Outcome of patients with HIV-1-related cognitive impairment on highly active antiretroviral therapy

Effective antiretroviral therapy reduces degradation of tryptophan in patients with HIV-1 infection

Antiretroviral therapy (ART) has a significant impact on HIV-1 RNA levels, the CD4 cell count, and immune activation. We examined whether these changes are associated with a change in the rate of tryptophan degradation (expressed as the kynurenine to tryptophan ratio, kyn/trp) as an estimate for the activity of interferon-gamma inducible enzyme indoleamine (, )-dioxygenase (IDO). Plasma levels of tryptophan, kynurenine, and neopterin were measured pretherapy and 6 months postinitiation of therapy in 45 patients with HIV-1 RNA levels of less than 1000 copies/ml 6 months after initiation of ART. Before ART, the patients had decreased tryptophan and increased kynurenine concentrations compared to healthy controls. During ART, average tryptophan levels increased; in the same time kynurenine and kyn/trp decreased (P < 0.001), although not to normal levels. Since pretherapy tryptophan concentrations correlated inversely with neopterin, and kynurenine correlated with viral load and neopterin but not with CD4 cell count, the data support the view that HIV production may induce immune activation and consequently tryptophan is degraded at a higher rate. In agreement, kyn/trp positively correlated with neopterin (r(s) = 0.60, P < 0.001), with virus load (r(s) = 0.37, P = 0.013), and very weakly with CD4(+) cells counts (r(s) = 0.30, P = 0.049). The change in the kyn/trp ratio during ART correlated more strongly with the change in neopterin levels (r(s) = 0.49, P = 0.001) than with the change in HIV RNA levels and weakly with the CD4 cell count. The data underscore the fact that both neopterin production and tryptophan degradation are triggered by immune activation. Tryptophan degradation is increased in HIV infection and partially reversed under ART. The data agree with the concept that immune activation is the common background of IDO activation which may be an important factor underlying T-cell hyporesponsiveness.

Cognitive and affective disorders associated to HIV infection in the HAART era: findings from the NeuroICONA study. Cognitive impairment and depression in HIV/AIDS. The NeuroICONA study

OBJECTIVE

To assess the natural story of HIV-associated affective and cognitive disorders and the relationship with clinical, pharmacological, immunological and behavioural factors.

METHOD

A total of 395 HIV-positive patients, naive to Highly Active Antirectroviral therapy (HAART), with no severe psychiatric disorders have been enrolled in the Neuro-ICONA Study. All participants were administered a comprehensive data collection instrument including an addiction behaviour survey, a medical problem list, a psychiatric assessment, a validated neuropsychological test battery.

RESULTS

The global prevalence of cognitive impairment and of prominent depressive symptomatology were 17.9 and 15.5%, respectively. A significant difference in the prevalence of prominent depressive symptomatology was observed between patients in HAART and those not taking HAART(14.1 vs. 23.8%; P = 0.05).

CONCLUSION

Depressive and cognitive disorders affect a substantial proportion of HIV-seropositive subjects. The prevalence of prominent depressive symptomatology appears to significantly vary in relationship to the therapeutic protocol.

Working memory performance predicts subjective cognitive complaints in HIV infection

The authors examined the contribution of working memory performance to subjective cognitive complaints in HIV infection beyond the influence of depressive symptoms. Thirty-six adults with HIV infection were administered neuropsychological (NP) tests of working memory, complex psychomotor efficiency, verbal learning, delayed recall, and questionnaires measuring depressive symptoms and cognitive complaints. Working memory performance, depression scores, and complex psychomotor efficiency were most strongly associated with self-reported cognitive complaints, whereas verbal learning scores and simple psychomotor efficiency showed more modest associations. Regression analyses revealed working memory performance to be the strongest NP predictor of self-reported cognitive complaints, comparable with depression scores in the amount of variance explained. These results suggest that working memory performance may be well suited to reflect how patients function in their everyday environment.

Severe, demyelinating leukoencephalopathy in AIDS patients on antiretroviral therapy

OBJECTIVES

To describe a severe form of demyelinating HIV-associated leukoencephalopathy in AIDS patients failing highly active antiretroviral therapy (HAART), its relationship to clinical and neuroimaging findings, and suggest hypotheses regarding pathogenesis.

