Aging and infectious diseases: workshop on HIV infection and aging: what is known and future research directions

HIV-infected persons continue to lose kidney function despite successful antiretroviral therapy

OBJECTIVE

To identify risk factors associated with kidney function decline in a contemporary cohort of treated and untreated HIV-infected patients.

METHODS

We followed individuals enrolled in the Study of the Consequences Of the Protease inhibitor Era cohort for longitudinal changes in kidney function, defined as glomerular filtration rate estimated from serum creatinine (eGFR). eGFR slope was calculated using linear mixed effects models adjusted for age, sex, race, and time-updated CD4 cell count, viral load, antiretroviral therapy (ART), and comorbid conditions.

RESULTS

We followed 615 patients for a mean of 3.4 (+/- 2.5) years. In multivariable adjusted analyses, predictors of eGFR decline included female sex, diabetes, and hyperlipidemia; CD4 cell count and viral load were not associated with eGFR loss. Among patients who initiated treatment, antiretroviral exposure was associated with a +2.8 (95% confidence interval 0.8-4.7) ml/min per 1.73 m per year effect on eGFR slope. Although these patients appeared to benefit from ART based on the slowing of their eGFR decline, they continued to lose kidney function at a rate of -1.9 (95% confidence interval -3.7 to -0.1) ml/min per 1.73 m per year. In the subgroup of individuals receiving suppressive ART with viral loads maintained below 500 copies/ml, intermittent viremic episodes (blips) were strongly associated with more rapid rates of eGFR loss [-6.7 (95% confidence interval -11.1 to -2.4) ml/min per 1.73 m per year].

CONCLUSION

Although ART appears to help curb kidney function decline, patients who achieved durable viral suppression continue to manifest substantial loss of eGFR. Loss of kidney function may be attributable to treatment-related factors, intermittent viremia, and traditional risk factors for kidney disease.

Coinfection with HIV-1 and HCV--a one-two punch

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease, cirrhosis, and death; it is estimated that 180 million persons are infected with HCV worldwide. The consequences of HCV are worse in those who are coinfected with human immunodeficiency virus 1 (HIV-1), which is unfortunately a common scenario because of shared risk factors of the viruses. More studies into effects of HCV/HIV-1 coinfection are needed, but efforts have been hampered by limitations in our understanding of the combined pathogenesis of the 2 viruses. Gaining insight into the mechanisms that underlie the immunopathogenesis of these persistent viral infections could lead to new therapeutic strategies for patients with HCV/HIV-1 coinfection.

Telomerase activity of HIV-1-specific CD8+ T cells: constitutive up-regulation in controllers and selective increase by blockade of PD ligand 1 in progressors

Exhaustion of virus-specific T cells may play an important role in the pathophysiology of chronic viral infections. Here, we analyzed telomere length and telomerase activity in HIV-1-specific CD8+ T cells from progressors or controllers to determine underlying molecular pathways of T-cell exhaustion and senescence. Telomere lengths of HIV-1-specific CD8+ T cells from progressors were significantly shorter compared with autologous cytomegalovirus (CMV)/Epstein-Barr virus (EBV)-specific CD8+ T cells or bulk CD8+ T cells, while telomere lengths from controllers significantly exceeded those of autologous bulk CD8+ T cells and reached a similar level as HIV-1-specific CD8+ T cells collected during primary HIV-1 infection. Telomere length stabilization in controllers corresponded to high levels of constitutive telomerase activity, which was associated with preservation of cytotoxic and proliferative properties. Conversely, limited constitutive telomerase activity was observed in HIV-1-specific CD8+ T cells from progressors, although an increase in both telomere length and telomerase activity was achieved in antigenic-peptide-stimulated cells from progressors after blocking the PD-1/PD ligand 1 (PD-L1) pathway. Collectively, these data suggest a causal role of telomere shortening for the functional deficiencies of HIV-1-specific CD8+ T cells in chronic progressive infection, while high constitutive telomerase activities appears to contribute to maintenance of polyfunctional HIV-1-specific CD8+ T cells from HIV-1 controllers.