Up-regulation of CD44 expression by interleukin-13 in a murine model of asthma.

Allergic asthma is a chronic inflammatory disease characterized by the infiltration of inflammatory cells, the elevated production of cytokines and enhanced airway hyperreactivity (AHR). CD44 is a widely expressed cell adhesion molecule that is involved in lymphocyte adhesion to inflamed endothelium. Previous studies showed that pulmonary eosinophils and CD4⁺ T cells express high levels of CD44 in bronchoalveolar lavage fluid following antigen administration. The aim of this study was to investigate whether interleukin (IL)-13 is capable of modulating CD44 expression in lung tissue and lymphocytes, further promoting inflammatory cell recruitment into the lungs and exacerbating asthmatic responses. Six- to eight-week-old male Balb/c mice were used. Quantitative PCR and immunohistochemistry were employed to determine the effect on CD44 expression. Our findings showed that IL-13 may play a significant role during the challenge phase in that CD44 expression was up-regulated in lung tissue and lymphocytes following IL-13 treatment, resulting in inflammatory cells infiltrating into lungs and enhancing AHR.