Functional restoration of CD56bright NK cells facilitates immune control via IL-15 and NKG2D in patients under antiviral treatment for chronic hepatitis B - PubMed (original) (raw)

. 2017 Sep;11(5):419-428.

doi: 10.1007/s12072-017-9803-4. Epub 2017 Jun 20.

Lin Zhu 1, Aichao Shi 1, Lin Ding 1, Xiaoping Zhang 1, Zhenmin Tan 1, Wei Guo 1, Weiming Yan 1, Meifang Han 1, Jidong Jia 2, Xiaoping Luo 3, Detlef Schuppan 4 5, Qin Ning 6

Affiliations

Functional restoration of CD56bright NK cells facilitates immune control via IL-15 and NKG2D in patients under antiviral treatment for chronic hepatitis B

Tao Chen et al. Hepatol Int. 2017 Sep.

Abstract

Background and aims: Hepatitis B virus (HBV) is intrinsically immunogenic, with long-lasting immune control in many patients. However, the mechanisms and key cell types underlying effective immune control are incompletely understood.

Methods: We studied the restoration of natural killer (NK) cell numbers and function post antiviral treatment in 52 hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients who received telbivudine (LdT) for 48 weeks. Blood samples were collected at week 0, 12, 24, 36, and 48 and tested for HBV DNA, hepatitis B surface antigen (HBsAg), HBeAg, liver enzymes, and NK cell parameters.

Results: Compared with baseline, the number of peripheral CD3-CD56bright NK cells increased significantly from week 24 to 48, especially in patients with baseline alanine transaminase (ALT) two- to fivefold the upper line of normal (ULN) or HBV DNA <9 log10 copies/ml. Expression (number and density) of activating receptors NKG2D and NKp46 on CD3-CD56bright NK cells was enhanced, while inhibitory receptor NKG2A decreased. Notably, numbers of CD3-CD56bright or NKG2D+CD3-CD56bright NK cells were significantly better restored in patients with HBeAg seroconversion. NK cell activating serum interleukin 15 (IL-15) was significantly increased during LdT treatment, especially in HBeAg seroconverters. LdT significantly enhanced expression of NKG2D and IL-15 in cultures of purified peripheral NK cells from treatment-naïve HBeAg-positive CHB patients.

Conclusions: Functional restoration of CD56bright NK cells via upregulation of IL-15 and NKG2D is a novel activity of LdT and likely other antivirals, independent of its effect on HBV replication. This also demonstrates the importance of host immune restoration in controlling chronic HBV infection.

Keywords: Chronic hepatitis B; IL-15; NKG2D; Natural killer cells; Telbivudine.

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Conflict of interest statement

Conflict of interest

Qin Ning is on the speakers’ bureau of and has received research support grants from Novartis. Tao Chen, Lin Zhu, Aichao Shi, Lin Ding, Xiaoping Zhang, Zhenmin Tan, Wei Guo, Weiming Yan, Meifang Han, Jidong Jia, Xiaoping Luo and Detlef Schuppan have no conflicts of interest to declare.

Ethical approval

All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1975 Helsinki Declaration and its later amendments or comparable ethical standards.

Informed consent was obtained from each patient included in the study.

Figures

Fig. 1

Fig. 1

Numbers of peripheral NK cells recovered during antiviral treatment. Both a percentage and b absolute number of peripheral NK cells significantly increased from week 36 to 48 on treatment. c The number of CD56bright NK cells was increased, accompanied with a decline of CD56dim NK cells from week 24 to 48 during LdT treatment when compared with baseline level (p < 0.001). d Significantly increased peripheral NK cells in patients with low viral load [<9 log10 (copies/ml)] at week 36 (p = 0.005) and 48 (p = 0.001). e More elevation of CD56bright NK cells and more decline of CD56dim NK cells were observed in patients with low viral load, but no significant difference was shown between groups with high and low viral load. Patients with baseline ALT 2–5 × the upper limit of normal (ULN) showed better total NK cell (f) and CD56bright NK cell (g) recovery

Fig. 2

Fig. 2

Activation of peripheral NK cells recovered during antiviral treatment. a Percentage of NKG2D+NK cells was significantly enhanced from week 24 to 48 (p < 0.05). b Percentage of NKp46+NK cells was significantly elevated from week 24 to 36 (p = 0.022 and p < 0.001), with a sharp decline at week 48. c Expression of inhibitory receptor NKG2A was significantly lower in weeks 12 to 48 than at baseline (p < 0.001 each). d NKG2D+CD56bright NK cells, without NKG2D+CD56dim NK cells, expanded from week 24 to 48 (p < 0.001). e Percentages of NKp46+CD56bright NK cells and NKp46+CD56dim NK cells significantly elevated from week 24 to 36 (p < 0.001), and showed a decline at week 48 subsequently. f NKG2A+CD56bright NK cells and NKG2A+CD56dim NK cells significantly decreased from week 24 to 48 (p < 0.001)

Fig. 3

Fig. 3

Increased NKG2D+CD56bright NK cells correlated with HBeAg seroconversion (eAg SC) during antiviral treatment. a Percentage of NK cells in patients with HBeAg seroconversion showed an elevating trend during LdT treatment, but without significance. b Expression of NKG2D on peripheral NK cells at week 36 was significantly higher in patients with eAg SC (p = 0.047). c Percentage of CD3−CD56bright and CD3−CD56dim NK cells in groups with or without eAg SC shown on scatter plot. d Percentage of NKG2D+CD3−CD56bright and NKG2D+CD3−CD56dim NK cells in groups with or without eAg SC shown on scatter plot. e Patients with eAg SC exhibited significantly higher percentage of CD3−CD56bright NK cells from week 12 to 48 compared with the group without eAg SC (p < 0.001). f Percentage of NKG2D+CD56bright NK cells was significantly elevated during LdT treatment in patients with eAg SC (p < 0.001)

Fig. 4

Fig. 4

Serum IL-15 level elevated during antiviral treatment. a Serum IL-15 significantly elevated at week 48 of LdT treatment (p = 0.041). b No significance was shown between patients with baseline HBV DNA less than 9 log10 (copies/ml) versus more than 9 log10 (copies/ml). c Patients with baseline ALT 2–5 ULN showed significantly enhanced IL-15 expression at week 48 (p = 0.012). d Patients with HBeAg seroconversion had higher IL-15 level at week 36 and 48 (p = 0.037 and p < 0.001, respectively)

Fig. 5

Fig. 5

Significant increase of NKG2D and IL-15 production in peripheral NK cells treated with LdT in vitro. Peripheral NK cells that were isolated from seven baseline patients and cultured for 4 h with LdT showed significant increases in NKG2D expression (p = 0.026) (a) and increased secretion of IL-15 (b, c, p = 0.042). d Detection of IL-15 by confocal microscopy in NK cells cultured with LdT. IL-15 was observed mainly in the endochylema (red) and was much higher in NK cells cultured with LdT than with lamivudine in semiquantitative assay (e, p < 0.001)

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