IL4 and asthma: Similarly, studies of asthma in humans suggest possible roles for interferon-gamma (IFN-γ): a) asthma has been associated with elevated production of IFN-γ but not IL-4 by bronchoalveolar lavage cells [4]; b) greater frequencies of peripheral blood CD8+ T cells expressing IFN-γ in asthmatic airways, correlating with asthma severity and bronchial hyperresponsiveness [5]; c) induced sputum from patients with atopic or non-atopic asthma presented increased eosinophils and IFN-γ [6].