Characteristics, determinants, and clinical relevance of CD4 T cell recovery to <500 cells/μL in HIV type 1-infected individuals receiving potent antiretroviral therapy

Background. The CD4 T cell count recovery in human immunodeficiency virus type 1 ( HIV- 1) - infected individuals receiving potent antiretroviral therapy ( ART) shows high variability. We studied the determinants and the clinical relevance of incomplete CD4 T cell restoration. Methods. Longitudinal CD4 T cell count was analyzed in 293 participants of the Swiss HIV Cohort Study who had had a plasma HIV- 1 RNA load < 1000 copies/ mL for >= 5 years. CD4 T cell recovery was stratified by CD4 T cell count 5 years after initiation of ART ( >= 500 cells/ mL was defined as a complete response, and < 500 cells/ mL was defined as an incomplete response). Determinants of incomplete responses and clinical events were evaluated using logistic regression and survival analyses. Results. The median CD4 T cell count increased from 180 cells/ mL at baseline to 576 cells/ mL 5 years after ART initiation. A total of 35.8% of patients were incomplete responders, of whom 47.6% reached a CD4 T cell plateau < 500 cells/ mu L. Centers for Disease Control and Prevention HIV- 1 disease category B and/ or C events occurred in 21% of incomplete responders and in 14.4% of complete responders (). Older age ( adjusted P > 1.05 odds ratio [ aOR], 1.71 per 10- year increase; 95% confidence interval [ CI], 1.21 - 2.43), lower baseline CD4 T cell count ( aOR, 0.37 per 100- cell increase; 95% CI, 0.28 - 0.49), and longer duration of HIV infection ( aOR, 2.39 per 10- year increase; 95% CI, 1.19 - 4.81) were significantly associated with a CD4 T cell count ! 500 cells/ mL at 5 years. The median increases in CD4 T cell count after 3 - 6 months of ART were smaller in incomplete responders () and predicted, in conjunction with baseline CD4 T cell count and age, incomplete response with 80% P < 001 sensitivity and 72% specificity. Conclusion. Individuals with incomplete CD4 T cell recovery to < 500 cells/ mu L had more advanced HIV- 1 infection at baseline. CD4 T cell changes during the first 3 - 6 months of ART already reflect the capacity of the immune system to replenish depleted CD4 T lymphocytes.