Neuropathic Pain Profile in Retroviral Infection
Research type
Research Study
Full title
Neuropathic Pain Profile in Retroviral Infection- The NIPPR Study
IRAS ID
254927
Contact name
Harriet Kemp
Contact email
Sponsor organisation
Imperial College
Duration of Study in the UK
2 years, 0 months, 0 days
Research summary
Research Summary
Between 5 and 10 million people worldwide are carriers of Human T-cell Lymphotrophic Virus(HTLV-1). The incidence in the United Kingdom is estimated to be 30,000, most of whom are of Caribbean and West African descent. Chronic pain is a prevalent symptom in all stages of HTLV-1 infection, for those with legs problems caused by the HTLV-1 infection( HTLV Associated Myelopathy(HAM)) and for those who have the virus but do not have any problems associated with being a carrier- known as asymptomatic cariers(AC). In this population, chronic pain affects between 35.3-88.4%9 of infected individuals. However, little is known about the mechanisms involved in the development of pain.
In this Cross-sectional observational study of participants who have the HTLV-1 infection, we are aiming to characterise burning pain(neuropathic pain), pain from damage to the body(nociceptive pain) and problems arising from changes in how pain from damage to body tissues(neoplastic)in patients with HTLV-1 works. Our study aims to define the burning pain presentations in HTLV-1 infection by identifying contributing pain mechanisms through a variety of testing mechanisms, including clarify the presence of small nerve fibre axonal degeneration by examining nerve fibre density in the skin tissues.
Summary of Results
This study recruited participants from the National Centre for Human Retrovirology in London.
Twenty-nine people joined the study. 14 participants had HTLV Associated Myelopathy (HAM) and 15 were asymptomatic carriers (ACs).
Quantitative Sensory Testing (QST) measures changes in sensitivity to different types of stimuli. This is a measure of small nerve fibre function. All participants underwent QST in the skin area on the top of their foot. They had a skin biopsy done at the lower leg. This was to determine number of small nerve fibres in the skin to identify if there was a loss of nerve fibres that could be associated with painful symptoms or QST measures. They also completed validated pain questionnaires about their pain.
In people with HTLV-1 infection, burning pain symptoms were reported in both ACs and those with HAM. ACs also experienced pain despite not reporting other symptomatic features of HTLV infection.
QST in both groups showed a trend towards loss of temperature sensation. It also found an exaggerated response to painful stimuli like pinprick. For people with HAM, there was greater loss of ability to detect light touch. Otherwise, QST findings were not dependent on the presence of HAM or neuropathic pain.
In the skin in the lower part of the leg, the number of small nerve fibres was lower in those with HAM compared to ACs. It was also lower in those with HTLV-1 infection compared to healthy people. Yet, the amount of fibres were not different between those with and without neuropathic pain.
More studies that investigate small nerve fibre function and structure in HTLV-1 infection. They may provide more information about how and what causes pain in this condition. Different patterns of neuropathic symptoms and QST findings, may represent different underlying disease causing mechanisms. This in turn could help direct more individualised pain therapy targeted at specific mechanism.
REC name
London - Riverside Research Ethics Committee
REC reference
18/LO/2124
Date of REC Opinion
30 Jan 2019
REC opinion
Further Information Favourable Opinion