Psychobehavioral and immunological characteristics of HTLV-1 carriers and non-carriers with persistently low natural killer cell activity

Comprehensive Insight into the Functional Roles of NK and NKT Cells in HTLV-1-Associated Diseases and Asymptomatic Carriers

Human T cell leukemia virus type 1 (HTLV-1) is the first human oncogenic retrovirus to be discovered and causes two major diseases: a progressive neuro-inflammatory disease, termed HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), and an aggressive malignancy of T lymphocytes known as adult T cell leukemia (ATL). Innate and acquired immune responses play pivotal roles in controlling the status of HTLV-1-infected cells and such, the outcome of HTLV-1 infection. Natural killer cells (NKCs) are the effector cells of the innate immune system and are involved in controlling viral infections and several types of cancers. The ability of NKCs to trigger cytotoxicity to provide surveillance against viruses and cancer depends on the balance between the inhibitory and activating signals. In this review, we will discuss NKC function and the alterations in the frequency of these cells in HTLV-1 infection.

Prevalence and factors associated with depression and anxiety in people living with HTLV-1: A systematic review with meta-analysis and meta-regression

OBJECTIVE

Human T-cell lymphotropic virus type-1 (HTLV-1) infection is a neglected tropical disease associated with many clinical manifestations, such as erythematous-scaling skin lesions, cutaneous lymphomas, and spastic paraparesis, which could be a potential cause of mental health concerns. This study investigates the prevalence of symptoms and diagnoses of depression and anxiety and its associated factors in people living with HTLV-1 (PLWH).

METHOD

A systematic review was performed in the Pubmed/MEDLINE, Embase, LILACS, and PsycINFO databases for original studies investigating symptoms of depression and anxiety and diagnoses of major depressive disorder and anxiety disorders in PLWH, and a random-effects meta-analysis with meta-regression was performed to obtain a summary frequency of symptoms and diagnoses of depression and anxiety.

RESULTS

Considering both symptoms and diagnoses, the pooled prevalence for depression was 35% (95% CI: 27 to 43) and for anxiety was 33% (95% CI: 23 to 45). Clinically significant symptoms were more prevalent than diagnosed disorders for depression (47% vs. 21%) and anxiety (44% vs. 11%). PLWH were more likely than seronegative controls to present symptoms and diagnoses of depression (pooled OR: 4.25; 95% CI: 2.7 to 6.68) and anxiety (pooled OR: 3.79; 95% CI: 2.6 to 5.52). Spastic paraparesis was significantly associated with symptoms and diagnoses of depression (pooled OR: 1.81; 95% CI: 1.11 to 2.95) and anxiety (pooled OR: 2.75; 95% CI 1.26 to 5.96).

CONCLUSIONS

PLWH present a much higher prevalence of symptoms and diagnoses of depression and anxiety than seronegative controls, which could be explained by social vulnerability or neurological impairment associated with spastic paraparesis. More studies comparing asymptomatic PLWH and seronegative controls are needed.