Cellular Immunity in the Joints of Patients with Rheumatoid Arthritis and Other Forms of Chronic Synovitis

Suppression of adjuvant arthritis by hesperidin in rats and its mechanisms

The citrus flavonoid hesperidin has been reported to possess a wide range of pharmacological properties. We have investigated the preventive and therapeutic effects of hesperidin on the development of adjuvant arthritis (AA), a rat model of rheumatoid arthritis (RA). Freund's complete adjuvant was used to induce AA in rats. Secondary paw swelling, polyarthritis index and histopathological assessment of ankle joints were used to evaluate the effects of hesperidin on AA rats. Concanavalin-A-induced T-lymphocyte proliferation and interleukin (IL)-2 production by splenocytes were measured using the MTT assay. Levels of IL-1, IL-6 and tumour necrosis factor (TNF)-α secreted by peritoneal macrophages (PM) were measured by RIA. Intragastric administration of hesperidin significantly attenuated secondary paw swelling and reduced the polyarthritis index of AA rats in a dose-dependent manner. In addition, hesperidin clearly ameliorated the pathological changes in AA rats. Hesperidin also restored the suppression of T-lymphocyte proliferation and IL-2 production, and downregulated production of IL-1, IL-6 and TNF-α by PM in AA rats. Our results suggest that hesperidin improves AA by downregulating the function of over-active macrophages and by up-regulating the activities of dysfunctional T lymphocytes. Hesperidin may therefore have therapeutic value for the clinical treatment of RA. Further research is required to clarify the detailed mechanisms of the protective effects of hesperidin on AA.

Elevated cytokine messenger RNA levels in the peripheral blood of patients with rheumatoid arthritis suggest different degrees of myeloid cell activation

OBJECTIVE

To determine whether monocytes in rheumatoid arthritis (RA) are activated to produce proinflammatory cytokines in the peripheral circulation before entering the synovium and whether the pattern of cytokines that is expressed correlates with disease activity.

METHODS

Cytokine messenger RNA (mRNA) levels were assessed in peripheral blood mononuclear cells (PBMC) from 14 RA patients and 14 healthy controls by semiquantitative reverse transcription-polymerase chain reaction technology. The method employed was sufficiently sensitive to assess cytokine mRNA levels in freshly isolated cells without the necessity of in vitro stimulation. Thus, an estimate of the in vivo state of activation could be obtained.

RESULTS

Interleukin-8 (IL-8) mRNA levels were elevated in all 14 RA patients compared with normal controls, whereas 7 of 14 RA patients had elevated levels of mRNA for IL-6 or IL-10. IL-1beta mRNA levels were below the normal range in 3 of 14 patients, within normal limits in 4 of 14, and elevated in 7 of 14. Tumor necrosis factor alpha mRNA levels were within the normal range in 9 of 14 patients and below normal in 5 of 14. There was a statistically significant difference between the mean IL-10 (P < 0.05) and IL-8 (P < 0.001) mRNA levels in RA patients and normal controls. Of note, the 7 patients with elevated IL-1beta mRNA levels also expressed the highest levels of IL-8 mRNA. Whereas a strong correlation between the expression of IL-1beta and IL-8 mRNA (P < 0.001) was found, expression of all other mRNA occurred independently of each other. Levels of cyclooxygenase 2 (COX-2) mRNA were also determined to evaluate the status of myeloid cell activation more completely. COX-2 mRNA levels were within the normal range in 4 of 11 patients and below normal in 7 of 11, but did not correlate with the expression of any of the cytokine mRNA.

CONCLUSION

Elevated levels of mRNA for selected cytokines that are predominantly produced by monocytes can be found in the PBMC of many RA patients. The data indicate that myeloid precursor cells become activated to produce cytokines before they enter the synovium, a finding which emphasizes the systemic nature of RA.

Immunohistochemical characterization of the cellular infiltrates in Sjögren's syndrome, rheumatoid arthritis and osteoarthritis with special reference to calprotectin-producing cells

The aim of this study was to analyse the nature of infiltrating cells in minor salivary glands of patients with Sjögren's syndrome (SS). Furthermore, we wanted to characterize the tissue distribution of calprotectin-producing cells in inflamed salivary gland tissue of SS and in synovial tissue of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Cryostat sections of labial salivary gland tissue from patients with SS and synovial tissue from RA and OA patients were stained (ABC-immunoperoxidase technique) using monoclonal antibodies (MoAbs) to T cells (CD3), monocytes/macrophages (CD14, CD68), and calprotectin. Monocytes and macrophages were widely distributed in focal infiltrates of salivary gland tissue from SS patients. Calprotectin markers showed a distinct staining of infiltrating macrophages and around blood vessel walls. In synovial tissue samples, calprotectin was expressed in a high percentage of cells in the synovial lining, the subsynovium, and vessel walls. The percentages of cells stained for calprotectin were significantly higher in RA than in OA and SS tissues. Antibodies to the calprotectin complex stained cells with a similar distribution as antibodies against the separate polypeptide chains of calprotectin. The localization and differentiated expression of calprotectin in these chronic inflammatory conditions indicate a role in the inflammatory process and may be an additional marker of macrophages/granulocytes in SS, RA and OA.

