High percentage of CD8+, Leu-7+ cells in rheumatoid arthritis synovial fluid.

OBJECTIVE. While analyzing the phenotype of the synovial fluid mononuclear cells (SFMC) clustered about dendritic cells in rheumatoid arthritis (RA) joint effusions, it was noted that most of the clustering cells were CD8+ and coexpressed Leu-7. Therefore, the present study was conducted to investigate the frequency of CD8+, Leu-7+ cells in RA SF. METHODS. SFMC from 13 patients with RA and from 12 patients with non-RA inflammatory arthritides were examined for CD8 and Leu-7 expression using 2-color immunofluorescence flow cytometry. RESULTS. RA SFMC had statistically significantly greater percentages of total CD8+ cells, total Leu-7+ cells, and CD8+, Leu-7+ cells, compared with SFMC from the non-RA patients. These RA CD8+, Leu-7+ SFMC had a distinctive electron microscopic appearance compared with CD8+, Leu-7- SFMC. When peripheral blood mononuclear cells (PBMC) from 31 RA patients (including 7 from the SFMC group) were compared with PBMC from 15 normal controls, the percentage of CD8+, Leu-7+ cells was not significantly greater in the RA patients. However, the combination of a modest increase in CD8+, Leu-7+ cells and a decrease in total CD8 cells in RA PBMC altered the composition of the RA CD8 population compared with normal PBMC, such that over 40% of RA peripheral blood CD8 cells coexpressed Leu-7. CONCLUSION. The increased frequency of CD8+, Leu-7+ cells in RA SFMC may arise from the fact that a high percentage of the CD8+ PBMC in RA patients are also Leu-7+. This altered composition of CD8 cells in RA SF may have a role in the pathogenesis of the disease.     

High percentage of CD8+, Leu-7+ cells in rheumatoid arthritis synovial fluid

Objective. While analyzing the phenotype of the synovial fluid mononuclear cells (SFMC) clustered about dendritic cells in rheumatoid arthritis (RA) joint effusions, it was noted that most of the clustering cells were CD8+ and coexpressed Leu-7. Therefore, the present study was conducted to investigate the frequency of CD8+, Leu-7+ cells in RA SF. Methods. SFMC from 13 patients with RA and from 12 patients with non-RA inflammatory arthritides were examined for CD8 and Leu-7 expression using 2-color immunofluorescence flow cytometry. Results. RA SFMC had statistically significantly greater percentages of total CD8+ cells, total Leu-7+ cells, and CD8+, Leu-7+ cells, compared with SFMC from the non-RA patients. These RA CD8+, Leu-7+ SFMC had a distinctive electron microscopic appearance compared with CD8+, Leu-7– SFMC. When peripheral blood mononuclear cells (PBMC) from 31 RA patients (including 7 from the SFMC group) were compared with PBMC from 15 normal controls, the percentage of CD8+, Leu-7+ cells was not significantly greater in the RA patients. However, the combination of a modest increase in CD8+, Leu-7+ cells and a decrease in total CD8 cells in RA PBMC altered the composition of the RA CD8 population compared with normal PBMC, such that over 40% of RA peripheral blood CD8 cells coexpressed Leu-7. Conclusion. The increased frequency of CD8+, Leu-7+ cells in RA SFMC may arise from the fact that a high percentage of the CD8+ PBMC in RA patients are also Leu-7+. This altered composition of CD8 cells in RA SF may have a role in the pathogenesis of the disease.     

Mechanisms of CD23 hyperexpression on B cells from patients with rheumatoid arthritis.

