B-Cells and Antibody-Mediated Pathogenesis in Chronic Rhinosinusitis with Nasal Polyps.

The sinonasal mucosa forms a dynamic immune barrier where epithelial cells and the immune system interact with the inhaled environment and nasal microbiome. Recent studies suggest that B-cells, plasma cells and antibody production are highly activated locally within the nasal mucosa of patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Findings additionally suggest that polyp tissue contains elevated levels of cytokines, chemokines and complement that may drive this profound B-cell response. Currently, the data are conflicting on whether the B-cell response found in the CRSwNP nasal mucosa is antigen-specific, a superantigen response or an expansion of natural antibody responses. Indeed, investigations into the specificity of the mucosal antibody responses find increased production of class-switched antibodies that bind to aeroallergens, staphylococcus aureus as well as autoantigens. A continuation of these studies is needed to elucidate whether extrinsic factors, like the inhaled environment, or intrinsic factors, like the mucosal microbiome and host inflammatory response, are key to the pathogenesis of CRSwNP. This chapter will cover the current evidence regarding local B-cell responses in CRSwNP.