New genetic variants that increase a person's likelihood of contracting infectious diseases including tuberculosis and malaria have been uncovered by an international team of researchers.
Their work revealed a "striking association" between a gene called CISH and increased susceptibility to a range of infectious diseases.
A group of five different genetic variants was discovered within the CISH gene, and having just one of these variations raised susceptibility to infectious disease by 18 percent.
"That is a substantial effect size for a single gene," said Frederick Vannberg, a doctor at the Wellcome Trust Centre for Human Genetics and a co-author of the study published in the May 20 issue of the New England Journal Medicine.
CISH is responsible for the production of a protein that plays a key role in the way the body's immune system responds to infectious diseases, effectively interfering with signals sent between immune system cells.
"What the results tell us is that CISH is well worth following up with more research to understand better how the immune system responds to these infectious diseases, and how this can contribute to disease risk," said Adrian Hill, also of the Wellcome Trust Center for Human Genetics.
The study's authors analyzed the genes of more than 8,000 people in clinics in Malawi, Kenya, Vietnam and Hong Kong over a five-year period.
Their research focused on susceptibility to tuberculosis, malaria and other serious blood infections called bacteraemia.
Chiea Khor of A*STAR's Singapore Institute for Clinical Sciences said the research left it unclear why having reduced CISH is linked to an increased vulnerability to infectious disease.
"But it does suggest that CISH is a key regulator of the immune system," she said.
"We hope that our findings will encourage clinical research to better understand the immunological processes that are going on, with a view to identifying targets for therapeutic intervention and the development of better therapies and vaccines."
Infectious diseases are a leading cause of death worldwide but are particularly devastating in the developing world, where treatments and vaccines are "urgently needed," the authors of the study said.