Novel complications with HTLV-1-associated myelopathy/tropical spastic paraparesis: interstitial cystitis and persistent prostatitis

HAM/TSP Pathogenesis: The Transmigration Activity of HTLV-1-Infected T Cells into Tissues

Slowly progressive spastic paraparesis with bladder dysfunction, the main clinical feature of human T-cell leukemia virus-1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is induced by chronic inflammation in the spinal cord, mainly the lower thoracic cord. A long-standing bystander mechanism, such as the destruction of surrounding tissues by inflammatory cytokines, etc., induced under the interaction between infiltrated HTLV-1-infected CD4⁺ T cells and HTLV-1-specific CD8⁺ cytotoxic T cells, has been considered implicated for the induction of chronic inflammation. As this bystander mechanism is triggered conceivably by the transmigration of HTLV-1-infected CD4⁺ T cells to the spinal cord, heightened transmigrating activity of HTLV-1-infected CD4⁺ T cells to the spinal cord might play a crucial role as the first responder in the development of HAM/TSP. This review evaluated the functions of HTLV-1-infected CD4⁺ T cells in HAM/TSP patients as the prerequisite for the acquisition of the activity such as adhesion molecule expression changes, small GTPases activation, and expression of mediators involved in basement membrane disruption. The findings suggest that HTLV-1-infected CD4⁺ T cells in HAM/TSP patients have enough potential to facilitate transmigration into the tissues. Future HAM/TSP research should clarify the molecular mechanisms leading to the establishment of HTLV-1-infected CD4⁺ T cells as the first responder in HAM/TSP patients. In addition, a regimen with an inhibitory activity against the transmigration of HTLV-1-infected CD4⁺ T cells into the spinal cord might be recommended as one of the therapeutic strategies against HAM/TSP patients.

Mother-to-Child HTLV-1 Transmission: Unmet Research Needs

Mother-to-child transmission (MTCT) of Human T-cell lymphotropic virus type 1 (HTLV-1) causes lifelong infection. At least 5–10 million individuals worldwide are currently living with HTLV-1. Studies of regional variation are required to better understand the contribution of MTCT to the global burden of infection. Although most infected individuals remain asymptomatic ∼10% develop high morbidity, high mortality disease. Infection early in life is associated with a higher risk of disease development. Adult T-cell leukemia (ATL), which is caused by HTLV-1 and has a median survival of 8 months is linked to MTCT, indeed evidence of ATL following infection as an adult is sparse. Infective dermatitis also only occurs following neonatal infection. Whilst HTLV-1-associated myelopathy (HAM) follows sexual and iatrogenic infection approximately 30% of patients presenting with HAM/TSP acquired the infection through their mothers. HAM/TSP is a disabling neurodegenerative disease that greatly impact patient’s quality of life. To date there is no cure for HTLV-1 infection other than bone marrow transplantation for ATL nor any measure to prevent HTLV-1 associated diseases in an infected individual. In this context, prevention of MTCT is expected to contribute disproportionately to reducing both the incidence of HTLV-1 and the burden of HTLV-1 associated diseases. In order to successfully avoid HTLV-1 MTCT, it is important to understand all the variables involved in this route of infection. Questions remain regarding frequency and risk factors for in utero peri-partum transmission whilst little is known about the efficacy of pre-labor cesarean section to reduce these infections. Understanding the contribution of peripartum infection to the burden of disease will be important to gauge the risk-benefit of interventions in this area. Few studies have examined the impact of HTLV-1 infection on fertility or pregnancy outcomes nor the susceptibility of the mother to infection during pregnancy and lactation. Whilst breast-feeding is strongly associated with transmission and avoidance of breast-feeding a proven intervention little is known about the mechanism of transmission from the breast milk to the infant and there have been no clinical trials of antiretroviral therapy (ARV) to prevent this route of transmission.

Prosultiamine for treatment of lower urinary tract dysfunction accompanied by human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis

OBJECTIVES

To evaluate oral prosultiamine treatment in patients with overactive bladder accompanied by human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis.

METHODS

This was a prospective, single-center, open-label study. Patients received oral prosultiamine (300 mg) once daily in the morning, and the overactive bladder symptom score and urine levels of overactive bladder-related biomarkers (nerve growth factor/creatinine and adenosine triphosphate/creatinine) 12 weeks after the initial administration were compared with the baseline values. In addition, the urodynamic parameters, including involuntary detrusor contraction and detrusor sphincter dyssynergia, were evaluated before and after treatment.

