Fig. 4

In coculture with autologous monocytes, Treg cells suppress their activation by poly- ICLC. As shown in a, a significant increase in CD38 expression was observed in poly-ICLC treated monocytes compared to monocytes cultured alone. However, the addition of autologous Treg cells resulted into a significant suppression of CD38 expression. The stimulation index (SI) was calculated by dividing the MFI of CD38 expression of poly ICLC treated monocytes by the MFI of CD38 expression in unstimulated monocytes. The suppressive activity of Treg cells defined as index of suppression (IS) was assessed based on the following formula: 1-(MFI of CD38 expression of poly ICLC treated monocytes in the presence of Treg cells / MFI of CD38 expression of poly ICLC treated monocytes in the absence of Treg cells). The SI and IS correlated positively with the helper CD4⁺ T cell count (r = 0.75, P = 0.0001 and r = 0.68, p = 0.0001, respectively for the SI and IS; b, c, d, e) and negatively with HIV-1 plasmatic viral loads (r = − 0.43, P = 0.01 and r = − 0.45, p = 0.01, respectively for the SI and IS; f, g, h, i), demonstrating a strong correlation between SI and IS (r = 0.83, P < 0.000; j). Horizontal bars represent the median values that were first compared using the Kruskal Wallis test, then followed by Dunn’s multiple comparison post-test. Correlation coefficients and their significance were calculated by Spearman test. The letters on horizontal bars identify which groups are significantly different from each other. The same letter implies there is no significant difference between the compared groups, while different letters indicate a significant difference between them