Scientists discover ethnic differences in immune response to TB bacterium

July 4, 2013

The immune response to the bacterium that causes tuberculosis (TB) varies between patients of different ethnic origin, raising important implications for the development of tests to diagnose and monitor treatment for the disease, according to new research published today in the journal PLOS Pathogens.

The study, led by researchers at Queen Mary, University of London, in collaboration with the Medical Research Council's National Institute for Medical Research (NIMR),analysed the of 128 newly-diagnosed TB patients in London who were divided by ethnicity into those of African (45), European (27), Asian (55) or mixed European/Asian (1) ancestry.

TB is an infection caused by the TB bacterium Mycobacterium tuberculosis. It commonly affects the lungs. While it grew rare in the UK due to BCG vaccination, improvements in living standards and the introduction of effective , it has been on the increase since the late 1980s. TB also remains a major global health problem, responsible for nearly nine million new cases and 1.4million deaths in 2011.

By analysing the levels of various in blood samples taken before treatment, the scientists showed that immune responses of Asians and Europeans were similar to each other, but different from those of Africans. This difference was caused by ethnic variation in the patients' genetic make-up and was not related to the strain of TB bacterium that the patients were infected with.

Dr Adrian Martineau, Reader in Respiratory Infection and Immunity at the Blizard Institute, part of Queen Mary, who led the research, said: "The TB bacterium has co-evolved with humans following migration to Europe and Asia some 70,000 years ago, and different strains of the TB bacterium disproportionately infect particular ethnic groups. Experiments with cultured in the lab have shown that different strains of the TB bacterium elicit different amounts of inflammation. One might therefore expect that TB patients' immune responses would differ according to the strain of TB bacterium that they are infected with.

"However our study has shown, for the first time, that it is actually ethnic differences in the patient's genetic make-up that cause most of this variation in immune responses – with little effect of the TB strain they are infected with."

By analysing taken from 85 of the original cohort after an eight-week period of intensive treatment, the researchers found that ethnic variation in immune responses became even more marked. A number of immunological biomarkers, which correlated with either fast or slow clearance of the TB bacteria, were identified and found to differ between Africans and Europeans/Asians.

Dr Anna Coussens, who measured immune responses in patient samples at NIMR, said: "These findings have important implications, both for the development of new diagnostic tests, which increasingly rely on analysing the immune response, and also for work to identify candidate biomarkers to measure response to anti-TB treatment. In the future, diagnostic tests and biomarkers will need to be validated in different ethnic populations."

A key factor in determining the ethnic variation identified in the study appears to be the patients' genetic type of vitamin D binding protein – a molecule which binds vitamin D in the circulation.

Dr Martineau said: "There are different genetic types of this protein which vary in frequency between ethnic groups, adding to the growing evidence that vitamin D and the way it is carried in the blood is crucial in determining how a patient's immune system will respond to TB."

Further studies in other populations are now needed to validate the ethnic difference identified.

This work was funded by the British Lung Foundation and the Medical Research Council (MRC).

Dr John Moore-Gillon, Honorary Medical Adviser at the British Lung Foundation, which co-funded the research, said:

"Targeted therapies have long been talked about as the future of medicine. However, in order to develop such treatments, you first need to understand the ways in which the of different people can affect how a disease develops in, and affects, the body. This new research makes great strides forward in doing this for TB, highlighting for the first time how using different approaches for people of differing ethnic backgrounds can help improve our ability to diagnose the disease and monitor the effectiveness of any subsequent treatment.

"TB is a growing problem in the UK. With TB bacteria being notoriously difficult to identify and eradicate from the body, research such as this, that helps improve diagnosis and treatment of the disease, will be vital if we are to keep on top of the battle against its spread."

Explore further: Experimental vaccine shows promise against TB meningitis

Related Stories

Experimental vaccine shows promise against TB meningitis

June 11, 2013

A team of Johns Hopkins researchers working with animals has developed a vaccine that prevents the virulent TB bacterium from invading the brain and causing the highly lethal condition TB meningitis, a disease that disproportionately ...

Treating TB: What needs to be done to improve treatment rates

July 1, 2013

People with tuberculosis (TB) in China often delay going to see a doctor for more than two weeks, finds research in BioMed Central's open access journal BMC Medicine. Reasons for this include a poor understanding of TB, increasing ...

Study finds vitamin C can kill drug-resistant TB (w/ video)

May 21, 2013

In a striking, unexpected discovery, researchers at Albert Einstein College of Medicine of Yeshiva University have determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture. The finding ...

Still long delays in diagnosing TB and HIV

May 31, 2013

It still takes a long time for TB and HIV patients in Uganda to be properly diagnosed. As a result, many patients are infectious without knowing it themselves. These diagnostic delays, and also adherence to therapy, can be ...

Recommended for you

Zika virus infection alters human and viral RNA

October 20, 2016

Researchers at University of California San Diego School of Medicine have discovered that Zika virus infection leads to modifications of both viral and human genetic material. These modifications—chemical tags known as ...

Food-poisoning bacteria may be behind Crohn's disease

October 19, 2016

People who retain a particular bacterium in their gut after a bout of food poisoning may be at an increased risk of developing Crohn's disease later in life, according to a new study led by researchers at McMaster University.

Neurodevelopmental model of Zika may provide rapid answers

October 19, 2016

A newly published study from researchers working in collaboration with the Regenerative Bioscience Center at the University of Georgia demonstrates fetal death and brain damage in early chick embryos similar to microcephaly—a ...

Scientists uncover new facets of Zika-related birth defects

October 17, 2016

In a study that could one day help eliminate the tragic birth defects caused by Zika virus, scientists from the Florida campus of The Scripps Research Institute (TSRI) have elucidated how the virus attacks the brains of newborns, ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jul 05, 2013
This goes a long way toward explaining the need for the W.H.O. to monitor regional distribution of prophylaxis. Relief efforts in sovereign states, often neglect testing, prior to distribution of antibiotics and vaccine. These nation states rationalize the testing to be prohibitively expensive. In reality, medical testing actually reduces the risk of producing antibiotic resistance, in an ethnic population. Antibiotics in the wrong population, may deactivate Intestinal Flora, causing secondary complications. Natural immunity is now compromised, as a result of intervention, while the target group introduces additional symptoms. The loss of nutritional support from reduced intestinal flora was already established during the dawn of Medicine. Genetics and ethnicity are two separate entities. Food preparation may be significant to the ethnic component including choice of beverage. Hippocrates himself , is quoted as saying: "Let food be thy medicine and medicine be thy food" . QED.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.