Interleukin 13 is an immunoregulatory cytokine predominantly secreted by activated Th2 cells. It has similar functions with interleukin 4 and they share a common receptor. However, unlike interleukin 4, l'interleukin 13 does not appear to be important in the initial differentiation of CD4 T into Th2-type cells, but rather appears to be necessary in the effector phase of inflammation and fibrosis. This cytokine has been involved in recent works in allergic inflammation and in some fibrotic diseases leading to a scientific interest to analysis the role of interleukin 13 in systemic sclerosis (scleroderma).Systemic sclerosis is an autoimmune disease characterized by vascular alteration and skin and visceral fibrosis. A genetic background associated with susceptibility is supposed. Knowing the profibrogenic properties of interleukin 13, we asked if polymorphisms located in interleukin 13 and interleukin 13 receptor genes could be associated with systemic sclerosis. We observed significant associations between IL13 and IL13RA2 gene polymorphisms and the disease, particularly the cutaneous diffuse form of the disease.Results concerning the involvement of interleukin 13 pathway in systemic sclerosis need to be confirmed on another larger population. Functional studies will be done to explain the effect of these associations. We feel that IL13/IL13R pathway is interesting as immunomodulation with the interleukin 13 receptor inhibitor is possible in therapy.