Study puts Indian population at higher risk of fast progression of HIV infections

Jayashree Padmini - New Delhi

A Study undertaken by researchers at the All India Institute of Medical Sciences (AIIMS) indicates a possible genetic predisposition and fast progression of HIV in infected Indian population. Reviewing the data on the distribution patterns of molecular subtypes of HLA (human leukocyte antigen) class I and class II extended haplotypes in India with reference to global distributions, the AIIMS researchers come to the conclusion that Indian HIV positive population is at higher risk of faster disease progression. The project, study of Genetic Diversity of Indian population sponsored by the Department of Biotechnology, was conducted by Dr N K Mehra, prof and head, and Dr Gurvinder Kaur of the Department Transplant Immunology & Immunologicals at AIIMS.

The study being undertaken over a period of 2001-2004, in 2000 odd sample population from Delhi has also come across several novel genes associated with HLA in Chromosome 6. "The data available from this study indicates that Indian HIV positive population is genetically programmed for disease progression at a faster rate compared to our western counterparts," explained Dr N K Mehra. In view of the findings of the HLA study, the team has submitted a proposal to the Indian Council of Medical Research to undertake a multi-centric study on a bigger population group across the country.

Dr N K Mehra said, "The long term goals of the study will be to identify genetic markers to predict predisposition to HIV and disease progression." Similar studies are going on in the western world also on the role of HLA antigen and susceptibility of HIV infection. "We would require about Rs 2 to 3 crore to take up a large study on at least two-three defined ethnic groups in the country on HIV viral load & CD4 T-cell count. We need to follow up for around five years to establish the prevalence as well as to identify genetic markers," informed Dr Mehra.

The report says that since there is selective predominance of different HLA alleles and haplotypes in different populations, a dedicated screening effort is required at the global level to develop MHC-based (MHC - major histocompatibility complex) vaccines against infectious diseases. This will lead to the development of multivalent, poly-epitope, subtype-specific HIV vaccines that are specific to the target geographical location. At present the range and diversity of the genetic and ethnic background of HIV-1 infected individuals are hardly known.

As the HIV-1 is a highly variable virus, the viral epitopes that trigger a protective response might differ depending on the HLA type of the individual, the genetic subtype of the infectious virus, and the predominant virus that causes the epidemic in a certain geographical region. Hence the need to study seropositive/negative populations.