Mitogen-induced interleukin 2 and gamma interferon production by CD4+ and CD8+ cells of patients with inflammatory arthritides. A comparison between cells from synovial fluid and peripheral blood

[Evidence-based recommendations for the management of undifferentiated peripheral inflammatory arthritis (UPIA). The German perspective on the international 3e initiative]

INTRODUCTION

Peripheral arthritis is the most common presenting complaint in clinical rheumatology. Unequivocal identification of the underlying entity can be difficult, particularly at an early stage. Such cases are commonly referred to as undifferentiated peripheral inflammatory arthritis (UPIA). Since evidence-based recommendations for the clinical management of UPIA are lacking, this international 3e initiative convened 697 rheumatologists from 17 countries to develop appropriate recommendations.

METHODS

Based on a systematic literature research in Medline, EMBASE, Cochrane Library, and the ACR/EULAR abstracts of 2007/2008, 10 multinational recommendations were developed by 3 rounds of a Delphi process. In Germany, a national group of experts worked on 3 additional recommendations using the same method. The recommendations were discussed among the members of the 3e initiative and the degree of consensus was analyzed as well as the potential impact of the recommendations on clinical practice.

RESULTS

A total of 39,756 references were identified, of which 250 were systematically reviewed for the development of 10 multinational recommendations concerning differential diagnosis, diagnostic and prognostic value of clinical assessments, laboratory tests and imaging techniques, and monitoring of UPIA. In addition, 3 national recommendations on the diagnostic and prognostic value of a response to anti-inflammatory therapy on the analysis of synovial fluid and on enthesitis were developed by the German experts based on 35 out of 5542 references.

CONCLUSIONS

The article translates the 2011 published original paper of the international 3e initiative (Machado et al., Ann Rheum Dis 70:15-24, 2011) and reports the methods and results of the national vote and the additional 3 national recommendations.

Role of cytokines, acute-phase proteins, and chemokines in the progression of rheumatoid arthritis

Rheumatoid arthritis (RA) has no firm etiologic basis. It progresses as an autoimmune disease and evolves into a chronic inflammatory joint disease complicated by recurrent episodes of systemic acute-phase reactions, which sometimes result in amyloidosis. Cytokines play a pivotol role in inflammation and the immune response. Proinflammatory cytokines such as interleukin-1, tumor necrosis factor alpha (TNF-alpha), and interleukin-6 are present at high levels in arthritic joints, and their blood concentration correlates with the severity of the RA. Some of the activities of the proinflammatory cytokines, such as stimulation of leukocyte infiltration and release of their proteolytic enzymes, may be mediated by acute phase proteins (APPs), such as C-reactive protein and serum amyloid A, and by chemokines such as interleukin-8. Cytokines, chemokines, and APPs reciprocally regulate each others' expression and activities, constituting a communication network between fibroblasts, macrophages, lymphocytes, and hepatocytes. Activation of the network results in inflammation and the progressive destruction of joints and systemic symptoms characteristic of RA.

Interleukin-2 is found in the synovium of psoriatic arthritis and spondyloarthritis, not in rheumatoid arthritis

Objective of this project was to determine whether synovial expression of interleukin-2 (IL-2) in arthritis is a disease-specific phenomenon. Immunohistological examination of needle biopsies from 7 rheumatoid arthritis (RA) patients never exposed to disease modifying antirheumatic drugs (DMARDs), 13 RA patients on DMARDs, 4 patients with seronegative spondyloarthritis (SpA), and 5 psoriatic arthritis (PsA) patients. Biopsies were either snap-frozen immediately or cultured for 48 hr, with and without phytohaemagglutinin (PHA) prior to APAAP staining. In snap-frozen biopsies, IL-2 was detected in none of 18 RA samples with significant T cell infiltrates. In contrast, IL-2 was seen in 7/9 PsA/SpA samples. After culture without PHA, IL-2 was detected in 0/14 RA and 5/6 PsA/SpA samples; with PHA, IL-2 was present in 1/14 RA and 2/2 PsA/SPA samples. Synovial IL-2 protein expression appears to distinguish between RA (absent) and PsA/SpA (present). This may reflect a difference in pathophysiology between these diseases.

Thyroid cell survival in coculture with autologous peripheral or intrathyroidal lymphocytes

OBJECTIVE

We have studied lymphocyte induced cytotoxicity and the production of interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) during coculture of thyrocytes and autologous lymphocytes from patients with Graves' disease and from normal subjects.

PATIENTS

Thyroid tissues and lymphocytes were obtained from 28 patients with Graves' disease and from 9 control subjects.

MEASUREMENTS

Lymphocyte induced cytotoxicity was evaluated on autologous thyrocytes using 5 metabolic tests: the MTT assay, the neutral red uptake, lactate dehydrogenase measurement and glutathione assay. IFN-gamma and TNF-alpha measurements were performed after 1, 5 or 7 days' coculture.

RESULTS

The lymphocytes isolated from peripheral blood (PB lymphocytes) altered the morphology and the metabolism of autologous thyrocytes. The intrathyroidal lymphocytes isolated after Dispase digestion were not toxic whereas mechanically isolated lymphocytes exerted a little toxicity. No difference was seen between Graves' disease and normal cells. The supernatants from cocultures had higher IFN-gamma levels than those from lymphocyte cultures. In coculture, PB lymphocytes secreted more IFN-gamma and TNF-alpha than intrathyroidal lymphocytes. The PB lymphocyte induced cytotoxicity was not due to IFN-gamma and TNF-alpha alone.

CONCLUSION

Peripheral blood lymphocytes are cytotoxic in vitro to autologous thyrocytes whereas intrathyroidal lymphocytes exert little or no cytotoxicity according to their isolation method. The mechanisms of lymphocyte induced toxicity remain to be explained.

