Gal d 6 is the second allergen characterized from egg yolk.

Only one allergen from the egg yolk, alpha-livetin (Gal d 5) has been described thus far. A new egg yolk allergen was detected studying 27 egg allergic patients. The study was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and IgE-immunoblotting and IgE-immunoblotting-inhibition assays. An egg yolk extract was fractioned by reverse-phase high-performance liquid chromatography (RP-HPLC), and the new allergen detected was characterized by N-terminal amino acid analysis. A total of 5 of the 27 patients (18%) detected a yolk allergen of an apparent molecular weight of 35 kDa by SDS-PAGE. Heating and reduction treatments did not affect its allergenicity, although digestion with simulated gastric fluid diminished the IgE-binding capacity of the allergen. The N-terminal amino acid sequence corresponded with the YGP42 protein, a fragment of the vitellogenin-1 precursor. Thus, a second egg yolk allergen has been described and designated Gal d 6 by the World Health Organization (WHO)/International Union of Immunological Societies (IUIS) Allergen Nomenclature Subcommittee.

Analysis of basophil activation by flow cytometry in pediatric house dust mite allergy.

Detection of allergen-induced basophil activation by flow cytometry has been shown to be a useful tool for allergy diagnosis. The aim of this study was to assess the potential of this technique for the diagnosis of pediatric house dust mite allergy. Quantification of total and specific IgE and basophil activation test were performed to evaluate mite allergic (n = 24), atopic (n = 23), and non-allergic children (n = 9). Allergen-induced basophil activation was detected as a CD63-upregulation. Receiver operating characteristics (ROC) curve analysis was performed to calculate the optimal cut-off value of activated basophils discriminating mite allergic and non-allergic children. ROC curve analysis yielded a threshold value of 18% activated basophils when mite-sensitized and atopic children were studied [area under the curve (AUC) = 0.99, 95% confidence interval (CI) = 0.97-1.01, p < 0.001] with a sensitivity and specificity of 96% for 16 microg/ml mite extract. Analysis of the data obtained with 1.6 microg/ml mite extract defined a cut-off value of 8% activated basophils (AUC = 0.96, 95% CI = 0.91-1.01; p < 0.001) with a sensitivity of 82% and specificity of 100%. Comparison between mite allergic and non-allergic children produced a cut-off of 8% activated basophils (AUC = 1.0) with 16 microg/ml allergen extract and a sensitivity and specificity of 100%. The same threshold and specificity values were obtained with 1.6 microg/ml extract (AUC = 97%, 95% CI = 0.92-1.02; p < 0.001) but sensitivity decreased to 83%. Two atopic children showed negative skin prick and basophil activation tests and high specific IgE (>43 kU/l) values for Dermatophagoides pteronyssinus allergen. They also showed positive prick (wheal diameter >1.0 cm) and basophil activation (>87%) tests and high specific IgE (>100 kU/l) with shrimp allergen. Shrimp sensitization was demonstrated by high levels of Pen a 1-specific IgE (>100 kU/l). Cross-reactivity between mite and shrimp was confirmed by fluorescence enzyme immunoassay (FEIA-CAP) inhibition study in these two cases. This study demonstrated that the analysis of allergen-induced CD63 upregulation by flow cytometry is a reliable tool for diagnosis of mite allergy in pediatric patients, with sensitivity similar to routine diagnostic tests and a higher specificity. Furthermore, this method can provide additional information in case of disagreement between in vivo and in vitro test results.

Diagnóstico de laboratorio de parotiditis en la era posvacunal / Laboratory diagnosis of parotitis in the post-vacinattion era

No disponible