Hemorheologic Abnormalities in HIV-Infected Individuals with CD4+ T-lymphocyte Counts >200/µL

Abstract

Abstract: : Purpose: It has been hypothesized that hemorheologic abnormalities (e.g., increased RBC aggregation, PMN rigidity) known to occur in severely immunosuppressed HIV-infected individuals may contribute to retinal microvascular damage. PMN rigidity remains persistently abnormal despite immune reconstitution attributed to highly active antiretroviral therapy (HAART), but less is known about the relationship between immune status and RBC properties. Our goal was to determine whether RBC abnormalities are present in HIV-infected individuals with CD4+ T-lymphocyte counts >200/µL who have never been severely immunosuppressed (defined as CD4+ T-lymphocyte counts <50/µL). Methods: Blood samples were obtained from 6 HIV-infected individuals and 8 HIV-negative controls. RBC aggregation was assessed by Westergren ESR, zeta-sedimentation ratio (ZSR, a hematocrit-independent measure of RBC aggregation), and Myrenne aggregometry. RBC deformability was measured by laser diffraction ektacytometry (LORCA). Statistical analysis was performed using the Wilcoxon and t-test. Results: HIV-infected subjects had CD4+ T-lymphocyte counts >200/µL, a history of previous or current HAART therapy, and no history of severe immunosuppression. ESR and Myrenne aggregation indices were comparable between HIV-infected and control subjects. Using LORCA, RBCs from HIV-infected subjects (elongation index = 0.392 ± 0.020) were more rigid than RBCs from controls (0.418 ± 0.017, p < 0.05). RBC aggregation as measured by ZSR was significantly higher in HIV-infected subjects (0.62 ± 0.07) than in previously studied HIV-negative controls (0.52 ± 0.03, p < 0.01). Conclusion: Our study suggests that RBC abnormalities are present in HIV-infected individuals despite CD4+ T-lymphocyte counts >200/uL and a history of HAART. Based upon these results and earlier reports of increased PMN rigidity in individuals who underwent immune reconstitution, HAART does not appear to prevent adverse hemorheological changes. Therefore, blood flow abnormalities and progressive microvascular damage may occur with time in individuals with longer life expectancies due to HAART. .

Keywords: AIDS/HIV