Correlation between food-specific IgG antibodies and phenotypes of chronic spontaneous urticaria / 中华皮肤科杂志

ABSTRACT

Objective:To investigate the correlation between food-specific IgG (sIgG) antibodies and phenotypes of chronic spontaneous urticaria (CSU) .Methods:Serum samples were collected from outpatients with active CSU, symptomatic dermographism (SD) , or acute urticaria (AU) , and healthy controls from 5 third-grade class-A hospitals such as the First Hospital of China Medical University between April 2014 and March 2015. Enzyme-linked immunosorbent assay was conducted to detect serum levels of 90 food-sIgG antibodies and total IgE, Western blot analysis to detect levels of 20 allergen-specific IgE antibodies, and chemiluminescent microparticle immunoassay to detect levels of anti-thyroid peroxidase IgG antibodies and anti-thyroglobulin IgG antibodies. Comparisons of normally distributed quantitative data between two groups and among several groups were performed by t test and one-way analysis of variance, respectively; comparisons of non-normally distributed quantitative data between two groups were performed by Mann-Whitney U test; for comparisons of proportions, chi-square test and Fisher′s exact test were used. Results:A total of 248 patients with CSU, 22 with SD, 15 with AU and 13 healthy controls were recruited. The cut-off level for sIgG positivity was 100 U/ml (at least 2+) , and the positive rate of food-sIgG antibodies was slightly higher in the patients with CSU (176/248, 70.97%) , SD (15/22, 68.18%) and AU (11/15) than in the healthy controls (7/13; χ2 = 1.80, P = 0.615) . Among the 248 CSU patients, the proportion of patients with family history of allergic diseases was significantly higher in the sIgG-positive group (71/176, 40.34%) than in the sIgG-negative group (19/72, 26.39%; χ2 = 4.30, P = 0.042) , while no significant difference was observed in the 1-day urticaria activity score (UASday) between the two groups ( Z = 0.18, P = 0.859) . Totally, 177 CSU patients completed 12- to 40-week treatment; their condition could be completely controlled by second-generation H1-antihistamines, and there was no significant difference in the required dosage of second-generation H1-antihistamines between the sIgG-positive group (128 cases) and sIgG-negative group (49 cases; Z = -1.06, P = 0.298) . Conclusions:The prevalence of family history of allergic diseases was relatively high in food-sIgG-positive patients with CSU. However, food-sIgG could not be used as an indicator to reflect the disease activity of CSU and treatment response.