The humoral immune response in patients with
opisthorchiasis was investigated using an
enzyme-linked
immunosorbent assay.
IgG antibody reactive with Opisthorchis viverrini
antigens was present in the serum of all patients. The
infection also stimulated specific
IgA and
IgE antibody responses in most patients and, in practically all patients, there was a marked increase of total
IgE. There was a moderate but significant correlation between serum
IgG antibody level and severity of
infection as judged from the quantity of eggs in the stool of the patients. There was also a significant elevation of antibody in the bile and serum of O. viverrini-infected patients who also had biliary obstruction. Analysis of paired samples from individual patients showed that while
IgG was the predominant class of antibody in the serum of all patients,
IgA was present at approximately the same level as
IgG or higher in the bile of many patients. In addition to
IgA and
IgG antibodies,
IgE antibody was also detectable in 50% of the bile samples. The high level of
IgA antibody in the bile together with its presence in association with the
secretory component suggested a selective transport and/or local production of
IgA antibody by the hepatobiliary system of these patients.