A Preliminary Investigation of microRNAs in Cerebrospinal Fluid Samples from Patients with Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis

Objectives: Previous research has demonstrated significant changes in microRNAs (miRNAs) from isolated immune cells obtained from patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME). However, the presence of miRNAs in the cerebrospinal fluid (CSF) is yet to be investigated in CFS/ME patients. Therefore, the purpose of this pilot study was to assess for the presence of miRNAs in cerebrospinal fluid from CFS/ME and healthy control patients. Methods: CSF samples were collected from 18 well-characterized CFS/ME patients and 5 healthy controls. RNA was extracted from all samples this was followed by cDNA synthesis. The CSF samples were examined for the presence of 5 miRNAs, miR-15b, miR-21, miR-124, miR-125b and miR-31 using qRT-PCR methods. Results: Of the 5 miRNAs examined, there were no significant differences in the expression levels of these miRNAs between the CFS/ME patients and the controls. However, miR-124 was the most abundant miRNA expressed in the CSF samples of both the CFS/ME patients and the controls. Conclusions: This is the first study to report on miRNAs in CSF from CFS/ME patients. However, further studies are required to investigate the role of other miRNAs that may potentially be implicated in the pathology and progression of this illness.