[Relapsing-remitting multiple sclerosis: clinical and immunological aspects of the pathology on the example of molecules Sema4D and CD72]. / Remittiruyushchii rasseyannyi skleroz: kliniko-immunologicheskie aspekty patologii na primere molekul Sema4D i CD72.

OBJECTIVE: To study the expression of Sema4D (CD100), receptor CD72 and a role of Sema4D-CD72-dependent signal in the control of the functions of immunocompetent cells in relapsing-remitting multiple sclerosis (RRMS). MATERIAL AND METHODS: We studied 76 patients, including 52 with RRMS (41 in remission and 11 in exacerbation), 35 women (67.3%) and 17 men (32.7%) aged 18-55 years, who did not receive disease-modifying drugs, and 24 healthy donors. A controlled clinical and immunological examination of patients with RRMS was carried out proving the involvement of the Sema4D molecule and its CD72 receptor in pathological reactions in this autoimmune disease. RESULTS AND CONCLUSION: The use of SemaD as a target in the treatment of RRMS is scientifically substantiated. In case of a positive decision on the use of anti-Sema4D drugs, it will be necessary to take into account the effects of semaphorin not only in the central nervous system, but also in the immune system of patients with RRMS.

Receptor Functions of Semaphorin 4D.

Semaphorin 4D (Sema4D) is a multifunctional protein widely expressed in an organism that plays an important role in the control of many physiological and pathological processes, including immunoregulation, neurogenesis, angiogenesis, and tumor progression. It was first described almost 30 years ago and has been actively studied since then. However, with rare exceptions, all studies of the Sema4D activity proceed from the assumption that semaphorin is a ligand that acts through specific receptors (CD72 and plexins) and that the main targets of Sema4D in different tissues are cells that carry these receptors on the membrane. This review analyzes the data indicating the presence of an alternative mechanism for the regulatory activity of Sema4D that involves the functioning of membrane semaphorin as a receptor ensuring the outside-in signaling. Cell signaling pathways mediated by the membrane Sema4D and their contribution to the Sema4D-dependent regulation of cell functions are discussed.

[Factors regulating the activity of b-lymphocytes, as potential biomarkers of multiple sclerosis]. / Faktory, reguliruiushchie aktivnost' V-limfotsitov, kak potentsial'nye biomarkery rasseiannogo skleroza.

AIM: To assess the possibility of using serum levels of chemokine CXCL13, B-cell activating factor (BAFF), interleukin 1 and 17 (IL-10, IL-17) as markers of the development/progression of multiple sclerosis (MS). MATERIAL AND METHODS: Sixty-seven patients with MS in remission and 14 healthy volunteers were examined. The levels of BAFF, CXCL13 and the main products of Th17 and Treg - interleukin 17 (IL-17) and IL-10 in the serum were determined, their relationship with clinical characteristics of MS during remission was assessed. RESULTS AND CONCLUSION: The content of IL-17 and BAFF in the serum of patients with MS did not differ significantly from the control group, and the levels of IL-10 and CXCL13 were lower than the corresponding indicators of healthy donors. In patients with MS, no correlation was found between IL-17, IL-10, BAFF and clinical characteristics of MS. The level of CXCL13 correlated with quality of life, fatigue, clinical and functional status of patients. According to the results of this study, BAFF and CXCL13 cannot be proposed as diagnostic biomarkers of MS.

Molecular Mechanisms of Control of Differentiation of Regulatory T-Lymphocytes by Exogenous Melatonin.

We investigated the role of epiphyseal hormone melatonin in the differentiation of naive CD4+ T cells into regulatory T cells (Treg). The hormone at physiological and pharmacological concentrations inhibited Treg differentiation, decreasing both the proportion of CD4+FOXP3+ cells in the culture and the level of TGF-ß, the key cytokine for this T cell subpopulation. The inhibitory effect of exogenous melatonin was due to its interaction with the membrane receptors MT1 and MT2. At the same time, the signals realized through RORα-the nuclear receptor for melatonin-stimulated Treg formation; however, they were considerably weaker than the signals from the membrane receptors and were overlapped by the latter. Since the Treg subpopulation plays an important role in physiological and pathological processes in the body, the revealed effects of melatonin should be taken into account in its therapeutic use.

[Relapsing-remitting multiple sclerosis: clinical and immunological aspects of the pathology on the example Sema4D and CD72]. / Remittiruiushchii rasseiannyi skleroz: kliniko-immunologicheskie aspekty patologii na primere molekul Sema4D i CD72.