RESULTS

A total of 16 patients were recruited for this clinical study. In the overactive bladder symptom score, night-time frequency, urgency and the total score improved after oral prosultiamine treatment (P = 0.028, 0.001 and 0.004, respectively). Both urinary nerve growth factor/creatinine and adenosine triphosphate/creatinine levels decreased significantly after the treatment (P = 0.004 and 0.017, respectively). Urodynamic studies showed that the maximum cystometric capacity increased significantly after the treatment. However, the symptoms disappeared because of the treatment in six of 10 patients with involuntary detrusor contraction (60%) and three of seven patients with detrusor sphincter dyssynergia (42.9%). There were no serious adverse events.

CONCLUSIONS

The changes in urodynamic parameters and urine levels of overactive bladder-related markers suggest that oral prosultiamine is a safe and effective treatment for overactive bladder with human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis.

Urinary Symptoms Associated with Human T-Cell Lymphotropic Virus Type I Infection: Evidence of Urinary Manifestations in Large Group of HTLV-I Carriers

OBJECTIVES

To describe the frequency of urologic manifestations in human T-cell lymphotropic virus type I (HTLV-I) seropositive individuals from Salvador and other cities in Bahia, Brazil, with or without clinical HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP).

METHODS

A total of 218 HTLV-I seropositive subjects referred from blood banks or neurologic clinics were admitted to the HTLV-I multidisciplinary outpatient clinic from January 2001 to April 2004. They were assessed using a standardized questionnaire to determine urinary complaints and quality of life. Neurologic impairment was established using the Expanded Disability Status Scale (EDSS). HAM/TSP was considered as an EDSS score of 2 or greater.

RESULTS

Nocturia (35.8%) was the most frequent finding, followed by incontinence (29.8%), urgency (25.2%), frequency (22.0%), and dysuria (15.6%). Differences were found between individuals with an EDSS score of 0 and those with an EDSS score greater than 0 but less than 2 regarding frequency, nocturia, urgency, urinary loss of any degree, and quality of life. Dysuria and great or total urinary loss were more frequent among those with severe HAM/TSP (EDSS score greater than 6).

CONCLUSIONS

Even HTLV-I subjects considered not to have HAM/TSP may have prominent urinary findings already present. Urologic manifestations, including nocturia and urinary loss, might be early manifestations of neurologic disease in those with HTLV-I.

Natural course of voiding function in patients with human T-cell lymphotrophic virus type 1-associated myelopathy

OBJECTIVES

Patients with human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) frequently experience voiding dysfunction. In patients with HAM/TSP, the major symptoms are gait disturbance and voiding dysfunction. However, the detailed natural course of voiding function and the management of their urination has not previously been investigated. We examined the correlation between voiding function and clinical features and evaluated the management of urination, in the patients with HAM/TSP.

PATIENTS AND METHODS

The voiding function of 47 patients (7 males, 40 females, aged 29-89 years, mean: 60.9 years) with HAM/TSP was analyzed retrospectively. All HAM/TSP patients are positive for HTLV-1. Patients were referred to a neurologist for analysis of bladder function. In the present study, we analyzed their clinical details, age at disease onset, voiding function and alterations in the management of their urination. Furthermore, we investigated the relationship between urological management and the clinical features of HAM/TSP.

RESULTS

Of the 47 patients, 20 (42.5%) were able to void with or without drug therapy. Thirty-four (72.3%) experienced clean intermittent self-catheterization (CIC), with 25 of these 34 continuing CIC, 7 changing to voiding and 2 changing to management with the Foley catheter. No relationship was noted between disruption of voiding function and either age or gender. However, significant inverse correlation was observed between the age at disease onset and the time to CIC (r=-0.77, P=0.00001).

CONCLUSIONS

These data suggest that the younger a patients is at HAM/TSP onset, the longer voiding function will be maintained.

Immunopathogenesis of HTLV-I-associated myelopathy/tropical spastic paraparesis

The main pathological feature of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is chronic inflammation of the spinal cord characterized by perivascular cuffing of mononuclear cells accompanied by parenchymal lymphocytic infiltration. Although the exact mechanism of the pathogenesis of HAM/TSP is still obscure, immunological abnormalities arising from a high HTLV-I proviral load in peripheral blood lymphocytes (PBL) play an important role in the pathological process of spinal cord lesions in HAM/TSP patients. The relationship between HLA haplotype and the risk of the occurrence of HAM/TSP will be elucidated by results from studies of HLA allele typing. In addition, recent data indicate that HTLV-I and its expression are localized in infiltrated lymphocytes within the spinal cord lesions of HAM/TSP patients rather than in resident central nervous system (CNS) parenchymal cells. Although a bystander damage of the surrounding CNS tissues, in which CD8+ HTLV-I-specific cytotoxic T lymphocyte (CTL) attack HTLV-I-infected lymphocytes, might be involved in the pathological events of the spinal cords of HAM/ TSP patients as one of the actual pathogenetic mechanisms, heightened transmigrating activity of HTLV-I-infected CD4+ T lymphocytes to the CNS tissues may have a key role in the development of HAM/TSP. Therefore, although the exact mechanism underlying the high HTLV-I proviral load in PBL in HAM/TSP patients is still unknown, we must consider therapeutic approaches in HAM/TSP that eliminate HTLV-I-infected CD4+ T lymphocytes.

