Interleukin– 17agene Polymorphism, Serum Level and Its Tissue Expression in Iraqi Patients Gastric Lesions

BACKGROUND: T-helper 17 plays a novel role in inflammation in gastritis by producing IL-17A, IL-17A gene polymorphisms that might be responsible for disease susceptibility and development of different gastric lesions. OBJECTIVE: The aims of study was to determine the association of IL-17A (G197A) genotype and allele frequency with disease phenotype and risk with different gastric lesions. METHODS: Case controlled study involved 30 gastroduodenal ulcer, 30 chronic gastritis and 30 subjects as a control group with negative endoscopic findings. After genomic DNA extraction, IL-17A (G197A)ARMS-PCR genotyping were done for all cases. Serum IL-17A was measured using ELISA method and tissue expression was visualized using immunohistochemistry staining method. RESULTS: The results showed that allele A was significantly frequent in gastroduodenal ulcer more than that in healthy control odd ratio= 4 (1.42-10.46), and none significantly with chronic gastritis p=0.071. Serum IL-17A was significantly higher in gastroduodenal ulcer (116.45±48.09 pg/ml), chronic gastritis (78.02±30.17pg/ml) and healthy control 19.36±9.28 pg/ml).However, the serum IL-17A level is not related to the allele pattern of each group. The tissue expression was expressed as dense granular cytoplasmic and membranous of inflammatory cells. Interestingly, the percentage of IL-17A protein expression was significantly higher in gastroduodenal ulcer (38.2±16.55%), chronic gastritis (30.89±14.02%) and normal mucosa (2.8±3.02%). Furthermore, patients with strong intensity of IL-17A stained mucosa were frequently carrier for mutant allele (68%). CONCLUSION: IL-17A might predispose for aggressive inflammation of advanced lesions in stomach like ulcer.