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- Arkestål, Kurt, et al.
(författare)
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Impaired allergy diagnostics among parasite-infected patients caused by IgE antibodies to the carbohydrate epitope galactose-alpha 1,3-galactose
- 2011
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 127:4, s. 1024-1028
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Tidskriftsartikel (refereegranskat)abstract
- Background: The carbohydrate epitope galactose-alpha 1,3galactose (a-Gal) is abundantly expressed on nonprimate mammalian proteins. We have recently shown that alpha-Gal is responsible for the IgE binding to cat IgA, a newly identified cat allergen (Fel d 5). Objective: We sought to investigate the diagnostic relevance of IgE antibodies to Fel d 5 and a-Gal among parasite-infected patients from central Africa without cat allergy compared with patients with cat allergy from the same region. Methods: Sera from 47 parasite-infected patients and 31 patients with cat allergy were analyzed for total IgE and IgE antibodies against cat dander extract (CDE) by using the ImmunoCAP system. Inhibition assay was performed with a-Gal on solid phase-bound CDE. The presence of IgE specific for the major cat allergen Fel d 1, Fel d 5, and alpha-Gal was analyzed by means of ELISA. Results: Among the 47 parasite-infected patients, 85% had IgE antibodies against alpha-Gal (OD; median, 0.175; range, 0.1021.466) and 66% against Fel d 5 (OD; median, 0.13; range, 0.1031.285). Twenty-four of the parasite-infected patients were sensitized to CDE, and 21 of them had IgE antibodies to Fel d 5 and a-Gal. There was no correlation between IgE levels to CDE and rFel d 1 among the parasite-infected patients but a strong correlation between CDE and Fel d 5 and alpha-Gal (P <. 001). Among the group with cat allergy, only 5 patients had IgE to alpha-Gal, and nearly 75% (n 5 23) had IgE to rFel d 1 (median, 7.07 kU(A)/L; range, 0.51-148.5 kUA/ L). In contrast, among the patients with cat allergy, there was a correlation between IgE levels to CDE and rFel d 1 (P <.05) but no correlation between CDE and Fel d 5 and alpha-Gal. Conclusion: IgE to alpha-Gal causes impaired allergy diagnostics in parasite-infected patients. Screening for IgE to rFel d 1 and other allergens without carbohydrates might identify patients with true cat sensitization/ allergy in parasite-infested areas.
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| 2. |
- Thors, Cecilia
(författare)
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Serodiagnostics of schistosomiasis using keyhole limpet hemocyanin (KLH) as antigen
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The diagnostics of invasive helminth infections is often indirect and based on antibody detection in serum specimens from infected individuals. This is the case in schistosomiasis (bilharzia) where no excreted eggs can be found in light, often asymptomatic, infection. Travellers, especially adventure tourists, and immigrants to endemic areas run a high risk of becoming infected. If the diagnosis is missed, infected individuals may carry intravascular worms for more than 30 years and thereby run a risk for tissue injury due to egg deposition. Early during infection antibodies against gut associated schistosome antigens (GAA) are detected by an indirect immunofluorescent assay where sections of adult worms are used as antigen. We observed a similar, previously unrecognised staining pattern in a significant proportion of GAA-positive sera, which subsequently was shown to be due to antibodies, which may cross-react with keyhole limpet hemocyanin (KLH). This cross-reacting glycoprotein, from the mollusk (Megathura crenulata), has been introduced as diagnostic antigen for the detection of antibodies against schistosomes. However,. in the literature the limited experience using KLH in diagnostics of early infection shows discrepant results. The aim of this study was to understand why antibodies, reacting with KLH, are produced during schistosomiasis and to evaluate the diagnostic potential of such antibodies. This was done by localisation of KLH-cross-reactive epitopes in the different life stages of the parasite and by partial identification by immunoblotting of electrophoretically separated schistosome egg components. We found that shared antigens are expressed in different life stages of the parasite: at the surface and in the secretions of the cercaria, at the schistosomula surface, in the excretory/secretory (E/S) ducts of the adult worms, in reproductive tissues, at the surface of the miracidia, in and around eggs in granulomas, and in Kupffer cells in the liver. These observations explain why an immune response against KLH-cross-reactive schistosome components is readily induced in infected individuals. However, when we evaluated a simple dotELISA for the detection of anti-KLH antibodies, it had poor specificity and the sensitivity varied when different patient groups were tested. A significant finding was that trichinellosis patients had anti-KLH antibodies and also reacted with schistosome ducts. We conclude that KLH is a potentially useful target antigen for serodi agnostics. However, multiple antigenic epitopes in KLH may explain reported discrepant results and specificity and sensitivity problems.
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