EM18, A NEW SERODIAGNOSTIC MARKER FOR DIFFERENTIATION OF ACTIVE AND INACTIVE CASES OF ALVEOLAR HYDATID-DISEASE

We determined whether detection of antibody response against a newly d etected epitope, designated Em18, among Echinococcus multilocularis an tigens could be a reliable marker for differentiation of active cases of alveolar hydatid disease (AHD) from inactive cases. Fifteen Alaskan patients with either active or inactive lesions of Al-ID previously c onfirmed clinically, pathologically, and serologically by the Em2-enzy me-linked immunosorbent assay (ELISA) were used for a blind test by We stern blotting. Ten and five cases were considered to be active and in active cases, respectively. One of the 10 cases classified serological ly as active was judged to be inactive based on clinical and pathologi c criteria; the patient had a recognizable parasitic lesion, and follo wing short-term treatment with albendazole, a biopsy of the liver show ed a degenerated lesion that did not grow in rodents. The five cases j udged to be inactive included two confirmed inactive cases with cicatr ized lesions and three active cases that showed the weakest values in the Em2-ELISA. The most predominant IgG subclass responding to Em18 wa s IgG,. In general, there were good correlations between 1) the antibo dy response against Em18 and the presence of active lesions and 2) the antibody response against Em18 and the Em2-ELISA values.