An association of human T-cell lymphotropic virus type I infection with vascular dementia

Association between Cognitive Function and Depression with Human T-Cell Lymphotropic Virus 1 Seropositivity and Serointensity in UK Adults

Several viral, bacterial, and parasitic diseases have been associated with cognitive function and neuropsychiatric outcomes in humans, including human T-cell lymphotropic virus 1 (HTLV-1). In this study, we sought to further generalize previously reported associations of cognitive function and depression with HTLV-1 seropositivity and serointensity using a community-based sample of adults aged approximately 40 to 70 years (mean = 55.3 years) from the United Kingdom. In this sample, the results of adjusted linear regression models showed no associations of HTLV-1 seropositivity or serointensity with reasoning, pairs-matching, or reaction-time cognitive tasks or with depression. In addition, neither age, sex, educational attainment, nor income moderated associations of HTLV-1 seropositivity or serointensity with cognitive function or depression. In this middle-aged to older middle-aged adult community sample, HTLV-1 seropositivity and serointensity do not appear to be associated with reasoning, pairs-matching, and reaction-time tasks or with depression.

Cognitive impairment in HTLV-1-associated myelopathy, proviral load and inflammatory markers

OBJECTIVES

Myelopathy is a well-established long-term clinical manifestation of HTLV-1 infection. Besides motor dysfunction, cognitive impairment may be another consequence of HTLV-1 infection. Moreover, inflammatory markers may be associated with cognitive impairment in these patients. The present study compared the cognitive performance of HAM/TSP patients with healthy controls and investigated the associations between cognitive performance, proviral load and blood inflammatory markers.

METHODS

Eighty-three patients fulfilling diagnostic criteria for HAM/TSP were submitted to a comprehensive clinical, cognitive and functional evaluation, brain magnetic resonance imaging and determination of levels of IL-1β, IL-6, TNF-α, immunoglobulins and HTLV-1 proviral load in blood and cerebrospinal fluid. The control group was composed of 88 cognitively healthy subjects, matched for age, sex and educational level.

RESULTS

Compared to healthy subjects, HAM/TSP patients displayed significant global cognitive impairment and executive function deficits. HAM/TSP cognitive impairment was significantly associated with altered levels of IgM, IgG, IL-6 and TNF-α in blood. There was no association between HAM/TSP cognitive impairment and HTLV-1 proviral load.

CONCLUSIONS

This study suggests cognitive impairment may be a long-term clinical manifestation of HTLV-1 infection, which seems to be linked to the persistent inflammatory activity that is found in the disease.

Commensal microbiota contributes to chronic endocarditis in TAX1BP1 deficient mice

Tax1-binding protein 1 (Tax1bp1) negatively regulates NF-κB by editing the ubiquitylation of target molecules by its catalytic partner A20. Genetically engineered TAX1BP1-deficient (KO) mice develop age-dependent inflammatory constitutions in multiple organs manifested as valvulitis or dermatitis and succumb to premature death. Laser capture dissection and gene expression microarray analysis on the mitral valves of TAX1BP1-KO mice (8 and 16 week old) revealed 588 gene transcription alterations from the wild type. SAA3 (serum amyloid A3), CHI3L1, HP, IL1B and SPP1/OPN were induced 1,180-, 361-, 187-, 122- and 101-fold respectively. WIF1 (Wnt inhibitory factor 1) exhibited 11-fold reduction. Intense Saa3 staining and significant I-κBα reduction were reconfirmed and massive infiltration of inflammatory lymphocytes and edema formation were seen in the area. Antibiotics-induced ‘germ free’ status or the additional MyD88 deficiency significantly ameliorated TAX1BP1-KO mice's inflammatory lesions. These pathological conditions, as we named ‘pseudo-infective endocarditis’ were boosted by the commensal microbiota who are usually harmless by their nature. This experimental outcome raises a novel mechanistic linkage between endothelial inflammation caused by the ubiquitin remodeling immune regulators and fatal cardiac dysfunction.

