ABSTRACT
Several genes of Helicobacter pylori, such as vacA, cagA, iceA and babA, have been reported to significantly increase the risk of gastrointestinal diseases. The aim of this study was to study the relationship between H. pylori virulence factors and clinical outcomes and identify the independent markers of peptic ulcer disease in Iraq. DNA was extracted from specimens taken from 154 unselected H. Pylori positive Iraqi patients. Genotyping was performed by the polymerase chain reaction [PCR] using specific primers for cagA, vacA [s, m], iceA and babA2 genes. A total of 56 [82%] peptic ulcer disease [PUD] patients carried cagA+ strains, significantly more than the 56 [65%] non-ulcer disease [NUD] patients [p = 0.017]. The difference in the prevalence ofbabA2 positivity was significant between patients with NUD [33.7%] and PUD [58.8%] [p = 0.002]. In addition, babA2 was associated as an independent factor, with PUD [p = 0.005; odds ratio [OR] = 0.4; confidence interval [CI] = 0.18-0.68] followed by cagA [p = 0.05; OR = 0.4; CI = 0.18-0.85]. Forty-five isolates [29%] were typed as 'triple positive' strains, and their presence was significantly associated with PUD [p = 0.001]. The cagA and babA2 genotypes might be considered as useful markers for PUD patients. However, iceAl and iceA2 seem not to be good markers for the disease. The presence of H. pylori strains with triple-positive status is of high clinical relevance to H. pylori-associated diseases
ABSTRACT
The duodenal ulcer promoting gene [dupA] has been identified recently and was found to associate with duodenal ulceration in some populations and gastric cancer in others. It was also found that this gene is polymorphic and dupAl [but not dupAZ] substantially increased H. pylori-induced IL-12 production from mononuclear cells. The aims of this paper were to determine the prevalence ofdupA polymorphisms in Iraq and Turkey and their effect on major cytokine secretion from peripheral blood mononuclear cells [PBMCs]. We studied a total of 85 H. pylon strains: 42 [non-ulcer disease [MUD]: 26; duodenal ulcer [DU]: 13; gastric ulcer [GU]: 3; gastric cancer [GC]: 0] which were isolated from Iraq and 43 [NUD: 28; DU: 12; GU: 2; GC: 1] from Turkey. dupA was PCR amplified then polymorphisms were studied by sequencing 10 and 9 dupA+ Iraqi and Turkish strains, respectively. It was found that none of the Iraqi strains and [22%] of Turkish strains typed as dupA1. Finally, 2 dupA1, 4 dupA2 and 2 dupA-negative strains were assessed for their ability to induce IL-12, IL-10 and IL-8 in PBMCs. The IL-12 response of PBMCs cultured for 48 hours with wild-type strains carrying the dupAl was significantly higher [strain: mean +/- sd pg/ml, WTD1A:416 +/- 22.8; WTD1B:405.9 +/- 22.4] than those induced by wild-type H. pylori carrying the dupA2 [WTD2A:290.7 +/- 16.3; WTD2B:252.5 +/- 5; WTD2C:262.1 +/- 14; WTD2D:279.5 +/- 17; p<0.02 for all] and than those typed dupA-negative [WTD-veA:258.5 +/- 12; WTD-veB:225.6 +/- 32; p<0.02 for all] . Regarding IL-8 and IL-10, we found no significant differences between dupAl and others. These data suggested that dupAl is rare in these two countries and dupAl plays an important role in IL-12 secretion from PBMCs. More research is needed to determine the functionality ofdupA and its relationship with disease