Natural Killer Cell Characteristics in Patients With Chronic Hepatitis B Virus (HBV) Infection Are Associated With HBV Surface Antigen Clearance After Combination Treatment With Pegylated Interferon Alfa-2a and Adefovir
Femke Stelma1,2, Annikki de Niet1,2, Marjan J. Tempelmans Plat-Sinnige2, Louis Jansen1,2, R. Bart Takkenberg1, Hendrik W. Reesink1,2, Neeltje A. Kootstra2 and Ester M. M. van Leeuwen2
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Author Affiliations
1Department of Gastroenterology and Hepatology
2Experimental Immunology, Academic Medical Center, Amsterdam, The Netherlands
Correspondence: Hendrik W. Reesink, MD, PhD, Academic Medical Center, Department Gastroenterology and Hepatology, Rm G4-215, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ([email protected]).
Presented in part: Annual Meeting of the Dutch Society for Immunology, 17–19 December 2014, Kaatsheuvel, The Netherlands. Abstract 79.
Abstract
Background. The role of natural killer (NK) cells in the process of hepatitis B virus (HBV) surface antigen (HBsAg) clearance and whether their phenotype is related to treatment outcome in patients with chronic hepatitis B are currently unknown.
Methods. Patients with chronic hepatitis B (HBV DNA load, >17 000 IU/mL) were treated with pegylated interferon alfa-2a and adefovir for 48 weeks. NK cell phenotype and function were analyzed in 7 responders (defined as individuals with HBsAg clearance by week 72; 3 HBV e antigen [HBeAg]-positive and 4 HBeAg-negative), 7 matched nonresponders, and 7 healthy controls. Subsequently, 34 baseline samples from HBeAg-positive patients with chronic hepatitis B were analyzed.
Results. During treatment, the percentage and absolute number of CD56bright NK cells increased significantly, whereas the percentage and absolute number of CD56dim NK cells decreased. At baseline, responders had a significantly lower expression of chemokine receptor CX3CR1 on CD56bright NK cells and inhibitory receptor NKG2A on CD56dim NK cells, compared with nonresponders. In addition, responders had higher CD56bright TRAIL expression and interferon γ production at end of treatment. These baseline differences were not found in HBeAg-positive patients who had HBeAg seroconversion without HBsAg clearance.
Conclusions. Combination therapy significantly influences NK cell phenotype and function. Differences between patients with chronic hepatitis B with HBsAg clearance and nonresponders suggest that NK cells play a role in the clearance of HBsAg during interferon-based combination therapy.