OBJECTIVE: To analyze the mechanisms involved in the characteristic hyperexpression of CD23 on peripheral blood B cells from patients with rheumatoid arthritis (RA). METHODS: Peripheral blood mononuclear cells (PBMC) were obtained from patients with active disease and activated during 18 h with an anti-CD3 monoclonal antibody in the presence or absence of blocking antibodies to CD154 or CD40. PBMC were further purified by rosetting and CD23 expression was assessed on B cells by flow cytometry after double staining (CD19/CD23). Lymphocytes were also isolated from synovial fluid (SF). CD154 expression was analyzed on PB or SF CD4+ T cells after double staining (CD4/CD154) by flow cytometry at basal conditions and after different stimuli [anti-CD3 or phorbol myristic acetate (PMA) plus ionomycin]. Co-culture experiments between SF and PB cells were performed to analyze the involvement of the CD40-CD154 interaction on CD23 expression. CD154 and CD23 expression was also analyzed on synovial membrane by immunohistochemical techniques. RESULTS: A high proportion of activated CD23 B cells was detected in patients with RA. Blocking experiments with both anti-CD40 and anti-CD154 Mab showed a significant reduction in the proportion of PB B cells expressing CD23. Following activation with anti-CD3 Mab or PMA plus ionomycin, CD154 expression was mainly induced on PB CD4+ T cells. In co-culture experiments, SF T cells were more efficient than PB T cells in inducing CD40 dependent CD23 expression on PB B cells. In addition, CD4+ T cells from synovial membrane clearly expressed CD154. CONCLUSION: Our results establish a link between CD154-CD40 pathway and CD23 expression on PB B cells from patients with RA. T cells from the synovial microenvironment were active participants in this CD23 expression, presumably in the context of cell recirculation.     

A study of the effect of rheumatoid synovial fluid on proliferation and IL-2 production by total mononuclear cells and purified CD4+ cells of synovial fluid and peripheral blood

T cells from synovial fluid (SF) of rheumatoid arthritis (RA) patients have previously been shown to proliferate less after mitogenic stimulation and produce less interleukin 2 (IL-2) than normal T cells. To test whether SF is responsible for the reduced T-cell responses, we studied the effect of inflammatory SF on peripheral blood (PB) RA and normal mononuclear cells (MNC) and CD4+ T cells and on RA SF MNC and CD4+ cells in vitro. Most rheumatoid SF present in concentrations of 50% and 5% during in vitro stimulation increased mitogen-induced IL-2 production and proliferative response by normal PB and RA MNC and CD4+ cells. Other rheumatoid SF samples did not influence the T cell responses, while only a few samples had an inhibitory effect. The results indicate that SF contain both stimulatory and inhibitory factors and that the resultant effect on T cells may depend on the net effect of these. The results do not support the hypothesis that the apparently impaired function of SF T cells is due to contact with SF.     

T lymphocytes in the synovial fluid of patients with active rheumatoid arthritis display CD134-OX40 surface antigen.

OBJECTIVE: To assess the percentage of T lymphocytes, bearing CD134, a member of the TNF receptor superfamily, primarily found on autoreactive CD4+ T cells in the peripheral blood (PB) and synovial fluid (SF) of rheumatoid arthritis (RA) patients. METHODS: The surface expression of CD134 on SF and PB mononuclear cells was performed by flow cytometry in 25 RA patients and correlated to the disease activity. RESULTS: CD134 expression on CD3+, CD4+, CD8+ and CD25+ cells was higher in SF than in PB of RA patients (P < 0.001). No differences were observed in the percentage of CD134+/CD4+ T lymphocytes in the PB of RA patients and controls. Patients with active RA had significantly higher percentage of CD3+/CD134+, CD4+/CD 134+, CD8+/CD134+ and CD25+/CD 134+ than those with inactive disease. CONCLUSION: These findings suggest that CD134+ T cells are involved in the immunopathological process of RA synovitis, maybe mirroring some other autoimmune disease in which autoreactive T cell infiltrating the target tissues largely coexpress CD134.     

