The function of the CD2 protein is abnormal in multiple sclerosis.

In active multiple sclerosis (MS), T cell adhesion to sheep red blood cells (SRBC) is deficient. The CD2 protein mediates adhesion to SRBC. Since ligands that bind CD2 can activate T cells, we studied adhesion and activation through CD2 in leukocytes from MS patients. Mononuclear cells (MNC) from patients with MS formed markedly fewer avid T cells (TA; T cells binding greater than or equal to 10 SRBC) than MNC from controls. CD2 antigen expression as measured by FACS analysis on T cells and on T cell subsets was equivalent in MS and controls and rose to a comparable extent in both groups after cell activation; yet activated MS MNC continued to form fewer TA than control cells. Avid rosette formation may be reduced by prostaglandins (PG) secreted by monocytes. Exposure to PG in vitro decreased TA% only in controls, suggesting refractoriness to exogenous PG in MS, perhaps because endogenous PG had already acted. The finding that indomethacin increased TA in MS cells favors this formulation. MNC were activated through CD2 using mAb 9-1 paired with mAb 9.6. Proliferation was significantly diminished in MNC from MS patients compared to MNC from normal controls. Thus, even though T cell membrane expression of CD2 appeared normal in MS, adhesion to SRBC and activation through the CD2 protein were defective.     

Intracellular signaling required for CCL25-stimulated T cell adhesion mediated by the integrin alpha4beta1

The alpha4beta1 integrin is expressed on thymocytes and mediates cell attachment to its ligands CS-1/fibronectin (CS-1/FN) and VCAM-1 in the thymus. The chemokine CCL25 is highly expressed in the thymus, where it binds to its receptor CCR9 on thymocytes promoting migration and activation. We show here that alpha4beta1 and CCR9 are coexpressed mainly on double- and single-positive thymocytes and that CCL25 strongly stimulates CD4(+)CD8(+) and CD4(+)CD8(-) adhesion to CS-1/FN and VCAM-1. CCL25 rapidly activated the GTPases Rac and Rap1 on thymocytes, and this activation was required for stimulation of adhesion, as detected using the CCR9(+)/alpha4beta1(+) human T cell line Molt-4. To study the role on CCL25-stimulated adhesion of the Rac downstream effector Wiskott-Aldrich syndrome protein family verproline-homologous protein 2 (WAVE2) as well as of Rap1-GTP-interacting proteins, regulator of adhesion and cell polarization enriched in lymphoid tissues (RAPL) and Rap1-GTP-interacting adapter molecule (RIAM), we knocked down their expression and tested transfectant attachment to alpha4beta1 ligands. We found that WAVE2 and RAPL but not RIAM were required for efficient triggering by CCL25 of T cell adhesion to CS-1/FN and VCAM-1. Although Rac and Rap1 activation was required during early steps of T cell adhesion stimulated by CCL25, WAVE2 was needed for the development of actin-dependent T cell spreading subsequent to adhesion strengthening but not during initial alpha4beta1-ligand interactions. These results suggest that regulation by CCL25 of adhesion of thymocyte subpopulations mediated by alpha4beta1 could contribute to control their trafficking in the thymus during maturation, and identify Rac-WAVE2 and Rap1-RAPL as pathways whose activation is required in inside-out signaling, leading to stimulated adhesion.     

Dual expression of CD45RA and CD45RO isoforms on myelin basic protein-specific CD4+ T-cell lines in multiple sclerosis

Myelin basic protein (MBP)-specific T-cell lines from patients with multiple sclerosis (MS) and healthy controls were analyzed for the expression of CD45 isoforms and adhesion molecules. In the multiple sclerosis group, 22 of 24 MBP-specific T-cell lines were CD4+. Two distinct patterns were observed with regard to CD45 isoform expression. Pattern I showed dual expression of CD45 isoforms (CD4+CD45RA+CD45RO+CD29+) and Pattern II included cells with a single CD45 isoform (CD4+CD45RA–CD45RO+CD29+). All 10 cell lines from healthy controls were CD4+ and displayed Pattern II (CD4+CD45RA–CD45RO+CD29+). The dual expression of CD45 isoform in T-cell lines from MS was stable, did not represent a transition stage from CD45RA to CD45RO, and was cell-cycle independent. All cell lines from MS and controls expressed increased levels of LFA-1 (CD11a), LFA-2 (CD2), LFA-3 (CD58), ICAM-1 (CD54), and VLA-4 (CDw49d). These data show the presence of unique MBP-specific T cells (CD4+CD45RA+CD45RO+CD29+) that might play a role in the pathogenesis of MS.     

