CD4 T-lymphocyte activation in acute severe asthma. Relationship to disease severity and atopic status.

Lymphocytes are prominent among the inflammatory cells infiltrating the asthmatic airways, and several studies have suggested that cell-mediated immunity may play a role in the pathogenesis of chronic asthma. We have measured (1) the expression of activation markers on the CD4+ and CD8+ T-lymphocyte phenotypic subsets in the peripheral blood of patients hospitalized with acute severe asthma ("status asthmaticus"), and (2) the serum concentrations of two proteins elaborated by activated T-lymphocytes (interferon-gamma and the soluble interleukin-2 receptor). The results were compared with those in control subjects (mild asthma, chronic obstructive airway disease, and normal). CD4+ lymphocytes from patients with acute severe asthma showed significant increases in the expression of three surface proteins associated with lymphocyte activation (interleukin-2 receptor [IL-2R], class II histocompatibility antigen [HLA-DR], and "very late activation" antigen [VLA-1]) as compared with those from normal control subjects. In contrast, CD8 cells were devoid of IL-2R and VLA-1, in both patients with acute severe asthma and control subjects, and the expression of HLA-DR on these cells was not increased above that of control subjects. The serum concentrations of interferon-gamma and soluble IL-2R were significantly elevated in patients with acute severe asthma as compared with all the control groups. Concentrations decreased as the patients improved clinically during the first 3-day period of hospital treatment.(ABSTRACT TRUNCATED AT 250 WORDS)