Skin test antigens for immediate hypersensitivity prepared from infective larvae of Strongyloides stercoralis

More rapid and simplified diagnostic procedures are needed for the diagnosi s of strongyloidiasis. One approach is the use of an immediate hypersensiti vity skin test that would reliably identify infected people. Accordingly, s omatic and excretion/secretion (E/S) antigens were prepared from filariform larvae of Strongyloides stercoralis and were treated to remove possible ad ventitious agents. By use of a quantitative method for measurement of skin reactions, several preparations of the 2 antigens were tested in uninfected controls and in various groups of patients. Doses of 0.35 mug of E/S and 4 mug of somatic antigens elicited positive skin tests in 82-100% of infecte d people, depending on clinical status. A lower frequency of positive skin tests was found in strongyloidiasis patients also infected with human T-cel l lymphotropic virus type 1. Cross-reactions, especially to somatic antigen s, were frequently found in patients with filarial infections. Despite thes e limitations and the need for further study of specificity, these results provide a basis for future development of a diagnostic skin test antigen fo r strongyloidiasis.