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Updated: May 8, 2026

Isolation and Th17 Differentiation of Naïve CD4 T Lymphocytes
Published on: September 26, 2013
Interleukin-17 immunity in pediatric Crohn disease and ulcerative colitis
Veera Hölttä1, Paula Klemetti, Harri M Salo
1Department of Vaccination and Immune Protection, Immune Response Unit, National Institute for Health and Welfare, Helsinki, Finland. veeruska@sci.fi
Objective:
The present understanding of inflammatory bowel disease pathogenesis mainly relies on studies of adult patients. Therefore, we studied the balance between T-effector and regulatory cells in pediatric inflammatory bowel disease.
Methods:
Quantitative polymerase chain reaction and immunohistochemistry served to quantify the expression of immunological markers in mucosal biopsies and flow cytometry analysis was used in peripheral blood mononuclear cells.
Results:
Colonic interleukin (IL)-17+, IL-22, and IL-6 mRNA upregulation and increase in the number of colonic IL-17 cells were demonstrated in both Crohn disease (CD) and ulcerative colitis (UC). Likewise, colonic forkhead box P3 (FOXP3+) mRNA expression and the number of colonic FOXP3 cells were increased both in CD and in UC and were accompanied in CD also with increased numbers of FOXP3+CD25 High CD4 cells in peripheral blood. Ileal relation of IL-17/CD4 cells was increased only in CD.
Conclusions:
We showed activation of colonic IL-17/IL-22 axis and upregulation of FOXP3 to occur both in pediatric CD and in UC, indicating shared immunological characteristics. Upregulation of IL-17 was restricted to colon in UC, but existed in the ileum and in the colon in active CD.
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