Long-term serological evaluation of patients with cystic echinococcosis treated with benzimidazole carbamates

Abstract

Seeking better immunological markers indicating the long-term outcome of cystic echinococcosis (CE) after chemotherapy we studied 23 patients receiving albendazole, clinically followed for 8 years, and grouped ultrasonographically according to therapeutic outcome. Antibody responses against a partially purified fraction of hydatid fluid (HFF) and antigen B (AgB) were evaluated by indirect haemagglutination (IHA), ELISA and immunoblotting (IB). Although IHA titres varied over the course of treatment, differences in mean antibody titres to HFF between groups were significant only at 4 years (P = 0.031). IgG isotype expression remained unchanged during follow-up whereas IgE expression decreased in patients with cured or stable disease. AgB disclosed higher IgG4 expression (P < 10(-4); P = 0.025) and lower IgG1 expression than HFF (P < 10(-4); P = 0.022). IHA antibody titres were higher in patients with progressive than in those with cured or stable disease, even in those with the same cyst type. ELISA isotype profiles differed between groups, particularly for type CE 3, 4 and 5 cysts: higher serum IgG1 and IgG3, lower IgG4 and IgE in patients with cured or stable disease. Although combined serological testing provides scarce information on the long-term outcome of CE after chemotherapy it may be useful for reviewing in a retrospective study the outcome of a cyst and for assessing the host-parasite relationship.

Fig. 1

Antibody response determined by indirect haemagglutination in the 23 patients with cystic echinococcosis pharmacologically treated with albendazole and grouped according to the outcome of chemotherapy. Serum samples were collected before chemotherapy (□), at 4 years after chemotherapy began () and at the end of follow-up (▪). Student's t-test was used to compare differences between arithmetic means. *P = 0·031

Fig. 2

Antibody isotype pattern determined by ELISA in the 23 patients with cystic echinococcosis pharmacologically treated with albendazole and grouped according to the outcome of chemotherapy. Serum samples were collected before chemotherapy (□), at 4 years after chemotherapy began () and at the end of the 8-year follow-up (▪). Student's t-test was used to compare differences between arithmetic means. *P < 10⁻⁴; †P = 0·022; ‡P = 0·025. Data represent means ± 2 SD of triplicate experiments.

Fig. 3

Immunoblotting after 12% SDS-PAGE of hydatid fluid fraction and antigen B under non reducing conditions revealed with antisera specific to total IgG (lane a), IgG1 (lane b), IgG2 (lane c), IgG3 (lane d), IgG4 (lane e), IgE (lane f).

Fig. 4

Antibody response determined by indirect haemagglutination in the 23 patients with cystic echinococcosis pharmacologically treated with albendazole and grouped according to the type of cyst as classified by ultrasonographic scans in accordance with the WHO Informal Group on Echinococcosis [12]. Differences between arithmetic means did not result statistically significant when tested by Student's t-test. □ Patients with cured or stable disease; ▪ Patients with progressive disease.

Fig. 5

Antibody isotype pattern determined by ELISA in the 23 patients with cystic echinococcosis pharmacologically treated with albendazole divided according to the type of cyst as classified by ultrasonographic scans in accordance with the WHO Informal Group on Echinococcosis [12]. Differences between arithmetic means did not result statistically significant when tested by Student's t-test. Note the higher IgG1 and IgG3 in stable disease and the higher IgG4 and IgE in progressive disease. Data represent means ± 2 SD of triplicate experiments. □ Patients with cured or stable disease; ▪ Patients with progressive disease.