Effect of Administration of Oral Steroids on T-Cells in Patients with Chronic Rhinosinusitis

Objective: Systemic corticosteroids are the most effective anti-inflammatory drugs for the control of symptoms in patients with chronic rhinosinusitis (CRS). The potential mechanisms for their beneficial effects include increasing the number and function of T regulatory cells (Tregs), a finding suggested in the local tissue post-intranasal steroid treatment. We investigated the effect of systemic corticosteroids on peripheral blood (PB) Tregs in CRS.

Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from CRS subjects before and after the administration of systemic steroids. Control subjects received no treatment and were studied at one visit for comparison. Main outcome measures evaluated were the nasal symptom scores.  CD4⁺-CD25⁺-Foxp3⁺ cells (Tregs) were analyzed by flow cytometry, and mRNA expression of IFN-γ, IL-4, IL-10, IL-13, IL-17A, TGF-b1, FoxP3 and GATA-3 were in PBMCs were analyzed using real-time PCR at each visit.

Results: CRS subjects reported an improvement in their symptoms post-corticosteroid administration (p<0.05). PB Tregs and mRNA levels of immunoregulatory transcription factors (FoxP3 and GATA-3; p<0.05, both) and pro-inflammatory cytokines [IFN-γ (p<0.05) and IL-4 (p=0.056)] from PBMCs were significantly reduced in CRS subjects after corticosteroid treatment.

Conclusion: In contrast to prior reports on the changes in local tissue, our study reports a reduction in PB Tregs after treatment with systemic corticosteroids. In addition, we report decreased T_H1 and T_H2 function. These data indicate that the effects of corticosteroid on Tregs in CRS are complex involving local signals in the tissue that differ from that in circulating cells.