Delineation of T cell subsets in chronic rhinosinusitis with nasal polyps.

Objectives: Detailed characterisation of CD45RA⁺ and CD45RO⁺ T cell subsets in both CD4⁺ and CD8⁺ cells in blood and tissue of patients with chronic rhinosinusitis with nasal polyps (CRSwNP) is lacking. We aimed to investigate T cell differentiation levels in blood and tissue and correlate this with CT score and white blood cell count.

Methods: This case-control study was conducted on 21 patients with CRSwNP and 20 healthy controls. Lund-Mackay score was used for radiologic staging of chronic rhinosinusitis. T cell subsets were characterised in blood and nasal polyp tissue using CD4, CD8, CCR7, CD45RA, CD45RO, CD27, and CD95 monoclonal antibodies.

Results: Most variations in T cell subsets were detected in tissue rather than blood. A higher level of CD8⁺ T_CM, CD4⁺ T_SCMs and lower level of CD8⁺ T_EM were detected in the blood of CRSwNP patients vs controls. In CRSwNP patients, substantial decrease of tissue CD8⁺ T_Ns, CD8⁺ T_CMs, CD4⁺ T_Ns, and CD4⁺T_SCMs with marked increase in the percentages of T_EMs and T_EMRAs were detected among CD4⁺ and CD8⁺ T cells compared with levels in blood.

Conclusions: The reduction of T_Ns, T_SCMs, and T_CMs and accumulation of T_EMs and T_EMRAs subsets that function as effector cells in sinonasal mucosa, especially CD8⁺ T cells, might indicate the role of immunomodulation of memory/effector T-cells in the pathogenesis of CRSwNP.