[The treatment by expanded ex vivo autologous regulatory T-cells CD4+CD25+FoxP3+CD127low restores the balance of immune system in patients with remitting-relapsing multiple sclerosis]. / Lechenie vyrashchennymi ex vivo autologichnymi regulyatornymi T-kletkami CD4+CD25+FOXP3+CD127low vosstanavlivaet balans immunnoi sistemy patsientov s remittiruyushchim rasseyannym sklerozom.

AIM: To assess clinical efficacy and safety of the autologous (own) regulatory T-cells (Tregs)CD4+CD25+Foxp3+CD127low isolated from the blood of patients with remitting-relapsing multiple sclerosis. Patients with autoimmune diseases have the decreased number of peripheral Tregs (pTreg) and impaired suppressive ability. In order to restore levels of pTreg, it is possible to isolate precursor cells, enter expanded ex vivo autologous Treg cells and introduce an expanded amount of autologous cells as Treg vaccine. MATERIAL AND METHODS: A method of ex vivo Tregs expansion by 30-40 times within 5-7 days has been developed. Expanded ex vivo Tregs are more than 90% CD4+CD25+Foxp3+CD127low and have high suppressor activity. Fourteen patients with remitting-relapsing multiple sclerosis were included in pilot studies.Ex vivoTregs were introduced subcutaneously in dosefrom 2.8 to 4.5 108 cell per injection. The duration of follow-up was 1 year. RESULTS AND CONCLUSION: The numbers of pTregs in the blood of these patients elevated by 1.5-2 times. No adverse-effects, a decrease of relapses and stabilization of disability index were observed. It has been suggested that ex vivo expanded Tregs can compensate the impaired function of pTregs and can be used for adoptive immunotherapyof multiple sclerosis.

[Clinical significance of T-regulatory cells in multiple sclerosis].

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system that develops due to the activation of selfreactive T-cells specific for myelin components. Regulatory T-cells CD4+CD25+Foxp3+ (T-reg) play an important role in the autoimmunity control and inhibition of T-cells-mediated myelin destruction. The aim of the study was to determine a number of T-reg in the blood of patients in different stages of disease, to evaluate their functional activity and to obtain T-reg induced ex vivo. The phenotypic analysis revealed the 2-3 fold reduction of T-reg in the exacerbation phase of MS and the increase of their content in the remission while the level of T-reg in the donor's blood remained significantly higher. The inverse correlation between the degree of severity and duration of MS and the number of T-reg was found. The suppression function of T-reg of MS patients was substantially decreased in the exacerbation and remission stages. The induction of ex vivo T-reg allows to increase the number of these cells by 30-90 times during 6-8 days. The induced T-reg have phenotypic and functional characteristics of native T-reg. The adaptive cell treatment using induced T-reg may become an instrument for correction of immune dysfunction in MS.

[The role of regulatory T cells in the development of autoimmune process in multiple sclerosis].

In the maintenance of immunological tolerance important role belongs to the recently discovered population of regulatory T-cells CD4+CD25+FoxP3 +. These cells have potential in suppressing pathologic immune responses observed at various autoimmune diseases including multiple sclerosis. We have shown a reduction in the number and functional activity of T-reg in peripheral blood of patients with multiple sclerosis in the acute stage, the increase in their number during remission, duration of the relationship of the autoimmune process and the degree of disability of patients with the contents of T-reg. The possibility of using the grown ex vivo T-reg for the correction of immunopathological process in multiple sclerosis.

Autologous progenitor cell implantation as a novel therapeutic intervention for ischaemic digits in systemic sclerosis.

