Serum levels of sCD23 and sCD25 in children with asthma and in healthy controls

To investigate whether markers of lymphocyte activation are useful markers of disease activity in childhood asthma, we studied serum levels of soluble CD25 (receptor for IL-2) and soluble CD23 (low-affinity receptor for IgE) in 178 children (aged 2-18 years) suffering from mild to moderate asthma (mean asthma severity score: 2, range: 1-4), and in 175 healthy age-matched controls. Levels of sCD23 and sCD25 were inversely related to age. sCD23 was lower in patients with asthma (means per age group: 4.93-2.29 micrograms/l; controls: 6.92-4.11 micrograms/l, P < 0.05), while sCD25 tended to be higher (1601-597 kU/ml, controls: 1350-661 kU/ml, P = NS). sCD25 correlated significantly with asthma severity score (r = 0.41; P < 0.01) and MEF25 (maximum expiratory flow at 25% of vital capacity, r = -0.43; P < 0.05) in children < 10 years, while sCD23 correlated with asthma severity (r = 0.28; P < 0.05) in children > 10 years. On follow-up, levels of sCD25 normalized with clinical improvement. In children with nonatopic asthma, levels of sCD25 were significantly higher than in atopic patients. Our observations provide further evidence of the role of T-cell activation in asthma. Monitoring of lymphocyte activation markers, particularly levels of sCD25, may be useful in the follow-up of asthmatic children.

Age related IgG subclass concentrations in asthma

The prevalence of IgG subclass deficiency in asthma is still controversial. Earlier studies often included patients receiving treatment with systemic steroids which can induce hypogammaglobulinaemia. Concentrations of IgG subclasses were studies in 200 children (aged 2-17 years) with asthma (mean asthma severity score (ASS) 2, range 1-4) who had not received systemic steroids for at least six weeks before investigation, and in 226 healthy age matched controls. The mean concentrations of IgG subclasses in children with asthma were within the 1SD range of those of the control group. In the group with asthma there was a trend towards higher levels of IgG1 and IgG4, whereas the number of children with low concentrations of IgG2 (< 2 SD of control serum samples; absolute concentrations 0.08-1.25 g/l) was slightly greater than in the group who did not have asthma (4.5 v 2.2%). Patients with subnormal concentrations of IgG2 could not be distinguished clinically or on the basis of case history and additional immunological studies did not show further abnormalities. Patients with severe asthma (ASS 3-4) had significantly higher concentrations of IgG4 (mean (SE) 0.53 (0.09) v 0.26 (0.04) g/l) than patients with mild asthma (ASS 1). No significant difference in subclass concentration was found between patients with atopic and those with non-atopic asthma. It is concluded that in an unselected group of children with asthma the mean IgG subclass concentrations do not differ significantly from a group of healthy age matched controls.