Bronchial asthma: clinical phenotypes and endotypes and their relation with glucocorticoids circadian rhythm and parasympathetic activity

Abstract

IntroductionAsthma is a heterogeneous disease and presents in different clinical patterns ‘phenotypes’ as a result of diverse pathobiological background ‘endotypes’.ObjectivesTheaim of this studywas to study serum interleukin-13 (IL-13) levels and the frequency of (IL-13) +1923C/T gene polymorphism in Egyptian children with asthma and to study glucocorticoids circadian rhythm in nocturnal asthma.Patients and methodsThe frequency of (IL-13) +1923C/T gene polymorphism genotypes was determined in 114 asthmatic Egyptian children and compared with a matched group of 152 healthy controls using PCR. Serum IL-13 and cortisol a.m. and p.m. concentrations in serum were assessed using enzyme linked immunosorbent assay.ResultsSerum IL-13 was found to be significantly higher in asthmatic patients when compared with the control group (P<0.0001). In the asthmatic group, forced expiratory volume in 1 s showed a significant negative correlation with serum IL-13 (ρ=−0.2, P=0.03), whereas peripheral blood eosinophilic % showed a significant positive correlation with serum IL-13 (ρ =0.18, P=0.05). No statistically significant differences were found between asthmatic patients and controls in IL-13 C1923T genotype frequency. A significantly lower serum cortisol pm was found in asthmatic patients with nocturnal symptoms when compared with those without nocturnal symptoms (P<0.0001).ConclusionSerum IL-13 is significantly higher in asthmatic patients when compared with controls. (IL-13) +1923C/T gene polymorphism is not a risk factor for development of asthma in Egyptian children. Nocturnal symptoms in some asthmatic patients can be partly attributed to lower serum cortisol level at night.