TCR-induced downregulation of protein tyrosine phosphatase PEST augments secondary T cell responses

We report that the protein tyrosine phosphatase PTP-PEST is expressed in resting human and mouse CD4(+) and CD8(+) T cells, but not in Jurkat T leukemia cells, and that PTP-PEST protein, but not mRNA, was dramatically downregulated in CD4(+) and CD8(+) primary human T cells upon T cell activation. This was also true in mouse CD4(+) T cells, but less striking in mouse CD8(+) T cells. PTP-PEST reintroduced into Jurkat at levels similar to those in primary human T cells, was a potent inhibitor of TCR-induced transactivation of reporter genes driven by NFAT/AP-1 and NF-kappaB elements and by the entire IL-2 gene promoter. Introduction of PTP-PEST into previously activated primary human T cells also reduced subsequent IL-2 production by these cells in response to TCR and CD28 stimulation. The inhibitory effect of PTP-PEST was associated with dephosphorylation the Lck kinase at its activation loop site (Y394), reduced early TCR-induced tyrosine phosphorylation, reduced ZAP-70 phosphorylation and inhibition of MAP kinase activation. We propose that PTP-PEST tempers T cell activation by dephosphorylating TCR-proximal signaling molecules, such as Lck, and that down-regulation of PTP-PEST may be a reason for the increased response to TCR triggering of previously activated T cells.     

Role of cell-cell communication in inhibiting butyric acid-induced T-cell apoptosis

We have previously demonstrated that human gingival fibroblasts rescue butyric acid-induced T-cell apoptosis via proinflammatory cytokines such as interleukin 6 (IL-6) and IL-11, which are produced by fibroblasts stimulated with butyric acid. In this study, we determined if T-cell adhesion to human gingival fibroblasts influenced the susceptibility of T cells to butyric acid-induced apoptosis. We have shown that the number of Jurkat T cells adherent to gingival fibroblasts (Gin-1 cells) was significantly increased by the addition of butyric acid. All Jurkat cells that adhered to Gin-1 cells remained viable, while the nonadherent Jurkat cells dropped into apoptosis. The increase in T-cell adhesion to fibroblasts was also observed when Jurkat cells, but not Gin-1 cells, were pretreated with butyric acid. The expression levels of CD44, very late antigen 2 (VLA-2) and VLA-5 but not of leukocyte function-associated antigen 1 (LFA-1) and VLA-4 on Jurkat cells were increased following treatment with butyric acid. Furthermore, pretreatment of butyric acid-sensitized Jurkat cells with monoclonal antibodies against CD44, VLA-2, and VLA-5, but not LFA-1 and VLA-4, followed by coculture with Gin-1 cells inhibited T-cell adhesion to fibroblasts and increased apoptosis of nonadherent T cells after coculture of gingival fibroblasts and Jurkat cells. These results indicate that T-cell adherence to fibroblasts is enhanced by butyric acid and that butyric acid-induced T-cell apoptosis is down-regulated by T-cell adhesion to gingival fibroblasts through an interaction with the adhesion molecules CD44, VLA-2, and VLA-5 expressed on T cells stimulated with butyric acid.     

Decrease of CD4(+)CD25(high)Foxp3(+) regulatory T cells and elevation of CD19(+)BAFF-R(+) B cells and soluble ICAM-1 in myasthenia gravis

Myasthenia gravis (MG) is caused by T-cell-dependent autoantibodies against muscle acetylcholine receptors (AChR) at the neuromuscular junction. Here, we adopted ELISA and flow cytometry techniques to measure the levels of Th1, Th2, Th3 cytokines, inflammatory cytokine and chemokine sICAM-1 and to analyze the phenotypes of CD4(+) and CD8(+) regulatory cells as well as the expression of BAFF-R on CD19(+) B cells in peripheral blood from 75 MG patients and 50 healthy controls. There were no differences in the levels of IL-2, IL-4, IL-10, IL-13, IFN-gamma, TNF-alpha, TGF-beta and sCTLA-4 in both sera and culture supernatants between MG patients and healthy controls. The level of IL-12 was decreased in culture supernatants from MG patients, and the level of sICAM-1 was increased in both sera and culture supernatants from MG patients. Although the populations of CD8(+)CD28(-) and CD8(+)CD122(+) regulatory T cells were not different between MG patients and healthy controls, MG patients exhibited the decrease of CD4(+)CD25(high)Foxp3(+) regulatory T cells and the increase of CD19(+)BAFF-R(+) B cells, revealing that MG patients should display the dysfunction of T cell balance and the activation of B cell maturation.     

