Retinal vascular changes and immune restoration in a cohort of HIV/AIDS patients on highly active antiretroviral therapy

Abstract

BackgroundRetinal microvascular changes have been shown to reflect systemic inflammation in vivo. We aimed to investigate whether retinal microvascular changes are correlated with, and predictive of, CD4 and CD8 cell count changes in patients with HIV/AIDS being treated with highly active antiretroviral therapy (HAART). MethodsWe did a longitudinal hospital-based study. 50 HIV/AIDS patients being treated with HAART were sequentially recruited from March, 2011, to September, 2011, from the Communicable Disease Center, Singapore, and then followed up at a 9 month visit. Demographic and socioeconomic information and history of HIV infection were collected at baseline. Blood pressure and anthropometric measurements, blood tests for immune status assessment (CD4 and CD8 cell counts), and retinal photography were done at baseline and at 9 months. Retinal vascular parameters (calibre, tortuosity, branching angle, and fractal dimension) were assessed by a semiautomated computer-based programme (Singapore I vessel assessment [SIVA], version 3.0, Singapore Eye Research Institute, Singapore). Changes of retinal vascular parameters and CD4 and CD8 cell counts were defined as the difference between baseline and 9 months. FindingsThe mean age of the 50 participants was 46·36 years (SD 8·67). Participants were ethnically Chinese, Malay, and Indian; most (82%) were Chinese and most male (96%). 35 of 50 patients had CD4 counts of fewer than 200 cells per μL at baseline. Years of HAART ranged from 0 to 11 years. There were significant increments in CD4 cell counts (153·42 vs 227·74 cells per μL; p<0·0001) and CD8 cell counts (819·90 vs 1014·1 cells per μL; p=0·012) between baseline and the 9 month visit, respectively. There were no temporal changes in retinal vascular parameters during this period. After adjustment for age, sex, ethnicity, and years of HAART, each 10 μm reduction in retinal venular calibre at baseline was associated with a 191·08 cells per μL increase in CD8 count (SE 63·54; p=0·004), but not in CD4 cell count, during the 9 month period. Changes of retinal arteriolar calibre and other retinal vascular geometric parameters were not associated with CD4 or CD8 cell count changes. InterpretationRetinal venular narrowing was associated with an increase in CD8 cell counts over time. Our findings suggest that improved retinal venular health was predictive of immune restoration in HIV/AIDS patients who had been on HAART for at least 9 months. Longer follow-up is warranted to monitor the retinal vascular calibre changes in response to HAART treatment. FundingSingapore Medical Research Counsel SIG/11016.