Identification of leukotrienes in the sputum of patients with cystic fibrosis.

Sputum extracts from 16 of 25 adult patients with CF produced a slow, sustained contraction of isolated guinea pig ileum which was partially inhibitable by the SRS-A antagonist FPL 55712. Following progressive purification and HPLC, the major ileum-contracting substance was identified as LTD4. LTC4 was also present but in smaller amounts. The sputum contained other SRS-A-like activity which was not inhibited by FPL 55712; this substance was of a smaller molecular size than LTD4. The presence of LTB4 was also established using HPLC and an assay of neutrophil chemotaxis. These studies raise the possibility that leukotrienes and other lipoxygenase products may contribute to the progressive lung disease characteristics of CF.