IFNG and pulmonary arterial hypertension: For instance, pulmonary arterial hypertension (PAH), one of the complications of SSc, where PSGL-1-deficient mice have increased numbers of T cells and B cells, increased production of IFN-γ, and decreased numbers of Tregs which in turn accelerated the development of PAH, making the condition of spontaneous SSc-like syndrome worse [69].