Increased soluble 4-1BB ligand (4-1BBL) levels in peripheral blood of patients with multiple sclerosis

4-1BB ligand (4-1BBL; CD137L) is a member of the tumour necrosis factor superfamily expressed primarily on antigen presenting cells such as B cells, macrophages and dendritic cells. Its engagement with the receptor 4-1BB (CD137) has been shown to promote T-cell activation and regulate proliferation and survival of T cells. The role of the costimulatory molecule in multiple sclerosis (MS) remains unclear. In this study, the expression of 4-1BBL and soluble 4-1BBL (s4-1BBL) protein levels were analysed in peripheral blood of MS patients. Compared with healthy controls, MS patients had an increase in both plasma s4-1BBL protein levels and expression of 4-1BBL in CD14(+) monocytes. In contrast, myelin basic protein-reactive T-cell proliferation was not found to be inhibited by the use of an anti-4-1BBL antibody. The elevated s4-1BBL protein levels in the MS patients may function as a self-regulatory mechanism of 4-1BB/4-1BBL interaction and costimulation.     

The T-cell pool is anergized in patients with multiple sclerosis in remission

Relapsing-remitting multiple sclerosis (RRMS) is a complex autoimmune disease of the central nervous system with oscillating phases of relapse and remission. RRMS has been considered to be driven by T helper type 1 (Th1) lymphocytes but new data indicate the involvement of Th17 responses. In the present study, blood samples from patients (n=48) and healthy individuals (n=44) were evaluated for their immunological status. T cells from patients with RRMS expressed high levels of the activation marker CD28 (P<0.05) and secreted both interferon-gamma (CD8: P<0.05) and interleukin-17 upon polyclonal mitogen or myelin oligodendrocyte glycoprotein antigen stimulation. However, T cells from patients with RRMS in remission, in contrast to relapse, had poor proliferative capacity (P<0.05) suggesting that they are controlled and kept in anergy. This anergy could be broken with CD28 stimulation that restored the T-cell replication. Furthermore, the patients with RRMS had normal levels of CD4(+) Foxp3(+) T regulatory cells but the frequency of Foxp3(+) cells lacking CD127 (interleukin-7 receptor) was lower in patients with MS (mean 12%) compared to healthy controls (mean 29%). Still, regulatory cells (CD25(+) sorted cells) from patients with RRMS displayed no difference in suppressive capacity. In conclusion, patients in relapse/remission demonstrate in vitro T-cell responses that are both Th1 and Th17 that, while in remission, appear to be controlled by tolerogenic mechanisms yet to be investigated.     

Syncytin-1/HERV-W envelope is an early activation marker of leukocytes and is upregulated in multiple sclerosis patients

Syncytin-1 is the envelope protein of the human endogenous retrovirus W (HERV-W). It has been related to multiple sclerosis (MS) but its role in cellular immunity and its pathogenic mechanism in the autoimmune context are not fully understood. We analyzed syncytin-1 levels in peripheral blood mononuclear cells (PBMC) subsets from healthy donors, MS patients in relapse or remission, and patients with acute infections by flow cytometry. PBMC cultures were also prepared to analyze protein expression kinetics. MS patients had higher levels of syncytin-1 levels than controls. We found that syncytin-1 is elevated in monocytes during MS relapses and infections. Cells expressing syncytin-1, including monocytes, T and B lymphocytes, and NKs presented mainly an activated phenotype and, upon stimulation with LPS, its levels increased rapidly on antigen-presenting cells. Syncytin-1 ligation promoted the activation of monocytes, as demonstrated by the upregulation of CD80 and the nonclassical subset CD14^low CD16⁺. Our results suggest an important role for syncytin-1 in the activation of leukocytes. Given that the expression of syncytin-1 is upregulated in MS patients, this protein might be contributing to the autoimmune cascade in the disease.     

