Abstract P167: Title: Prediction of Arterial Stiffness from Early T-cell Activation among HIV and HCV Co-infected Women in the Women's Interagency HIV Study (WIHS)
Introduction: Activation of T-lymphocytes, a hallmark of HIV infection, reaches a set point early in HIV infection and persists even after viral suppression with highly active antiretroviral therapy (HAART). Early T-cell activation predicts subsequent CD4 depletion, progression to AIDS and survival. HIV-infected subjects are at high risk for premature atherosclerosis. Little is known regarding the impact of early T cell activation on arterial stiffness. While Kaplan et al. (2011) were the first and only group to show a cross-sectional association, we investigate here if early T cell activation can predict future arterial stiffness.
Hypothesis: High early T cell activation will predict increased arterial stiffness, measured 5.5 (IQR=2.5-7.5) years later, in HIV and HCV co-infected women.
Methods: A longitudinal study nested within the WIHS, an ongoing prospective cohort study. Percentages of CD4 and CD8 T cell activation, assessed by CD38 and HLA-DR co-expression using 3-color flow cytometry, were measured on average 5.5 years before arterial stiffness assessments (carotid artery distensibility, and Young’s elastic modulus for elasticity) using B-mode carotid ultrasound. Multiple linear regression models evaluated the association between log-transformed T cell activation markers (independent variables) and arterial stiffness (dependent variable). Analyses were stratified by HCV co-infection status and by pre- and post-HAART assessment of T cell activation.
Results: A total of 376 HIV+ women (185 HCV+) were included in the analysis. Participants were on average 46(SD=9) years old, 59% Black, and 49% were current smokers. Activation of both CD4 and CD8 T cells significantly univariately predicted reduced distensibility and elasticity among HIV-infected women. CD4 activation continued to significantly predict distensibility (β(SEM)= −3.51(1.30) 10−6*N−1*m2, p=0.01), and elasticity (0.11(0.04)105*N*m2, p=0.004) with adjustment for age, race, BMI, smoking, ART, CD4 count, and HIV RNA. CD8 activation was no longer associated after adjustment. When stratified by HCV co-infection status, the prediction of arterial stiffness parameters from early CD4 activation was somewhat stronger among the HIV+/HCV+ women compared to HIV+/HCV- women (β(SEM)= −4.44(1.93), p=0.02 vs. −3.04(1.84), p=0.10 for distensibility, and 0.17(0.06), p=0.003 vs. 0.09(0.05), p=0.09 for elasticity); however the test for interaction was not statistically significant. In a subset of 188 women, CD4 activation measured both pre- and post-HAART significantly predicted later arterial stiffness.
Conclusions: CD4 activation level predicts future arterial stiffness in HIV-infected women, perhaps more markedly among HCV co-infected women. These data confirm the proinflammatory impact of activated T cells that can cause vascular dysfunction and shed light on the early onset of atherogenesis.
- © 2012 by American Heart Association, Inc.