ME/CFS shares its symptoms with a range of illnesses, a fact which will complicate diagnosis and research of the condition until a specific biological marker is found. One ‘overlapping’ diagnosis is Lyme disease (caused by Borrelia bacteria transmitted via tick bites), particularly the neurological Lyme disease syndrome which seems to emerge after treatment. In fact, it has long been suspected that a subgroup of people with ME/CFS do, in fact, have undiagnosed Lyme disease, particularly those in areas of the world where tick bites are common.
Researchers at the New Jersey Medical School have been developing what they call a ‘proteomics strategy’ – a way of using the number and distribution of proteins to answer questions about specific diseases. To test their strategy, they chose to examine proteins in the cerebrospinal fluid (a key body fluid providing information on the central nervous system) of patients with ME/CFS or post-treatment Lyme disease, two ‘syndrome’ diagnoses that pose particular challenges. For analysis, the researchers used chromatography coupled to mass spectrometry, a new technique that allows examination of complex biological specimens containing thousands of proteins.
The key findings, published in the journal PLoS ONE, were that the patients in the Lyme group and ME/CFS group shared significantly more proteins (305) than either group shared with healthy controls (135 and 166, respectively), but that nevertheless there were clear differences between the ME/CFS and Lyme groups regarding specific cerebrospinal fluid proteins. Using a preliminary pathway analysis to look in greater detail at some proteins found to be specific for ME/CFS, the researchers found the CDK5 signalling pathway (which has been linked to Parkinson’s and Alzheimer’s disease) to be significantly enriched – illustrating the feasibility of the research strategy to give information about pathogenetic mechanisms behind diseases.
Might the distribution of cerebrospinal fluid proteins become a useful way of separating ‘syndrome’ illnesses that presently share similar symptoms? Well, it’s early days, and Prof. Schutzer, who helped lead the study, says that the next step is to narrow down the list of proteins to find “the best biomarkers for what is going wrong in the central nervous system” of ME/CFS patients.
Reference: Distinct cerebrospinal fluid proteomes differentiate post-treatment lyme disease from chronic fatigue syndrome. Schutzer SE et al. PLoS One 2011 Feb 23; 6(2): e17287.