HIV subtype A is associated with poorer neuropsychological performance than subtype D in children, investigators from Uganda report in the online edition of AIDS.
Children infected with subtype A had significantly poorer memory, learning and visual-spatial analysis and problem-solving skills than those infected with subtype D.
“Subtype A may be more directly encephalopathogenic than HIV subtype D in children”, comment the investigators, who call for more research into this issue.
There are numerous subtypes of HIV. The most common in Africa are A, C, and D.
Subtype D infection in adults has been associated with faster HIV disease progression and a greater risk of developing neuropsychiatric symptoms than subtype A.
Little is known about the impact of subtype on the neuropsychiatic performance of HIV-positive children. Both subtype A and subtype D are present in Uganda, therefore investigators conducted a cross-sectional study analysing the neuropsychiatric performance of HIV-positive children aged between 6 and 12 years, comparing the results according to subtype.
A total of 54 children were included in the study. Most (37) were infected with subtype A, with 16 having subtype D infection, and one subtype C. None was taking antiretroviral therapy.
A variety of tests were used to measure the neuropsychiatric performance of these children.
These included assessments of memory, problem solving, learning, planning, and attention. The results were controlled to take account of stimulation and learning opportunities offered by at home, and for CD4 cell count and viral load.
The children with subtypes A and D had similar characteristics. However, viral load was significantly higher in those infected with subtype A (5.01 copies/ml/ log10 vs. 4.57 copies/ml/log10).
Children with subtype A performed significantly more poorly than those with subtype D in the tests assessing memory (p = 0.01), visual spatial analysis (p = 0.005), learning (p = 0.02) and attention (p = 0.004).
After controlling for viral load, children with subtype A still had significantly poorer memory (p = 0.05) and visual spatial analysis (p = 0.007) skills.
The investigators calculated that 19% of the children with subtype A infection and 17% of those with subtype D had neurocognitive impairment.
“We found evidence that HIV-subtype influences neurocognitive disability in HIV-infected Ugandan children”, write the investigators.
However, unlike earlier research involving adults, subtype A rather than subtype D was associated with a greater risk of impairment.
“This stark difference in subtype association may partly be due to the fact that the adults in the study were at a more advanced disease stage”, suggest the researchers, who believe that their research could have clinical implications.
They conclude: “If future studies confirm that HIV subtype A is more neuropathogenic for children in the long-term…they might suggest that HIV subtype should be considered in deciding the timing of antiretroviral therapy initiation and that the encephalopathic risk of a given subtype should be considered in selecting antiretroviral drugs with varying central nervous system penetration characteristics.”
Boivin MJ et al. HIV-subtype A is associated with poorer neuropsychological performance compared with subtype D in antiretroviral therapy-naïve Ugandan children. AIDS, online edition DOI: 10.1097/QAD.0b013e3283389dcc, 2010.