A controlled study of lymphocyte subsets in rheumatoid arthritis

The purpose of this study was to determine if patients with rheumatoid arthritis (RA) exhibited unique patterns of peripheral blood lymphocyte (PBL) subsets in comparison to patients with osteoarthritis (OA) and, further, if such differences related to disease activity or nondisease factors. Data from 63 RA patients and 47 OA patients revealed that the RA patients had lower absolute numbers of CD2+ and CD4+ lymphocytes. Small differences also were found in selected B-cell subsets and subsets of lymphocytes expressing CD16 and/or CD57 antigens. Further analysis revealed that these differences were due primarily to the effects of cytotoxic medications in the RA group. However, there were also alterations in some subsets independent of medication groups. PBL subsets in RA patients did not relate to chronic low-dose prednisone or measures of disease activity. This study demonstrated the need to control carefully for variables such as age and medication in immunophenotypic investigations of RA.

Evidence for the presence of activated CD4 T cells with naive phenotype in the peripheral blood of patients with rheumatoid arthritis

We have investigated whether T cell activation in rheumatoid arthritis (RA) preferentially engages distinct T cell subpopulations in the peripheral blood (PB) and in the synovial fluid. We found that CD25 expression was enhanced among PB CD4 T cells of RA patients as compared with CD4 cells of patients with reactive arthritis, degenerative joint disease or of healthy controls. Within the CD4 T lymphocytes subset we found that the CD45RO- (naive) cells selectively in RA displayed higher levels of CD25 protein and of interferon-gamma mRNA expression when compared with the respective subset of all other investigated groups. These results show that in the PB of RA, but not in the PB of the other arthropathies or healthy controls, CD45RO-CD4 T lymphocytes exist which display well-defined signs of activation.

Immunohistologic study of T-cell receptor delta-chain expression in rheumatoid synovial membranes

Lymphocytes expressing gamma delta T-cell receptors (TCRs) have been shown to be reactive to mycobacterial antigens as well as the so-called stress proteins. The detection of increased numbers of gamma delta cells in the synovial fluid and peripheral blood of some patients with rheumatoid arthritis has suggested a potential role for these lymphocytes in the pathogenesis of this disorder. Twenty-three rheumatoid synovial membranes were studied using immunohistology and monoclonal antibodies in an attempt to define the patterns of distribution of gamma delta T cells in rheumatoid synovitis. Consecutive sections were stained for T1(CD5), T4(CD4), T8(CD8), TAC(CD25), the delta-chain markers delta TCR1 and delta TCS1, and the beta-chain marker beta F1. Our results show some regional differences in the distribution of CD4 and CD8 cells, the former being prominent in the lymphocytic aggregates and the latter most prominent in diffuse infiltrates immediately adjacent to the synovial lining layer. All tissues showed extensive staining for beta F1; an estimated average of more than 90% of T cells expressed alpha beta TCR. The majority of samples showed limited staining for both delta-chain antibodies, with 20 of the 23 tissues appearing to have less than 1% of T lymphocytes expressing these markers. Three tissues stained extensively for both delta TCR1 and delta TCS1 in particular areas of the section. In these areas, small perivascular lymphocytic aggregates appeared to be composed mainly of gamma delta cells. TAC staining was virtually absent in all areas and tissues. It was concluded that the majority of T lymphocytes infiltrating rheumatoid synovial membranes express alpha beta TCR.(ABSTRACT TRUNCATED AT 250 WORDS)

Limiting dilution analysis of proliferative T cell responses to mycobacterial 65-kDa heat-shock protein fails to show significant frequency differences between synovial fluid and peripheral blood of patients with rheumatoid arthritis

Recent evidence has pointed to the mycobacterial 65-kDa heat-shock protein (hsp 65) as an antigen that may be important in the pathogenesis of rheumatoid arthritis (RA). Using limiting dilution analysis the frequency of purified protein derivative of tuberculin (PPD) and hsp 65-responsive T cells was measured in paired peripheral blood and synovial fluid samples of patients with RA. There was no increase in the anti-PPD or anti-hsp 65 frequency in synovial fluid compared with peripheral blood. In addition, no difference was found between peripheral blood of RA patients and healthy controls. These results do not support the idea of an important pathogenic role of T cells responding to hsp 65, or a cross-reacting antigen, in RA.

