NELFCD and occupational asthma: The aim of this study was to establish the sputum inflammatory profile and changes in levels of leukotriene B4 (LTB4) and a panel of Th1/Th2 cytokines in subjects with suspected occupational asthma (OA) following specific inhalation challenge (SIC) to high-molecular-weight (HMW) and low-molecular-weight (LMW) agents.