RationaleChronic rhinosinusitis (CRS) can be clinically divided into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Recent findings suggest plasma cells are increased in mucosae of patients with CRSwNP. BAFF and APRIL are cytokines that are essential in B cell and plasma cell responses. We report increased production of BAFF in primary human nasal epithelial cells (PNEC) activated in vitro and increased BAFF in sinonasal tissues and nasal lavage fluids derived from patients with CRSwNP.MethodsWe investigated the expression of BAFF and APRIL in PNEC using real-time PCR. We also collected nasal tissue extracts and nasal lavage from healthy subjects and patients with CRS, and assayed BAFF protein using specific ELISA.ResultsIn resting PNEC, expression of BAFF and APRIL was minimal. However, BAFF mRNA was significantly up-regulated by TLR3 ligand (dsRNA; 312-fold, p < 0.05), IFN-β (21-fold, p < 0.05) and IFN-γ (6-fold, p < 0.05). APRIL mRNA was weakly but significantly up-regulated by dsRNA (2-fold), IL-4 (2-fold), IFN-β (2-fold) and IFN-γ (2-fold) (p < 0.05 in all cases). We assessed the expression of BAFF and APRIL in nasal tissue from patients with CRS and controls. BAFF mRNA was significantly increased in patients with CRSwNP (p < 0.01) compared to patients with CRSsNP or healthy subjects. BAFF protein was also elevated in polypoid tissue and nasal lavage in patients with CRSwNP.ConclusionsPatients with CRSwNP have elevated levels of BAFF mRNA and protein in the nasal mucosa. The role of BAFF in the production of immunoglobulins by B cells in the epithelium of patients with CRSwNP is worthy of investigation. RationaleChronic rhinosinusitis (CRS) can be clinically divided into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Recent findings suggest plasma cells are increased in mucosae of patients with CRSwNP. BAFF and APRIL are cytokines that are essential in B cell and plasma cell responses. We report increased production of BAFF in primary human nasal epithelial cells (PNEC) activated in vitro and increased BAFF in sinonasal tissues and nasal lavage fluids derived from patients with CRSwNP. Chronic rhinosinusitis (CRS) can be clinically divided into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Recent findings suggest plasma cells are increased in mucosae of patients with CRSwNP. BAFF and APRIL are cytokines that are essential in B cell and plasma cell responses. We report increased production of BAFF in primary human nasal epithelial cells (PNEC) activated in vitro and increased BAFF in sinonasal tissues and nasal lavage fluids derived from patients with CRSwNP. MethodsWe investigated the expression of BAFF and APRIL in PNEC using real-time PCR. We also collected nasal tissue extracts and nasal lavage from healthy subjects and patients with CRS, and assayed BAFF protein using specific ELISA. We investigated the expression of BAFF and APRIL in PNEC using real-time PCR. We also collected nasal tissue extracts and nasal lavage from healthy subjects and patients with CRS, and assayed BAFF protein using specific ELISA. ResultsIn resting PNEC, expression of BAFF and APRIL was minimal. However, BAFF mRNA was significantly up-regulated by TLR3 ligand (dsRNA; 312-fold, p < 0.05), IFN-β (21-fold, p < 0.05) and IFN-γ (6-fold, p < 0.05). APRIL mRNA was weakly but significantly up-regulated by dsRNA (2-fold), IL-4 (2-fold), IFN-β (2-fold) and IFN-γ (2-fold) (p < 0.05 in all cases). We assessed the expression of BAFF and APRIL in nasal tissue from patients with CRS and controls. BAFF mRNA was significantly increased in patients with CRSwNP (p < 0.01) compared to patients with CRSsNP or healthy subjects. BAFF protein was also elevated in polypoid tissue and nasal lavage in patients with CRSwNP. In resting PNEC, expression of BAFF and APRIL was minimal. However, BAFF mRNA was significantly up-regulated by TLR3 ligand (dsRNA; 312-fold, p < 0.05), IFN-β (21-fold, p < 0.05) and IFN-γ (6-fold, p < 0.05). APRIL mRNA was weakly but significantly up-regulated by dsRNA (2-fold), IL-4 (2-fold), IFN-β (2-fold) and IFN-γ (2-fold) (p < 0.05 in all cases). We assessed the expression of BAFF and APRIL in nasal tissue from patients with CRS and controls. BAFF mRNA was significantly increased in patients with CRSwNP (p < 0.01) compared to patients with CRSsNP or healthy subjects. BAFF protein was also elevated in polypoid tissue and nasal lavage in patients with CRSwNP. ConclusionsPatients with CRSwNP have elevated levels of BAFF mRNA and protein in the nasal mucosa. The role of BAFF in the production of immunoglobulins by B cells in the epithelium of patients with CRSwNP is worthy of investigation. Patients with CRSwNP have elevated levels of BAFF mRNA and protein in the nasal mucosa. The role of BAFF in the production of immunoglobulins by B cells in the epithelium of patients with CRSwNP is worthy of investigation.