Among these, seven hub genes—FCER1A, RGS1, CXCL13, DPEP2, LAG3, APOL1, and GZMB—were extracted by constructing a PPI network, and subsequently validated in peripheral blood samples of SLE patients through RT-qPCR and flow cytometry. The gene discussed is LAG3; the disease is systemic lupus erythematosus.