The science of ME – what do we know?
There are over 4000 scientific publications on ME and significant progress has been made in the scientific understanding of the disease, particularly in the last 20 years. This list below gives some of the headline findings:
• Inflammation and immune activation are involved. The evidence of chronic T cell activation, increased cytokines, raised oxidative stress, and low natural killer cells point to a chronic state of low-grade immune upregulation.
• Infection is important. Illness starts with an acute, infectious-like episode in many patients. The main agents implicated in causing or maintaining the disease include enteroviruses (such as coxsackievirus), Epstein-Barr virus, cytomegalovirus and human herpes virus 6.
• Neurocognitive abnormalities are prevalent. It is well established that cognitive problems – mainly with memory, attention/concentration and reaction time – frequently occur.
• Endocrine (hormonal) abnormalities can be found. Hypothalamic-pituitary-adrenal axis dysfunction is a well-recognised feature.
• Symptoms are serious, and chronic illness is common. We now know that the most common symptoms of ME – including pain, sleep disorders and problems with vision – are day-to-day challenges affecting the quality of life of patients, most of whom endure long-term chronic illness. A significant number of patients (between 10% and 25%) are severely affected – housebound, bedbound or immobile – and severely overlooked.
• Psychiatry is not the answer. We know that the illness is not a form of depression, nor a primary psychiatric condition. As in other chronic diseases, psychological interventions can help some people to cope and to manage their symptoms until a cure is found.
• Genetic factors play a part, as shown by family and twin studies.
• Neurological abnormalities can be detected. There is good evidence of autonomic nervous system dysfunction, including ‘orthostatic intolerance’ which causes problems on standing. Also, brain structure and blood flow abnormalities have been identified, and central sensitization, due to an abnormal increase in the firing of nerve cells in the spine, may be important.
• Muscle function is impaired in some patients, with abnormalities to both skeletal muscle and cardiac ‘bioenergetics’.
• Prevalence is high. Epidemiological studies show that ME – under its many different names, such as postviral fatigue syndrome, ME/CFS, chronic fatigue syndrome, chronic fatigue immune dysfunction syndrome etc. – affects around 200,000 people in the UK and 1 million in the USA. This makes the disease more prevalent than multiple sclerosis, systemic lupus and HIV infection.
Biomedical research has made significant progress, but imagine the advances that could be made by a concerted effort to fund programs of research across the globe! Our strategy for ME has to mirror that of other illnesses, such as cancer, which obtains most of its revenue (£500 million per year in the UK) from private sources and ground-level fundraising. It is a huge task, but much can be achieved by a determined effort to mobilise the resources of the wider community.