In human studies, pulmonary sub‐segmental bronchial challenges with allergens (house dust mite, pollen) and irritants (diesel particles) have shown that the airways of both asthmatic and non‐asthmatic individuals generate innate inflammatory chemokines/cytokines (IL‐8, TNF‐α, CCL2, CCL5) shortly after exposure; however, the magnitude of these responses are increased in individuals with asthma 46, 47, 48, 49. Here, TNF is linked to asthma.