Human cystic echinococcosis: diagnostic value of different antigenic fractions of hydatid cyst fluid with different specific immunoglobulin G subclasses by enzyme linked immunoelectrotransfer blot.

The present study intended to evaluate the usefulness of immunoblot analysis of hydatid cyst fluid (HCF) for diagnostic verification of human cystic echinococcosis (CE). HCF of camel origin was resolved by SDS-PAGE gel electrophoresis and transblotted on nitrocellulose membrane. Immunoglobulin G (IgG) subclass-specific antibody responses in 25 sera from surgically confirmed CE cases, 44 persons with other parasitic infections and 20 normal controls were analyzed. Total IgG and IgG subclass1-4 in CE sera preferentially recognized several polypeptide bands in the range of 14-200 kDa. The most predominant band recognized by total IgG antibodies was at 21 kDa (sensitivity, 96%; specificity, 98.5%; J index, 94.5%), by IgG1 at 38 kDa (sensitivity, 92%; specificity, 100%; J index, 92%) and by IgG3 at 60 kDa (sensitivity, 96%; specificity, 100%; J index 96%). Sera from the normal controls did not recognize any of these polypeptides. These data suggest that detection of any of these polypeptides bands could be used for confirmation of human cystic echinococcosis in Egypt.