Cytokine profile of blood serum in patients with demyelinating diseases affecting the spinal cord and associated pain syndrome

Demyelinating diseases (DD) are chronic autoimmune disorders of the central nervous system (CNS) with a high level of disability. The prevalence of pain syndrome (PS) in DD is 66.5%. The most common type of PS is central neuropathic pain syndrome (CNPS), which is difficult to treat. The neurobiological mechanism underlying CNPS remains unclear. Recent studies have shown that neuroinflammation, mediated by pro-inflammatory cytokines and chemokines, plays an important role in the onset and maintenance of neuropathic pain (NP). Determining the level of pro-inflammatory cytokines may be of prognostic value in patients with DD and CNPS for determining further management tactics. Objective: to study the concentration of proand anti-inflammatory cytokines in patients with DD and concomitant CNPS. Material and methods . Based on the interferon laboratory of the I.I. Mechnikov Vaccine and Serum Research Institute and the cytokine laboratory of Vector-Best JSC, the cytokine profile was studied in 23 patients with DD (9 patients with MS with lesions of demyelination in the spinal cord and 14 patients with NMOSD). The main group consisted of 13 patients with concomitant pain syndrome, and the comparison group consisted of 10 patients who did not complain of pain. The control group consisted of 13 healthy volunteers. The concentration of cytokines was studied: interferon α (IFNα), IFNγ, interleukin 6 (IL-6), IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein 1, IL-1β, IL-18, tumour necrosis factor α (TNFα), soluble tumour necrosis factor receptor 1 (S-TNF-R1), and vascular endothelial growth factor. Results . Patients in the main group with CNPS had higher concentrations of IL-8 (p 3 =0.016), IL-18 (p3=0.021) and S-TNF-R1 (p 3 =0.013) in their blood serum compared to patients in the control group. The concentrations of TNF-α (p 1 =0.006; p 2 =0.039) and S-TNF-R1 (p 1 =0.027) were significantly higher in the groups of patients with DD compared to healthy individuals. With mitogen-induced stimulation, patients in the main group showed increased IL-10 production compared to the control group (p 1 =0.002) and the comparison group (p 3 =0.003). The nature of IL-18 production (both during spontaneous synthesis and mitogen-induced stimulation) differed significantly in the group of patients with CNPS – both types of production of this cytokine were significantly higher than in other comparable groups (p 1 =0.004; p 1 =0.006; p 3 =0.002). Conclusion . The results of this study confirm the key role of pro-inflammatory cytokines in the pathogenetic mechanisms of neuroinflammation, which requires further study in clinical practice to develop new effective therapeutic strategies.