Immunomodulatory Effect of Mesenchymal Stem Cells on T Lymphocyte and Cytokine Expression in Nasal Polyps

Objectives. Adipose tissue-derived stem cells (ASCs) have been reported to have immunomodulatory effects in various inflammatory diseases, including asthma and allergic rhinitis, through the induction of T cell anergy. Nasal polyps (NPs) are a chronic inflammatory disease in the nose and paranasal sinus characterized histologically by the infiltration of inflammatory cells, such as eosinophils or lymphocytes. This study was performed to investigate whether ASCs have immunomodulatory effects on T lymphocyte and cytokine expression in eosinophilic NPs. Study Design. Basic science experimental study. Setting. University tertiary care facility. Subjects and Methods. NP specimens were obtained from 20 patients with chronic rhinosinusitis and eosinophilic NPs. ASCs were isolated and cultured from the abdominal fat of 15 subjects undergoing intra-abdominal surgery. Infiltrating cells (1 x 10(6)) were isolated from NP tissue and co-cultured with 1 x 10(5) ASCs. To determine whether ASCs affect infiltrating T lymphocyte and cytokine expression in eosinophilic NP, T lymphocyte subsets and cytokine expression were analyzed before and after ASC treatment. Results. ASC treatment significantly decreased the proportions of CD4(+) and CD8(+) T cells. After ASC treatment, Th2 cytokine (interleukin [IL]-4 and IL-5) levels decreased significantly. In contrast, levels of Th1 (interferon-g and IL-2) and regulatory cytokines (transforming growth factor-beta and IL-10) increased significantly after ASC treatment. Conclusions. ASCs have immunomodulatory effects in the eosinophilic inflammation of NPs, characterized by down-regulation of activated T lymphocytes and a Th2 immune response. These effects would be expected, over time, to significantly contribute to the control of eosinophilic inflammation and, possibly, growth of eosinophilic NPs.