OBJECTIVES: The effects of local stem cell implantation on clinical and functional characteristics of peripheral vascular disease were studied in two SSc patients with non-healing ischaemic ulcers. METHODS: The local injections of CD34(+) cells from peripheral blood (PB) after mobilization by G-CSF (Case 1) and bone marrow (BM) (Case 2) were used for ischaemic skin ulcers in hands, while mononuclear cells (MNCs) were implanted in lower extremities of the same patients. Ischaemic status was evaluated by measuring ulcer healing, Raynaud's condition score (RCS), visual analogue pain, RP and ulcer scales. To evaluate vasculoprotective action of the implanted cells, we studied weekly the changes in endothelial function, using measurement of flow-mediated brachial artery reactivity by high-resolution ultrasonography, circulating endothelial precursors (CD34(+)VEGFR2(+), CD133(+)VEGFR2(+) CEP) by FACS analysis, cutaneous blood flow (laser Doppler flowmetry), skin surface temperature (thermograph), peripheral arterial diameter and blood flow characteristics by Duplex ultrasonography. RESULTS: CD34(+) cells and MNCs both from BM and PB showed rapid and evident beneficial effect on vascular symptoms resulting in ulcer healing, remarkably decreased daily frequency and duration of RP attacks, RCS, visual analogue scale for RP, ulcers and pain. Physical function and disability measured with HAQ and SHAQ improved. Therapeutic efficacy of stem cell therapy was associated with restoration of endothelial function, augmentation of microcirculatory blood flow and significant increase in circulating CD133(+)VEGFR2(+) progenitors, known as cell effectors of angiogenesis. CONCLUSION: This first open-label pilot study demonstrates the feasibility and short-term safety of local CD34(+) cell therapy for SSc ischaemic complications.

[Significance of bone marrow endothelial progenitor cells in disturbance of angiogenesis and endothelial dysfunction in systemic scleroderma].

The study is aimed to investigate the process of endothelial repair related to endothelial progenitor cells (EPC) in systemic sclerosis (SS), and analyze the role of EPC abnormalities in endothelial dysfunction and impaired angiogenesis. Correlation between EPC circulating levels, measured by flowcytometry, and peripheral vascular manifestations, cardiac involvement, carotid artery disease, Framingham risk factor score, endothelial function and morphological signs of microangiopathy is explored. Our data demonstrate, that EPC reduction with disease progression is closely linked with endothelial dysfunction and destructive microangiopathy, and significantly contribute into development of severe cardiac disease and pulmonary hypertension in SS patients.

Circulating endothelial progenitor cells in systemic sclerosis: relation to impaired angiogenesis and cardiovascular manifestations.

OBJECTIVE: Given the essential role of endothelial progenitor cells (EPCs) in endothelial repair and neovascularization, it is likely that insufficient angiogenesis seen in systemic sclerosis (SSc) is related to EPC alterations. The present study was aimed to analyze in SSc the number of circulating EPCs and their contribution into cardiovascular involvement. METHODS: EPC (CD34+VEGF-R2+ and CD133+VEGF-R2+) circulating levels were evaluated in 40 SSc patients and 24 controls by FACS; their correlations with peripheral vascular manifestations, heart involvement, Framingham risk score, carotid artery disease, endothelial function and morphological signs of microangiopathy were studied. RESULTS: Early stage SSc and high disease activity were accompanied by a rise in circulating EPC levels in association with increased membrane expression of Fas (CD95) that correlated positively with severity of peripheral vascular manifestations. EPC reduction with disease progression was linked with endothelial dysfunction and capillary loss, and showed a strong relation to the development of severe internal organ (predominantly cardiac) involvement and pulmonary hypertension. There was a tendency to decreased EPC levels in SSc pts with low HDL values, but no significant correlations were found between EPCs and Framingham risk factor score, carotid artery IMT and traditional cardiovascular risk factors. CONCLUSIONS: In early stage SSc mobilization of EPCs in response to tissue ischemia was preserved, but dropped with disease progression. EPC reduction may contribute to endothelial dysfunction and impaired angiogenesis, leading to the development of severe vascular life-threatening complications of SSc. Traditional cardiovascular risk factors and subclinical atherosclerosis did not influence EPC levels in SSc patients.

[The role of regulatory cells CD4+CD25+ in the development of chronic infective diseases].

Regulatory T-cells CD4+CD25+Foxp3 (Treg) present a small subpopulation of CD4+ T lymphocytes, which develop in the thymus and are disseminated into peripheral lymphoid organs on the 3rd or the 4th day of the neonatal period. Treg play a decisive role in the pathogenesis of autoimmune diseases and the development of tolerance to transplantation antigens, regulate the immune response to allergens, and suppress antimicrobial immunity. Treg suppress proliferation as well as the cytotoxic effect and the secretion of Th1 and Th2 cytokines by effectory T lymphocytes, thus limiting the strength of the immune response of effectory T-cells, which makes them impossible to adequately control viral and bacterial infections. Recognition via antigen-presenting cells and the subsequent induction of the proliferation of antigen-reactive T and B lymphocytes, directed towards infectious agent elimination, is accompanied by the activation of regulatory T cells as well, which leads to immune response suppression; repeated microbial infections are not only able to strengthen T-cell immunity by generating memory T-cells, but can also strengthen the suppressive activity of endogenous T regulators CD4+CD25+. Moreover, T reg are capable of the direct recognition of a microbial product; these cells selectively express Toll-like receptors (TLR)-2, -4, -5, -7, and -8. Under normal conditions T reg are anergic, but are capable of direct proliferation in response to stimulation by TLR ligands, expressed on microbes and parasites. Treg removal enforces protective immune response to contagious microorganisms, including bacteria, viruses, and fungi, which leads to the elimination of pathogens from the host organism. The removal of Treg population will help to accomplish infectious pathogen elimination and diminish inflammation within a short period of time.

