GENE variants associated with fast progression to AIDS are common in people of Indian origin. That鈥檚 the worrying finding of immunologists at the All India Institute of Medical Sciences in New Delhi.
Narinder Mehra鈥檚 team sequenced parts of key immune genes in 2000 healthy people and 200 HIV-positive people. They found that a gene variant called HLA-B*35px, which other studies have linked to fast progression from HIV infection to AIDS, is two and half times as common as a protective variant, HLA-B*35py. A variant of the CCR2 gene that slows progression to AIDS was not present in any of the subjects.
What鈥檚 more, the delta 32 variant of the CCR5 gene, which helps protect against infection by the virus and occurs in about 10 per cent of people of European origin, was also entirely absent. Other studies have also found this variant is very rare in non-Europeans. The results were presented at the first national conference of the AIDS Society of India in New Delhi last week.
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鈥淥ur results show that Indians carry genetic variants in the immune system which favour faster progression to AIDS,鈥� Mehra says. The study has also revealed many previously unknown genetic variants in the immune systems of Indians, he says, meaning that vaccines tailored for western populations might not be effective in India.
鈥淧reviously unknown genetic variants in Indians mean that vaccines tailored for western populations may be ineffective鈥�
But Mehra is cautious against drawing any conclusions about how these variations will affect the spread of HIV in India and whether people who do not get treatment will die faster there than elsewhere. Bigger studies need to be conducted in India and other parts of the world to work out exactly what effect these variants have, he says. Ramesh Paranjpe of the National AIDS Research Institute in Pune agrees. 鈥淲e need to study more HIV-infected people in greater detail to arrive at any such conclusions.鈥�
The National AIDS Control Organization calculated that there were 5.1 million HIV-positive people in India in 2003, the highest number for any country except South Africa, but the figure is contested. Paranjpe says debating the numbers misses the point. 鈥淭he NACO figures may be slightly off but that does not affect the gravity of the situation. We have a huge problem at hand,鈥� he says.
