Figure 2.

Correlation between high endothelial venules (HEVs) and T cell subpopulations. Lymphocyte subsets as well as maturation state of T lymphocytes was assessed with flow cytometric immunophenotyping of biopsy specimens taken from the same inflamed colonic tissues during the same ileocolonoscopy. Patients are divided into HEV^high (n = 10) or HEV^low (n = 20) groups using the median density of extrafollicular peripheral lymph node addressin (PNAd) expressing HEV‐like vessels in inflamed colon of ulcerative colitis (UC) patients as cut‐off value. Statistically significant results are indicated with an asterisk (*). (a) Shows more central memory T cells (T_CM, CD45RA^–CD27⁺, P = 0·0009), fewer effector memory T cells (T_EM, CD45RA^–CD27^–, P = 0·022) and fewer effector memory T cells re‐expressing RA (T_EMRA, CD45RA⁺CD27^–, P = 0·008) in HEV^high patients when compared with HEV^low patients. There was no statistically significant difference for naive T cells (T_N CD45RA⁺CD27⁺). (b) Shows fewer cytotoxic T cells (CD3⁺CD8⁺, P = 0·00008), a higher CD4 : CD8 ratio (P = 0·0008) and fewer mucosal T cells (CD3⁺CD103⁺, P = 0·015) in HEV^high patients. There was no statistically significant difference for B cells (CD19⁺), T cells (CD3⁺), T helper cells (CD3⁺CD4⁺) and regulatory T cells [CD3⁺CD25^highforkhead box protein 3 (FoxP3⁺)]. (c) Representative flow cytometric dot‐plots from inflamed colonic biopsy specimens of inflammatory bowel disease (IBD) patients which show the distribution of the maturation of (CD3⁺) T lymphocytes. (c1) A HEV^high patient with mainly T_N (CD45RA⁺CD27⁺, 54%) and T_CM (CD45RA^–CD27⁺, 38%) lymphocytes. (c2) A HEV^low patient with mainly (91%) T_EM (CD45RA^–CD27^–) lymphocytes. [Colour figure can be viewed at wileyonlinelibrary.com]