study of Helicobacter pylori duodenal ulcer promoting gene [cfupA] polymorphisms in Iraq and Turkey and their role in IL-12 secretion

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, WTD1A416 +/- 22.8; WTD1B405.9 +/- 22.4] than those induced by wild-type H. pylori carrying the dupA2 [WTD2A290.7 +/- 16.3; WTD2B252.5 +/- 5; WTD2C262.1 +/- 14; WTD2D279.5 +/- 17; p<0.02 for all] and than those typed dupA-negative [WTD-veA258.5 +/- 12; WTD-veB225.6 +/- 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