For the first time, researchers have shown a link between power Doppler ultrasound results and the activity of Th17 cells (a type of white blood cells) in the joints of rheumatoid arthritis patients. The findings may help predict the progression of joint damage and guide treatment decisions in future.
The research, which was supported by the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre at Guy’s and St Thomas’ and King’s College London - part of King’s Health Partners - has been published in PLoS One.
Rheumatoid arthritis is a chronic inflammatory disease affecting more than 350,000 people in the UK. The disease affects the joints, including those of the fingers, toes, knees and elbows. People with the condition are often in constant pain, suffer from fatigue and in the worst cases, can become wheelchair-bound.
Dr Bruce Kirkham, consultant rheumatologist at Guy’s and St Thomas’ and co-author of the study said: “A key challenge for doctors is to find ways to better predict disease progression. For example, if we could identify which patients with rheumatoid arthritis are most likely to see their condition advance rapidly, we would be in a position to make better informed treatment decisions.”
The team of researchers at Guy’s and St Thomas’ and King’s College London wanted to build on two growing areas of evidence:
* imaging techniques, in particular power Doppler ultrasound (which measures blood flow), are a useful tool to identify inflammation in the joints
* a type of white blood cell – Th17 cells - is particularly aggressive in rheumatoid arthritis.
Dr Nicola Gullick, a Clinical Research Fellow and the study’s lead author explained: “Finding markers which can be used to predict the progression of rheumatoid arthritis and help guide treatment decisions is an important aim for both clinical and academic researchers. Although power Doppler ultrasound is increasingly being used to assess joint inflammation in rheumatoid arthritis, it doesn’t provide us with information about what’s going on immunologically. We wanted to assess the relationship between the positive power Doppler ultrasound signals and the activity of white blood cells, to establish whether these can be used together as useful clinical markers for patients with rheumatoid arthritis.”
The team of researchers studied groups of patients with established rheumatoid arthritis who were being treated for their condition and age and sex-matched healthy controls. They analysed blood samples taken from both groups and carried out power Doppler ultrasound scans of the inflamed joints in the patient group. Synovial fluid was also aspirated from patients with active disease and analysed.
The data collected demonstrated a link between the presence of pro-inflammatory Th17 cells in the synovial fluid of patients with rheumatoid arthritis and the power Doppler ultrasound scores of the same joint.
Leonie Taams, a senior lecturer in immunology at King's College London and senior author of the study, said: “Our work offers a new immunological explanation for the observation that rapid joint damage progression occurs in patients with persistent positive power Doppler ultrasound signals. The next step is to confirm what we’ve found in a larger study involving patients over a longer period of time to relate these findings directly to joint damage progression.”
The results of the research are already having an impact on the rheumatology service on offer at Guy’s and St Thomas’. Power Doppler ultrasound is being used more routinely in the rheumatology clinics with two dedicated imaging outpatient sessions per week.
Dr Bruce Kirkham continued: “This is a fantastic example of work taking place in the NIHR Biomedical Research Centre having a rapid impact on the services we offer to our patients. We are already routinely using ultrasound in the early arthritis clinic at Guy’s Hospital to increase detection and improve the early diagnosis of rheumatoid arthritis.”
Biomedical Research Centre
