登革病毒感染目前被認為是全球最主要的蚊媒傳染病。登革病毒感染的臨床表現相當多樣性，從輕微的發燒，到合併出血、休克均有可能發生。由於目前並無安全有效的疫苗與抗病毒藥物，主要仰賴臨床的早期診斷與支持性療法，若病情進展至登革出血熱/登革休克症候群時，有很高的致死率。因此如何早期預測登革感染的嚴重度與治療嚴重登革感染，一直是全球登革研究的重點所在。我們經由分析急性登革病毒感染病人常見的臨床與實驗室特徵，發現多種有助於早期預測急性登革熱感染的重要指標，包含：白血球低下(leucopenia)、血小板低下(thrombocytopenia)、轉氨酶濃度上升(elevated aminotransferases)、C-反應蛋白下降(low C-reactive protein)、活化部份凝血活酶時間延長(prolonged activated partial thromboplastin time)等結合可達成極高陽性預測率(positive predictive value, 93.1%)。過去的研究亦發現，病毒非結構蛋白1（NS1）和高遷移率族蛋白-1（HMGB1）蛋白與登革感染的疾病嚴重程度可能有關。然而，病毒蛋白與這類先天免疫調節因子之間的互動關係仍不清楚。我們追蹤了不同臨床嚴重度的實驗室確診登革熱患者之動態變化。發現所有登革熱患者的血中HMGB1濃度明顯升高，且與疾病嚴重度有關。 臨床病人之周邊血液單核細胞中發現HMGB1會由細胞核內易位至細胞質，同時伴隨HMGB1 mRNA合成增加；這種現象在嚴重度高的病患最為明顯。為了研究此一現象之機轉，我們使用登革病毒感染人類K562細胞株模式，成功地在體外重現臨床檢體之發現。進一步發現，只有登革和茲卡病毒NS1蛋白可有效誘導K562細胞中HMGB1的細胞內易位，而其他黃病毒的NS1蛋白中則無明顯效果，且NS1中和抗體可逆轉此現象。病毒NS1和HMGB1血中濃度均與登革熱感染的臨床嚴重程度相關，而登革病毒NS1是造成HMGB1細胞內易位之原因，這些發現將有助於了解登革重症發生之致病機轉與治療藥物之研發。
理想上，若能早期診斷登革熱重症，即可以提供有效的病情監控管理，降低併發症與死亡率。 然而，目前現有的檢驗技術尚無法滿足預測登革熱嚴重度的臨床需求。我們亦以偵測病人血清中非結構性蛋白1與凝血酶複合物來發展登革感染的酵素免疫分析法(enzyme-linked immunosorbent assay, ELISA)與側流式免疫分析(lateral flow immunoassay, LFIA)快速診斷套組，經成大醫院的登革病人血清庫進行先期試驗驗證，發現新檢驗試劑之敏感度較市售試劑套組高且可以預測登革重症，此發現已獲得台灣專利，目前持續進行產品優化中。

Dengue has become a globally important mosquito-borne infectious disease. The clinical manifestations of dengue virus infection are quite diverse, ranging from mild fever to hemorrhage and shock. Since there are no effective vaccines and antiviral drugs, it relies mainly on early clinical diagnosis and supportive medical care. If the disease progresses to dengue hemorrhagic fever/dengue shock syndrome, there is a high mortality rate. Therefore, how to predict the severity of dengue infection and treat severe dengue infection early has been the focus of global dengue research. We identified that the combination of leucopenia, thrombocytopenia, elevated aminotransferase, low C-reactive protein and prolonged activated partial thromboplastin time severed as good predictive markers (positive predictive value 93.1%) of laboratory-confirmed dengue during an outbreak in Southern Taiwan. Viral nonstructural protein 1 (NS1) and host high mobility group box-1 (HMGB1) protein were related to the severity of illness in dengue infections. HMGB1 nucleocytoplasmic translocation was also observed in dengue-infected cells. However, the interaction between viral NS1 protein and host HMGB1 remains unclear. Serum HMGB1 levels were elevated in all dengue patients and tended to be higher in those who with severe disease. Serum NS1 levels was also elevated in dengue patients. HMGB1 translocated from the nucleus to the cytoplasm in peripheral blood mononuclear cells (PBMC) of dengue patients, accompanied by an increase in HMGB1 mRNA. Both dengue and Zika viral NS1 proteins could induce intracellular translocation of HMGB1 in human K562 cells, while the NS1 proteins of other flaviviruses have no obvious effects. These findings will help to understand the pathogenesis and develop new treatment for severe dengue. Besides, NS1 was found to form complex with host coagulation factors, i.e. thrombin especially in severe dengue infection. We developed novel diagnostic kits for detecting NS1-thrombin complex using enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay (LFIA). Higher sensitivity for detecting dengue infection is achieved by detecting NS1-thrombin complex. The diagnostic kits could successfully detect all four serotypes of dengue viruses. Serum NS1-thrombin complexes were elevated earlier in fatal dengue cases and correlated well with the clinical deterioration. The newly developed diagnostic kits for dengue severity had good performance in the pilot study.

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