To explore the potential function of differential expressed FRGs (CYBB, CTSB, SLC38A1, TLR4, PEX2 and ABCC1) in the pathogenesis of TAO, we further analyzed the relationship between these genes and 18 immune cells (T cells CD4 memory activated, T cells gamma delta, eosinophils, and dendritic cells activated were not included in the analysis because they did not show infiltration in TAO samples) in TAO groups. The gene discussed is TLR4; the disease is thromboangiitis obliterans.