AIM: To explore the expression of Sema4D, CD72 receptor and a role of Sema4D-CD72 signal in the control of immunocompetent cell function in remitting-relapsing multiple sclerosis (RRMS). MATERIAL AND METHODS: Fifty-two patients with RRMS diagnosis according to 2010 revised McDonald's criteria were studied. The control group included 24 healthy people. A flow cytometry method was used to measure the expression of semaphorin Sema4D by T-lymphocytes of peripheral blood, expression of CD72 receptor by B-lymphocytes, percentage of cells containing pro- and anti-inflammatory cytokines. The level of soluble Sema4D (sSema4D) was evaluated by ELISA. RESULTS: The level of Sema4D expression on T-lymphocytes (Mean Fluorescence Intensity - MFI) prevailed in cell subpopulations in patients with RRMS compared with the control group. Characteristics of membrane and sSema4D correlate with clinical presentations of the autoimmune disease. An increase in sSema4D level during cell cultivation was identified in RRMS patients. The results show the involvement of Sema4D in the hyperactivation of B-cell-mediated immunity through CD72 receptor and induction of proinflammatory cytokine synthesis. CONCLUSION: RRMS is associated with elevated expression of Sema4D in the immune system. Membrane and sSema4D involved in the pathological process in RRMS. The authors suggest several mechanisms of the involvement of semaphorin and its receptor in the pathogenesis of RRMS: the direct damage of nervous tissues by sSema4D penetrated through the blood brain barrier disrupted in RRMS or by membrane Sema4D due to the infiltration of the central nervous system by T-lymphocytes and hyperactivation of B-cell-mediated immunity.

Role of Endogenous Melatonin in the Regulation of Th17/Treg Balance during Pregnancy.

We studied the role of endogenous melatonin in the development and functioning of T cells that produce IL-17 (Th17) and regulatory T cells (Treg) during pregnancy. The study was performed ex vivo and in vitro with auto-serum as the source of endogenous melatonin under conditions of blockade of melatonin-dependent signaling. Participation of the hormone in the regulation of differentiation of both CD4+RORγt+ and CD4+FoxP3+T cells and their key products IL-17A and TGF-ß was demonstrated. It is known that the normal gestational process is accompanied by a decrease in Th17/Treg ratio due to hormonal changes. The sensitivity of the studied subpopulations to melatonin during pregnancy can affect its outcome.

New aspects of the Seam4D-dependent control of lymphocyte activation.

Novel targets for action of the class IV semaphorin Seam4D have been identified in the immune system. The low-affinity CD72 receptor for Seam4D was detected not only on B lymphocytes, but also in a proportion of T cells, whereas the high-affinity semaphorin receptor, plexin B1, originally considered to belong to non-immune cells, proved to be in a great proportion of intact T and B cells. Seam4D is constitutively expressed in B cells, which, along with T cells, can serve as a source of both membrane and soluble semaphorin. The results obtained make significant adjustments in understanding of Seam4D effects in lymphoid cells.

[Melatonin as an inducing factor for multiple sclerosis].

Melatonin is one of the most multifunctional regulators in the organism. It plays a key role in the control of nerve, endocrine, and immune systems. Due to hormone neuroprotective activity, the possibility is now discussed on its clinical usage in treating neurodegenerative diseases, including multiple sclerosis. At the same time, melatonin is an effective regulator of immune reactions, in part, the reactions toward autoantigens. In this respect, the subset ofT lymphocytes producing IL-17 (Th17) is of special interest. As the Th17 subset plays a key role iri multiple sclerosis pathogenesis, the immunomodulating hormone effects toward Th17, may, in theory, nullify its positive neuroprotective activity.

Role of Melatonin in the Regulation of Differentiation of T Cells Producing Interleukin-17 (Th17).

We studied the ability of melatonin in physiological and pharmacological concentrations to induce and/or regulate differentiation of T cells producing IL-17 (Th17). This hormone produced the opposite effect on CD4+T cells, which depended on their activation status. Melatonin induced the synthesis of IL-17A by intact T cells, but had little effect on activated cells. Melatonin in high (pharmacological) concentration decreased the intracellular expression of this cytokine under conditions of polyclonal activation. Melatonin had a dose-depended effect. Taking into the fact that Th17 cells play an important role in the immune defense, it can be suggested that the regulation of their activity by melatonin contributes to this process.

