The impact of KIR-HLA genotype on hepatitis B virus clearance in Iranian infected individuals.

Killer cell immunoglobulin like receptors (KIRs) have a principal role in regulating the effector functions of NK cells, particularly in viral infections. The major ligands for KIRs are human leukocyte antigen (HLA) class I molecules. The aim of this study is to investigate the possible association of KIR genes, their known HLA ligands and compound KIR-HLA genotypes with hepatitis B virus (HBV) infection. Our study group consisted of 202 Iranian HBV-infected patients (52 spontaneously recovered, 50 asymptomatic carriers, 50 chronic sufferers and 50with liver cirrhosis) and 100 ethnic-matched healthy control subjects. KIR and HLA genotyping was performed by a polymerase chain reaction-sequence-specific primer (PCR-SSP). The frequencies of the KIR2DL5A, KIR2DS1, and KIR3DS1 genes were significantly elevated in recovered individuals when compared with both control and patient groups. Also, KIR2DL5, and KIR3DP1 full were escalated in recovered individuals in comparison with patient groups. In addition, HLA-Bw4 ligand and HLA-A Bw4 were highly frequent in recovered individuals compared with healthy controls. Furthermore, the KIR3DS1 + HLA-Bw4, KIR3DS1 + HLA-Bw4 Iso80 , and KIR3DS1 + HLA-A Bw4 genotypes were significantly more common in recovered individuals than both healthy control and patient groups. Interestingly, AA genotype had less frequency and Bx had higher frequency in recovered individuals compared with both healthy control and patient groups. Our findings suggest a potential impact of the NK cells' activating phenotype that leads to the HBV clearance in infected individuals.

FAS and FAS-Ligand Promoter Polymorphisms in Hepatitis B Virus Infection.

BACKGROUND: The FAS and FAS-Ligand (FASL) system is an important apoptosis pathway in the liver. The FAS-mediated pathway functions by binding the FASL on the activated cytotoxic T lymphocytes and Natural Killer (NK) cells to the FAS receptor on infected hepatocytes. FAS and FASL polymorphisms, which are related to apoptosis, might influence the outcome of Hepatitis B Virus (HBV) infection. OBJECTIVES: Thus, the present study aimed to determine if FAS and FASL promoter polymorphisms are associated with the clinical outcome of HBV infection. PATIENTS AND METHODS: DNA samples were obtained from the infected individuals including chronic carrier (n = 50), chronic hepatitis (n = 50), cirrhosis (n = 25), naturally recovered (n = 26) and compared with those of their matched healthy controls (n = 100). Genotyping for polymorphisms of FAS-670 A/G and -1377 G/A, and FASL -844 C/T was performed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assays. RESULTS: Multiple analyses for genetic association of FAS and FASL polymorphisms were not statistically different between HBV patients (n = 125) and healthy controls (n = 100). However, genotype and allele frequencies of FASL-844 C/T were significantly different between recovered individuals and patients with cirrhosis (P = 0.02 and P=0.01, respectively). Whereas, FAS-670A/G and -1377G/A polymorphisms were similarly distributed in these two groups (P = 0.8 and P = 0.47, respectively). CONCLUSIONS: The current study results showed that bearing -844T allele in FASL promoter region has a protective effect on cirrhosis and is involved in recovery from infection. In conclusion, it is proposed that HBV infection outcome might be influenced by FASL-844C/T polymorphism through alteration in apoptosis of hepatocytes.