The CD69 activation pathway in rheumatoid arthritis synovial fluid t cells

Objective. To study the CD69 activation pathway in synovial fluid (SF) T lymphocytes from patients with rheumatoid arthritis (RA). Methods. Peripheral blood mononuclear cells (PBMC) or SF mononuclear cells (SFMC) were used in proliferation assays with anti-CD69, anti-CD28, anti-CD3, phorbol myristate acetate (PMA), and/or recombinant interleukin-2 (IL-2). CD69+, CD69—, and resting SF T cells were also proliferated. CD25 expression and production of IL-2 after CD69 activation were assessed by flow cytometry and in a bioassay with the IL-2-dependent cell line CTLL-2. Results. RA SFMC did not proliferate either in the presence of anti-CD69 monoclonal antibodies alone or with concomitant PMA activation, when compared with paired or control PBMC. Similar low proliferative responses via the CD3 or CD28 pathway with PMA were observed. This defective proliferation of RA SFMC after stimulation through the CD69 molecule was explained in part by a failure to express CD25 and to produce IL-2. SF CD69- T cells and resting SF T cells had higher rates of proliferation through the alternative costimulatory pathway CD28 than did SF CD69+ T cells or freshly isolated SF T cells. Conclusion. Freshly isolated SF T cells present a profound state of hyporesponsiveness through the CD69 and CD28 costimulatory pathways. This state appears to be dependent on the activation status of SF T cells, since CD69— and resting SF T cells showed recovery of the ability to proliferate through the CD28 activation pathway.     

Overexpression of osteopontin in rheumatoid synovial mononuclear cells is associated with joint inflammation, not with genetic polymorphism

OBJECTIVE: Osteopontin (OPN) is thought to play an important role in rheumatoid synovitis. We investigated the expression of OPN in rheumatoid synovial fluid mononuclear cells (SFMC) and its potential association with genetic polymorphism of the OPN gene and joint inflammation in rheumatoid arthritis (RA). METHODS: 1. The expression of OPN mRNA in peripheral blood mononuclear cells (PBMC) and SFMC of patients with RA was analyzed quantitatively by real-time polymerase chain reaction (PCR). Results were analyzed in paired PBMC and SFMC and control PBMC. 2. Six single nuclear acid polymorphisms of the OPN gene were genotyped in a cohort of 192 Chinese patients with RA and controls (n = 288) by restriction fragment length polymorphism PCR or direct DNA sequencing. 3. SF derived from RA patients was examined for the stimulating effect on mRNA expression of the OPN gene in PBMC. RESULTS: The expression of OPN gene was significantly increased in SFMC and, to a lesser degree, in PBMC of patients with RA compared to control PBMC (p < 0.01). However, the prevalence of OPN genotype and allele frequencies at the selected positions did not differ significantly between RA patients and the control group (p > 0.05). Further characterization indicated that SF known to contain a variety of proinflammatory factors significantly stimulated mRNA expression of OPN in PBMC obtained from RA patients or healthy controls. CONCLUSION: Overexpression of OPN mRNA in SFMC is associated with proinflammatory factors produced in inflamed joints, but not with OPN genetic polymorphisms. OPN gene polymorphisms do not correlate with susceptibility to RA.     

Differences in responses of normal and rheumatoid arthritis peripheral blood T cells to synovial fluid and peripheral blood dendritic cells in allogeneic mixed leukocyte reactions

We examined the response of normal T cells to dendritic cells isolated from the synovial fluid (SF) of patients with either rheumatoid arthritis (RA) or seronegative spondylarthropathies (rheumatoid variants) and to dendritic cells from normal and RA peripheral blood (PB) in the allogeneic mixed leukocyte reaction. Despite the differences in the response kinetics, the stimulatory capacity of SF dendritic cells was similar to that of PB dendritic cells in a 7-day mixed leukocyte reaction. We also tested the responsiveness of normal and RA PB T cells to various allogeneic dendritic cells and found that RA PB T cells responded poorly to both rheumatoid variant SF dendritic cells and normal PB dendritic cells. However, when dendritic cells from RA SF were used as stimulators, the response of RA PB T cells was significantly greater than that of normal PB T cells (P less than 0.02). This difference in response was explained in part by a proliferation of the CD8 T cell subset. There was also a shift of low-intensity CD4+, CDw29+ cells to high-intensity CD4+, CDw29+ cells seen in RA PB T cells but not in normal PB T cells, by fluorescence-activated cell sorter analysis.     