Importance of immune deviation toward Th1 in the early immunopathogenesis of human T-lymphotropic virus type I-associated myelopathy

Although the principal neuropathological feature of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) is chronic inflammation of the spinal cord, characterized by perivascular cuffing of mononuclear cells accompanied by parenchymal lymphocytic infiltration, the precise mechanisms by which HTLV-I infection causes chronic inflammation of the spinal cord are still obscure. In patients with HAM, peripheral blood CD4(+)T lymphocytes, particularly HTLV-I-infected CD4(+)T lymphocytes, have increased adherent activity to endothelial cells and transmigrating activity through basement membranes. In addition, the profile of cytokine expression suggests increased numbers of Th1 cells in peripheral blood CD4(+)T lymphocytes of patients with HAM. These findings strongly suggest that immune deviation toward Th1, which might be based on high viral load of HTLV-I, plays an important role in tissue damage in the central nervous system of patients with HAM. We herein emphasize the importance of activated Th1 cells as the first trigger in the immunopathogenesis of HAM.

Human T-cell lymphotropic virus-I in Latin America

HTLV-1 infection is endemic in several Latin American countries. HTLV-1-associated myelophathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia lymphoma (ATLL) are emerging diseases in the region. Documented risk factors for acquiring the virus include breast-feeding, contaminated blood transfusion, and sexual intercourse, all of which are amenable to prevention efforts. Strongyloides stercoralis hyperinfection syndrome and therapeutic failure in apparently healthy patients with nondisseminated strongyloidiasis may be markers of HTLV-1 infection. HTLV-1 co-infection may adversely effect the clinical course of scabies and HIV disease. The new enzyme-linked immunosorbent assays (ELISA) are sensitive and specific, and Western blot technology is reliable for differentiating HTLV-1 from less common HTLV-2. HTLV-1 screening of blood donors and individuals with any disorder that suggests infection has become a necessity in Latin America to prevent the spread of this important emerging pathogen.

On the etiology of tropical spastic paraparesis and human T-cell lymphotropic virus-I-associated myelopathy

The purpose of this review is to present some concepts on the etiology of tropical spastic paraparesis or human T-cell lymphotropic virus-I (HTLV-I)-associated myelopathy (TSP/HAM). The large number of syndromes that have been associated with HTLV-I (60 to date), the existence of TSP/HAM cases associated with other retroviruses (human immunodeficiency virus-2 [HIV-2], HTLV-II), the existence of many TSPs without HTLV-I, and the evidence of clear epidemiologic contradictions in TSP/HAM indicate that the etiopathogenesis of TSP/HAM is not yet clear. Tropical spastic paraparesis/HAM affects patients of all human ethnic groups, but usually in well localized and relatively isolated geographic regions where HTLV-I has been endemic for a long time. Environmental factors and geographic locations appear to be critical factors. Because the neuropathology of TSP/HAM suggests a toxometabolic, rather than a viral cause, it is proposed that an intoxication similar to neurolathyrism could account for some of TSP/HAM cases, mainly in tropical and subtropical countries. If this were the case, HTLV-I could be a cofactor or act as a bystander. it is possible that co-infection with another agent is necessary to produce TSP/HAM and most of the syndromes associated with HTLV-I.

HTLV-I-associated myelopathy associated with multi-organ inflammatory disease: a case report

We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) complicated with multi-organ inflammatory disease, including Sjögren's syndrome, interstitial cystitis, and uveitis. The presence of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC), cerebrospinal fluid, salivary gland, mucosa of urinary bladder, and aqueous humor was confirmed by polymerase chain reaction using HTLV-I pX region primer. Western blot analysis revealed the presence of anti-HTLV-I antibodies in serum, CSF, saliva, and urine, suggesting replication of HTLV-I in each tissue. A high load of HTLV-I proviral DNA (20 copies out of 100 PBMC) was present, associated with increased spontaneous proliferation of peripheral blood lymphocytes (24,747 cpm). Our results suggest that the high load of HTLV-I in patients with HAM may potentially induce systemic inflammation in several organs.