Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Complexities Of Genetic Susceptibility To Tuberculosis Revealed

28.03.2008
Researchers working in Vietnam have identified a genetic variant that predisposes people to developing a lethal form of tuberculosis (TB), tuberculous meningitis, if they are infected with a strain of TB known as the Beijing strain. The work, described in a study published March 28th in the open-access journal PLoS Pathogens, underlines the importance of studying both sides of the complex host-pathogen interaction and its role in susceptibility to disease.

TB, which is caused by the bacterium Mycobacterium tuberculosis, kills over 2 million people each year. It is estimated that well over 2 million people are infected with M. tuberculosis, though the majority will never show symptoms. Some will develop a latent infection, with symptoms only showing if they become sick or immunocompromised, for example through HIV infection.

A small number will develop an active TB infection, usually in their lungs, occasionally progressing to "disseminated TB" – a condition in which failure of the immune system to control the infection allows its spread to other parts of the body.

Some of the risk factors that determine whether individuals develop active TB following exposure are well known; these include HIV infection, malnutrition and smoking. Sarah Dunstan and colleagues from the Wellcome Trust Major Overseas Programme based at the Hospital for Tropical Diseases and the Oxford University Clinical Research Unit (OUCRU), Ho Chi Minh City, Vietnam previously identified the link between TB susceptibility and the role of a gene involved in the immune system, known as TLR2, which is important for recognising and initiating the defensive response when the bacterium enters the body.

People with a particular variant of TLR2, commonly found in the Vietnamese population, are particularly susceptible to developing the most severe form of TB, in which the infection spreads to the meninges, the membranes that envelope the brain and the spinal cord. One in three people who develop TB meningitis die, even amongst those who receive hospital treatment.

Now, Caws and her colleagues have shown that the predisposition to developing TB meningitis appears to be strongest in people who carry the variant of TLR2 and who are infected with the specific Beijing strain of TB.

"We are seeing an increasing number of cases of the Beijing strain worldwide, a strain that is becoming more and more resistant to drugs," says Dr Caws.

The World Health Organisation estimates that around 5% of the TB cases in the world are now multi-drug resistant. In people who have multi-drug resistant TB meningitis mortality approaches 100% because there are no effective treatment regimens.

"Our findings are important because they show that we need to look at both the patient's susceptibility to the disease and the genetics of the pathogen that is infecting them at the same time," says Dr Caws. "Many studies have shown a genetic association with disease in one population but the finding has not been repeated in different populations. This might be not only because of ethnic differences in the population, but also because the pathogen populations are different.

"Understanding the mechanisms that influence our susceptibility to infectious diseases may allow us to develop more sophisticated and targeted treatments and vaccines. This is particularly important in this era of emerging 'untreatable' bacterial infections due to antibiotic resistance."

This study was funded by the Wellcome Trust.

CITATION: Caws M, Thwaites G, Dunstan S, Hawn TR, Lan NTN, et al. (2008) The Influence of Host and Bacterial Genotype on the Development of Disseminated Disease with Mycobacterium tuberculosis. PLoS Pathog 4(3): e1000034. doi:10.1371/journal.ppat.1000034

Andrew Hyde | alfa
Further information:
http://www.plospathogens.org/doi/ppat.1000034

Further reports about: Meningitis Tuberculosis develop strain susceptibility

More articles from Life Sciences:

nachricht Nerves control the body’s bacterial community
26.09.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Ageless ears? Elderly barn owls do not become hard of hearing
26.09.2017 | Carl von Ossietzky-Universität Oldenburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Nerves control the body’s bacterial community

26.09.2017 | Life Sciences

Four elements make 2-D optical platform

26.09.2017 | Physics and Astronomy

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>