Laboratory detection of strongyloidiasis: IgG-, IgG₄- and IgE-ELISAs and cross-reactivy with lymphatic filariasis.

摘要

Enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of IgG, IgG₄ and IgE antibodies against Strongyloides stercoralis. A commercial ELISA (IVD Research, USA) was also used, and the sensitivities and specificities of the four assays were determined. Serum samples from 26 patients with S. stercoralis infection and 55 patients with other infections or no infection were analysed. Sensitivities of the IgG₄, IgG, IgE and IgG (IVD) assays were 76.9%, 84.6%, 7.7% and 84.6%, respectively, while the specificities were 92.7%, 81.8%, 100% and 83.6%, respectively. If filariasis samples were excluded, the specificities of the IgG₄-ELISA and both IgG-ELISAs increased to 100% and 98%, respectively. A significant positive correlation was observed between IgG- and IgG₄-ELISAs (r=0.4828; P=0.0125). IgG- and IgG- (IVD) ELISAs (r=0.309) were positively correlated, but was not significant (P=0.124). Meanwhile there was no correlation between IgG₄- and IgG- (IVD) ELISAs (r=0.0042; P=0.8294). Sera from brugian filariasis patients showed weak, positive correlation between the titres of antifilarial IgG₄ and the optical densities of anti-Strongyloides IgG₄-ELISA (r=0.4544, P=0.0294). In conclusion, the detection of both anti-Strongyloides IgG₄ and IgG antibodies could improve the serodiagnosis of human strongyloidiasis. Furthermore, patients from lymphatic filariasis endemic areas who are serologically diagnosed with strongyloidiasis should also be tested for filariasis.