Analysis of the changes in Th9 cells and related cytokines in the peripheral blood of spontaneous urticaria patients

Spontaneous urticaria (SU) is characterized by immune deregulation of mast cells and T helper (Th) cells. Th9 cells, a subset of Th cells, serve a key role in initiating mast cell accumulation and activation. To understand the role of Th9 cells in the pathogenesis of SU, the authors conducted a control study of 28 patients with acute SU (ASU) and chronic SU (CSU) and 28 healthy controls. The percentage of Th9 cells in peripheral blood was assessed using flow cytometry and levels of Th9 related serum cytokines including interleukin (IL)-4, IL-9, IL-17A, IL-33, IL-1β and transforming growth factor-β1 (TGF-β1) using Luminex 200. ASU patients exhibited higher percentages of Th9 cells and increased serum levels of cytokines IL-9, IL-4 and TGF-β1 compared to healthy controls. In addition, high mRNA expression of the PU.1 transcription factor was observed in ASU patients. However, the percentage of Th9 cells was similar between patients with CSU and healthy controls. Furthermore, the percentage of Th9 cells demonstrated a positive correlation with IL-4 and IL-9 levels in the peripheral blood of ASU patients, but not with disease severity. The current findings suggested that the numbers of Th9 cells increased in ASU patients and indicated its novel role in the pathogenesis of ASU.