The CD14+CD16+ monocytes in erysipelas are expanded and show reduced cytokine production

In human peripheral blood the classical CD14(++)DR(+) monocytes and the pro-inflammatory CD14(+)CD16(+)DR(++) monocytes can be distinguished. In erysipelas we found strongly increased numbers of CD14(+)CD16(+) monocytes on the day of diagnosis (day 1) in 11 patients with an average of 150.5+/-76.0 cells/microl, while 1 patient had low levels (35 cells/microl, control donors 48.8+/-19.8 cells/microl). The classical monocytes were only moderately elevated in the erysipelas patients (factor 1.7 as compared to controls). Patients exhibited increased body temperature, erythrocyte sedimentation rate and increased serum levels for C-reactive protein (CRP), IL-6 and macrophage-colony-stimulating factor. Among these, body temperature and CRP showed a significant correlation to the numbers of CD14(+)CD16(+) monocytes. In 4 of 4 patients with high levels of CD14(+)CD16(+) monocytes, these levels returned to that seen in controls by day 5 of antibiotic therapy. Determination of intracellular TNF was performed by three-color immunofluorescence and flow cytometry after ex vivo stimulation with lipoteichoic acid, a typical constituent of streptococci. Here, patient CD14(+)DR(++) pro-inflammatory monocytes showed a twofold lower level of intracellular TNF. By contrast, expression of TNF was unaltered in the classical CD14(++) monocytes. These data show that in erysipelas the pro-inflammatory CD14(+)CD16(+)DR(++) monocytes are substantially expanded and selectively tolerant to stimulation by streptococcal products.     

Alpha4beta1 and alpha4beta7 CD4 T cell numbers increase and CLA CD4 T cell numbers decrease in systemic sclerosis

We studied the expression of adhesion molecules affecting recirculation and homing on peripheral blood CD4(+) T cells of patients with systemic sclerosis (SSc), in order to evaluate whether the distribution of tissue targeted subsets could reflect the participation of internal organs or the extent of cutaneous involvement [i.e. limited cutaneous (lc) and diffuse cutaneous (dc)]. Peripheral blood mononuclear cells (PBMC) from 51 patients with SSc and 19 sex- and age-matched controls were investigated by cytofluorimetric analysis for lymphocyte subpopulations carrying the following surface molecules: CD3, CD4, CLA, alpha4beta7 and alpha4beta1. Standard routine biochemistry and clinical examinations were also performed in all patients. We found that both alpha4beta1(+) and alpha4beta7(+) cells within the CD4(+) T cell population were significantly increased, while CLA(+) CD4(+) T cells were significantly reduced in SSc, compared to healthy donors. Significantly lower absolute numbers of alpha4beta7(+) cells were found in lc- compared to dc-SSc. Patients with oesophageal involvement had high numbers of alpha4beta7(+) cells, while those with nephritis also showed low levels of CLA(+) cells. Lung involvement was related directly to alpha4beta1(+) cell numbers and inversely to alpha4beta7(+) CD4 cell numbers. Taken together, our findings demonstrate that distinct CD4(+) T cell populations with selective homing properties show changes from normal distribution in SSc, and such changes are related to clinical expression and organ involvement in the course of the disease.     

Expression of nonmuscle cofilin-1 and steroid responsiveness in severe asthma

BACKGROUND: Glucocorticoids are the mainstay of asthma therapy; however, a proportion of patients with asthma has a severe form of the disease that fails to respond to therapy. Understanding the molecular mechanisms behind glucocorticoid-insensitive asthma is therefore of clinical importance. Evidence in glucocorticoid-unresponsive Henrietta Lack (HeLa) cells indicated that cofilin-1 could act as an inhibitor of glucocorticoid function. OBJECTIVE: To determine whether cofilin-1 expression is abnormally expressed in cells from patients with severe glucocorticoid-insensitive asthma and examine the effect of cofilin-1 overexpression on glucocorticoid function. METHODS: Peripheral blood CD4(+) T cells were purified from 16 subjects with severe glucocorticoid-insensitive asthma and 16 subjects with mild glucocorticoid-sensitive asthma, and cofilin-1 expression was determined by quantitative real-time RT-PCR and Western blotting. The effect of dexamethasone on cofilin-1 expression was determined in Jurkat T cells, and the effect of cofilin-1 overexpression on anti-CD3/CD28-stimulated IL-2 release was measured. RESULTS: Peripheral blood CD4(+) T cells from subjects with severe glucocorticoid-insensitive asthma are less responsive to dexamethasone than cells from subjects with mild glucocorticoid-sensitive asthma. Cells from these patients express significantly (P < .05) higher levels of cofilin-1 than cells from subjects with mild asthma. Dexamethasone did not affect cofilin-1 expression in Jurkat T cells. Functionally, dexamethasone suppression of anti-CD3/CD28-stimulated IL-2 was attenuated in Jurkat cells overexpressing cofilin-1. CONCLUSION: These results suggest that increased cofilin-1 expression may be important in the regulation of glucocorticoid sensitivity in peripheral blood lymphocytes of patients with severe treatment-insensitive asthma. CLINICAL IMPLICATIONS: Understanding the mechanisms of enhanced cofilin-1 expression may lead to the development of new therapies for severe treatment-insensitive asthma.     

