ANALYSIS OF CYTOKINE TRANSCRIPTS IN THE BRONCHOALVEOLAR LAVAGE CELLS OF PATIENTS WITH ASTHMA

A panel of steady-state cytokine mRNAs was analyzed in the bronchoalve olar lavage (BAL) cells from asthmatic subjects or patients challenged with ragweed allergen. This was achieved by combining both qualitativ e and quantitative assays using the reverse transcription-polymerase c hain reaction (RT-PCR). Analysis of BAL cells from six mild allergic a sthmatic and five nonasthmatic, nonallergic subjects showed no qualita tive differences in the profile of cytokine mRNAs (including interleuk in [IL]-1beta, IL-2, IL-5, IL-6, IL-8, and granulocyte/macrophage colo ny-stimulating factor), except for tumor necrosis factor-alpha, which was detected in three out of six asthmatic BAL samples but in none of the controls. A key cytokine, IL-5, has been implicated in the pathoge nesis of allergic inflammation through the recruitment of eosinophils. We found a significant enhancement of steady-state IL-5 transcripts i n the BAL cells from allergen-challenged as compared with the saline-c hallenged control sites of four asthmatic patients; furthermore, the c ellular source for IL-5 mRNA was identified in the mononuclear cell fr action, but not in the purified eosinophils, of the allergen-challenge d BALs. These results suggest that the,significant increase of IL-5 tr anscripts is primarily from the infiltrating mononuclear cells. Our st udy also demonstrates the power of qualitative and quantitative PCR an alysis in determining the molecular basis of allergic inflammatory dis eases.