Increased helper inducer and decreased suppressor inducer phenotypes in the rheumatoid joint

Cells isolated from the joints of patients with rheumatoid arthritis (RA) exhibit functional immune abnormalities, such as diminished suppressor activity, depressed response to mitogens, and enhanced immunoglobulin production. We sought to characterize the T lymphocyte subsets in the synovial fluid (SF) and peripheral blood (PB) of RA patients in an attempt to clarify the mechanism(s) responsible for these functional immune abnormalities. We used dual-immunofluorescence staining techniques with several combinations of monoclonal antibodies, including anti-4B4 and anti-2H4, which define, respectively, the helper inducer and suppressor inducer subsets of CD4+ (Leu-3+ and T4+) cells. Mononuclear cells from normal PB (n = 9), RA PB (n = 6), and RA SF (n = 9) were analyzed, after staining, by flow cytometry. We observed a significant increase (P less than 0.0002) in the number of cells bearing the helper inducer phenotype (CD4+, 4B4+), and a significant decrease (P less than 0.0002) in the number of cells bearing the suppressor inducer phenotype (CD4+, 2H4+), in RA SF compared with the levels in PB from RA patients or normal control subjects. We also observed that the CD8+, 2H4+ subset was significantly decreased (P less than 0.0001) in SF compared with that in PB. There was no significant difference in the lymphocyte subset levels in PB from RA patients and from normal subjects. These observations may account, in part, for the reduced suppressor activity, the poor response to mitogens, and the autologous mixed lymphocyte reaction, as well as the enhanced production of Ig and rheumatoid factor, that are observed in the rheumatoid joint.     

Expression and function of inducible costimulator on peripheral blood T cells in patients with systemic lupus erythematosus

OBJECTIVE: To investigate the role of inducible costimulator (ICOS) in the pathogenesis of SLE, we assessed its expression on peripheral blood CD4 and CD8 T cells and functional roles in patients with systemic lupus erythematosus (SLE). METHODS: Expression of ICOS on peripheral blood CD4 and CD8 T cells and ICOS ligand (ICOSL) on peripheral blood CD19 B cells from patients with SLE, patients with rheumatoid arthritis (RA) and healthy volunteers were determined by two-colour flow cytometry. The functional costimulatory effects of ICOS on peripheral blood mononuclear cells (PBMC) were assessed by T-cell proliferative responses, cytokines, anti-double-stranded DNA (anti-dsDNA) antibody and total IgG production. RESULTS: Peripheral blood CD4 and CD8 T cells expressing ICOS were significantly increased in patients with SLE compared with patients with RA and healthy subjects. Peripheral blood CD19 B cells expressing ICOSL in SLE were markedly reduced compared with RA. Proliferative responses of anti-CD3/ICOS costimulation were significantly higher than those of anti-CD3/hamster IgG (HIgG) in healthy subjects, but not in patients with SLE. Anti-CD3/ICOS-stimulated SLE PBMC secreted similar levels of IL-10 and IFN-gamma but a significantly lower level of IL-2 than healthy PBMC. Anti-CD3/ICOS-mediated costimulation significantly enhanced the production of anti-dsDNA antibodies and total IgG in patients with SLE. CONCLUSION: Hyperexpression of ICOS on peripheral blood CD4 and CD8 T cells from patients with SLE contributed to the dysregulated T-cell proliferation, T-cell activation and pathogenic autoantibody production, which showed that the abnormality of ICOS costimulation may play an immunopathological role(s) in the pathogenesis of SLE.     