Haem oxygenase 1 expression is altered in monocytes from patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple functional alterations affecting immune cells, such as B cells, T cells, dendritic cells (DCs) and monocytes. During SLE, the immunogenicity of monocytes and DCs is significantly up-regulated, promoting the activation of self-reactive T cells. Accordingly, it is important to understand the contribution of these cells to the pathogenesis of SLE and the mechanisms responsible for their altered functionality during disease. One of the key enzymes that control monocyte and DC function is haem oxygenase-1 (HO-1), which catalyses the degradation of the haem group into biliverdin, carbon monoxide and free iron. These products possess immunosuppressive and anti-inflammatory capacities. The main goal of this work was to determine HO-1 expression in monocytes and DCs from patients with SLE and healthy controls. Hence, peripheral blood mononuclear cells were obtained from 43 patients with SLE and 30 healthy controls. CD14(+) monocytes and CD4(+) T cells were sorted by FACS and HO-1 expression was measured by RT-PCR. In addition, HO-1 protein expression was determined by FACS. HO-1 levels in monocytes were significantly reduced in patients with SLE compared with healthy controls. These results were confirmed by flow cytometry. No differences were observed in other cell types, such as DCs or CD4(+) T cells, although decreased MHC-II levels were observed in DCs from patients with SLE. In conclusion, we found a significant decrease in HO-1 expression, specifically in monocytes from patients with SLE, suggesting that an imbalance of monocyte function could be partly the result of a decrease in HO-1 expression.     

Lck tyrosine kinase is important for activation of the CD11a/CD18-integrins in human T lymphocytes

CD11a/CD18 (beta2)-integrins are expressed on leukocytes and are involved in cell adhesion and signaling. Despite extensive studies the signaling pathways and molecular mechanisms involved in integrin regulation in T cells remain not completely understood. We have now studied the involvement of the tyrosine kinase Lck in the regulation of CD11a/CD18 function in Jurkat T cells. Using the Src-family kinase inhibitor PP2, we found that CD3 ligation-induced adhesion to ICAM-1 was inhibited by PP2 at the same concentration required for complete inhibition of the MAP kinase pathway, implicating a role for Lck in integrin activation. We therefore used the Lck-deficient Jurkat cell line JCaM1.6 to further examine the involvement of Lck in integrin regulation. Interestingly, JCaM1.6 cells showed dramatically reduced levels of both CD3- and phorbol ester-induced adhesion to coated ICAM-1 as compared to normal Jurkat cells. By using flow cytometry and cell surface labeling, it was found that the surface expression of the CD11a/CD18-integrins was significantly lower in Lck-deficient T cells as compared to normal Jurkat cells. CD18 was expressed as a mature and an immaturely glycosylated form in Jurkat T cell lines, and predominantly the immature form, not associated with CD11a, was found in Lck-deficient cells. Retransfection of human Lck in JCaM1.6 cells restored adhesion. Thus, Lck is involved in regulating CD11a/CD18-integrins in T cells.     

Circulating CD4+CD25+ T Regulatory Cells Are Not Altered in Multiple Sclerosis and Unaffected by Disease-Modulating Drugs

