Alterations of T-lymphocyte subsets, soluble IL-2 receptor, and IgE in peripheral blood of children with acute asthma attacks.

Abstract

T-cell activation and alteration of cytokines are involved in the pathogenesis of atopic asthma. However, the profile of circulating T-lymphocyte subsets, related cytokines, and plasma IgE during acute asthma attacks is still unclear. In an attempt to illustrate the dynamics of these parameters in asthma attacks, we investigated the changes of T-cell subsets, lymphocyte activation, soluble IL-2R, and IgE in peripheral blood in children during and after acute asthma attacks. This study was carried out in a cohort of Chinese children (n = 59) with acute asthma attacks. Immunoassays were performed when the patients had acute attacks before treatment, and the patients were reexamined in the 4 weeks after the resolution of acute attacks with therapy. Paired t tests were used for the statistical analysis of these patients to compare the data obtained during and after the acute attacks. Twenty healthy, age-matched subjects were used as normal control subjects. Nine children with long-term stable asthma were used as control subjects with stable asthma. CD3+, CD4+, CD8+, and IL-2R+ (CD25+) cells; plasma soluble IL-2 receptor; and IgE were significantly higher in patients with acute attacks than in control subjects. (P <.05, P <.05, P <.001, P <.05, P <.0001, and P <.0001, respectively). Immunoelectron microscopy exhibited an increased expression of IL-2R on lymphocytes in acute attacks as compared to control subjects. The abnormalities returned to normal, with the exception of IgE, when clinical remission was achieved after treatment. Correlation analyses revealed a positive relationship between plasma IgE and soluble IL-2R in asthma attacks (r = 0.83, P =.0001). Plasma IgE and soluble IL-2R of those who were in remission positively correlated with their production in acute attacks (r = 0.58, P =.001 and r = 0.71, P =.0001, respectively). This study suggests that (1) the percentage of CD4+, CD8+, or IL-2R+ lymphocytes in peripheral blood was significantly elevated during acute attacks and returned to normal ranges after complete remission was achieved; (2) plasma soluble IL-2R is a sensitive marker for asthma activity; and (3) atopic asthmatic children seem to have a hereditary predisposition of having higher levels of soluble IL-2R in asthma attacks, coinherited with the trait of IgE.