Host Genetic Factors In Predicting Response Status In Chronic Hepatitis B Patients Discontinuing Nucleos(t)ide Analogs

Background:Chronic hepatitis B(CHB),which is caused by the hepatitis B virus(HBV),affects about 240 million people worldwide and is likely to cause hepatocellular necrosis,inflammation and liver fibrosis.Further progression of the disease may lead to cirrhosis,hepatic decompensation and hepatocellular carcinoma.It is crucial to treat patients of active stage affected with HBV to prevent the progression of the disease.Over the past thirty years,treatment for CHB have greatly improved the prognosis and reduced the associated mortality,especially for the introduction of nucleos(t)ide analogs(NAs).However,discontinuation of NAs therapy still remains a conundrum in clinical practice.Although current guidelines have paid close attention to the optimal duration of NAs therapy,the "unknown" or"indefinite" treatment period is less than satisfactory.Previous studies have been performed to explore predictors for response status after discontinuation of NAs.Hepatitis B surface antigen(HBsAg)seroclearance/conversion has been proved as a favorable clinical outcome for CHB patients.It has also been recommended as an optimal endpoint for discontinuation of NAs.However,the scarce occurrence of HBsAg loss/conversion makes it unrealistic for most CHB patients.Previous studies also revealed that the duration of consolidation therapy were related to relapse rates in Hepatitis B e antigen(HBeAg)-positive CHB patients who have achieved HBeAg seroconversion.However,the relapse rates remain high in HBeAg-negative CHB patients even when stringent cessation criteria are applied.Our previous studies also revealed age as a predictive factor for relapse after discontinuation of NAs,though a cut-off value of<30 years(HBeAg-positive CHB patients)or<20 years(HBeAg-negative CHB patients)for lower relapse rate may not be a good news for older CHB patients.Therefore,the prognostic value of current factors for response status was limited.It is necessary to discover new predictors for clinical decision making process.The progression of CHB depends on interaction between human body and hepatitis B virus(HBV).Previous studies have confirmed the important role of host genetic factors in determining the outcome of HBV infection.Several single-nucleotide polymorphisms(SNPs)involving progression of CHB have been revealed by genome-wide association studies(GWASs)recently,most of which locate in human leukocyte antigen(HLA)regions.A new locus locating at 20q13.1(rs1883832 in the Kozak sequence of CD40)was also found to be associated with CHB susceptibility in Chinese population by Jiang et al in 2015.However,there are few studies focusing on the correlation between host genetic factors and response status after discontinuation of NAs therapy.Objective:Based on our prospective NAs-discontinuation cohort and the follow-up for more than 10 years,we conducted this study to define the role of host genetic factors in predicting response status in CHB patients discontinuing NAs by applying stringent cessation criteria.Methods:Patients participated in our study came from a prospective NAs-discontinuation cohort since June 1999.The cessation criteria were defined as follows:(1)HBeAg-positive patients:at least 6 months' additional consolidation treatment after achieving HBeAg seroconversion with undetectable HBV DNA and normal ALT plus a total therapy duration more than 12 months.Some CHB patients with HBeAg loss were also underwent discontinuation of NAs prudently with more than 18 months'total therapy duration and at least 6 months' consolidation treatment before December 2013.(2)HBeAg-negative patients:at least 18 months' additional consolidation treatment after achieving undetectable HBV DNA and ALT plus an at least 24 months'total treatment duration.Virological relapse was defined as the reappearance of serum HBV DNA(>104 copies/mL)by PCR assay.Six SNPs were selected according to previous report and were confirmed from SNP database in NCBI(www.ncbi.nlm.nih.gov/SNP):rs9277535 at HLA-DP,rs7453920 at HLA-DQ,rs2856718 at HLA-DQ,rs12614 in complement factor B,rs422951 in NOTCH4,rs1883832 in the Kozak sequence of CD40.DNA was extracted from the peripheral blood mononuclear cells of each patient.SNaPshot assay was used for DNA SNPs analyses.Results:Seventy-six CHB patients were included in our study,of which 61 patients were HBeAg-positive(34 HBeAg seroconversion and 27 HBeAg loss/no seroconvert to anti-HBe)and 15 patients were HBeAg-negative.Seven patients have achieved HBsAg loss/conversion by the time of discontinuation.Another 10 patients were found to achieve HBsAg loss/conversion later on during the follow-up process.Twenty-eight patients relapsed after a median of 39 months,follow-up,7 patients in HBeAg seroconversion group,12 patients in HBeAg loss group and 9 patients in HBeAg-negative group.Patients with sustained response were found to be younger(p=0.006)and more HBsAg loss/conversion(p=0.042)than relapse patients.Rsl 883832 in the Kozak sequence of CD40 was correlated with response status after NAs discontinuation(p=0.042,?2 test).A Spearman correlation coefficient of 0.424(p=0.013)also revealed the same conclusion.Rs1883832 displayed an AUROCof 0.778 in predicting response status in CHB patients with HBeAg seroconversion and a genotype of CT was associated with sustained response in this subpopulation.The diagnostic performance of combinative index(rs1883832,age and HBsAg at discontinuation)seemed to be better than that of rs1883832,but there is no statistical difference.Rsl 883832 was also evaluated as an independent factor for response status by multivariate logistic regression.For HBeAg-positive patients failing to obtain HBeAg seroconversion,we did not found any SNP with predictive value for response status.For HBeAg-negative CHB patients,rs9277535 at HLA-DP presents a Spearman correlation coefficient of 0.582(p=0.023)with virological relapse after discontinuation of NAs.Conclusions:The present study revealed rs1883832 in the Kozak sequence of CD40 as a valuable predictive factor for CHB patients with HBeAg seroconversion and a genotype of CT was associated with sustained response.Rs9277535 at HLA-DP might also be a valuable predictive factor for CHB patients with HBeAg-negative but this is a half-boiled view that requires further verifications.