CYTOKINE PRODUCTION AT THE SITE OF DISEASE IN CHRONIC EOSINOPHILIC PNEUMONITIS

Chronic eosinophilic pneumonitis (CEP) is characterized by longstandin g respiratory symptoms accompanied by a massive pulmonary eosinophil i nfiltration. We hypothesized that cytokine(s) produced in the disease sites are implicated in the pathophysiology of CEP. We studied periphe ral blood and bronchoalveolar lavage fluids (BALE) obtained from two l ung segments of a patient with CEP. Seventy times more eosinophils wer e found in the BALF from an involved lung segment (showing patchy opac ification on a chest roentgenogram) than from an uninvolved segment. T he eosinophil-active cytokines interleukin-5 (IL-5), IL-6, and IL-10 w ere strikingly elevated in the BALF from the involved lung segment, wh ereas no or minimal levels of these cytokines were detectable in the B ALE from the uninvolved segment or serum, respectively. Leukocytes in the involved lung segment, but not those in peripheral blood, expresse d messenger ribonucleic acid (mRNA) for IL-5, IL-6, and IL-10. In cont rast, IL-2, IL-3, IL-4, interferon-gamma (IFN-gamma), granulocyte-macr ophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-a lpha (TNF-alpha) were not detected in any sample. These findings sugge st that increased production of several cytokines, such as IL-5, IL-6, and IL-10, in the involved lung segment, but not in the uninvolved lu ng segment or peripheral blood, is a critical pathophysiologic feature of CEP.