Diagnostic Potential of an IgE-ELISA in Detecting Strongyloidiasis

Abstract

Strongyloides stercoralis infection is prevalent worldwide and can cause lifelong infection in immunocompetent individuals, and potentially death in immunosuppressed patients. The diagnosis is hindered by the low sensitivity of microscopic examination, thus making serology an important complementary test to improve the detection rate. However, there were reports that some Strongyloides-infected individuals were negative with specific IgG and IgG4 assays, and other helminth infections were positive with commercial Strongyloides IgG-ELISAs. Thus, there is a need to develop better serodiagnostic methods for strongyloidiasis. We investigated the diagnostic potential of IgE-ELISAs using Strongyloides larval lysate. Sera from two groups infected with Strongyloides served as the positive reference, that is, 1) positive by commercial IgG-ELISAs and IgG4 rapid test, and stool samples positive by microscopy and/or PCR (group IA; n = 20); and 2) negative by IgG-ELISAs and IgG4 rapid test, but stool samples were PCR positive (group IB sera; n = 11). Sera from another two groups served as negative reference (controls), that is, 1) infected with other parasites (group II; n = 73) and 2) healthy donors (group III; n = 22). Results showed a 100% diagnostic sensitivity in detecting sera from groups IA and IB. The latter group of individuals probably had early infection because their IgG and IgG4 assays were negative. The optical density values of group IB sera were also significantly lower than those of group IA (P < 0.003). The IgE-ELISA was 100% specific when tested against sera from groups II and III. This study highlights the diagnostic potential of IgE-ELISA using larval lysate to detect strongyloidiasis, especially those with probable early infection.

Strongyloides-Specific IgE Phage cDNA Clones and Development of a Novel ELISA for Strongyloidiasis

“…The initial evaluation results show it has good potential for further studies to confirm its diagnostic value in detecting both acute and chronic cases of strongyloidiasis. The sensitivity and specificity findings in this study are consistent with those observed in our earlier IgE-ELISA using larval lysate [38]. The results are also consistent with other researchers' reports that IgE is an important marker for strongyloidiasis, especially in cases of probable early/acute infection [33,48].…”

“…In our earlier report on IgE-ELISA using sonicated Strongyloides larval crude (unpurified) lysate antigen, the range of OD 405 values obtained with Group IA sera was 0.231 to 0.680 (mean 0.432), and Group IB ranged from 0.227 to 0.429 (mean 0.297) [38]. In the present study, the IgE-ELISA OD 405 values of Group IA ranged from 0.280 to 1.220 (mean 0.730), and Group IB ranged from 0.351 to 0.573 (mean 0.442).…”

“…Furthermore, we have shown that IgE-enzyme linked immunosorbent assay (ELISA) using larval lysate was sensitive and specific in detecting strongyloidiasis [38]. For sustainable production of a diagnostic test, the use of recombinant protein is much preferred to native parasite antigens; thus, in the present study, we screened an S. stercoralis complementary DNA (cDNA) library with serum samples to identify cDNA clones specifically reactive to IgE antibodies in sera of Strongyloides-infected patients.…”

Seroprevalence of Strongyloides stercoralis in Patients about to Receive Immunosuppressive Treatment in Gran Canaria (Spain)

“…For this reason, the meta-analysis published by Buonfrate in 2018 [ 19 ] concludes that PCR might not be suitable for screening purposes, whereas it might have a role as a confirmatory test. Multiple serological techniques have been described for the diagnosis of strongyloidiasis that differ in several aspects: (i) the applied methodology; (ii) the immunoglobulin isotype detected, and (iii) the type of antigen used [ 21 , 22 , 23 , 24 , 25 , 26 ]. In different studies, the applied methodology is variable (i.e., enzyme-linked immunosorbent assay [ELISA], dipstick methods, luciferase immune-precipitation systems [LIPS] or immunofluorescence antibody test [IFAT] [ 22 , 25 ].…”

“…The humoral response to Strongyloides stercoralis infection includes the generation of different immunoglobulin isotypes (IgM, IgA, IgG1, IgG4, and IgE). The generation of IgM or IgA declines quickly and, therefore, does not have great diagnostic value in infected persons except in the initial acute phase (4–6 weeks) [ 24 ].…”