Protease/antiprotease network in allergy: The role of Staphylococcus aureus protease-like proteins.

Staphylococcus aureus is being recognized as a major cofactor in atopic diseases such as atopic dermatitis, chronic rhinosinusitis with nasal polyps, and asthma. The understanding of the relationship between S aureus virulence factors and the immune system is continuously improving. Although the precise mechanism of the host's immune response adaptation to the variable secretion profile of S aureus strains continues to be a matter of debate, an increasing number of studies have reported on central effects of S aureus secretome in allergy. In this review, we discuss how colonization of S aureus modulates the innate and adaptive immune response, thereby predisposing the organism to allergic sensitization and disrupting immune tolerance in the airways of patients with asthma and chronic rhinosinusitis with nasal polyps. Next, we provide a critical overview of novel concepts dealing with S aureus in the initiation and persistence of chronic rhinosinusitis with nasal polyps and asthma. The role of the S aureus serine protease-like proteins in the initiation of a type 2 response and the contribution of the IL-33/ST2 signaling axis in allergic responses induced by bacterial allergens are discussed.