Specific cytokines and chemokines were lower in fibromyalgia patients than in individuals with rheumatoid arthritis or systemic lupus erythematosus and in healthy control participants, according to new research.
Researchers obtained peripheral blood mononuclear cells (PBMC) from 160 patients with fibromyalgia (FM) confirmed according to the American College of Rheumatology criteria and no autoimmune comorbidities. Patients discontinued all FM medications 2 weeks prior to blood collection. The researchers also collected blood from 100 patients with systemic lupus erythematosus (SLE) and 98 patients with rheumatoid arthritis (RA) — most of whom had disease “under good control” with medication at the time of the study. Blood samples were also collected from 119 age- and sex-matched healthy control participants on no medications.
Supernatent cytokine concentrations of interleukin-6 (IL-6), IL-8, macrophage inflammatory protein-1 alpha (MIP-1a) and MIP-1 beta were analyzed from the samples.
Using statistical analysis, a single, combined scoring system was utilized to determine differences between the groups, with a positive score deemed as 50 or above. Positive scores were seen in 93% of all FM patients compared with only 11% of healthy individuals, according to the researchers. Patients with SLE showed negative scores in 71% of cases, and 69% of RA patients had negative scores.
Concentrations of cytokines were lower in FM patients with the exception of IL-8 in both the FM and RA cohorts. Patients with FM had the lowest levels of IL-6 compared with all other groups. According to the researchers, the cytokine profile test has 93% sensitivity and 89.4% specificity for diagnosing FM, but was not as sensitive in detecting RA or SLE. – by Shirley Pulawski
Disclosure: Wallace was a consultant for EpicGenetics in 2013. Please see the full study for a list of all other authors’ relevant financial disclosures.