Genetic Risk Factor For Deadly Parasitic Disease Raises Hopes Of Vaccine

Scientists have uncovered a major genetic risk factor for visceral leishmaniasis which is caused by the Leishmania parasite.

AsianScientist (Jan. 11, 2013) – Scientists have uncovered a major genetic risk factor for visceral leishmaniasis which is caused by the Leishmania parasite. The discovery paves the way for the development of a vaccine against the fatally infectious parasite which is carried in the bite of sandflies.

Visceral leishmaniasis, also known as kala-azar or black fever, is the second-largest parasitic killer in the world after malaria. Leishmaniasis affects 12 million people and there are an estimated 1.5 million new cases annually mainly in India, Bangladesh, Nepal, Sudan, South Sudan, Ethiopia. and Brazil.

The parasite can cause fever, weight loss, mucosal ulcers, fatigue, anemia, and substantial swelling of the liver and spleen. If left untreated, the disease is almost always fatal.

To identify genetic risk factors for visceral leishmaniasis, scientists from India, Australia, Brazil, the UK, and the USA conducted a large-scale genome-wide association study of over 2,000 visceral leishmaniasis patients and more than 3,000 healthy subjects in India and Brazil.

In their study, published online in Nature Genetics, they found that variation in a specific region of the major immune response locus, known to immunologists as the major histocompatibility complex (MHC), is the single most important genetic risk factor for the disease.

Teams in Australia, the UK, and the USA are using the results in vaccine research to study the way the immune system interacts with the disease in mice.

“Earlier genetic studies of visceral leishmaniasis in inbred mice allowed us to clearly demonstrate the importance of the MHC in regulating this disease,” said Professor Jenefer Blackwell, who led the LeishGEN Consortium that carried out all of the field work and sample collection.

“Now, major advances in human genetics and the ability to compare the genomes of large numbers of people with and without the disease have allowed us to identify the precise molecular basis to this MHC control in humans.”

“This will have a major impact on refining research towards the ultimate goal of a vaccine.”

The first vaccine against fatal visceral leishmaniasis entered phase I clinical trials last year.

The article can be found at: LeishGEN Consortium & Wellcome Trust Case Control Consortium (2013) Common Variants In The HLA-DRB1–HLA-DQA1 HLA Class II Region Are Associated With Susceptibility To Visceral Leishmaniasis.


Source: University of Western Australia
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Yew Chung is a postdoctoral research fellow at the Duke-NUS Graduate Medical School, Singapore.

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