Western blot analysis was carried out in order to evaluate new serodiagnostic markers, Em18 and
Em16, for differentiation of
alveolar echinococcosis (AE) from
cystic echinococcosis (CE) using 36 serum samples from hydatid patients from Xinjiang, China, where AE and CE are both endemic and one double
infection case has been reported. All AE cases except one (5/6) who exhibited a calcified lesion and a single case of double
infection showed antibody responses against Em18 and
Em16. Some of CE patient sera (6/22) showed antibody response against
Em16 except one who showed that against Em18. Analyses of
IgG subclass responses against Em18 and
Em16 were carried out using all serum samples showing antibody responses against Em18 and/or
Em16 (seven CE, five AE, and one AE + CE) and additional samples of three CE and 22 AE from Sichuan, China.
IgG4 was the most predominant antibody subclass. Em18 and
Em16 were recognized by both
IgG4 and
IgG1 (in most cases) or by either
IgG4 or
IgG1 (in minor cases) or by
IgG3 (in very rare cases). Neither Em18 nor
Em16 was recognized by
IgG2 antibodies. The usefulness of Em18 and
Em16 as potential new markers for serological differentiation of human AE and CE, respectively, is discussed.