Apart from playing a role in the acute phase response to systemic inflammation, fibrinogen has been shown to be hydrolyzed by proteinases from Aspergillus melleus and other allergenic organisms to yield cleavage products that drive distinct antifungal mechanisms and initiates allergy (airway hypersensitivity, innate allergic inflammation and antifungal immunity) through Toll-like receptor 4 and CD11c48. This evidence concerns the gene TLR4 and allergic disease.