Ratio of myeloid and plasmacytoid dendritic cells and T(H)2 skew in CRS with nasal polyps

P>Background: The role of myeloid and plasmacytoid dendritic cells and its consequences for the T(H)2 skew in chronic rhinosinusitis (CRS) with nasal polyps (CRSNP+) should be detailed. Methods: In 18 CRS patients without nasal polyps (CRSNP-), 35 CRSNP+ patients and 22 patients with nasal structural abnormalities without rhinosinusitis (controls), dendritic cells (DC) were differentiated into myeloid (mDC) and plasmacytoid (pDC) subtypes using an antibody cocktail including CD1c (BDCA-1) and CD303 (BDCA-2) in peripheral blood mononuclear cells (PBMC) and single cell preparations of sinonasal mucosa by flow cytometry. Moreover, cells were analysed for expression of CD45, CD3, CD4, CXCR3 (T(H)1) and CCR4 (T(H)2) and IFN-gamma, IL-5, TGF-beta 1, TGF-beta 2, ECP and total IgE in nasal secretions were determined. As a possible confounder, Staphylococcus aureus in nasal lavages was detected. Results: The tissue mDC/pDC-ratio was 1.7 (1.0-2.4) in controls, 3.0 (1.8-4.0) in CRSNP- and 0.8 (0.6-1.0) in CRSNP+ (P < 0.01). In tissue samples, the T(H)1/T(H)2 ratio was 12.6 (6.4-16.0) in controls, 12.5 (6.9-21.2) in CRSNP- and 1.8 (1.3-3.6) in CRSNP+ (median and interquartile range, P < 0.001). Less pronounced differences were found in PBMC. S. aureus detection rates or TGF-beta levels did not differ between patient groups and S. aureus detection had no influence on the parameters investigated. Conclusion: A significant T(H)2 skew in CRSNP+ could be confirmed on the cellular level. It was driven by low myeloid dendritic cell numbers. The T(H)2 skew did not correlate with S. aureus detection. The data support the concept that CRSNP+ and CRSNP- are pathophysiologically distinct.