IFNG and synovial sarcoma: In CD25KO mice (lacking CD25, the α-chain of the IL-2 receptor, resulting in Treg deficiency), absence of commensal bacteria at the OS amplified autoreactive CD4+IFN-γ+ T-cell responses and accelerated SS-like dacryoadenitis, whereas fecal transplantation restored immune regulation, highlighting a key microbiome–T cell axis in DED pathogenesis [41].