ON SEROLOGIC AND SKIN TESTS FOR STRONGYLOIDIASIS

Abstract. The aim of this study was to determine whether human T-cell lymphocytotropic virus type 1 (HTLV-1) infection may affect the levels of parasite-specific immunoglobulin (Ig) G and IgE and the positivity of the skin test for strongyloidiasis. Participants included 67 patients with strongyloidiasis (40 without HTLV-1 infection and 27 coinfected with HTLV-1). We determined IgG and IgE levels by enzyme-linked immunosorbent assay, and the im-mediate hypersensitivity skin test was performed with the metabolic Strongyloides stercoralis antigen. Specific IgE levels and the size of skin reactions in patients without HTLV-1 were higher (P 0.01) than those observed in patients coinfected with HTLV-1. Additionally, 89 % of patients without HTLV-1 had specific IgE and 92.5 % had positive skin tests; however, these values were significantly reduced (P 0.01) in patients coinfected with HTLV-1 (44 % and 59%, respectively). These data show that HTLV-1 infection decreases the sensitivity of detection of S. stercoralis-specific IgE, the size of the immediate hypersensitivity reaction, and the sensitivity of these tests in the diagnosis of strongyloidiasis