Zeinab N.Said , Magda I.M.El Mahdy*,Mona M.Morsy**

and Hanaa Hassan ***

Microbiology,*Clinical Pathology,**Internal Medicine and***Pathology

Departments, Faculty of Medicine(for girls). AL Azhar University

ABSTRACT

Helicobacter pylori (H.pylori) is a Gram negative microaerophylic bacterium that is closely associated with gastroduodenal diseases. The prevalence of H.pylori infection is high world wild. Cytotoxin –associated protein (cag A)encoded by cag A gene has been reported to be a major virulence factor of H.pylori infection. The aim of this study is to investigate the H.pylori cag A status and its relationship to endoscopic and histopathological findings as well as serum and local interleukin-18 (IL-18) production. Sera and antral biopsy were taken from 40 patients with dyspepsia.The presence of H.pylori was confirmed by culture, histopathology and polymerase chain reaction (PCR),while cag A gene was detected by PCR. Serum and gastric tissue IL-18 were measured. H.pylori was detected in 30 out of the 40 patients (75%) and cag A gene was detected in 16 out of 40 (40%) and was absent in 14 out of 40 (35%) patients.Ten out of the 40 patients (25%) were H.pylori -negative. Serum Il-18 was significantly higher in cag A-positive patients as compared to cagA –negative H.pylori infected patients (p<0.001)and to H.pylori-negative patients (p<0.001). Tissue IL-18 also showed significant increase in cag A-positive patients as compared to cag A-negative patients (p<0.05) as well as compared to non infected patients (p<0.001).There was significant positive correlation between serum and tissue IL-18 (r=0.951.p<0.01). Also, there was significant positive correlation between tissue IL-18 and mucosal H.pylori density (r=0.072;p<0.01), neutrophil (r=0.84;p<0.01) and mononuclear leucocyte infiltration (r0.54=;p<0.05) in cag A positive H.pylori infected patients. It was concluded that cag A –positive strains of H.pylori are associated with higher bacterial density, greater histopathological changes and increased systemic and local IL-18 production. This enhanced inflammatory response is thought to have role in disease pathogenesis, explaining the occurrence of peptic ulcer and sever gastritis with cag A positive strains.

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