HIV Subtype Better Predictor of Early Death from AIDS
than Viral Load Test
February 6th 2006
AIDS in Africa
Scientists say that HIV subtype is more important than determining the
“viral load” as a predictor of early death. Viral load has been the
standard method of determining the progress of the disease, but now
scientists have begun to investigate HIV subtypes.
The scientists divided the HIV virus into three group types where D made
a person with HIV likely to die more rapidly compared with a person in
the A subtype group. Viral load had little to do with mortality in
comparison. According to the John Hopkins study, “Ten percent of those
infected with subtype D died within three years, while none with subtype
A died. However, viral load ranged from 20,000 particles per cubic
milliliter of blood to 100,000 particles per cubic milliliter of blood
in those with both subtypes, and was not found to be an accurate
predictor of rapid death within the same timeframe.”
Participants in the study came from the Rakai cohort. More than 300
newly infected men and women in Uganda participated in the study which
took place between 1995 and 2001. Of this group, 53 were infected with
subtype A and 203 were infected with subtype D. 70 were infected with a
recombinant version of the two types.
There was a difference in survival periods between the three groups.
Those in group A survived on average 8.8 years. Those in group D had an
average survival period of 6.9 years while those in the AD group
survived an average of 5.8 years.
The researchers believe that subtype D is more virulent because it binds
to key receptors on immune cells. Subtype A viruses could only bind to
one type of receptor, the CCR5. “But 25 percent of subtype D virus
bound to both CCR5 and another receptor, CXCR4. Indeed, two-thirds of
those infected with CXCR4-binding virus died within three years,”
according to the report.
Lead researcher Oliver Laeyendecker, M.S., M.B.A., a senior research
associate at The Johns Hopkins University School of Medicine and senior
research assistant at the National Institute of Allergy and Infectious
Disease, "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."
Best Syndication Staff Writer
Books on Genetics
Keywords and misspellings: sub-types sub types