Investigation of the relationship between serum follistatin-like protein 1 level and disease activity in behçet patients

Behçet's disease (BD) is defined as a systemic vasculitis that can hold all vessels of different diameter and placement, of arterial and venous type, with chronic periods of exacerbation and well-being.Although the etiology of BD has not been fully clarified, genetic, immunological, environmental factors, previous infections, vascular endothelial pathologies and clotting disorders are blamed.Today, there is still no definitive cure for BD.In addition, there are no specific biomarkers that can precisely predict progression and therapeutic response.A better understanding of the cellular and molecular mechanisms involved in BD's pathogenesis will enable the development of new strategies for treating the disease. In recent years, many studies have demonstrated that Follistatin-like protein 1 (FSTL-1) plays an important role in inflammation and in the regulation of immune system cells.Although the role of FSTL-1 in the immune system is not fully understood, both pro-inflammatory and anti-inflammatory functions have been reported for FSTL-1.The possible role of FSTL-1 in human inflammatory diseases was first demonstrated by isolating it from the synovial tissue of patients with rheumatoid arthritis (RA).In addition, serum FSTL-1 levels were significantly higher in various autoimmune diseases such as RA, ulcerative colitis, systemic lupus erythematosus, sjogren's syndrome, systemic sclerosis and polymyositis / dermatomyositis. Overexpression of FSTL-1 in macrophages and fibroblasts increased the activity of pro-inflammatory cytokines, including IL-1 beta, TNF-alpha, and IL-6, and caused severe arthritis in normal mice in animal experimental models.Neutralization of FSTL-1 has been shown to improve arthritis by inhibiting the production of IFN-gamma and chemokine ligand 10 in the arthritic joints of collagen tissue disease associated arthritis (CIA) mouse models. In this study, we aimed to determine serum levels of FSTL-1, which has been shown to play a role in the pathogenesis of many inflammatory diseases, and to investigate its relationship with disease activation in BD. 45 newly diagnosed and followed-up patients who met the criteria of the 1990International Behçet Disease Working Group between June and September 2019were included in the study in the outpatient clinics of Physical Medicine andRehabilitation Department of Dicle University Faculty of Medicine.As a control group, 36 healthy volunteers were enrolled in the study, which was compatible with the patient group in terms of age and gender.Peripheral blood samples were taken from patients and controls and serum FSTL-1 levels were measured by ELISA method. Serum FSTL-1 levels of the patient and control groups were significantly higher in the patient group (p<0.001).Serum FSTL-1 levels were significantly higher in female patients than in male patients (p = 0.029).When The Behcet's Disease Current Activity Form (BDCAF) score was compared in female and male patients, the BDCAF scoreof female patients was significantly higher (p=0.008).There was also a positive correlation between ESR and serum FSTL-1 levels (p=0,006). FSTL-1 may be involved in the pathogenesis of BD and may be one of the markers of disease activation.