The Effect of Autoreactive Autoantibodies on Peripheral and Central Disease Mechanisms in Fibromyalgia.

The Effect of Autoreactive Autoantibodies on Peripheral and Central Disease Mechanisms in Fibromyalgia.

This observational study aims to compare disease burden and pain characteristics between fibromyalgia patients with high levels of autoreactive autoantibodies, fibromyalgia patients with low levels of autoreactive autoantibodies, and healthy controls. The primary hypothesis is that patients experience more symptoms (as measured with questionnaires) depending on their antibody titer, and that high levels of autoantibodies correlate with other biological markers, such as inflammatory profile in serum, and density of intraepidermal nerve fibers in skin.

The secondary aim of this study is to characterize central markers of disease, which will be done using a number of methods: the investigators will quantify immune profile in the cerebrospinal fluid, measure thalamic neurotransmitter levels with magnetic resonance spectroscopy (MRS), blood-brain barrier permeability with both biochemical markers and T1-weighed gadolinium-enhanced magnetic resonance imaging (MRI), and resting state activity of the brain (MRI). The investigators hypothesize that there are signs of upregulation of the immune system of the central compartment, and that this will be correlated with altered neurotransmitter levels and an altered resting state activity.

Inclusion criteria:

• Female sex
• Age 20-70
• Fibromyalgia according to the ACR 1990+2016 criteria for the FM cohort.

Exclusion Criteria:

• Reported BMI > 35 during screening over a phone call.
• Other dominant chronic pain states.
• Autoimmune diseases (exception: primary hypothyroidism).
• Serious somatic or psychiatric disease.
• Current pregnancy.
• Non-fluency in Swedish.
• For HC: history of chronic pain or current pain exceeding 20 on a 0-100 scale or having received an FM diagnosis.
• For NINS: having received an FM diagnosis.