[Neuroinflammatory, Neurodegenerative and Structural Brain Biomarkers of the Main Types of Post-Stroke Cognitive Impairment in Acute Period of Ischemic Stroke].

Background: Post-stroke cognitive impairment is a clinically heterogeneous condition, some types of which cannot be fully differentiated neuropsychologically that necessitates the active search for biomarkers. Aims: Analyze parameters of neuroinflammation and neurodegeneration in combination with neuroimaging markers in patients with different types of post-stroke cognitive impairment in acute ischemic stroke. Materials and Methods: In 72 patients we performed the assessment of cognitive status and distinguished 3 types: normal cognition, dysexecutive, and mixed cognitive impairment. In each group we determined the concentration of cytokines (IL-1ß, IL-6, TNFα, IL-10) in liquor and serum, ß-amyloid 1−40 in liquor and a number of MRI morphometric parameters and fractional anisotropy. Results: In all groups of patients we detected higher level of IL-10 in serum compared with the control. Patients with dysexecutive cognitive impairment had higher concentration of IL-1ß, IL-10 in liquor, IL-6 level in serum, lower fractional anisotropy of ipsilateral thalamus compared with patients with normal cognition and largest size of infarct. Patients with dysexecutive and mixed cognitive impairment had the higher area of leukoareosis and ventricular volume, reduced fractional anisotropy of contralateral cingulum compared with patients with normal cognition. Patients with mixed cognitive impairment characterized by lower fractional anisotropy of contralateral fronto-occipital fasciculus compared with patients with dysexecutive cognitive deficit. Conclusions: Serum and cerebrospinal fluid concentrations of cytokines studied in combination with MRI parameters particularly fractional anisotropy seems to be informative biomarkers of pathogenic types of PSCI.

[THE RELATIONSHIP BETWEEN SERUM AND LIQUOR IL-1ß, IL-6, TNFα, IL-10 LEVELS AND CLINICAL, COGNITIVE AND FUNCTIONAL CHARACTERISTICS IN ACUTE ISCHEMIC STROKE].

Introduction: Inflammation is probably the main process that links cardiovascular risk factors with damage to blood vessels and neurons. Elucidation of mechanisms of this relationship is an important issue. Materials and methods: 70 acute stroke patients were studied to assess their neuropsychological (MMSE, MoCA, FAB, Clock Drawing Test, Shulte Tables and Verbal Fluency) and functional status (mRS, Rivermead Mobility Index). The serum and liquor IL-1ß, IL-6, TNFa and IL-10 levels were analyzed. Control group included subjects without cerebrovascular diseases. Results: Stroke patients had higher IL-10 serum concentration than controls. No difference was found for other cytokines. There was correlation between serum and liquor cytokines levels. We found positive correlation between IL-1ß, IL-6 and IL-10 levels. High IL-1ß concentration was associated with vascular risk factors, cardio embolic stroke, enhanced severity of cerebral stroke, low processing speed, impaired executive and visual-spatial functions and higher grade of mRS on discharge. The same pattern was revealed for IL-6 and IL-10. IL-6 level was related to mRS without relation to NIHSS on admission. High TNFa concentration was linked with vascular risk factors, low MMSE score and processing speed. Discussion: Despite the antagonistic effects of IL-1ß, IL-6 and IL-10 on inflammation, associations of these cytokines with anamnestic, clinical, neuropsychological and functional characteristics were similar in acute ischemic stroke. Probably, this fact indicates that during the acute ischemic brain damage process the immune response develops at the same time in pro- and anti-inflammatory directions. Its magnitude correlates with the damage severity and is associated with the effects of vascular risk factors before stroke.

Role of B cells in presentation of autoantigens to CD4(+) T cells in patients with autoimmune thyroiditis.

The antigen-presenting activity of B cells and expression of molecules involved in antigen presentation by B cells have been studied in patients with autoimmune thyroiditis (AIT). The disease is characterized by enhanced expression of the costimulatory molecule CD80 in naive B cells (CD19(+)CD27(-) cells) both ex vivo and under the conditions of polyclonal cell activation in a culture. Under in vitro conditions, antigen-loaded B cells have been shown to be capable of inducing proliferation of autologous CD4(+) cells, in particular, proliferation of autospecific T cells in patients with AIT. Given that an intense infiltration of thyroid tissue by B cells is a typical sign of AIT, the antigen-presenting activity of B cells appears to contribute to this pathology.

