Distribution of levels of antibody to NIE, as determined by ELISA (A) and luciferase immunoprecipitation systems (LIPS) assay (B), in patients infected with Strongyloides stercoralis, filaria, or helminths and in healthy, uninfected control subjects (normals). The 6 helminth-infected patients were a subset of the filaria-infected group. C, Levels of antibody to S. stercoralis immunoreactive antigen, as determined by LIPS assay. A significant difference between S. stercoralis–infected and uninfected control subjects was found for all 3 assays (P < .0001; Mann-Whitney U test). No significant difference was found between the control subjects and the filaria-infected patients for the NIE LIPS assay (P = .6909; Mann-Whitney U test).