[The role of regulatory T-cells in autoimmune rheumatic diseases].

Regulatory T-cells CD4+CD25+Foxp3, possessing suppressory activity, play the key role in the development of autoimmune diseases, maintenance of peripheral tolerance in transplantation immunity, and the prevention of a pathological immune response to intestinal microflora or microbial infection. A decrease in the total number of circulating CD4+CD25+ regulatory T-cells and their suppressive activity have been found in patients suffering from various autoimmune diseases, such as type 1 diabetes, multiple sclerosis, autoimmune hepatitis, psoriatic arthritis, juvenile idiopathic arthritis, and systemic lupus erythematosus (SLE). The authors of this study investigated the phenotypic characteristics of peripheral blood lymphocytes in 31 SLE patients and the effect of treatment on the content of CD4+CD25+ T-cells before and after pulse therapy with methylprednisolone and cyclophosphan. The total number of regulatory T-cells in the group of untreated patients was almost twice lower vs. the group of healthy donors. As a result of the therapy, the proportion of regulatory T-cells increased significantly, although it did not reach the values in the control group. The data from this research confirm the development of a defect of CD4+CD25+ T-cells at the active phase of SLE, and a possibility to partially correct this defect with an effective therapy.

Neuroblastoma-derived gangliosides inhibit dendritic cell generation and function.

Neuroblastoma (NB), a tumor of the sympathetic nervous system, is the most common extracranial solid tumor in children. NB-derived gangliosides inhibit the functional activity of T and natural killer cells, contribute to tumor-induced bone marrow suppression, and cause multiple alterations of hematopoiesis, resulting in pancytopenia. However, the role of gangliosides in the regulation of dendritic cell (DC) generation (dendropoiesis) has not been studied. Using murine and human NB cell lines, we demonstrated that coincubation of murine bone marrow progenitors or human CD34+ progenitor cells with NB cells resulted in a significant inhibition of dendropoiesis in vitro up to 90%. The number of DCs was assessed by FACScan determination of CD83+ or CD11c+ cells coexpressing MHC class II and CD86 molecules. In addition, inhibition of antigen-presenting properties of DCs cultured in the presence of NB cells was observed in allogeneic mixed leukocyte reaction (33,508 +/- 1,613 cpm for control DCs versus 17,428 +/- 152 cpm for NB-treated DCs; P < 0.05). Treatment of NB cells with 10 microM DL-threo-1-phenyl-2-decanolylamine-3-morpholino-1-propanol HCl, an inhibitor of glucosylceramide synthase, markedly abrogated ganglioside synthesis and was accompanied by blockade of NB ability to inhibit dendropoiesis. Furthermore, purified gangliosides added to DC cultures significantly inhibited DC generation. The percentage of CD83+ cells decreased from 51.8 +/- 6.1% in the control group to 12.9 +/- 2.7% in cultures treated with GD2 (P < 0.05). Thus, our results demonstrate that NB-derived gangliosides inhibit the generation of functionally active DCs and may play a role in tumor-induced immunosuppression and subsequent tumor escape from immune recognition and elimination.

Human small cell lung carcinoma and carcinoid tumor regulate dendritic cell maturation and function.

