Soluble interleukin-2 receptor in sputum from patients with bronchial asthma.

: To evaluate the activation of T-lymphocytes in the airways of patients with asthma, we attempted to measure the concentration of soluble interleukin-2 receptor (sIL-2R) in sputum extracts from asthma patients with acute attacks or in remission. The large amount of alkaline phosphatase in the sputum extracts excluded the use of an ELISA kit. Measurement was attempted by radiolabeling the second antibody in the ELISA kit. sIL-2R was detectable in 10/23 (43%) of the sputum extracts from patients with acute asthma attacks, but not in those from patients in remission (n = 12, p < 0.02). These observations suggest that T-lymphocyte activation takes place in the airways of patients with acute asthma attacks.