CD4 LYMPHOCYTE-T ACTIVATION IN ACUTE SEVERE ASTHMA

The expression of activation molecules on peripheral-blood CD4 and CD8 T lymphocytes and the serum concentrations of two products of activated T lymphocytes [interferon-gamma (IFN-gamma) and soluble interleukin-2 receptor (sIL-2R)] were measured in patients with acute severe asthma (ASA) and controls. Significantly higher percentages of CD4+ cells from patients with ASA expressed IL-2R, HLA-DR and VLA-1 as compared to controls (p < 0.01). In contrast, CD8+ cells from both asthmatics and controls did not express IL-2R and VLA-1, and their expression of HLA-DR in asthmatics was not increased. Serum concentrations of IFN-gamma and sIL-2R were significantly elevated in patients with ASA as compared to control groups (p < 0.01). Concentrations decreased as the patients improved clinically following therapy. Significant correlations were observed between the improvements in airways obstruction and (1) the decreases in the percentages of peripheral-blood IL-2R+ T lymphocytes and (2) the decreases in serum concentrations of sIL-2R. These observations suggest that CD4 T lymphocyte activation is important in the pathogenesis of ASA.