Interferon modulates the leukotriene C4-induced non-adherence properties of leukocytes: acquisition of an asthmatic phenotype.

We have previously shown that peripheral blood leukocytes (PBL) of asthmatic patients acquire non-adherence properties after challenge with leukotriene C4 (LTC4), whereas PBL of normal individuals do not. Hence the use of the LTC4-induced leukocyte-adherence-inhibition (LAI) assay enables one to recognise an asthmatic phenotype on the basis of the ability of PBL to respond in vitro to LTC4. To examine the possibility that alpha interferon (IFN alpha) may have relevance to the pathogenesis of bronchial asthma, various concentrations of IFN were incubated with normal PBL and the acquisition of non-adhering properties was measured. We found that following 24 h incubation with 500 U/ml IFN, normal PBL were induced to respond to a standard dose of LTC4, and this reaction was abrogated by FPL 55712 and cyclohexamide.