Restricted cytokine expression in rheumatoid arthritis

OBJECTIVE

To determine the cytokine profile of the phenotypically activated T cell in rheumatoid arthritis (RA) synovium.

METHODS

Interleukin-2 (IL-2), IL-2 receptor (IL-2R), IL-6, IL-4, and interferon-gamma (IFN gamma) gene expression was examined in T cells from freshly isolated synovial fluids (SF) and synovial tissues (ST) from patients with RA. Estimates of baseline expression were determined using unstimulated peripheral blood (PB) T cells from healthy individuals. The corresponding positive controls were phytohemagglutinin-activated tonsil T cells.

RESULTS

In studies of paired PB and SF T cell samples from 17 RA patients, IL-2 messenger RNA (mRNA) levels in only 1 PB and 3 SF samples were more than 2 standard deviations above the mean of levels in unstimulated PB from healthy donors. Similarly, only 5 PB and 7 SF samples exhibited elevated IL-2R mRNA levels. IFN gamma gene expression was not detected in any of the paired RA PB or SF samples. Fractionated T cells from 12 RA ST were screened with similar results: Only 1 of 12 samples exhibited IL-2 mRNA levels more than 2 standard deviations above levels in baseline controls. IL-2R mRNA levels were low or not detected, and IFN gamma mRNA was absent. Subsequent studies showed that IL-4 and IL-6 gene expression levels were also low in RA tissues compared with tonsil T cell-positive controls.

CONCLUSION

These data provide evidence for restricted cytokine expression in the T cell population in RA tissues.

Enhanced chondrocyte destruction by lymphokine-activated killer cells. Possible role in rheumatoid arthritis

OBJECTIVE

The lysis of chondrocytes, the parenchymal cells of cartilage, by lymphocytes may provide a potent mechanism by which the immune system participates in sustaining joint damage in rheumatoid arthritis (RA). We studied the capability of lymphocytes from healthy individuals and patients with arthritis to lyse chondrocytes.

METHODS

Peripheral blood mononuclear cells (PMBC) were tested for their ability to lyse chondrocytes in a 51Cr-release assay. Enhancement of the chondrolytic activity was determined by preincubating the cells with T cell growth factor (TCGF) or recombinant interleukin-2 (rIL-2) before cytotoxic testing.

RESULTS

PBMC from healthy individuals possessed a low ability to lyse chondrocytes, whereas cells from the synovial fluid of patients with RA displayed higher chondrolytic activity. In RA, modulating factors must come into play because not all synovial fluid sample cells showed high chondrolytic activity and cells from synovial tissue had little or no lytic action on chondrocytes. Chondrolytic activities of cells from all sources, including PBMC from healthy subjects and patients with arthritis and cells isolated from synovial fluid or from the synovial tissue of RA patients, were greatly increased by incubating the cells with TCGF or rIL-2. In contrast, treatment of chondrocytes with interferon-gamma, which enhances major histocompatibility complex gene expression, decreased the susceptibility of chondrocytes to lysis.

CONCLUSION

These observations suggest a mechanism for joint damage in which the destruction of chondrocytes by lymphocytes is controlled by cytokines released during the inflammatory process in arthritic diseases.

Differential responses of CD4+CD45RA+ and CD4+CD29+ subsets to activated CD8+ cells: enhanced stimulation of the CD4+CD45RA+ subset by cells from patients with multiple sclerosis

To examine whether functionally different CD4+ cells respond uniformly to the immunoregulatory influences of allogeneic activated CD8+ cells (*CD8+), we subfractionated the CD4+ population into two subsets, based on the high expression of either CD45RA or CD29. We confirmed that the CD45RA+ cells proliferated poorly in response to soluble anti-CD3 mAb, compared to the vigorous response obtained with the CD29+ subset; the CD45RA+ cells were more responsive to stimulation with Con A. Using normal healthy controls, we found that whereas *CD8+ had a significant suppressive effect on the proliferation of the CD29+ subset, they augmented the mitogen-induced proliferative response of the CD45RA+ cells. We further demonstrated that *CD8+ derived from MS patients augmented the response of the CD45RA+ subset to a significantly higher degree compared to healthy age- and sex-matched controls. There were no significant differences between the degree of suppression exerted by the *CD8+ of either the MS or the control group on the CD29+ cells. These results demonstrate that helper/memory CD4+CD29+ cells are more sensitive to the suppressive influences of *CD8+ compared to the CD4+CD45RA+ subset. In addition, in MS, *CD8+ may contribute to a more pronounced "on" signal for virgin CD4+CD45RA+ cells, which might serve as a means to perpetuate the autoimmune disease process.

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.

IL-6 in synovial fluids, plasma and supernatants from cultured cells of patients with rheumatoid arthritis and other inflammatory arthritides

The purpose of this investigation was to measure interleukin 6 (IL-6) levels in synovial fluid (SF) and plasma from patients with rheumatoid arthritis (RA) and other inflammatory arthritides (non-RA) and to examine the in vitro production of IL-6 by T cells and monocytes from SF and peripheral blood (PB). All patients had high levels of IL-6 in SF. Although the median level was higher in the group of non-RA arthritides, the difference was not statistically significant. Supernatants from both unstimulated and stimulated highly purified CD4+ and CD8+ cells from SF and PB did not contain IL-6, while high levels of IL-6 were detectable in supernatants of mononuclear cells (MNC) and plastic adherent cells without any specific in vitro stimulant. Since IL-6 is so readily produced by normal mononuclear cells in vitro without any specific stimulant, spontaneous in vitro production by SF MNC cannot be considered as evidence for in vivo production by the same cells.