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HTLV-1-associated myelopathy in Spain
Carmen de-Mendoza1, Leire Pérez2, Ariadna Rando3
1Puerta de Hierro University Hospital & Research Foundation-IDIPHISA, Madrid, Spain.
Summary
Human T-lymphotropic virus type 1 (HTLV-1) infection leads to HTLV-1-associated myelopathy (HAM) in Spain, primarily affecting middle-aged women migrants. Most patients require wheelchairs, with limited treatment efficacy.
Area of Science:
- Neurology
- Infectious Diseases
- Epidemiology
Background:
- Human T-lymphotropic virus type 1 (HTLV-1) is a neglected global infection affecting over 10 million people.
- HTLV-1-associated myelopathy (HAM) is a progressive neurological disorder affecting approximately 5% of HTLV-1 carriers.
- Spain, a non-endemic country, experiences HTLV-1 transmission primarily through migration from endemic regions.
Purpose of the Study:
- To characterize the main features of patients diagnosed with HAM in Spain.
- To analyze the incidence, demographics, transmission routes, and clinical outcomes of HAM in a non-endemic setting.
Main Methods:
- Retrospective analysis of HTLV-1 and HAM cases recorded in Spain up to 2022.
- Demographic data collection, including age, sex, and origin of patients.
- Investigation of transmission routes, viral subtypes, and proviral load.
- Evaluation of treatment efficacy and patient outcomes.
Main Results:
- 58 out of 451 HTLV-1 cases (12.9%) were diagnosed with HAM, with 2-3 new cases annually.
- The majority of HAM patients were middle-aged women (76%), with nearly 60% being Latin American migrants.
- Sexual transmission is the most common route, but solid organ transplantation was identified as a transmission source in 6 cases, leading to rapid myelopathy.
- HTLV-1 subtype 1a was the only variant found in HAM patients.
- HAM patients had significantly higher HTLV-1 proviral loads compared to asymptomatic carriers.
- Antiretroviral therapy showed limited efficacy; physiotherapy and symptom relief were the mainstays of management.
- Two-thirds of HAM patients experienced severe disability, including wheelchair dependence and sphincter incontinence.
Conclusions:
- HAM is the most common clinical manifestation of HTLV-1 in Spain, disproportionately affecting middle-aged migrant women.
- Despite treatment, a significant proportion of patients develop severe neurological impairment and disability.
- The findings highlight the importance of recognizing HTLV-1 and HAM in non-endemic countries with significant migrant populations.
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