Role of innate and adaptive immune system in patients with restless LEG syndrome

Restless legs syndrome (RLS) is a sleep disorder that occurs with uncomfortable sensation and an urge to move, especially in the legs (limps) at rest. It has been shown that iron/ferritin deficiency, dysregulation of dopaminergic mechanisms and genetic factors play an active role in the disease. In addition, reports show that infectious diseases such as small intestinal bacterial overgrowth and HIV infection increase the prevalence of restless legs syndrome. Obstructive sleep apnea syndrome (OSAS) is one of the most common sleep disorders. Studies conducted with OSAS patients have shown that inflammatory processes associated with OSAS may play a role in the pathophysiology of the disease. The objective of this study was to investigate the relationship between RLS and immune system elements. In addition, it was aimed to show which of the adaptive immune system and/or innate immune system elements play a role in RLS. Fourteen RLS patients, 15 RLS patients with OSAS (RLS+OSAS) and 10 healthy subjects were included. In our study: T, B, NK, NKT and ILC cell ratio; intracellular IFN-γ, IL-6, IL-10, IL-13 cytokines in T, B, NK cells; CD8+ T and NK cell cytotoxic activity was analyzed by flow cytometry. IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, IL-13 levels in plasma samples were evaluated with bead-based soluble molecule assay. Our results showed that compared to the healthy controls the ratio of ILC-1 subset and IL-13+CD4+ T cells were increased in RLS and RLS+OSAS patients but the levels of ILC-2 cells were decreased. When the NK cytotoxic activity of RLS patients were evaluated, it was found that the NK perforin levels were lower than OSAS+RLS patients and healthy controls. Plasma IFN-γ and IL-13 levels were found elevated in the RLS group with OSAS compared to the healthy control and RLS group. In conclusion, our study revealed that both innate and adaptive immune system elements play a role in RLS.