Interleukin 7 stimulates tumour necrosis factor alpha and Th1 cytokine production in joints of patients with rheumatoid arthritis

BACKGROUND: A large number of activated T cells are found in the joints of patients with rheumatoid arthritis (RA). Interleukin 7 (IL7), a T cell growth factor and a regulator of Th1 and Th2 cytokine production, is produced by synoviocytes from patients with RA. OBJECTIVE: To investigate the effect on proinflammatory cytokine production of synovial fluid mononuclear cells (SFMC) and the mechanism by which IL7 influences CD4+ T cell activity in patients with RA. METHODS: In a cross sectional group of patients with RA, IL7 levels were compared with those of healthy controls and related to disease activity. The effect of IL7 on cytokine production was tested by RA SFMC and on SF CD4+ T cells in the presence of mononuclear cells (MC). Production of tumour necrosis factor alpha (TNF alpha), IL1 beta, interferon gamma (IFN gamma), and IL4 was measured by enzyme linked immunosorbent assay (ELISA) and by single cell FACS analysis. Expression of the IL7 receptor alpha chain on CD4+ T cells (essential for IL7 signalling) was assessed. Direct effects of IL7 on isolated synovial fluid (SF) CD4+ T cells were studied by cytokine analysis. By neutralisation of IL12 in MC cultures, indirect effects of IL7 on T cells through accessory cells were studied. RESULTS: IL7 serum levels were higher in patients with RA than in healthy controls and correlated positively with C reactive protein levels. IL7 stimulated TNFalpha production by SFMC and very potently stimulated IFN gamma and TNF alpha production by SF CD4+ T cells. These effects were probably mediated through the IL7 receptor alpha chain, which was abundantly expressed on SF CD4+ T cells. Besides the direct stimulation of T cell cytokine production by IL7, its action was partly dependent on IL12, indicating that IL7 also stimulates accessory cell function, leading to T cell activation. CONCLUSION: IL7 stimulates proinflammatory cytokine production of intra-articular CD4+ T cells and accessory cells from patients with RA. The correlation with measures of disease activity indicates that IL7 might substantially contribute to the perpetuation of Th1 and TNF alpha mediated proinflammatory responses in patients with RA.     

Shift toward T helper 1 cytokines by type II collagen-reactive T cells in patients with rheumatoid arthritis

OBJECTIVE: To investigate the impact of type II collagen (CII)-reactive T cells on the Th1/Th2 cytokine balance in patients with rheumatoid arthritis (RA). METHODS: T cell proliferative responses to bovine CII were examined in synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) by mixed lymphocyte culture. CII-reactive T cell lines were generated from the SFMC and PBMC. Interferon-gamma (IFNgamma), interleukin-12 (IL-12), and IL-4 were measured by enzyme-linked immunosorbent assay in the SF, sera, and culture supernatants of PBMC and SFMC that had been stimulated with CII. RESULTS: The frequency of CII-reactive T cells was higher in the PBMC from RA patients than in that from osteoarthritis patients and healthy control subjects. In RA patients, CII-reactive T cells were more prevalent in SFMC than in PBMC. The mean level of IFNgamma and the ratio of IFNgamma to IL-4 were significantly higher in the culture supernatants of T cells stimulated with CII; these differences were more prominent in SFMC. Levels of IL-12 in the culture supernatants of SFMC and PBMC stimulated with CII were significantly higher than those in unstimulated supernatants. T cell responsiveness correlated well with the level of type 1 cytokines in culture supernatants from RA T cells stimulated with CII. In the CII-reactive cell lines, the increased production of IFNgamma was consistent with clonal expansion. CONCLUSION: CII-reactive T cells are more abundant in SFMC than in PBMC and are strongly associated with a shift toward Thl cytokine in the inflamed joints of RA patients. Our results suggest that a skewing toward type 1 cytokines by CII-reactive T cells may play an important role in the chronic inflammatory process of RA.     

