• Junpu Li, Shaoshen Li, Lunhui Huang, Yaqiong Cui, Tiantian She, Ying Bian, and Huiqiang Li.
• School of Medical Laboratory, Tianjin Medical University, 1 Guangdong Road, Hexi District, Tianjin 300203, China.
• Clin. Chim. Acta. 2019 Feb 1; 489: 83-88.

BackgroundAn increase in allergen-specific IgG4 (sIgG4), which serves as a blocking antibody, is associated with acquisition of immune tolerance after immunotherapy. In this study, we developed a rapid, sensitive, and homogeneous immunoassay based on the light-initiated chemiluminescent assay (LICA) technology for quantifying allergen sIgG4 in serum samples.MethodsAllergen sIgG4 was measured in vitro by incubating the sample with biotinylated allergens and chemiluminescent beads coated with anti-human IgG4 antibody, followed by the addition of streptavidin-coated sensitizer beads. Multiple tests were performed to optimize the working conditions of the LICA and evaluate its performance.ResultsWe established the optimal concentration of biotinylated allergens (250 ng/mL), the optimal dilution range (1:8 for Gal d 1, Gal d 2 sIgG4 and 1:4 for Gal d 3, Gal d 4 sIgG4), and the optimal incubation time (20 min for Gal d 1, Gal d 2 sIgG4 and 40 min for Gal d 3, Gal d 4 sIgG4). The lower limit of quantification (LLOQ) was 0.261 ng/mL. The coefficient variation (CV) of the LICA was <10%. The assay was unaffected by general interfering substances at physiological concentrations. It exhibited excellent accuracy to detect allergen-sIgG4 in human serum. Additionally, we demonstrated that the levels of Gal d 1, Gal d 2, and Gal d 3-sIgG4 were significantly higher in the egg allergy group (p < .05), but no differences were found between the groups for Gal d 4-sIgG4.ConclusionsThe LICA demonstrated satisfactory performance and can be used for quantifying allergen sIgG4 in clinical practice.Copyright © 2018 Elsevier B.V. All rights reserved.

19 keywords...

hide…