Type II macrophage is regulated by Th2 factor to produce IL‐10 and TGF‐β, and is associated with allergy, apoptosis and fibrosis.39 It is well established that TGF‐β1 is one of the main factors in the induction of fibrosis.39 It can promote the aggregation of fibroblasts and inflammatory cells, as well as the synthesis of collagen and fibrin, which further results in extracellular matrix deposition and degradation.40 The content of TGF‐β1 in normal liver cells is extremely low to none. This evidence concerns the gene TGFB1 and allergic disease.