S100A8 regulates CD3+ T lymphocytes in ITP patients. MiR-21-5p regulates the differentially expressed gene LTF by inhibiting the core downstream target gene VCL and participates in the immune mechanism of T lymphocytes in ITP patients. miR-155-5p involved in the immunoregulatory mechanism of T lymphocytes in ITP patients. The gene discussed is S100A8; the disease is autoimmune thrombocytopenic purpura.