DESIGN AND METHODS

AIDS patients who failed HAART and displayed severe leukoencephalopathy were included. All cases had detailed neuromedical, neuropsychological, neuroimaging and postmortem neuropathological examination. Immunocytochemical and PCR analyses were performed to determine brain HIV levels and to exclude other viruses.

RESULTS

Seven recent autopsy cases of leukoencephalopathy in antiretroviral-experienced patients with AIDS were identified. Clinically, all were severely immunosuppressed, six (86%) had poorly controlled HIV replication despite combination antiretroviral therapy, and five (71%) had HIV-associated dementia. Neuropathologically, all seven had intense perivascular infiltration by HIV-gp41 immunoreactive monocytes/macrophages and lymphocytes, widespread myelin loss, axonal injury, microgliosis and astrogliosis. The extent of damage exceeds that described prior to the use of HAART. Brain tissue demonstrated high levels of HIV RNA but evidence of other pathogens, such as JC virus, Epstein-Barr virus, cytomegalovirus, human herpes virus type-8, and herpes simplex virus types 1 and 2, was absent. Comparison of the stages of pathology suggests a temporal sequence of events. In this model, white matter damage begins with perivascular infiltration by HIV-infected monocytes, which may occur as a consequence of antiretroviral-associated immune restoration. Intense infiltration by immune cells injures brain endothelial cells and is followed by myelin loss, axonal damage, and finally, astrogliosis.

CONCLUSIONS

Taken together, our findings provide evidence for the emergence of a severe form of HIV-associated leukoencephalopathy. This condition warrants further study and increased vigilance among those who provide care for HIV-infected individuals.

Relationships between cognition and structural neuroimaging findings in adults with human immunodeficiency virus type-1

Infection of the central nervous system with human immunodeficiency virus type-1 (HIV) is associated with cognitive impairments that range from mild cognitive and motor difficulties to dementia. Structural neuroimaging abnormalities are also common in HIV-infected patients both with and without cognitive disturbances. The most common abnormalities include high signal intensities in the white matter and atrophy. Research over the past 12 years has helped define the relationship between these neuroimaging abnormalities and the manifestation of cognitive disturbance in HIV. In the present paper, we provide a synopsis of these studies and report the current state of the literature. Our review revealed that atrophy of the caudate nucleus is most consistently associated with cognitive impairment in HIV. The current literature does not support a strong relationship between cortical atrophy or white matter abnormalities and cognitive dysfunction in this population, though methodological issues may have influenced the results. Suggestions for study design and new research directions are provided.

The CD28/HLA-DR expressions on CD4+T but not CD8+T cells are significant predictors for progression to AIDS

To investigate the changes of CD28 and HLA-DR molecules on CD4+ and CD8+ T cells during HIV infection, we classified 130 HIV-infected Koreans into four groups by the CD4 level as follows: group I (> or = 500 cells/mm3), group II (201-499 cells/mm3), group III (51-200 cells/mm3), and group IV (< or = 50 cells/mm3). In CD4+ T cells, the proportion of CD28 expression decreased significantly with the CD4 level while the proportion of HLA-DR expression increased gradually. In particular, the changes of HLA-DR expressions on CD4+ T cells were parallel to the loss of CD28 molecules from stage III to IV. However, the CD28 expression on CD8+ T cells decreased dramatically in the early stage of HIV infection, and the sum and pattern of CD28 and HLA-DR expressions on CD8+ T cells was stable after the first stage. Even though CD28 down-regulation on CD8+ T cells was very severe from the early stage of HIV infection, it might not influence the survival time of HIV-infected Koreans. The sum of the CD28+ subsets and HLA-DR subsets in each T cell was stable in all stages of disease progression. The sums of the CD28+ subsets and HLA-DR+ subsets in CD4+ T and CD8+ T cells were constant as approximately 100% and 55-60% of each T cell. These results suggested that the changes of CD28/HLA-DR expressions on CD4+ T cells were more predictable than those on CD8+ T cells in the evaluation of the disease progression during HIV-infected periods. However, we need further studies to understand why the sum of two molecules in each T cell are constant.