Figure 2.

T_FH are more abundant in lymphoid tissue of children than adults. (A) Gating strategy of tonsil T_FH (CD4⁺CD45RA⁻CXCR5⁺PD1^high; light blue) and GC-T_FH cells (%CCR7⁻ of total tonsil T_FH; dark blue) in secondary lymphoid tissue. Levels of Bcl-6 expression of the different subsets are expressed in MFI (median fluorescent intensity). (B) No significant difference in the frequency of tonsil T_FH in secondary lymphoid tissue of infected children (blue squares; n = 4) compared to infected adults (n.s.; Kruskal-Wallis test). Red triangles: Adults on ART (n = 3), red diamonds: Adults not on ART (n = 3). (C) Same as in (B) but showing a significantly increased frequency of GC-T_FH cells (% CCR7⁻ of tonsil T_FH) (p = 0.01; Kruskal-Wallis test) in infected children. (D) Increased frequency of tonsil T_FH (p = 0.06; Kruskal-Wallis test) in secondary lymphoid tissue of uninfected children (open blue squares; n = 6) compared to uninfected adults (open red triangles; n = 3). (E) Same as (D) but showing the increased frequency of GC-T_FH cells in uninfected children (p = 0.02; Kruskal-Wallis test) compared to uninfected adults. (F) Increased frequency of circulating effector T_FH in HIV uninfected adults (open red triangles; n = 8) compared to uninfected children (open blue squares; n = 7) (p = 0.03; Kruskal-Wallis test). In scatter plots medians are shown.