RESUMEN
Interleukin 33 (IL 33) is a recently described member of the IL 1 family and widely exists in cells and tissues.IL 33/ST2 axis is mainly associated with the secretion of IL 4,IL 5 and IL 13,which are involved in the initiation or progression of specific Th2 responses.It contributes to the macrophage alternative polarization,dendritic cell regulation,and direct effects on T cells.These effects explain how IL 33/ST2 axis plays contrasting roles in lung diseases.Although IL 33/ST2 axis has been extensively studied in various lung inflammatory diseases,a comprehensive overview on the role of this cytokine in infectious pneumonia is actually lacking.Therefore,we summarize the recent advances on the role of IL 33/ST2 axis in pneumonia caused by various viral,bacterial,fungal and helminth.