Immunopathogenesis of Progressive Scarring Trachoma: Results of a 4-Year Longitudinal Study in Tanzanian Children
INFECTION AND IMMUNITY
Authors: Derrick, Tamsyn; Ramadhani, Athumani M.; Macleod, David; Massae, Patrick; Mafuru, Elias; Aiweda, Malisa; Mbuya, Kelvin; Makupa, William; Mtuy, Tara; Bailey, Robin L.; Mabey, David C. W.; Holland, Martin J.; Burton, Matthew J.
Abstract
Trachoma is initiated during childhood following repeated conjunctival infection with Chlamydia trachomatis, which causes a chronic inflammatory response in some individuals that leads to scarring and in-turning of the eyelids in later life. There is currently no treatment to halt the progression of scarring trachoma due to an incomplete understanding of disease pathogenesis. A cohort study was performed in northern Tanzania in 616 children aged 6 to 10 years at enrollment. Every 3 months for 4 years, children were examined for clinical signs of trachoma, and conjunctival swabs were collected for C. trachomatis detection and to analyze the expression of 46 immunofibrogenic genes. Data were analyzed in relation to progressive scarring status between baseline and the final time point. Genes that were significantly associated with scarring progression included those encoding proinflammatory chemokines (CXCLS, CCL20, CXCL13, and CCL18), cytokines (1L23A, 119, and IL1B), matrix modifiers (MMP12 and SPARCL1), immune regulators (IDOo1, SOCS3, and IL10), and a proinflammatory antimicrobial peptide (S100A7). In response to C trachomatis infection, IL23A and PDGF were significantly upregulated in scarring progressors relative to in nonprogressors. Our findings highlight the importance of innate proinflammatory signals from the epithelium and implicate interleukin 23A (IL-23A)-responsive cells in driving trachomatous scarring, with potential key mechanistic roles for PDGFB, MMP12, and SPARCL1 in orchestrating fibrosis.
Differential mucosal expression of Th17-related genes between the inflamed colon and ileum of patients with inflammatory bowel disease
BMC IMMUNOLOGY
Authors: Bogaert, Sara; Laukens, Debby; Peeters, Harald; Melis, Lode; Olievier, Kim; Boon, Nico; Verbruggen, Gust; Vandesompele, Jo; Elewaut, Dirk; De Vos, Martine
Abstract
Background: Immunological and genetic findings implicate Th17 effector cytokines in the pathogenesis of inflammatory bowel disease (IBD). Expression of Th17 pathway-associated genes is mainly studied in colonic disease. The present study assessed the mRNA expression levels of Th17 effector cytokines (IL17A, IL17F, IL21, IL22 and IL26) and genes involved in differentiation (IL6, IL1B, TGFB1, IL23A and STAT3) and recruitment of Th17 cells (CCR6 and CCL20) by quantitative real-time PCR analysis of colonic and ileal biopsies from 22 healthy control subjects, 26 patients with Crohn's disease (CD) and 12 patients with ulcerative colitis (UC). Inflammation was quantified by measuring expression of the inflammatory mediators IL8 and TNF. Results: Evaluation of mRNA expression levels in colonic and ileal control samples revealed that TNF, TGFB1, STAT3 and CCR6 were expressed at higher levels in the ileum than in the colon. Expression of all the Th17 pathway-associated genes was increased in inflamed colonic samples. The increased expression of these genes was predominantly observed in samples from UC patients and was associated with more intense inflammation. Although increased expression of IL17A, IL17F, IL21 and IL26 was detected in inflamed ileal samples, expression of the indispensable Th17 cell differentiation factors TGFB1 and IL23A, the signaling molecule STAT3 and the Th17 recruitment factors CCR6 and CCL20 were unchanged. Conclusions: Our findings suggest that immune regulation is different in colonic and ileal disease, which might have important consequences for therapeutic intervention.