Figure 1.

TFH cell frequencies correlate with CD activity. (A) TFH cell frequencies in ileal biopsies of CD patients (n = 15) were significantly increased in patients with active inflammation (Simple Endoscopic Score for Crohn’s Disease [SES-CD] ≥3 points) as compared with patients in endoscopic remission (SES-CD ≤2 points). Mann-Whitney test was used to test for statistical significance. (B) Patients with active inflammation (stool calprotectin >200 mg/kg; n = 11) showed significantly higher TFH cell frequencies in the peripheral blood compared with patients in remission (stool calprotectin <200 mg/kg; n = 7). Mann-Whitney test was used to test for statistical significance. Note that this cohort contained patients with both ileal and colonic CD manifestations. (C) Representative flow cytometry plot of TFH cells isolated from a lymph node (LN), the ileum, and the peripheral blood of a CD patient. (D) Representative histograms of phenotypic and functional TFH markers gated on non-naïve CD4+ T cells, CXCR5+ CD4+ T cells, CXCR5+ PD-1+ CD4+ T cells, and CXCR5+ PD-1 high CD4+ T cells isolated from the peripheral blood of a CD patient. (E) CXCR5+ PD-1 high CD4+ T cells from the peripheral blood of CD patients show increased expression of TFH cell activity markers (n = 43) and increased IL-21 production (n = 42) compared with broader TFH definitions (CXCR5+ PD-1+ CD4+ T cells; CXCR5+ CD4+ T cells) and non-naïve CD4+ T cells. Expression after z-score transformation is depicted. TFH cell frequencies are shown as percentage of non-naïve CD4+ T cells.