Occult Hepatitis B Virus Infections Remain Low in Iran

Despite prevalence increasing elsewhere across the globe, occult hepatitis B virus infections (OBI) remain low in Iran.

A team, led by Azam Khamseh, Research Center for Clinical Virology, Tehran University of Medical Sciences, determined the OBI prevalence among Iranian liver transplant recipients.

“The prevalence of occult hepatitis B infection among Iranian liver transplant recipient patients has not been explored yet,” the authors wrote.

Occult Hepatitis B Infections

Occult hepatitis B infections are when hepatitis B virus (HBV) DNA is detected in the absence of hepatitis B surface antigen (HBsAg). However, these infections can retain the same pro-oncogenic features and could contribute to the acute exacerbation and development of HBV-associated diseases, including liver diseases, cirrhosis, and hepatocellular carcinoma (HCC).

“One of the main clinical implications of OBI is usually observed in the setting of liver transplantation,” the authors wrote. “In particular, livers from donors with OBI carry a risk of HBV transmission, with infection arousing in 25%-95% of the liver grafts donated from patients being HBsAg negative and anti-HBc positive.”

Rates of Infections

In the study, the investigators examined 97 patients who underwent transplantation because of several clinical backgrounds in the Liver Transplantation Center in Tehran between 2005-2018.

The patient population age ranged from 15-65 years, with a mean age of 47.66 ± 11.71 for males and 38.72 ± 13.07 for females (P = .002).

Overall, Iran is considered to be a low HBV prevalence area with less than 2% of the population having the infection.

The patients were diagnosed with various diseases, including cryptogenic cirrhosis (n = 49; 50.6%), HBV-related cirrhosis (n = 13; 13.4%), HCV-related cirrhosis (n = 12; 12.4%), HBV/HCV-related cirrhosis (n = 1; 1%), cirrhosis due to autoimmune hepatitis (n = 17; 17.6%), fulminant hepatitis (n = 1; 1%), Budd-Chiari (n = 1; 1%), and primary sclerosing cholangitis (n = 3; 3%). The majority of patients received a liver transplantation in the previous 3 years.

The investigators also collected blood samples of each participant.

The team conduced serological evaluation and applied 2 different types of PCT methods for amplification of HBV DNA, followed by the direct sequencing of whole hepatitis B virus surface genes.

At the time of admission, there were no patients positive for HBsAg, but 25% (n = 24), 12.3% (n = 12), and 5.1% (n = 5) cases were positive for anti-HBc, hepatitis C virus (HCV), and hepatitis delta virus (HDV) antibodies, respectively. In addition,

There were also 2 male patients in the study positive for OBI (2.1%) that were positive for anti-HBc and negative for anti-HBs, anti-HCV, and anti-HDV. The main reason for liver transplantation was HBV-related cirrhosis. Both patients were diagnosed 2 years following transplantation.

Finally, the investigators sequenced HBsAg and found no amino acid substitution.

“The prevalence of OBI in the Iranian liver transplantation patients was relatively low,” the authors wrote. “Future longitudinal studies with a larger sample size are suggested to explore the significance of this clinical finding, including the reactivation of cryptic HBV DNA, in liver transplant subjects.”

The study, “Characterization of occult hepatitis B infection among Iranian liver transplant recipients,” was published online in the Journal of Clinical Laboratory Analysis.