Bioactive tumor necrosis factor in the sputa of cystic fibrosis patients

Eighty sputum samples from 37 cystic fibrosis patients were assayed for tumor necrosis factor alpha (TNF-alpha) in the L929 bioactivity assay. In addition, the presence of TNF-alpha-specific mRNA in the sputum was determined by using TNF-alpha-specific DNA probes in a PCR amplification step after reverse transcription of the mRNA to cDNA. Bioactive TNF-alpha was detected in 69 (86%) of the 80 sputum samples tested and, on at least one occasion, in 35 (95%) of the 37 cystic fibrosis patients sampled. The highest levels of TNF-alpha were observed in sputa obtained from patients presenting with an exacerbation of their disease.