Cytokine Tissue Levels as Markers of Disease Activity in Pediatric Crohn Disease

Abstract

The mucosal immune system is overactivated in Crohn disease (CD) and viral infections have been associated with clinical exacerbations. To investigate the potential association between mucosal inflammation and the cytokines involved in the early response to viruses, we analyzed colonic tissue levels of IL-2Ralpha, interferon-alpha, and IL-15 in CD. Patients undergoing diagnostic colonoscopy were classified into controls (n = 22) and three CD groups based on the histologic severity of inflammation and clinical activity: a) severely active CD (n = 3); b) mild to moderately active CD (n = 14); and c) quiescent CD (n = 23). Rectal biopsies (two per patient) were homogenized and cytokine levels determined by ELISA kits. Statistical analysis was performed by ANOVA with Tukey and Scheffé tests. IL-2Ralpha levels were increased in the active CD group compared with the quiescent CD group: a) 405 +/- 87, b) 159 +/- 31, and c) 33 +/- 15 pg/mg DNA (p < 0.001). The latter group was similar to controls (39 +/- 20 pg/mg DNA). Furthermore, a linear correlation (r = 0.98) between IL-2Ralpha and disease activity (Van Hees index) was observed. IL-15 levels were also higher in active compared with quiescent CD and controls: a) 0.69 +/- 0.23 and b) 0.72 +/- 0.31 versus c) 0.28 +/- 0.21 and 0.28 +/- 0.14 pg/mg DNA for controls (p < 0.05). Interferon-alpha levels were undetectable in all samples. Our data suggest that IL-2Ralpha tissue levels correlate with CD activity. IL-15 is also overproduced in inflamed CD tissue. The lack of a parallel elevation of interferon-alpha does not support a role for viral induction of IL-15 in inflamed CD samples.

Assessment of Histologic Disease Activity in Crohnʼs Disease

“…These scoring systems have not become widely used in clinical research because they are based exclusively on rectal biopsies, which limit their generalizability to most patients with CD. 8,42 35 Numerical…”

“…Six features graded as normal (0), mild (1), moderate (2), and severe (3), and summed for a total score corresponding to normal (0-3), mild (4-8), moderate (9)(10)(11)(12)(13)(14), and severe (15)(16)(17)(18) Single prospective study of cytokines in pediatric CD 35 A. Acute inflammatory cell infiltration B.…”

Intestinal epithelial barrier dysfunction and dendritic cell redistribution during early stages of inflammation in the rat: Role for TLR-2 and -4 blockage

“…20 Homogenates were then centrifuged at 13,000 rpm for 15 minutes at 4°C and stored at Ϫ70°C until assay. Protein concentration was determined using a Bradford microplate assay.…”

Dendritic Cells and Toll-Like Receptors 2 and 4 in the Ileum of Crohn's Disease Patients

“…For the large intestine, one block per patient was obtained and histologically normal lymphoid follicles were avoided due to the scant amounts detected [4]. Tissues were classified as non-inflamed or inflamed according to a standard scoring protocol for CD histopathology that has been previously described [4,26]. Non-inflamed controls with normal histology from distal ileal (four male, two female; mean age 51.2 ± 8.0 years) and colonic (five male, two female; 65.8 ± 3.3 years; one cecum, one ascending colon, one transverse colon, one descending colon and three sigmoid specimens) samples were obtained, respectively.…”