Objective To explore the relationship between the expression of Toll like receptor 4(TLR4)and Janus protein tyrosine kinase 3(JAK3)genes and the imbalance of helper T cell 17(Th17)/regulatory T cells(Treg)in peripheral blood mononuclear cells(PBMCs)of patients with ankylosing spondylitis(AS).Methods A total of 101 AS patients were selected as the AS group.According to the AS Disease Activity Index(BASDAI)score,patients were divided into the AS stable phase(ASS)group(＜4 points,42 cases)and the AS active phase(ASA)group(≥4 points,59 cases).Additionally,50 healthy volunteers who underwent physical examinations at our hospital during the same period were selected as the control group(health group).Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)was used to determine the mRNA expression of TLR4 and JAK3 in PBMCs,and the proportion of serum Th17 and Treg was measured and Th17/Treg levels were calculated.Results The levels of TLR4 mRNA and JAK3 mRNA in PBMCs of peripheral blood were higher in the AS group than those in the health group(P＜0.05).The levels of Th17,proportion and Th17/Treg in peripheral blood were higher in the AS group than those of the health group(P＜0.05).Higher levels of TLR4 mRNA,JAK3 mRNA,Th17,and Th17/Treg were risk factors for AS,while higher level of Treg was protective factors for AS.TLR4 mRNA and JAK3 mRNA in AS patients were positively correlated with Th17 ratio and Th17/Treg ratio,and negatively correlated with Treg ratio(P＜0.05).Conclusion TLR4 and JAK3 genes are highly expressed and Th17/Treg is unbalanced in PBMC of AS patients.The high expression of TLR4 and JAK3 genes is closely related to Th17/Treg imbalance in AS patients.