In assessing cytokine production and cytotoxic activity of circulating γδ T lymphocytes obtained from SSc patients and to evaluate their potential role during this disorder, both the proportion and the absolute number of IFNγ producing γδ T cells (i.e., displaying a Th1 polarization) in SSc were found to be significantly higher than the proportion and the absolute number of IL-4 producing γδ- T cells in SSc, or the proportion and the absolute number of IFNγ -producing γδ T cells in HC (p < 0.05 for both groups). This evidence concerns the gene IFNG and systemic sclerosis.