Exposure to hepatitis B virus activates immunity in young people, suggesting benefits for earlier treatment
A computer-generated image of the hepatitis B virus. Credit: iStockphoto/Thinkstock
Infectious disease experts have long thought that children, teenagers and young adults who are chronically infected with the hepatitis B virus (HBV) lack the immune cells needed to fight this pathogen. As such, physicians currently withhold therapeutic interventions from younger patients until they have reached an advanced age—typically around 30 years old—at which time the immune system is thought to have 'awakened' to the virus.
Yet, contrary to the conventional medical wisdom, new research from the A*STAR Singapore Institute for Clinical Sciences (SICS) indicates that there is no such inherent age-associated period of so-called 'immune tolerance' to HBV. In fact, older people with chronic hepatitis B seem to have a weaker immune response, represented by weaker antiviral T-cell repertoires, than younger individuals infected with the virus.
"These findings can have major implications for the clinical management of chronic hepatitis B infections," says the SICS's Antonio Bertoletti, who led the research. "It might be better to start treatment early, as young people have a less compromised HBV-specific immune response, and [because] functional recovery of HBV-specific T cells is associated with successful control of the infection."
Scientists from Bertoletti's laboratory, together with clinical collaborators in the UK, isolated T cells from 44 people with chronic HBV infections between the ages of 10 and 30, the majority of whom were of Asian descent. Around 75% of the world's 400 million people with chronic hepatitis B can be found within the region of Asia.
They compared the immune samples to those from healthy age-matched controls, and showed that young patients infected with HBV expressed increased levels of virus-associated T cells, and these T cells displayed the ability to expand and produce pro-inflammatory signaling molecules known as cytokines, which are involved in antiviral responses. Furthermore, these HBV-specific T cells became more dysfunctional with age, the authors found, suggesting that the longer a patient is left untreated, the less effective the immune system becomes at clearing the virus.
The study upends the idea that immune recognition of HBV is somehow averted in certain individuals, thus indicating that all patients, regardless of age, could be suitable for treatment. It also highlights the inadequacy of measuring biomarkers of liver inflammation—the current proxy for immune activity in people with chronic hepatitis B infections. Such indicators are typically absent in young patients despite the study's suggestion of the presence of active T-cell responses to the virus.
More information: Kennedy, P. T. F., Sandalova, E., Jo, J., Gill, U., Ushiro-Lumb, I. et al. Preserved T-cell function in children and young adults with immune-tolerant chronic hepatitis B. Gastroenterology 143, 637–645 (2012). dx.doi.org/10.1053… .2012.06.009
Journal reference: Gastroenterology
- Earlier treatment for young patients with chronic hepatitis B more effective in clearing virus Sep 06, 2012 | not rated yet | 0
- Hepatitis B virus triggers cell 'suicide' in patients with chronic infection Apr 08, 2008 | not rated yet | 0
- Liver transplant recipients with hepatitis B may need lifelong antiviral treatment Feb 26, 2009 | not rated yet | 0
- Why are T cells tolerant to hepatitis B virus? Oct 14, 2008 | not rated yet | 0
- Scientists shed light on mystery surrounding hepatitis B virus: Discovery is decades in the making Jan 09, 2013 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
(AP)—Government health officials are investigating several health problems reported with potentially contaminated medications made by a Tennessee specialty pharmacy.
Diseases, Conditions, Syndromes 32 minutes ago | not rated yet | 0
(HealthDay)—Comorbid conditions often accompany alopecia areata, according to a study published online May 22 in JAMA Dermatology.
Diseases, Conditions, Syndromes 1 hour ago | not rated yet | 0
(HealthDay)—As a world-class golfer, Stacy Lewis' accomplishments are remarkable. But it was a physical challenge in her childhood that defined her ascent to the top of her sport.
Diseases, Conditions, Syndromes 2 hours ago | not rated yet | 0
Saudi Arabia said Friday it would send samples taken from animals possibly infected with a deadly SARS-like virus to the United States for testing in a bid to find the source of disease.
Diseases, Conditions, Syndromes 5 hours ago | not rated yet | 0
The World Health Organization voiced deep concern Thursday over the SARS-like virus that has killed 22 people in less than a year, saying it might potentially spread more widely between humans.
Diseases, Conditions, Syndromes 8 hours ago | 5 / 5 (1) | 0
Two mutations central to the development of infantile myofibromatosis (IM)—a disorder characterized by multiple tumors involving the skin, bone, and soft tissue—may provide new therapeutic targets, according to researchers ...
37 minutes ago | not rated yet | 0 |
Talking on a hands-free device while behind the wheel can lead to a sharp increase in errors that could imperil other drivers on the road, according to new research from the University of Alberta.
5 minutes ago | not rated yet | 0
(Medical Xpress)—A new study by researchers in the US has shown that an ancient virus can be modified to help in the fight against the simian immunodeficiency virus SIV, which is the equivalent in monkeys ...
6 hours ago | 5 / 5 (3) | 0 |
Women at a particular stage in their monthly menstrual cycle may be more vulnerable to some of the psychological side-effects associated with stressful experiences, according to a study from UCL.
3 hours ago | 5 / 5 (1) | 0 |
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to ...
3 hours ago | 5 / 5 (2) | 0 |
Kate O'Reilly's spring allergy survival kit includes the usual stuff - nasal sprays, allergy pills and a box of tissues. This season, she's added a new weapon to her line of defense: an app on her smartphone.
1 hour ago | not rated yet | 0