The aim of this study was to determine if IL-4 and IL-4R play any role in chronic EAA pathogenesis by: (i) comparing bronchoalveolar lavage fluid (BALF) concentrations in chronic EAA and sarcoidosis patients (sarcoidosis being considered a typical Th1 mediated disease) and (ii) looking for correlations among IL-4 and IL-4R BALF concentrations and clinical parameters of patients with chronic EAA (gender, smoking status, pulmonary function tests, BALF differential cell counts, high resolution computed tomography pattern of the disease). The gene discussed is IL4R; the disease is glycogen storage disease VI.