US scientists have announced that they have taken a crucial step towards understanding why some people have natural immunity to HIV.

There are a very few people who may contract HIV, but in whom the virus will only progress very slowly or not develop at all when they are exposed to it, as their bodies are better at making white blood cells to fight the virus. The team studied a group of such people, who are known as ‘elite controllers’.

They discovered that the gene that these individuals share, known as HLA B57, encourages the body to make killer T cells, the cells in the body that fight infection. The gene was first discovered in the late 1990s, and is thought to be present in about every 200 people who are infected with HIV.

The white blood cells can make people more susceptible to autoimmune diseases, which occur when the body’s immune system starts working against itself.

The research was carried out with the help of computer modelling, which map how T-cells develop in the thymus.

Though the discovery is a huge step forward, the team, lead by MIT professor Arup Chakraborty and Harvard’s Professor Bruce Walker, say that any vaccine that results from the findings will take at least a decade to reach doctors on the ground.

As the disease is causing devastation in many parts of Asia and Africa, while the vaccine is the dream in the meantime huge energy is being devoted to finding better treatments and funding prevention and awareness programs.

The full study is published in the journal Nature.