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.