According to study results published in JAMA Network Open, there may be an association between decreased brain volume in the hippocampus and thalamus and decreased white blood cell counts in patients with HIV who are receiving antiretroviral therapy.
This cross-sectional study examined data from 1,203 adult HIV patients (mean age 45.7 years) from 13 studies in Africa, Asia, Australia, Europe and North America. A team of researchers extracted regional and whole-brain segmentations from data sets as studies continued to join the HIV working group within the ENIGMA (Enhancing Neuro Imaging Genetics through Meta Analysis) consortium. They performed extractions between 2014 and 2019.
Specifically, the study’s researchers extracted volume estimates for 8 subcortical brain regions from T1-weighted magnetic resonance images to assess associations with blood plasma markers indicative of immunosuppression or detectable plasma viral load (dVL).
The results showed a significant association between lower CD4 + cell counts and a smaller hippocampus volume (mean β = 16.66 mm3 per 100 cells / mm3; P <0.001) and thalamus (mean β = 32.24 mm3 per 100 cells / mm3; P <0.001)) volumes. In addition, lower current CD4 + cell counts were associated with larger ventricles (mean β = -391.50 mm3 per 100 cells / mm3; P = 0.001).
Lower current CD4 + cell counts in patients who were not receiving combination antiretroviral therapy (cART) were associated with significantly lower putamen volumes (mean β = 57.34 mm3 per 100 cells / mm3; P = 0.003). The study researchers also found that dVL correlated with smaller hippocampal volumes (P = 0.005). In patients taking cART, dVL correlated with smaller amygdala volumes (P = 0.004).
Limitations of this study were the inclusion of only patients who were positive for HIV infection and the lack of seronegative controls.
The study’s researchers added that further examination of the neurological signatures of HIV infection could improve understanding of “neurobiological changes that may contribute to neuropsychiatric and cognitive outcomes in HIV-positive individuals.” Ultimately, this understanding will “be critical in identifying individuals at risk for neurological symptoms, advancing novel treatments that can protect the CNS, and monitoring treatment response.”
Disclosure: Several authors of the study have stated that they are part of the pharmaceutical industry. For a full list of the authors’ information, see the original reference.
Nir ™, Fouche JP, Ananworanich J. et al. Association of immunosuppression and viral load with subcortical brain volume in an international sample of people living with HIV. JAMA Netw Open. Published online January 15, 2021. doi: 10.1001 / jamanetworkopen.2020.31190