Publication Abstract Display
Type: Published Abstract
Title: Latent toxoplasmosis may affect neurocognitive functioning in HIV-infected individuals.
Authors: Bharti A, Smith D, Ellis R, Cherner M, Woods S, Heaton R, McCutchan A, Grant I, Letendre S
Year: 2012
Publication: International AIDS Conference, Washington, DC
Volume: Issue: Pages:
Abstract:Background: Toxoplasma gondii infects up to one-third of the world's population. After acute infection, cell mediated immunity (CMI) controls the parasite that remains dormant in the brain and muscle tissues and causes latent toxoplasmosis (LT). Loss of CMI, as in AIDS, can result in severe disease due to reactivation. However, LT is not benign and can cause behavioral and cognitive changes in HIV- individuals. We conducted this study to determine the prevalence of LT in our HIV+ cohort and to evaluate its impact on neurocognitive functioning. Methods: 120 HIV+ participants were randomly selected from an NIH-funded cohort project. Toxoplasma IgG was measured in serum by commercial immunoassay. Levels > 0.75 diagnosed LT. The HNRC neurocognitive test battery that tests 7 ability areas was administered. Performance was summarized as the validated global deficit score (GDS). GDS ≥ 0.5 defined neurocognitive impairment. Data were analyzed by routine statistical methods, including Pearson's correlations and linear regression. Results: LT was detected in 12 (10%) participants. LT+ subjects were similar to LT- subjects except that they were significantly older. Overall, LT+ subjects were more likely to have neurocognitive impairment, although this did not reach statistical significance. This difference was greater among subjects who were older than the median age of 44 years (60% vs. 33%, p = 0.11). Among LT+ subjects, higher IgG titers titers were associated with both higher CD4+ T-cell counts (R2 0.78, p=0.001) and worse GDS (R2 0.51, p=0.039).Conclusions: In this small, cross-sectional analysis, 10% of HIV+ subjects had evidence of prior Toxoplasma infection. LT+ was more common among older subjects. LT+ older subjects trended towards worse neurocognitive functioning and higheranti-Toxoplasma IgG titers were associated with worse functioning. Studies with a larger number of LT+ individuals are needed to validate this finding.

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