Figure 5.

Relationship between neutralization activity against the Omicron-derived variant and IL-6, and the frequency of circulating follicular helper T cells in the CD4⁺ T cell population in vaccinated (n = 36) and unvaccinated patients (n = 17). (A) Representative flow cytometry plots of the gating strategy used to identify CXCR5⁺CD4⁺ cTfh cells. (B, C) Correlations between the cTfh cell population frequency and the neutralization activity against the Omicron-derived variant (red) or IL-6 levels (blue) in vaccinated (n = 37) (B) and unvaccinated patients (n = 17) (C). The Pearson correlation was calculated, and the P value and r value are shown. The general linear regression lines are shown. Each level was measured at admission (within 5 days after symptom onset) and each dot represents an individual value. cTfh, circulating follicular helper T; NT, neutralizing activity; IL, interleukin.