TNF and asthma: To investigate whether asthmatic human lung fibroblasts have enhanced cytokine responses that drive asthmatic inflammation, we stimulated lung fibroblasts from non-asthmatic and asthmatic human subjects with TNFα (20 ng/ml) for 24 h and then measured the mRNA expression of proinflammatory cytokines and chemokines that are critically involved in asthma, including IL-6, IL-8, CCL5, and TSLP.