THE ROLE OF CAGA+ STRAINS IN THE IMMUNE RESPONSE IN HELICOBACTER PYLORI PATIENTS

Abstract

The aim of this study was to elucidate the role of certain host factors (IL-17A andTreg), and bacterial factor (CagA) in the immunity against Helicobacter pylori (Hp)associated diseases. Sixty dyspeptic patients (as diagnosed by endoscopy and confirmedby histopathology) and thirty apparently healthy individuals were enrolled in this study.All subjects were evaluated for their serum IgG anti-Hp, IgG anti-CagA, and IL-17A,and blood Treg cells. The results reveal positive IgG anti-Hp in 92.5% of Hp patientsamong which 40.8% was CagA+. The frequency and the mean titer of IL-17A as well asthe Treg cell count were significantly high among the Hp-patients. This was true for theTreg: IL-17A ratio. However, no significant difference for such results was noticedbetween the CagA+ and CagA- strains. Finally, the IgG anti-Hp titer was significantlyhigher in CagA+ than CagA- patients for cases with gastritis and gastric ulcer. Inconclusion, detection of IgG anti-Hp in dyspeptic patients is helpful in the diagnosis ofHp-associated diseases and avoidance of endoscopy and biopsy. Treg cell count and IL-17A level are both high in the Hp patients indicating that both play an impairment roleof the host's immune mechanisms in eradication of the bacteria. CagA+ strain of Hp isnot a sufficient indicator for the prediction of the type and severity in Hp-associateddisease, however, this strain type plays a role in the modulation of the immune responsethrough induction of high titer of IgG anti-Hp.