Plain English Summary
Background and study aims
PD-1 and PD-L1 are proteins found on the surface of cells that are involved in immune responses (defence against foreign substances) in the human body. We currently know, the cause of neuropathic pain is associated with an unusual immune response. Identification of these proteins in patients with neuropathic pain may suggest a potential target for the treatment of neuropathic pain in the future.
We aim to investigate the presence of PD-1 and PD-L1 in the spinal fluid of patients with neuropathic pain.
Who can participate?
Patients with chronic radicular pain who are scheduled to undergo pulsed radiofrequency treatment (PRF).
What does the study involve?
The study involves performing a lumbar puncture on patients with neuropathic pain, to sample cerebrospinal fluid (CSF) and perform flow cytometry analysis on these samples to identify if PD-1 and PD-L1 are present and on which cells.
What are the possible benefits and risks of participating?
Possible benefits include the identification of a new target for the treatment of neuropathic pain. All patients will have standard treatment given as currently recommended (PRF to DRG) and will be offered subsequent repeat procedure if a benefit is seen.
Potential risks include the 1 in 200 risk of developing a post dural puncture headache secondary to the lumbar puncture. The risk of this is reduced as much as possible by the use of the smallest lumbar puncture needle with needle least likely to cause tearing of spinal fibres.
Where is the study run from?
St James Hospital, Dublin.
When is the study starting and how long is it expected to run for?
October 2018 to August 2019.
Who is funding the study?
Who is the main contact?
Dr Deborah Galvin,
2016-12 List 47 97, 2018-10 List 33
An investigation on cerebrospinal fluid (CSF) concentrations of PD-1 and PD-L1 and quantification of cellularity of CSF in patients with chronic radicular lumbar pain
PD 1 Study
To investigate the presence of PD-1 and PD-L1 in patients with chronic radicular lumbar pain
Approved 18/10/2019, SJH/TUH Research Ethics Committee (Tallaght University Hospital, Tallaght, Dublin 24, D24 NR0A; ResearchEthics@tuh.ie; +353(0)1-414 2199), ref: 2016-12 List 47 97, 2018-10 List 33 (10) (8).
Cross-sectional observational trial
Primary study design
Secondary study design
Patient information sheet
Not available in web format, please use contact details to request a participant information sheet
Neuropathic lower limb pain
Patients are undergoing pulsed radiofrequency treatment (PRF). CSF is taken at the time of the procedure (just before it is performed) via lumbar puncture with subsequent flow cytometry performed. It is performed by the principal investigator.
(PRF consists of 120 seconds of electric current to the dorsal root ganglion (nerve root) of the spinal nerves in the back which results in a change in the activity or "firing" of the nerve. Routine follow-up is at 3 months post-procedure or sooner at patient request.)
Follow-up data consists of all patients being routinely reviewed at an outpatient appointment 3 months later (consisting of direct questioning and a repeat completion of a neuropathic pain questionnaire called DN4- already completed by them prior to first CSF sampling). Contact details for the pain department are given to all participants after the procedure regarding any issues after the procedures.
Primary outcome measure
Presence of PD-1 and PD-L1 in the patients spinal fluid (as quantified by flow cytometry)
Secondary outcome measures
Change in pain score of patient at 3 month interview and use of Douleur Neuropathique pain questionnaire at baseline (day of procedure) and 3 months later (when back in clinic)
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Chronic radicular pain
2. Scheduled to undergo pulsed radiofrequency treatment (PRF).
Target number of participants
Participant exclusion criteria
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
St James Hospital
Dept. of Pain James Street
Investigator initiated and funded
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Aiming for International Pain Journal or Immunology Journal
IPD sharing statement:
All data generated or analysed during this study will be included in the subsequent results publication
Intention to publish date
Participant level data
Basic results (scientific)