Co-stimulatory Molecules And FOXP3 MRNA Expression In Peripheral Blood Mononuclear Cells In Patients With Chronic Hepatitis B Virus Infection

AimTo explore the roles of co-stimulatory molecules B7-2 and PD-L1 and FOXP3 mRNA expression in peripheral blood mononuclear cells in the mechanism of immune tolerance in chronic hepatitis B virus infection.MethodThirty HBV infected patients in immune reactive phase and ten patients in immune tolerant phase were enrolled in the study;ten healthy volunteers were used as controls.RT-PCR method was used to detect the expression levels of B7-2,PD-L1 and FOXP3 mRNA in peripheral blood mononuclear cells in chronic HBV infected patients.ResultsThe results showed that B7-2 expression in immune reactive and immune tolerant patients was 0.826±0.055 and 0.880±0.036 respectively,significantly lower than 0.942±0.029 in the controls(P value was 0.000 and 0.002 );B7-2 expression in immune reactive patients was significantly lower than that in immune tolerant patients(P = 0.004 ). PD-L1 expression in immune reactive patients(0.763±0.090) and immune tolerant patients (0.741±0.032) was significantly higher than that in normal controls(0.663±0.040 )(P value was 0.000 and 0.000);the expression of PD-L1 in immune reactive patients was slightly higher than that in immune tolerant patients,but no significant difference was found between the two groups(P=0.564).PD—L1/B7—2 ratio in immune reactive,immune tolerant patients and healthy controls was 0.926±0.102,0.842±0.049 and 0.704±0.042 respectively; PD—L1/B7—2 ratio in immune reactive and immune tolerant patients were significantly higher than that in the healthy controls(P value was 0.000 and 0.000);the difference of PD—L1/B7—2 ratio between immune reactive patients and immune tolerant patients was significant in favor of the former(P=0.005).FOXP3 expression in immune reactive patients was higher than that in immune tolerant patients(P = 0.000) and healthy controls (P =0.000),but no significant difference was found between immune tolerant patients and the healthy controls(P =0.675).PD—L1/B7—2 ratio was positively correlated with FOXP3 expression in the immune reactive patients(r =0.491,P =0.006).ConclusionsIn chronic HBV infection,the changed expression levels of co-stimulatory and co-inhibitory molecules implies a protective adjustment against immune response.The expression of co-stimulatory molecules was associated with expression of FOXP3 in the immune reactive patients;co-stimulatory molecules and CD4~+ CD25~+ Treg may play an important role in synergistically regulating the immune reaction in chronic HBV infection.