IL-6 for 48 hours. CD40, CD80, CD83, CD86, DC-SIGN and HLA-DR expression was evaluated before and after the HIV-1-stimulation and IL-12 concentration were measured by ELISA. HIV-1-specific lymphoproliferation was analyzed by flow cytometry in 6-day cocultures of MDDC and lymphocytes. Nonparametric tests were employed (p<0,05).Results: The %mDC wasn't different among groups (medians: 1.9% for AP, 2.45% for VP and 1.95% for controls; Kruskal-Wallis test, p=0.071) and there was a difference of %pDC between patients and controls (medians: 0.3% for AP, 0.1% for VP and 0.3% for controls; Kruskal-Wallis test, p=0.038). VL inversely correlated with %pDC (Spearman's rho=-0.314; p=0.016) and mDC inversely correlated with %CD4 (Spearman's rho=-0.390; p=0.003).Before HIV stimulation, MDDC from VP had high level of CD83 expression than controls (p=0.011). After HIV stimulation, MDDC from all groups had higher HLA-DR, CD40, CD80, CD83 and CD86 and lower DC-SIGN expression. We didn't find a difference in IL-12 concentration among groups (medians: 2053.8pg/mL for AP, 2458.4pg/mL for VP and 1626.2pg/mL for controls; Kruskal-Wallis test, p=0.539). Higher HIV-specific proliferation was found in patients with AP in comparison to VP (medians: 12.4% for AP and 0.69% for VP; Mann-Whitney test, p=0.006).Conclusion: Therefore, in children under ART, viremia was associated with lower %pDC, altered MDDC phenotype and reduced HIV-specific lymphoproliferation.