Patients carrying a certain type of HIV virus are likely to die faster than those carrying the other subtypes, a study by John Hopkins University School of Medicine researchers has found. The study said that those infected with HIV subtype D will die faster than those with the subtypes A, B or C. This means that the subtype is a better indicator of the disease's progression than the viral load, which measures the extent of infection in the patient's blood.
“Knowing a person's HIV subtype is important for the management of the infection because the disease can progress more rapidly in those infected with subtype D and recombinant virus incorporating subtype D than in those with other subtypes,” said Oliver Laeyendecker, lead author of the study.
Under the study, researchers studied a group of 12,000 people from the Rakai cohort in Uganda. Around 300 men and women from this group, infected between 1995 and 2001, were studied for their subtype of HIV. Fifty-three were found to have the subtype A, while 203 had subtype D. The remaining 70 had HIV that was recombinant type of subtypes A and D.
A follow-up of several years showed that those who had subtype D succumbed to AIDS within three years, much earlier than those who were carrying HIV with subtype A. Even though the viral load for all the subjects was nearly the same, those with subtype A lived an average of 8.8 years, as compared to the 6.9 years of subtype D patients and the 5.8 years of those with the recombinant version.
Researchers speculated that the fast progression of the disease in those with the D subtype might be because of its ability to bind with the immune cells' key receptors, CCR5 and CXCR4, thereby killing the cells off quicker than A, which binds only to CCR5. While HIV virus with subtypes A and D is common in Uganda, countries like India, China, and South Africa show greater occurrence of subtype C. United States and Europe show greater prevalence of subtype B than the others.
The findings have implications for the treatment of the disease to increase the lifespan of the patient. So far, drugs have concentrated on keeping the viral load in a patient's blood low to increase their years of life. However, with these findings, it might be necessary to change the drug therapy according to the subtype of the patient's HIV. The results were presented at the Conference on Retroviruses and Opportunistic Infections in Denver.
According to World Health Organization (WHO) statistics, AIDS has claimed the lives of over 25 million ever since it surfaced in 1981. In spite of the development of specialized antiretroviral drugs, the immunodeficiency disease killed around 3.1 million people in 2005. As of now, around 40 million people from all over the world are living the HIV virus. In 2005, between 2.8 to 3.6 million succumbed to the disease and between 4.3 and 6.6 million were newly diagnosed with the HIV virus.
An opportunistic disease, AIDS manifests itself as pneumonia, tuberculosis, meningitis, cancers and other disease, as the body's ability to fight infections declines rapidly.
