Serum amyloid A (SAA) 1 is an endogenous risk for inducing neutrophilic airway inflammation and can be triggered by viral infections.[54] SAA1 is an acute-phase SAA protein that acts as an immune mediator to induce the production of pro-inflammatory cytokines and chemokines (IL-1β, IL-6, TNF-α, TGF-β1, and IL-8) by M0 macrophages and stimulate the transfer of M0 macrophages to the M1 (iNOS, CD86) phenotype. Here, SAA1 is linked to inflammation.