The induction of apoptosis in dendritic cells (DC) is a key mechanism by which tumors escape immune recognition and elimination. In fact, a number of studies have showed the correlation between the number of DC within the tumor and the clinical prognosis, suggesting that increased infiltration of tumor tissue by DC was associated with better patient survival and low incidence of metastatic disease. We compared the number of DC and their distribution pattern in human small-cell lung carcinoma and bronchial carcinoid tumor (CT) tissues. Immunohistochemical analysis revealed the presence of cells expressing DC markers CD1a and CD83 in small-cell lung carcinoma tissues and the complete absence of these cells in CT samples. Next, we examined whether human lung tumor cells produce soluble factors that inhibit differentiation of hematopoietic precursors into mature DC. The addition of small-cell lung carcinoma-conditioned medium to CD34+ precursor cell cultures significantly inhibited colony-forming units of DC formation when compared with nontreated control DC cultures. Furthermore, DC generation and differentiation was completely abrogated in CD34+ cell cultures treated with CT-conditioned medium, suggesting that CT-derived factors blocked CD34+ cell differentiation into DC or induced their apoptosis. Finally, flow cytometry analysis of cultured DC confirmed these results. Thus, analysis of our data suggests that human lung tumors produce factors that inhibit DC generation or maturation and may also induce apoptotic death of DC precursors in vitro.

Cytokine-mediated protection of human dendritic cells from prostate cancer-induced apoptosis is regulated by the Bcl-2 family of proteins.

Prostate cancer is the most common cancer in men in the United States, and second in cancer-induced mortality. It is likely that tumour-induced immunosuppression is one of the reasons for low treatment efficacy in patients with advanced prostate cancer. It has been recently demonstrated that prostate cancer tissue is almost devoid of dendritic cells (DC), the major antigen-presenting cells responsible for the induction of specific antitumour immune responses. In this study, we have tested the hypothesis that prostate cancer induces progressive suppression of the DC system. We found that co-incubation of human DC with three prostate cancer cell lines led to the high levels of premature apoptosis of DC, which were significantly higher than in DC cultures co-incubated with normal prostate cells or blood leucocytes. Stimulation of DC for 24 hours with CD40 ligand (CD154), IL-12 or IL-15 prior to their co-incubation with prostate cancer cells resulted in a significant increase in DC survival in the tumour microenvironment. Furthermore, activation of DC with these cytokines was also accompanied by increased expression of the anti-apoptotic protein Bcl-x(L) in DC, suggesting a possible mechanism involved in DC protection from apoptotic death. In summary, our data demonstrate that prostate cancer induces active elimination of DC in the tumour microenvironment. Stimulation of DC by CD154, IL-12 or IL-15 leads to an increased expression of the anti-apoptotic protein Bcl-x(L) and increased resistance of DC to prostate cancer-induced apoptosis. These results suggest a new mechanism of tumour escape from immune recognition and demonstrate the cytokine-based approaches which might significantly increase the efficacy of DC-based therapies for cancer.

Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6.

Defensins contribute to host defense by disrupting the cytoplasmic membrane of microorganisms. This report shows that human beta-defensins are also chemotactic for immature dendritic cells and memory T cells. Human beta-defensin was selectively chemotactic for cells stably transfected to express human CCR6, a chemokine receptor preferentially expressed by immature dendritic cells and memory T cells. The beta-defensin-induced chemotaxis was sensitive to pertussis toxin and inhibited by antibodies to CCR6. The binding of iodinated LARC, the chemokine ligand for CCR6, to CCR6-transfected cells was competitively displaced by beta-defensin. Thus, beta-defensins may promote adaptive immune responses by recruiting dendritic and T cells to the site of microbial invasion through interaction with CCR6.

The generation of human dendritic and NK cells from hemopoietic progenitors induced by interleukin-15.

Interleukin-15 (IL-15) is a pleiotropic cytokine that induces the generation and differentiation of lymphoid cells and shares many biological activities with IL-2. We have shown here the development of dendritic cells (DC) from human CD34+ hemopoietic precursor cells cultured for 2-4 weeks with IL-15 alone. DC generated with IL-15 have typical morphological, immunocytochemical, phenotypic, and functional characteristics of mature DC. Dual flow cytometry analysis performed weekly demonstrated increasing co-expression of CD1a or CD83 with HLA-DR, CD80, CD86, IL-2R alpha, beta, and gamma. Two populations of cells were distinguished among CD34+ progeny. Small and medium-size cells were mainly natural killer (NK) cells (72.6-85.2% CD56+) and low numbers of DC (9.1-21.3% CD1a+). Large cells were mostly DC (75.4-95.4% CD1a+). Isolated CD34+ cells did not express IL-2R subunits but after 2-3 days in culture with IL-15, they were found to express IL-2Rgamma. Induced expression of IL-2Rgamma on CD34+ cells may explain the primary mechanism of IL-15-regulated differentiation of hemopoietic precursor cells. Thus, our data suggest that IL-15 stimulates CD34+ cells to differentiate into NK and DC and may represent a new growth and survival factor for lymphoid DC.