Objective: CD4 and CD8 T-cell activation are independent predictors of AIDS. The complete activation profile of both T-cell subtypes and their predictive value for AIDS risk is largely unknown.
Design: A total of 564 AIDS-free women in the Women's Interagency HIV Study were followed over 6.1 years (median) after T-cell activation assessment. A cluster analysis approach was used to evaluate the concurrent activation patterns of CD4 and CD8 T cells at the beginning of follow-up in relation to AIDS progression.
Methods: Percentages of CD4 and CD8 T cells with HLA-DR± and CD38± were assessed by flowcytometry. Eight immunologic variables (four on each CD4+ and CD8+: DR± and CD38±) were assessed to yield a 4-cluster solution on samples obtained before clinical endpoints. Proportional hazards survival regression estimated relative risks for AIDS progression by cluster membership.
Results: Compared with the other three clusters, outstanding activation features of each distinct cluster of women were: Cluster 1: higher CD8+CD38−DR− (average = 41% of total CD8 T-cell pool), CD4+CD38−DR− (average = 53% of total CD4 T-cell pool), and CD8+CD38−DR+ (28%); Cluster 2: higher CD8+CD38+DR− (44%) and CD4+CD38+DR− (58%); Cluster 3: higher CD8+CD38+DR+ (49%) and CD4+CD38+DR− (48%); Cluster 4: higher CD8+CD38+DR+ (49%), CD4+CD38+DR+ (36%) and CD4+CD38−DR+ (19%). Compared with cluster 1, women in cluster 4 had two-fold increased risk of AIDS progression (Hazard ratio = 2.13; 95% confidence interval = 1.30–3.50) adjusted for CD4 cell count, HIV RNA, and other confounders.
Conclusion: A profile including CD4 and CD8 T-cell activation provided insight into HIV pathogenesis indicating concurrent hyperactivation of CD4 and CD8 T cells is associated with AIDS progression.