MTOR and lysosomal storage disease: While cellular apoptosis and deficient autophagy are two of the most well-described mechanisms contributing to SAI (23) and based on the previous findings, we hypothesized that CTLA-4 expression on CD4+ T cells could be modulated by the mTOR pathway mediated autophagic–lysosomal disorders and play a key role in the development and prognosis of SAI.