVAN), grouped according to histological patterns and clinical presentation. Moreover, in the group of non-HIVAN patients, the possible differences in histological characteristics from non-HIV lesions were investigated. Materials and methods: Renal tissues were obtained by percutaneous biopsies and were studied by light microscopy, immunofluorescence and electron microscopy. For the histological description three histological groups were identified: HIVAN, immune complex glomerulonephritis (GN) and glomerulopathies not related to immune-mediated mechanisms (so-called "various" glomerulopathies). Results: HIVAN was observed in 9 cases, immune complex GNs in 40 cases (10 mesangial proliferative GN, 8 membranoproliferative GN, 5 lupus-like GN, 4 "acute" GN, 2 crescentic GN, 4 IgA nephropathy, 4 membranous GN and 3 immunotactoid GN) and "various" glomerulopathies in 24 cases (13 non-collapsing focal segmental glomerulosclerosis, 3 minimal changes, 3 end-stage renal disease, 4 diabetic nephropathy and one amyloidosis). Conclusions: Our 20-year biopsy series of HIV-related glomerular involvement confirmed the heterogeneity of lesions. In our series, the vast majority of HIV-related GN are the so-called immune complex GNs, with some peculiar aspects, as multiple site location of deposits and a frequent tendency towards sclerosis, in agreement with experimental data regarding HIV and fibrosis