Determination of antibodies to crude Opisthorchis viverrini antigen in sera of cholangiocarcinoma patients

Abstract

Over 8 million people in the northeastern region of Thailand are infected with liver flukes Opisthorchis viverrini (Ov), a cause of opisthorchiasis associated cholangiocarcinoma (CCA), a malignant tumor arising from bile duct epithelium. The proven oncogenic risk factor is Ov infection that can induce chronic inflammation and immune response. The present study aimed to investigate the level of serum IgG antibody to a crude Ov antigen in CCA patients, compared with a normal ultrasonography group by enzyme-linked immunosorbent assay (ELISA) and to study the correlations with clinicopathological parameters of CCA patients. Of 45 each for CCA and normal cases, 35.6% and 53.3% were positive for Ov IgG antibody, respectively. In addition, the level of IgG to Ov antigen was statistically associated with severity of tumor stage (P=0.036) and also had a trend to associate with shorter survival time of CCA patients. Statistical difference of IgG antibody level was not observed between CCA and normal ultrasonography group. In summary, antibody to crude Ov antigen in sera may not be used as a biomarker to predict the risk of CCA patients. The levels of Ov IgG antibody seem to be associated with the severity of CCA patients. However, molecular mechanisms in this issue are needed to be proven.