CCR3, CCR5, interleukin 4, and interferon-gamma expression on synovial and peripheral T cells and monocytes in patients with rheumatoid arthritis

OBJECTIVE: To characterize cytokine and chemokine receptor profiles of T cells and monocytes in inflamed synovium and peripheral blood (PB) in patients with rheumatoid arthritis (RA) and other arthritides. METHODS: We studied PB and synovial fluid (SF) samples taken from 20 patients with RA and 9 patients with other arthritides. PB cells from 8 healthy adults were used as controls. CCR3, CCR5, and intracellular interferon-g (IFN-g) and interleukin 4 (IL-4) expression in CD8+ and CD8- T cell populations and in CD14+ cells were determined with flow cytometry. RESULTS: Expression of CCR5 and CCR3 by CD8-, CD8+ T cells and CD14+ monocytes was increased in SF compared to PB cells in patients with RA and other arthritides. The number of CD8+ T cells spontaneously expressing IL-4 and IFN-g was higher in SF than in PB in RA patients. Spontaneous CCR5 expression was associated with intracellular IFN-g expression in CD8+ T cells derived from SF in RA. In CD8- T cells the ratio of CCR5+/CCR3+ cells was increased in patients with RA compared to patients with other arthritides. The number of PB CD8- T cells expressing IFN-g after mitogen stimulation was higher in controls than in patients. In PB monocytes the ratio of CCR5+/CCR3+ cells was increased in patients with RA compared to patients with other arthritides and controls. CONCLUSION: T cells and monocytes infiltrating joints in RA and in other arthritides showed increased activation of both type 1 and type 2 immune markers. More pronounced type 1 immune response in joints, shown as an increased CCR5/CCR3 ratio, was found in the patients with RA versus those with other arthritides. Monocytes but not T cells in PB showed increased activation in RA.     

Quantitation of IL-2Rp75 (CD122) expression on mononuclear cells in rheumatic disease.

OBJECTIVE: To compare expression of the p75 chain of the interleukin-2 receptor (IL-2Rp75, CD122) on peripheral and synovial mononuclear cells in rheumatoid and non-rheumatoid inflammatory arthritis. METHODS: Peripheral blood (PBMC) and synovial (SFMC) mononuclear cells were isolated from subjects with rheumatoid arthritis (n = 16) and non-rheumatoid inflammatory arthritis (n = 12). PBMC were isolated from six healthy controls. Expression of CD122 was examined using indirect immunofluorescence and quantitative flow cytometry. RESULTS: There was no difference in IL-2Rp75 expression on PBMC from rheumatoid arthritis patients, non-rheumatoid arthritis patients, and controls. In subjects with rheumatoid arthritis there was no difference in IL-2Rp75 expression on PBMC and SFMC. However, in the non-rheumatoid arthritis group there was an increase in IL-2Rp75 expression on SFMC compared with PBMC (P = 0.0032). On SFMC there was a greater expression of IL-2Rp75 in non-rheumatoid arthritis than in rheumatoid arthritis (P = 0.0007). Expression was greater on CD8 positive cells and in subjects with shorter duration of disease. CONCLUSIONS: The p75 chain of the IL-2 receptor, an important T cell activation antigen, is not upregulated in synovial fluid. This appears to be a disease specific defect and provides further support for the concept of "frustrated" or incomplete T cell activation in this disease.     

Quantitation of interferon gamma- and interleukin-4-producing T cells in synovial fluid and peripheral blood of arthritis patients.