Experimental animal models for autoimmunity have demonstrated the existence and crucial role of CD4(+)CD25(+) T regulatory (Tr) cells in suppressing autoreactive T cells and promoting peripheral tolerance. Recent in vitro functional studies showed that Tr cells are enriched in the CD25(high) cell population among CD4(+) T cells, and that they totally inhibit proliferation and cytokine secretion by CD4(+) T cells. It is not yet known if circulating Tr cells are involved in multiple sclerosis (MS). This study was done firstly to determine whether alterations of the CD4 (+) CD25(high) T cells occur in MS, examining their frequencies. As it was reported that the suppressive activity of CD4(+)CD25(+) Tr cells is mainly through cell surface contact pathway, we secondly analyzed the expression of the functionally important cell surface molecules of CD4(+)CD25(high) Tr cells. Two- or three-colour flow cytometry was used to identify and quantify CD4(+)CD25(+) Tr cells and CD4(+)CD25(high) Tr cells among blood CD4(+) T cells in MS patients without treatment vs. patients treated with either interferon-beta (IFN-beta) or glatiramer acetate (GA) or IFN-beta + GA in combination vs. healthy controls (HC). Expression of functionally important surface molecules CD45RO, CD69, CD95, HLA-DR, and intracellular CTLA-4 and IL-10 production by CD4(+)CD25(high) Tr cells were investigated. CD4(+)CD25(+) T cells constituted around 6% of CD4(+)T cells in all MS patient groups, and 7% in HC. There were also no changes in the proportions of CD4(+)CD25(+) Tr cells and CD4(+)CD25(high) Tr cells in a longitudinal follow-up of MS patients before and during IFN-beta treatment. Frequencies of circulating CD4(+)CD25(high)Tr cells among CD4(+) T cells were also similar and their surface or intracellular molecular expression did not vary in MS patients, irrespective of treatment, compared to HC. This study suggests that levels of circulating CD4(+)CD25(+) Tr cells and CD4(+)CD25(high) Tr cells are not altered in MS, and are unaffected by substances currently used to modulate the disease.     

Alterations in T-lymphocyte sub-set profiles and cytokine secretion by PBMC of systemic lupus erythematosus patients upon in vitro exposure to organochlorine pesticides

Chronic exposure to organochlorine pesticides (OCP) has been suspected of causing immunoregulatory abnormalities that eventually lead to development and progression of systemic lupus erythematosus (SLE), but the role of these non-genetic stimuli has remained poorly understood. The objectives of the study were to quantify the levels of different OCP residues in the blood of SLE patients and to study the effects of in vitro treatment of peripheral blood mononuclear cells (PBMC) from these patients and healthy controls with OCP. Levels of different OCP residues in the blood were measured by gas-liquid chromatography. Isolated PBMC were treated in vitro with hexachlorocyclohexane (HCH), o,p'-dichlorodiphenyltrichloroethane (DDT), or phytohemagglutinin-M (PHA-M) for 72 h, then stained with different dye-labeled monoclonal antibodies to analyze alterations in T-lymphocytes using flow cytometry. Levels of different T(H)1 and T(H)2 cytokines were also estimated by ELISA. Significantly higher levels of p,p'-DDE and β-HCH were detected in the blood of SLE patients than in healthy controls. HCH exposure markedly increased the percentages of CD3(+)CD4(+) T-lymphocytes and expression of CD45RO(+) on CD4(+) and CD8(+) T-lymphocytes, but decreased CD4(+)CD25(+) T-lymphocytes in SLE patients. DDT exposure increased the percentages of CD3(+)CD4(+) T-lymphocytes and decreased those of CD4(+)CD25(+) T-lymphocytes in SLE patients as compared to healthy controls. No significant responsiveness of patient PBMC to PHA-M stimulation was observed indicating suppression of T-lymphocytes by these OCP. Further, both HCH and DDT decreased the levels of IL-2 and IFNγ but had no effect on IL-4 levels in SLE patients. DDT also increased significantly the levels of IL-10 in patients. It is likely that higher levels and prolonged durations of exposure to HCH and DDT may significantly influence T-lymphocyte sub-sets and cytokine expression in vivo that could lead to the development or exacerbation of SLE.     

The role of CD4+CD25+ regulatory T cells in patients with Rheumatoid Arthritis]

CD4(+)CD25(+) regulatory T cells play an important role in preventing autoimmunity. We investigated the presence of CD4(+)CD25(+) regulatory T cells in the peripheral blood of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic sclerosis (SSc), using flow cytometry. The percentage of CD4(+)CD25(+) regulatory T cells was significantly decreased in RA, especially in patients with high serum levels of either CRP or MMP-3. In SSc and SLE, the percentage of CD4(+)CD25(+) regulatory T cells was higher in patients than in controls, but not significant. We also investigated the serum levels of IL-10, which influences the function of CD4(+)CD25(+) regulatory T cells and other regulatory T cells. In RA, on contrast to CD4(+)CD25(+) regulatory T cells, the serum levels of IL-10 increased in patients with higher serum levels of CRP, or MMP-3. In SLE and SSc, the serum level of IL-10 increased significantly in patients than in controls. These data thus indicated that CD4(+)CD25(+) regulatory T cells contributes to occurrence and progression of RA, and other regulatory T cells or cytokines contribute to occurrence and progression of SSc and SLE.