Abnormalities in serum osteocalcin values in children with chronic rheumatic diseases

We studied bone mineral metabolism prospectively in 113 children with chronic rheumatic diseases (juvenile arthritis, systemic lupus erythematosus, and juvenile dermatomyositis) to determine the relationship of serum levels of osteocalcin to rheumatic disease activity and corticosteroid usage, and to determine, in part, the cause of osteopenia in this population. Disease activity was quantitated by historical, clinical, and serologic means and an activity score derived. The 113 children were divided according to the expression of their disease, which was active (group 1: mean score 3.42, mean erythrocyte sedimentation rate 28 mm/hr) or inactive (group 2: score 1.7, erythrocyte sedimentation rate 15 mm/hr) (p less than 0.02 group 1 vs group 2 for each value), or which remitted during the study (group 3). We found that serum levels of osteocalcin, but not those of ionized calcium, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and parathyroid hormone, were reduced in group 1 children even before corticosteroid therapy was employed. Children in both group 2 and group 3 had normal osteocalcin levels despite the use of corticosteroids. The reduced levels of osteocalcin were predictive of a reduction in bone mass measured by photon absorptiometry in 16 of 19 children so studied. We conclude that skeletal abnormalities that result in a reduced bone mass occur in the clinical course of the majority of children with active chronic rheumatic diseases, are associated with reduced osteocalcin levels, and are not related to the use of corticosteroids. Serum osteocalcin levels may be a sensitive marker for reduced osteoblast activity and bone formation in children with chronic rheumatic diseases.

Psychoimmunology and rheumatoid arthritis: concepts and methodologies

The recent growth of knowledge about the immune-neuroendocrine network has important implications for future research into psychosomatic hypotheses about the aetiology of rheumatoid arthritis. The available evidence suggests that three phases of the aetiological process in rheumatoid arthritis need to be considered separately because of the different role that psychological and social variables may play at different points of the disease. These are the loss of immunological tolerance, the onset of joint inflammation and the long-term disease course. It is suggested that future studies will need to be prospective, include multiple sampling techniques and comparisons within patient groups if they are to elucidate the precise role of psychoneuroimmunological factors in rheumatoid arthritis.

An introduction to rheumatoid arthritis

To understand the many forms of treatment available for patients with rheumatoid arthritis and the variable responses to these therapies, one must appreciate the complexity of this disease, the role played by immune mechanisms in its initiation and perpetuation, and its natural history, including factors that may predict a good or bad outcome. This introduction to rheumatoid arthritis will focus briefly on each of these areas.

New perspectives on the pathogenesis of rheumatoid arthritis

In the pathogenesis of rheumatoid arthritis, locally produced antibodies complex with an inciting antigen, yet to be identified, within the joint and activate the complement system, resulting in articular inflammation mediated primarily by polymorphonuclear leukocytes and their products. Chronic inflammatory cells then produce soluble factors that induce both tissue destruction and inflammation. A major issue is how and why apparently normal immune responses in the acute stage progress to chronic inflammation in subsequent months to years. Although it is often assumed that the initial etiologic agent, persisting in the joint or at an extra-articular site, is responsible for continued synovitis, this need not be the case. It is possible that once the inciting agent is cleared from the joint through a normal immune response, the presence of activated cells rich in surface class II histocompatibility (Ia) antigens could, under the influence of multiple genetic or environmental factors, become the target of autoimmune attack. Alternatively, the process might result from the interactions of synovial lining cells and their products with T cells assuming a secondary role. Further research into the relative contributions of soluble products, T helper and suppressor subsets, synoviocytes, and antigen determine which model is correct.

Phenotypic analysis of synovial tissue and peripheral blood lymphocytes isolated from patients with rheumatoid arthritis

Cytofluorometric analysis was performed to characterize the surface phenotype and activation status of freshly isolated synovial tissue lymphocytes (STL) and peripheral blood lymphocytes (PBL) from 7 patients with rheumatoid arthritis (RA). Proliferative synovium was enzymatically digested to obtain tissue-derived lymphocytes. Indirect immunofluorescent staining of patient PBL and STL with a variety of monoclonal antibodies failed to reveal a consistent alteration in the number of CD4+ (helper/inducer) PBL or STL. However, there was a significant decrease in the number of CD8+ (suppressor/cytotoxic) cells in rheumatoid STL (P less than 0.05). A significant reduction in the density of the T cell differentiation antigens CD3 and CD4 was observed in RA PBL and STL, compared with control PBL. These differences in antigen density were not seen when normal PBL were subjected to the same enzymatic digestion. Both RA PBL and STL manifested increased expression of HLA-DR antigens, without augmentation of interleukin-2 receptor expression. Alterations in the expression of the T cell differentiation antigens and activation antigens by patient PBL closely paralleled the abnormalities observed in STL. In contrast, STL of patients with RA exhibited an increase in the expression of the adhesion-related glycoproteins (leukocyte function-associated 1 [LFA-1] and very late activation 1 [VLA-1] antigens), not observed with autologous PBL. These studies demonstrate that lymphocytes isolated from the synovial tissues of RA patients bear an activated phenotype, exemplified by the modulation of CD3 and CD4 and the expression of HLA-DR.(ABSTRACT TRUNCATED AT 250 WORDS)