There is controversial evidence on the abundance and relevance of these cells in patients with systemic sclerosis [53, 54]; however, in a murine model of pulmonary fibrosis it was found that the IL-13 derived from these cells increases the deposit of collagen by the fibroblasts and induces the differentiation of macrophages towards a profibrotic phenotype [55]. This evidence concerns the gene IL13 and systemic sclerosis.