ANALYSIS OF IMMUNOGLOBULIN-G SUBCLASS IN THE SERUM ANTIBODY-RESPONSESOF ALVEOLAR ECHINOCOCCOSIS PATIENTS AFTER SURGICAL-TREATMENT AND CHEMOTHERAPY AS AN AID TO ASSESSING THE OUTCOME

Immunoglobulin G (IgG) subclass-specific antibody responses were evalu ated for the follow-up of alveolar echinococcosis (AE) patients. Seven ty-four sequentially collected sera from 25 Chinese and French AE case s who underwent surgery including hepatectomy, liver transplant and/or chemotherapy were analysed quantitatively and qualitatively during th e clinical follow-up period. These AE patients were classified in 4 gr oups-cured, improved, stabilized, or aggravated. Serum antibody levels of the subclasses IgG1 and IgG4 were significantly higher in the AE p atients than in healthy controls. IgG1 and 1gG4 isotypes in AE patient s were the most sensitive IgG antibody response in an enzyme-linked im munosorbent assay (ELISA) and in binding to antigens of 44kDa, 35kDa, 27kDa, 21kDa and 17.5kDa in an Echinococcus multilocularis proto-scole x extract after Western blotting. In AE cases classed as cured or impr oved, IgG subclass antibody levels tended to decrease earlier than tot al IgG levels, especially IgG4 antibody levels which became negative w ithin one year after successful treatment. IgG4 antibody levels also d ecreased in most of the improved cases. Increasing or unchanged levels ofIgG4 and IgG1 antibodies were demonstrated in both stabilized and a ggravated AE cases using both ELISA and immunoblot assays. Reappearanc e of specific IgG4 antibodies was a strong indication of recurrence, e specially in liver transplant patients. Combined quantitative and qual itative assessment ofIgG1 and IgG4 antibodies may be potentially usefu l for the serological follow-up of human AE.