Study the change of NK cells phenotype in acute and the various periods of chronic HBV infection

Objective This study aimed atevaluating the difference of natural killer(NK) cells in the normal population, the patients with acute and chronic HBV infection. Methods Venous whole blood samples were obtained from 12 cases of healthy adults(HI) and a cohort of patients: 17 cases of acute hepatitis B(AHB), patients with chronic HBV infection including 24 cases of immune tolerance period(IT), 15 cases of immune clearance phase(IC). Detect the frequency of peripheral blood NK and its phenotype like CD56brightNK, CD56dimNK, NKp46highNK, the expression of NKp46(one of the activated receptor NKG2D) in the AHB, IC, IT, HIby flow cytometry.And then analyze its relationship with the clinical outcome. Results The results of variance analysis on the experimental data were as follows: the frequency of NK cells was significantly reduced in the AHB group(9.84±5.34%) and IC(10.17±6.23%) than the HI(14.32±4.82%) and the IT group(17.47± 8.14%),(AHB vs IT, P=0.001; IC vs IT, P=0.002; P=0.025 ABH vs HI; IC vs HI P=0.035). CD56brightNK phenotype in HI group(5.09±3.03%) and IT(3.51±2.13%) decreased than the AHB group(6.99±5.27%) and IC(8.41±6.15%), and the IT group was reduced more significantly(P=0.007, P=0.001). CD56dimNK cells in the IT group(96.78±7.24%)were significantly increased than the HI group(91.71± 3.28%), the AHB group(92.08±5.65%) and the IC group(90.98±6.27%)(P=0.024, P=0.024, P=0.004). NKp46highNK cells in the IT group(7.9±7.26) decreased than the AHB(12.79±8.42and the IC group(11.78±4.76)(P=0.019, P=0.019). Conclusions In the respect of the frequency of NK cells and the distribution of CD56brightNK subgroup, CD56dimNK phenotype and NKp46highNK subsets in patients with HBV infection, the difference between AHB, IC patients and IT patients were statistically significant.No significant differences were found between AHB and IC patients.HI and IT in the frequency of NK cells.And the distribution of CD56brightNK subgroup and NKp46highNK subsets had the differences of no statistical significance.Theses changes of the frequency of NK cells and the different phenotype in IC, AHB and IT, support the choice of clinical antiviral period after HBV infection. Key words: Hepatitis B virus; Natural killer cells; immune tolerance phase; immune clearance phase