Figure 7. Immune activation and immune regulation influence influenza Ab responses in HIV. (A) The frequency of the PDL1+ B cells before vaccination was correlated with the frequency of the plasmablasts before vaccination. (B) Frequencies of the CD80+ Naïve B cells at T0 were correlated with the H1N1 specific HAI titer fold change (T2/T0). Age groups are depicted as squares (young, <40 years), triangles (middle, 40-59 years) and circles (old, ≥60 years). Spearman correlation was performed.