Tubulointerstitial Nephropathies in Patients with HIV

Tubulointerstitial nephropathies are found in more than one-fourth of kidney biopsy specimens obtained from HIV-infected patients, reports a study in the Clinical Journal of the American Society of Nephrology.

The retrospective study included 59 consecutive renal biopsy specimens showing predominantly tubular lesions, interstitial lesions, or both in patients with HIV infection. The patients were referred to the nephrology department of a French hospital between 1995 and 2011; the analysis excluded patients with HIV-associated nephropathy and vascular diseases. Patterns of tubulointerstitial nephropathies in HIV-infected patients were analyzed, along with their therapeutic implications.

The cases of tubulointerstitial nephropathy represented 26.6 percent of 222 native renal biopsies performed in HIV-infected patients. Approximately equal numbers of tubulopathy cases and interstitial nephritis cases were included.

At referral, about three-fourths of patients had acute kidney injury, and close to 60 percent had high-grade proteinuria. A little more than half had drug-related nephrotoxicity. Other identified causes included infections, dysimmune disorders, and malignancies. Acute and chronic tubulointerstitial nephropathies of unknown origin accounted for 10 percent of cases each.

Toxic effects of antiretroviral drugs accounted for three-fourths of tubulopathies. Tenofovir toxicity was involved in more than half of these cases, causing proximal tubular dysfunction in nearly 90 percent of cases. Other manifestations included overt Fanconi’s syndrome and nephrogenic diabetes inspidus. The causes and pathologic findings were more variable in cases of interstitial nephritis.

With advances in HIV treatment and improved patient outcomes, patterns of HIV-related renal complications have changed. This study finds a high rate of tubulointerstitial nephropathies among HIV-infected patients referred for nephrology evaluation. Drug toxicity is the most common diagnosis, but other causes are possible. The findings highlight the need for monitoring of renal function in patients with HIV infection and the importance of renal biopsy for accurate diagnosis [Zaidan M, et al. Tubulointerstitial nephropathies in HIV-infected patients over the past 15 years: a clinico-pathological study. Clin J Am Soc Nephrol 2013, in press].