Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.

中文翻译：

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新型幽门螺杆菌东亚型CagA ELISA的特征，用于检测感染了各种cagA基因型的患者。

当前，在大多数商业幽门螺杆菌CagA ELISA试剂盒中，西方型CagA用于检测CagA，而不是东亚型CagA。我们评估了我们小组开发的东亚型CagA ELISA在感染了不同幽门螺杆菌cagA基因型的患者中检测抗CagA抗体的能力。来自南亚和东南亚的四个不同国家。表达重组CagA蛋白，随后使用GST-tag亲和色谱法纯化。使用东亚型CagA固定化ELISA来测量来自不丹，印度尼西亚，缅甸和孟加拉国的750个血清样品中的抗CagA抗体水平。通过接收者操作特征（ROC）分析确定每个国家的血清抗体的临界值。在研究的四个国家中，临界值不同（不丹为18.16 U / mL；印度尼西亚为6.01 U / mL；缅甸为10.57 U / mL；孟加拉国为6.19 U / mL）。我们的ELISA在主要感染东亚型CagA幽门螺杆菌的受试者中具有更好的灵敏度，特异性和抗CagA抗体检测准确性（不丹和印度尼西亚）的感染率高于以西方CagA幽门螺杆菌感染的人群（缅甸和孟加拉国）。我们在所有四个国家的受试者中发现抗CagA抗体与肛门单核细胞浸润之间呈正相关。细菌密度与胃窦或体中的抗CagA抗体之间没有显着关联。东亚型CagA ELISA在感染东亚型CagA幽门螺杆菌的受试者中检测到的抗CagA抗体得到了改进。因此，应在主要感染东亚型CagA的人群中使用东亚型CagA ELISA。