SERUM ANTIBODY-RESPONSE TO OPISTHORCHIS-VIVERRINI ANTIGEN AS A MARKERFOR OPISTHORCHIASIS-ASSOCIATED CHOLANGIOCARCINOMA

The liver flukes Opisthorchis viverrini and Clonorchis sinensis chroni cally infect over 30 million people in south-eastern Asia, resulting i n significant morbidity and a predisposition to cholangiocarcinoma (CC A). Liver fluke-associated CCA carries a poor prognosis, partly becaus e it is often detected at a late and advanced stage. The development o f improved diagnostic methods, particularly for early CCA, may improve chances of survival and cure. Accordingly, we explored the use of imm unological responses to liver fluke antigens as a potential means of i dentifying individuals at high risk for liver fluke-associated CCA. Se rum antibody responses to O. viverrini adult worm homogenate and metac ercaria homogenate (MH) were studied using enzyme-linked immunosorbent and immunoblot assays in 65 infected residents of an opisthorchiasis- endemic area in Thailand. Antibody levels correlated with liver ultras onography (U/S) findings, and immunoblot analysis revealed a 91/93 kDa MH doublet recognized only by sera of individuals with severe liver U /S findings, including CCA. These results suggest that serum antibody responses to liver fluke antigens may be useful in the identification of infected individuals who are at high risk for liver fluke-associate d CCA.