OBJECTIVE: The balance between T cells able to produce interferon gamma (IFN-gamma) (type 1) and interleukin-4 (IL-4) (type 2) is considered to be important in the development of autoimmunity. In this study, we quantitated the percentage of both cell types in synovial fluid (SF) and peripheral blood (PB) of rheumatoid arthritis (RA) patients, non-rheumatoid arthritis patients and healthy controls. METHODS: After short-term stimulation of synovial mononuclear cells with phorbol ester and ionomycin, cytokine-producing cells were quantitated using an intracellular staining technique and flow cytometric analysis. RESULTS: Although no significant differences in CD8 + cells were found, significantly higher percentages of IFN-gamma-producing CD4 + (Th 1) and IL-4-producing CD4 + (Th2) cells were found in the peripheral blood of RA patients in comparison with healthy controls. However, the Th1/Th2 ratio was not different between the two groups. Comparative studies between PB and SF showed that in both RA and non-RA patients, percentages of Th1 cells were higher in SF than in PB, while Th2 cells were preferentially found in the PB, resulting in a higher Th1/Th2 ratio in the SF. The Th1/Th2 ratio in the SF correlated with disease activity as estimated by the erythrocyte sedimentation rate. CONCLUSION: These results are in agreement with the hypothesis that Th1 cells preferentially home to inflamed joints in both RA and non-RA patients, but show that this does not result in an altered Th1/Th2 ratio in the PB of RA patients.     

CD4+ PD-1+ T cells accumulate as unique anergic cells in rheumatoid arthritis synovial fluid

OBJECTIVE: The PD-1 receptor, whose deficiency in mice causes autoimmune diseases such as arthritis, is considered to be a negative regulator of activated T cells and to play a crucial role in peripheral tolerance. To clarify the involvement of the PD-1 system in rheumatoid arthritis (RA), we investigated PD-1 expression on synovial fluid (SF) T cells from patients with RA. METHODS: FACS analysis for PD-1 was performed on SF T cells from 44 patients with RA and 6 with osteoarthritis (OA), and also on peripheral blood (PB) T cells from 12 RA patients and 7 healthy controls. Two-color analysis of cell surface PD-1 expression and the intracellular concentration of cytokine production was used to investigate CD4+ T cells from SF of patients with RA and PB from controls. RESULTS: Scarcely any PD-1 expression was detected on control PB T or OA SF T cells. In contrast, PD-1+ cells made up 20.9 +/- 8.6% (mean +/- SD) of RA SF T cells. In RA SF, PD-1 was expressed more predominantly on CD4+ T cells than on CD8+ T cells. As well as expressing CD45RO and CXCR3, CD4+ PD-1+ T cells were mostly CTLA-4 positive and CD26 negative, and were enriched in CD45RB(low) cells. Intracellular cytokine staining revealed that CD4+ PD-1+, but not CD4+ PD-1-, T cells produced interleukin 10 (IL-10), and that CD4+ PD-1+ T cells produced less IL-2 than CD4+ PD-1- T cells. CONCLUSION: PD-1+ T cells in RA SF are enriched, and phenotypic analysis suggests that these cells constitute a unique anergic T cell subset in RA SF.     

Enrichment of differentiated CD45RBdim,CD27 – memory T cells in the peripheral blood,synovial fluid,and synovial tissue of patients with rheumatoid arthritis

Objective. To delineate in greater detail the phenotype of T cells that reside in the synovial tissue (ST) and synovial fluid (SF) of patients with rheumatoid arthritis (RA), in order to determine their precise differentiation status, and to determine whether the accumulation of these specific T cell subsets in these synovial compartments could be related to their capacity for transendothelial migration. Methods. Lymphocytes from normal subjects or from the peripheral blood (PB), ST, and/or SF of RA patients were phenotypically analyzed by flow cytometry. Normal PB CD4+ T cells were also characterized using an in vitro assay of transendothelial migration. Results. ST and SF were found to be enriched with memory (CD45RA-, CD45RO+, CD11a^bright, CD44^bright) and activated (CD69+) T cells. Moreover, ST and SF cells from RA patients were enriched in differentiated CD4+, CD45RB^dim, CD27- T cells, a subset of mature memory T cells that develops after prolonged antigenic stimulation. In addition, PB of some RA patients contained an increased number of CD4+, CD45RB^dim, CD27- T cells. The CD4+, CD11a^bright, CD44^bright memory T cells, which included the CD45RB^dim, CD27- more mature memory cells, exhibited an enhanced capacity for transendothelial migration that is likely to contribute to their enrichment in the rheumatoid synovium. Conclusion. RA patients manifest an increased number of mature memory T cells in the SF and ST, and some also have an increased number of these cells in PB that is likely to reflect chronic antigenic stimulation. The enrichment of these cells in the SF and ST reflects, in part, an enhanced capacity to migrate from the vascular space into inflamed tissue.     

