Immunopotentiation in the Presence of Tenofovir-induced Phosphaturia in HIV-infected Patients on Tenofovir

Tenofovir disoproxil fumarate (TDF) remains the most widely use and prescribed first line antiretroviral therapy in the treatment of patients infected HIV-infection but unfortunately it is possibly nephrotoxic especially on the kidney tubules. In this longitudinal study we evaluated the influence of TDF on the renal tubules, measuring urinary phosphate and protein. 57 patients infected with HIV were recruited and grouped as follows: TDF group (21 patients), Non-TDF group (21 patients) and treatment naive group (15 patients). Indicators of renal tubular injuriousness together with other common biomarkers of renal injury were evaluated. Phosphaturia was defined as urinary phosphate 20.0 mg/dl and the prevalence of phosphaturia after 12 weeks of follow-up were as follows: TDF group (8), Non-TDF group (1) and treatment naive group (3). Proteinuria was defined as positive protein on dip stick urine and the prevalence among the different ART regimen groups after 12 weeks were as follows: TDF group (4), Non-TDF group (1) and treatment naive group (1). CD4 count for the different regimen groups after 12 weeks were as follows: TDF (659.95 ul/cells/<50 copies/ml), non-TDF (363.24 ul/cells/<500 copies/ml) and treatment naive (276.63 ul/cells/<1000 copies/ml). This higher incidence in phosphaturia and proteinuria in the presence of increased CD4 counts in HIV patients exposed to TDF is believed to be progressive and may subsequently result in a generalized renal tubular toxicity before any rise in serum creatinine.