Neuropsychological assessment in HTLV-1 infection: a comparative study among TSP/HAM, asymptomatic carriers, and healthy controls

BACKGROUND

Human T cell lymphotropic virus type 1 (HTLV-I) can cause tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM) and adult T cell leukaemia/lymphoma. More recently other diseases such as isolated peripheral polyneuropathy, myopathy, artropathy, and uveitis have been associated with this retrovirus. Only a few uncontrolled studies, without necessary exclusion criteria, have described mild cognitive deficits among TSP/HAM patients. To further clarify this the authors evaluated, through neuropsychological testing patients with TSP/HAM and asymptomatic infected carriers, comparing both groups with healthy controls.

OBJECTIVES

To verify the presence of cognitive deficits among TSP/HAM patients and asymptomatic HTLV-1 infected carriers. In addition, the authors aimed to investigate if these deficits correlated with the degree of motor impairment in TSP/HAM patients.

METHODS

From a cohort of 501 HTLV-1 infected people the authors selected, according to predefined inclusion and exclusion criteria, 40 asymptomatic HTLV-1 carriers and 37 TSP/HAM patients. Neuropsychological testing was blindly performed in both groups and their scores were compared with those obtained from controls.

RESULTS

Both the HTLV-1 carrier group and the group of patients with TSP/HAM exhibited a lower performance in neuropsychological tests when compared with controls. Asymptomatic infected carriers and TSP/HAM patients did not differ in their cognitive results. Also, there was no relation between the degree of motor disability and cognitive deficits in the TSP/HAM group. Psychomotor slowing and deficits in the some domains characterised the neuropsychological impairment in HTLV-1 infection: verbal and visual memory, attention and visuomotor abilities.

CONCLUSIONS

TSP/HAM as well as asymptomatic infection can be associated with mild cognitive deficits. This finding, if confirmed by further studies, will permit the inclusion of cognitive impairment among the neurological manifestations of HTLV-1.

Are peripheral blood cells from patients with Alzheimer disease more sensitive to apoptotic stimuli?

One of the reasons for the increased susceptibility to infections in patients with Alzheimer disease may be enhanced apoptotic death of their peripheral leukocytes. If this is the case, the enhanced apoptosis may be due to components in the patients' sera or to an increased sensitivity of the cells to apoptotic stimuli. To examine this possibility, the percentage of apoptotic cells in the peripheral blood mononuclear cells (PBMC) from 12 patients with Alzheimer disease was compared with that of 12 age-matched non-demented persons and 12 middle-aged healthy control subjects. In addition, the effect of sera from subjects in the three groups on the apoptosis, interleukin (IL)-1beta, IL-2, IL-6, IL-10, and tumor necrosis factor (TNF)alpha production by peripheral blood cells from healthy control subjects was examined. It was found that the percentage of apoptotic PBMC from patients with Alzheimer disease was higher than that from the remaining two groups. However, incubation of control cells with sera from patients with Alzheimer disease and non-demented elderly persons did not affect the number of apoptotic cells. Sera from patients with Alzheimer disease and non-demented elderly subjects caused an increase in IL-2 and a decrease in IL-10 production by PBMC from middle-aged control subjects but did not affect IL-1beta, IL-6, and TNFalpha secretion, indicating alterations of the immune system related to aging.

HTLV-1 and its neurological complications

BACKGROUND

Since its discovery in 1980, human T-cell lymphotropic virus type-1 (HTLV-1) has been associated with a number of neurological diseases. The distribution of HTLV-1-associated neurological disease is worldwide. In endemic areas, up to 30% of the population may be infected with HTLV-1; however, only a small percentage of infected persons develops neurological disease.

REVIEW SUMMARY

In 1986, HTLV-1 infection was reported in patients of chronic progressive myelopathy of uncertain etiology, and the disease entity was called HTLV-1-associated myelopathy/tropical spastic paraparesis. Recently, HTLV-1 infection has been associated with polymyositis and uveitis. Interestingly, a single patient may display more than one syndrome. Although other neurological syndromes occur in HTLV-1-infected individuals, there is not enough epidemiologic data that show a strong association. Treatment of HTLV-1-associated neurological disease is challenging, and well-controlled studies are lacking.

CONCLUSION

As neurologists and other scientists begin to understand the pathophysiology of HTLV-1 infection, improved therapies should be developed. Randomized trials with longer follow-up are required to understand the effect of treatment on disability and quality of life.