Immunodiagnosis of schistosomiasis patients in The Netherlands: comparison of antibody and antigen detection before and after chemotherapy.

We investigated in a retrospective study the application of an enzyme-linked immunosorbent assay (ELISA) for the quantitative detection of the schistosome circulating anodic antigen (CAA) to the diagnosis of schistosomiasis in our laboratory. CAA-titres were compared with IgG-titres as determined with an ELISA using soluble egg antigen (SEA) and IgM-titres as determined in an immuno fluorescence assay (IFA) on sections of Rossman's fixed schistosomes. Pre- and post-treatment serum samples of 182 individuals, suspected for schistosomiasis, were used for this study, including 100 control samples. CAA was detected in 20.7% of all patients who were positive in either IFA or SEA-ELISA or both. CAA-titres did not correlate with either IgM-titres or IgG-titres. No significant drop in IgG level was found after specific treatment (Wilcoxon's P = 0.35). In contrast, a significant fall in both IgM-titre (P less than 0.01), and CAA-level (P less than 0.01) was observed. All CAA-titres became negative after chemotherapy.