CXCL9 Associated with Sustained Virological Response in Chronic Hepatitis B Patients Receiving Peginterferon Alfa-2a Therapy: A Pilot Study

BACKGROUND AND AIMS There is lack of a practical biomarker to predict sustained virological response (SVR) in chronic hepatitis B (CHB) patients undergoing peginterferon alfa-2a (PEG-IFN). The aim of this pilot study was to identify immunological features associated with SVR. METHODS Consecutive 74 CHB patients receiving 24 weeks (for hepatitis B e antigen (HBeAg)-positive) or 48 weeks (for HBeAg-negative) PEG-IFN, were prospectively enrolled. Serum HBV viral loads, hepatitis B surface antigen (HBsAg), CXCL9, IFN-γ-inducible protein 10 (IP-10), interferon-gamma (IFN-γ) and transforming growth factor beta (TGF-β) were measured at baseline and week 12. SVR was defined as HBeAg seroconversion combined with viral load <2000 IU/mL in HBeAg-positive (n=36), and viral load <2000 IU/mL in HBeAg-negative patients (n=38) at 48 weeks after the end of treatment. RESULTS Nineteen patients (25.7%), 7 in HBeAg-positive and 12 in HBeAg-negative, achieved SVR. There were significant declines of HBV DNA, HBsAg, IP-10 and IFN-γ levels at week 12. In multivariate analysis, pre-treatment CXCL9 >80 pg/mL, HBV DNA <2.5 x 10(7) IU/mL and on-treatment HBV viral load, HBsAg decline >10% at week 12 were predictors of SVR. The performance of CXCL9 in predicting SVR was good in patients with HBV DNA <2.5 x 10(7) IU/mL, particularly in HBeAg-negative CHB cases (positive predictive value, PPV= 64.3%). CONCLUSIONS Pre-treatment CXCL9 level has the potential to select CHB patients who can respond to PEG-IFN, especially in HBeAg-negative patients with low viral loads.