Anti-Human type II collagen CD19+ B cells are present in patients with rheumatoid arthritis and healthy individuals.

OBJECTIVE: To determine the frequency and repertoire of CD19+ B cells capable of producing antibodies reactive to type II collagen (CII) in synovial fluid (SF) and peripheral blood (PB) of patients with rheumatoid arthritis (RA) and PB of healthy control individuals. METHODS: CD19+ B cells were isolated and activated to secrete immunoglobulins (Ig) by CD4+ T cells. Frequencies of anti-CII B cells were determined by limiting dilution analysis. The isotype and cross-reactivity of the antibodies produced were determined by ELISA. RESULTS: SF and PB from 5 patients and PB from 4 healthy controls were analyzed. Anti-CII CD19+ B cells were identified in all samples tested. In the RA SF, the percentage of activated B cells reactive to human CII was significantly higher than in the PB of patients with RA (p < 0.05) or controls (p < 0.01). A majority of anti-human CII B cells from patients' SF secreted IgG isotype, whereas most anti-human CII B cells in PB of patients and controls secreted IgM. The anti-CII B cells, regardless of source, are usually reactive to both native and denatured human CII, to different types of human collagens, and to type II collagens from different species. CONCLUSION: Anti-CII CD19+ B cells responsive to activated helper T cells are present in both patients with RA and healthy individuals. However, these B cells, especially those secreting the IgG isotype, accumulate in the inflamed joints of RA patients.     

CD4+CD25+ regulatory T cells in rheumatoid arthritis: Differences in the presence,phenotype, and function between peripheral blood and synovial fluid

Objective

In mice, CD4+CD25+ regulatory T cells play a pivotal role in preventing autoimmunity. Regulatory T cells are also present and functional in healthy humans. We investigated the presence, phenotype, and function of CD4+CD25+ regulatory T cells in peripheral blood (PB) and synovial fluid (SF) from patients with rheumatoid arthritis (RA).

Methods

The presence and phenotype of CD4+CD25+ regulatory T cells were determined by flow cytometry. Anergy and suppressive activity were assessed by culturing CD4+CD25− and CD4+CD25+ T cells with anti‐CD3 monoclonal antibodies and antigen‐presenting cells, followed by proliferation and cytokine detection.

Results

The percentage of CD4+CD25+ T cells in RA SF was significantly increased compared with that in RA PB, and both of these percentages were higher than that in PB from controls. The cells in RA PB were similar in phenotype and function to CD4+CD25+ regulatory T cells from controls. In SF, however, ∼40–50% of CD4+CD25+ T cells expressed an activated phenotype, i.e., CD69+, class II MHC+, OX‐40+, with high levels of CTLA‐4 and glucocorticoid‐induced tumor necrosis factor receptor. These synovial CD4+CD25+ T cells displayed an increased suppressive capacity compared with blood CD4+CD25+ T cells. However, this enhanced suppressive activity was counterbalanced, because activated responder T cells from SF were less susceptible to CD4+CD25+ T cell–mediated suppression than were responder cells from PB.

Conclusion

We demonstrate that CD4+CD25+ regulatory T cells are present and functional in patients with RA, with higher numbers of regulatory T cells with increased suppressive activity found in SF compared with PB. These findings suggest a negative feedback system that is active at the site of inflammation. The balance between activated responder and regulatory T cells appears to influence the extent of immunoregulation in RA.