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Interleukin 6 (IL-6) is one of the key cytokines that are involved in inflammation and that has pleiotropic properties. Diverse effects of IL-6 result from the transmission of an intracellular signal in two ways: via direct binding to a membrane receptor having a molecular mass of 80 kDA (a classical way) or absorption of the IL-6 complex with its soluble receptor on another transmembrane receptor – gp-130 (trans-signaling). Different signaling pathways lead to various consequences. The classical way of signal transmission activates mainly protective and regenerative processes; trans-signaling has a proinflammatory potential. The review gives schemes of signal stimuli and shows that IL-6 and its receptors are a dynamic intricately organized regulatory system that can adapt to stress-induced homeostatic changes. It considers in detail evidence suggesting the effect of IL-6 on the development and maintenance of a number of systemic sclerosis (SS)-specific pathogenetic disorders, such as the activation of the endothelium, the development and maintenance of inflammation, and excessive deposition of extracellular matrix components in tissues. Endothelial cell activation during trans-signaling gives rise to an enhanced adhesion molecule expression, chemokine release, and further production of IL-6. Excessive secretion of the latter may initiate a fibrosing process and favor the further development of pathological conditions. Autoimmune disorders theoretically associated with IL-6 overproduction occur in SS. Elevated blood IL-6 concentrations in SS are related to disease clinical parameters, such as activity, severity, worse prognosis, and reduced survival. Taken together, the data presented suggest that IL-6 blocking may have a therapeutic potential in SS. The first clinical data on successfully using the IL-6 receptor antagonist tocilizumab to treat SS are given.

Objective: to study the efficiency and tolerance of rituximab (RTM) treatment in patients with scleroderma systematica (SDS) with interstitial lung injury (ILI). Subjects and methods. The trial included 27 patients (26 women and 1 man) (mean age 45.7±13.0 years), with diffuse (n=13) and circumscribed (n = 14) forms and a disease duration of > 5 years in 63%. All the patients underwent chest computed tomography; examination of external respiratory function, including forced vital capacity (FVC) and diffusing capacity of the lung (DCL), as well as echocardiographic study. The efficiency of the treatment was evaluated from changes in FVC, skin score, and disease activity index. The indicators were compared prior to the treatment and one year after the first administration of RTM. The latter was injected with premedication (125–500 mg of methylprednisolone intravenously) 500–1000 mg per administration. The mean dose of RTM was low and amounted to 1.3 g per year. Results. As estimated by the physician, good, satisfactory, no effects were seen in 81.5, 14.8, and 3.7% of the patients, respectively. There was a significant increase in mean FVC one year after the first administration of RTM and a reduction in the total activity of the disease, including skin syndrome. DCL was substantially unchanged in the entire group. In the diffuse and circumscribed forms of the disease, FVC increased significantly and to the same extent. A clinically significant increase in FVC (by 11%) was achieved in patients with a disease duration of ≤5 years and mild lung injury. In people with a more than 5-year disease duration, FVC was initially decreased to a greater extent and the treatment-induced increase was only 3.7%. A significant and permanent decline in peripheral blood B lymphocytes was noted when both the standard dose (2 g) of RTM and its lower doses (0.5–1 g) were administered. RTM treatment was well tolerated, but complicated by mild intercurrent infections in 11% of cases within the first 2 months after RTM administration. Conclusion. The findings substantiate the indications for RTM use primarily in the early stage of the disease. The admittedly low doses of RTM have an inadequate effect if the disease is long-lasting. Further study of dosage regimens for RTM is required within the framework of controlled trials.

Objective: to study the specific features of regulation of peripheral vascular tone and their association with the endothelial structure and function of large vessels in patients with scleroderma systematica (SDS). Subjects and methods. The investigation enrolled 25 patients with SDS (mean age, 47±2.6 years; mean disease duration, 8.3+1.7 years) and 15 apparently healthy individuals matched for age and gender. Comprehensive examination involved laboratory and instrumental studies, laser Doppler study to evaluate endothelium-dependent and endothelium-independent vasodilation, as well as applanation tonometry calculating the pulse wave velocity and augmentation index. Results. All the patients were found to have impaired peripheral vascular responsiveness as compared to the controls. The examination established a relationship between the magnitude of endothelium-dependent vasodilation and the stiffness index of large vessels. There was no association between endothelium-independent vasodilation and vascular elasticity parameters.

Objective: to study the efficacy and safety of the endothelin 1 receptor inhibitor traclir in patients with pulmonary hypertension (PH) asso ciated with systemic connective tissue diseases. Subjects and methods. The study included 4 patients: 3 with scleroderma systematica and 1 with exanthematous lupus erythematosus. The diagnosis of PH was established on the basis of right heart catheterization data and after exclusion of all its other causes of HP. In addition to hemodynamic evaluation, the female patients underwent echocardiography (EchoCG), lung function tests, 6-minute walk test, and blood biochemical study (determination of uric acid levels). Traclir was given in a dose of 62.5 mg twice in the first 4 weeks of the study and then in a dose of 125 mg twice for the subsequent 12 weeks. Every 4 weeks, the levels of transaminases were monitored and a pregnancy test was carried out in patients of fertile age. Results. After 16-week intake of the drug, all the female patients were found to have obvious positive changes as a longer 6-min walk test distance and two female patients had improvement in the functional class of PH. Estimation of hemodynamic parameters suggested a posi tive effect in all the female patients, as confirmed primarily by an increase in cardiac index and a reduction in pulmonary vascular resist ance. According to EchoCG data, there was a substantial increase in tricuspid annular plane systolic excursion; other parameters had no informative value. During traclir therapy, there was also an increase in lung diffusion capacity and a reduction in uric acid levels. There were no adverse events throughout the trial. Conclusion. Thus, the experience with traclir used in patients with PH associated with systemic autoimmune diseases suggests its high effi cacy and safety.