Association between Eosinophilic Airway Inflammation and Persistent Airflow Limitation in Asthmatic Children

Abstract

T U E S D A Y 855 IgG and IgG4 Isotype Antibodies to Fel d 1 In Allergic and Non-allergic Students (n5963): Relationship to Symptoms of Asthma T. A. E. Platts-Mills, B. Lundback, J. M. Roper, M. Mori, E. Ronmark; University of Virginia, Charlottesville, VA, University of Umea, Umea, SWEDEN. RATIONALE: Previous data on 963 randomly chosen sera from a cohort of 3,400 children in northern Sweden showed that the titer of IgE antibodies to cat, dog, and horse allergens was a major predictor of asthma symptoms. By contrast, neither high titer IgG antibodies nor cat ownership influenced symptoms. METHODS: Sera with IgG to Fel d 1 (n5100) were assayed for IgG4 using a two step radio-immunoprecipitation assay (RIPA). This assay uses a monoclonal anti-IgG4 (Sigma Aldrich) and a precipitation with goat antimouse IgG, fully absorbed against human IgG. RESULTS: Among patients with elevated IgG ab to Fel d 1, the presence of IgG4 correlated significantly with titer of IgG and was associated with cat ownership. Among 100 students who had high titer IgG to Fel d 1, the prevalence of high IgG4 ab to Fel d 1 was not significantly related to the presence of IgE ab to Fel d 1 (16/55 in negative sera vs. 10/45 in IgE positive sera, p50.4 n.s.). However, among the cat-allergic students, the presence of high IgG4 was inversely correlated with wheezing (5/16 vs. 19/29, p50.027). Among those who did not have a cat at home, the numbers of sera with high titer IgG were too low to analyze. CONCLUSIONS: Among students with high IgG ab to Fel d 1, the presence of high titer IgG4 ab was related to decreased prevalence of wheeze among allergic subjects, but this ab was equally common among the non-allergic subjects.