[Extrathymic Differentiation of αßT Lymphocytes].

Extrathymic differentiation is an alternative way of αßT lymphocyte development. In normal conditions it is expressed slightly and limited mainly to the liver and intestinal mucous. However, it increases significantly with age, as well as in certain physiological and pathological conditions, buying more widespread. In the review, the phenotypical and functional features of extrathymic T lymphocytes have been considered in detail depending on their localization and a way of the process activation. The mechanisms of such differentiation induction have been analyzed. Special attention is paid to the biological significance of extrathymic αßT cell development.

Semaforin Sema4D in the immune system in multiple sclerosis.

The expression of class IV semaforin Sema4D and its CD72 receptor on lymphocytes was studied in patients with multiple sclerosis. The disease was associated with an increase in Sema4D level on intact T lymphocytes and with its more intense shedding from the membrane of activated cell. Multiple sclerosis was also associated with a decrease of CD72 receptor expression by B lymphocytes. Possible contribution of Sema4D to the disease development via the direct effects in the CNS and the immunomodulatory effect, specifically, B cell activity regulation, was discussed.

[The CD100 semaphorin expression on peripheral blood T-lymphocytes in patients with relapsing-remitting multiple sclerosis].

The expression of CD100 semaphorin by the intact peripheral blood T lymphocytes in multiple sclerosis (MS) has been studied. The level of middle florescence intensity (MFI) and the number of B-lymphocytes bearing CD72 were evaluated. There were significant differences in the level of CD100 in patients compared to healthy volunteers. These data suggest the use of semaphorin as a possible therapeutic target in pathological inflammation in MS.

[Extrathymic differentiation and antigen response of alphabetaT lymphocytes in pregnancy].

We studied reactivity of alphabetaT lymphocytes in CBA pregnant females toward male antigens and the presence of gene rearrangement in T-cells antigen receptor in peripheral lymphoid organs of mice in the case of three breeding variants: CBA x BALB/c (normal allogenic pregnancy), CBA x CBA (syngenetic pregnancy), and CBA x DBA/2 (prone to abortion combination). It was shown that proliferative response of alphabetaT lymphocytes in pregnant CBA females to male spleen cells was the most marked at normal allogenic pregnancy, the least marked at syngenic pregnancy, and was not observed at the combination CBA x DBA/2. In addition, cells ofparaaortic lymphatic nodes (draining uterus) respond to male antigen reliably more effectively than lymphocytes in mesenterial and axillary lymphatic nodes. Simultaneous estimation of recombinase RAG-1, the key enzyme in rearrangement of T-receptor genes, revealed similar principles: predominant activity of recombinase in T lymphocytes in paraaortal lymphatic nodes of CBA pregnant females. This points to the relationship between extrathymic rearrangement of antigen receptor genes and change in the antigen-detecting repertoire of these cells. The possible biological significance of the discovered phenomenon is discussed.

Molecular mechanisms of T-cell anergy.

Anergy is a long-term stable state of T-lymphocyte unresponsiveness to antigenic stimulation associated with the blockade of IL-2 production and proliferation. Anergy is a pathway of peripheral tolerance formation. In this review, mechanisms underlying T-cell tolerization are considered in a classical in vitro model of clonal anergy, and these mechanisms are compared with different pathways of anergy induction in vivo. Special attention is given to regulatory T-lymphocytes because, on one hand, anergy is a specific feature of these cells, and on the other hand anergy is also a mechanism of their action on target cells - effector T-lymphocytes. The role of this phenomenon in the differentiation of regulatory T-cells and also in the development of activation-induced apoptosis in effector T-lymphocytes is discussed.

Role of CD40-dependent signal in induction of recombinase RAG-1 expression in peripheral T cells of patients with autoimmune diabetes mellitus.

We studied the mechanisms of induction of recombinase activity in peripheral T cells of patients with autoimmune type 1 diabetes mellitus. It was shown that the presence of CD40 on T cell membrane (not typical of these cells) is crucial for this process: expression of recombinase RAG-1 in diabetic patients was detected primarily in αßTCR(+)CD40(+) lymphocytes; targeted CD40-dependent activation of intact T cells in vitro increases, while blockade of CD40 signal in the culture of stimulated T cells abolishes recombinase expression.