Participation of substance P distribution in the cytokine production of rheumatoid synovium

Based on findings which suggested the involvement of the neuropeptide substance P in the pathogenesis of rheumatoid arthritis (RA), we investigated the mechanism of synovial pannus formation in RA, and examined the interaction between the cytokine production of synovial tissues and the concentration of substance P in the cartilage–pannus junction (CPJ). The CPJ and other peripheral synovial tissues were separately obtained from each part of the synovium from the knee joints of seven RA patients. The concentrations of substance P and the cytokines interleukin (IL)-1β and IL-6 in the CPJ and peripheral synovial tissues were determined by enzyme-linked immunosorbent assays. In addition, synovial cells were isolated from the CPJ and peripheral synovial tissues and treated with substance P or neurokinin-1 receptor antagonist to analyze the changes in cytokine production. The substance P levels were 211.2 and 50.5 pg/mg protein in the CPJ and the peripheral synovium, respectively. The IL-1β and IL-6 levels in the CPJ were 24.6 and 12.8 pg/mg protein, respectively. In the peripheral synovium, these levels were 4.3 and 2.5 pg/mg protein, respectively. In the CPJ, the IL-1β and IL-6 levels in tissue containing a high concentration of substance P (>200 pg/mg protein) were 39.4 and 21.6 pg/mg protein, respectively, and those in tissue containing a low concentration of substance P (≤200 pg/mg protein) were 11.6 and 5.1 pg/mg protein, respectively. Synovial cells from the CPJ produced higher levels of IL-1β and IL-6 than those from peripheral tissues. In addition, treatment of the cells with an NK-1 antagonist significantly reduced the production of these cytokines by the synovial cells. The theory that substance P plays a role in the pathogenesis of RA via the upregulation of cytokine production should be considered in further studies on the immunomodulatory properties of substance P in arthritis. Received: June 17, 1998 / Accepted: February 4, 2000     

Interleukin-10 promoter polymorphism in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which interleukin (IL)-10 plays an important role. There are, however, controversial reports that IL-10 promoter polymorphism may be an independent marker of susceptibility and severity of RA. The aim of the present study was to examine the IL-10 promoter polymorphism in patients with RA. We examined 95 patients with rheumatoid arthritis diagnosed according to the criteria of the American College of Rheumatology. Polymerase chain reaction amplification was used for analysis of the promoter polymorphism of the IL-10 gene. In RA patients, the prevalence of genotypes encoding high expression of IL-10 was observed. Nevertheless, there was no association between IL-10 genotypes and age at disease diagnosis, disease activity in a physicians global assessment, and joint and extra-articular involvement. There was also no correlation between IL-10 polymorphism and disease activity parameters—erythrocyte sedimentation rate, C-reactive protein, number of swollen and tender joints, and duration of morning stiffness. We suggest that IL-10 promoter polymorphism is not a genetic risk factor for RA activity.     

Interleukin-10 promoter polymorphisms in rheumatoid arthritis and Felty's syndrome

OBJECTIVE: To examine whether promoter polymorphisms associated with variation in interleukin-10 (IL-10) production are relevant to the development of rheumatoid arthritis (RA) or Felty's syndrome (FS). METHODS: DNA was obtained from 44 FS patients, 117 RA patients and 295 controls. The promoter region between -533 and - 1120 was amplified by polymerase chain reaction, and polymorphisms detected by restriction enzyme digest or sequence-specific oligonucleotide probing. RESULTS: We found no significant difference in allele or haplotype frequencies between the groups. CONCLUSION: There is no association between FS or RA and these recently identified IL-10 promoter polymorphisms. Other genetic or environmental factors could explain the alterations in IL-10 levels seen in these conditions.      

Differential in vitro effects of IL-4, IL-10, and IL-13 on proinflammatory cytokine production and fibroblast proliferation in rheumatoid synovium

The purpose of this study was to compare the potential of interleukin-4 (IL-4), IL-10, and IL-13 to interrupt two major inflammatory pathways in rheumatoid arthritis (RA), i.e., overexpression of proinflammatory cytokines and cytokine-mediated fibroblast growth. IL-4, IL-10, and IL-13 were all able to significantly inhibit the production of IL-1β, tumor necrosis factor-α (TNF-α), IL-6, and IL-8 by freshly isolated RA synovial tissue cells; IL-10 was most effective in terms of IL-1β and TNF-α reduction. The IL-1 receptor antagonist was enhanced by IL-4 and IL-13, but only slightly enhanced by IL-10. Spontaneous interferon-γ secretion was diminished by IL-4 and IL-10 but not by IL-13. Addition of anti-IL-10 neutralizing antibody to RA synovial tissue cells resulted in a substantial increase in IL-1β and TNF-α levels, whereas neither anti-IL-4 nor anti-IL-13 antibody had a significant effect. IL-1β-stimulated proliferation of RA synovial fibroblast cell lines was inhibited by IL-4 and IL-13, but not by IL-10; IL-4 was over tenfold more effective than IL-13. These results suggest that IL-4, IL-10, and IL-13 all have the therapeutic potential to regulate the disease activity mediated by proinflammatory cytokines in RA, but each cytokine may have different potencies. Received: 29 June 2000 / Accepted: 20 July 2000     

Interleukin-6 functions as an autocrine growth factor in a cholangiocarcinoma cell line

Abstract The tumour cells of a human cholangiocarcinoma cell line, HuCC-T1, were found to express mRNA of interleukin-6 (IL-6) and to secrete a large amount of biologically active IL-6 in the culture medium at the concentration of 22.6 ng/mL. Interleukin-6 was demonstrated in the cytoplasm of the cells by immunohistochemical staining. Furthermore, these cells showed the presence of receptors for IL-6 on the surface, and DNA synthesis of the cells was stimulated by the exogenous addition of recombinant human IL-6 into the culture medium. The cell growth was significantly inhibited in the presence of anti-human IL-6 antibody in the culture medium. These findings indicate that IL-6 is one of the autocrine growth factors of this cell line in vitro.     

Interleukin-10 receptor expression in systemic lupus erythematosus and rheumatoid arthritis

OBJECTIVE: We aimed to determine the expression of the interleukin-10 receptor (IL10R) on circulating leukocytes in SLE and rheumatoid arthritis, and correlate this with plasma IL-10 levels and disease activity. METHODS: Peripheral blood was sampled from 20 SLE patients, 14 rheumatoid arthritis patients, and 14 healthy controls. IL-10R expression was determined by immunofluorescence labelling and flow cytometric analysis. Plasma IL-10 levels were measured by ELISA. RESULTS: IL-10R was highly expressed on monocytes, and to a lesser degree on neutrophils in all 3 patient groups. Only a small percentage of lymphocytes expressed IL-10R in all three groups. There was no significant difference in IL-10R expression on the surface of monocytes, neutrophils or lymphocytes in any of the 3 groups. IL-10R expression did not correlate with plasma IL-10 levels or disease activity. CONCLUSION: This study has shown no difference in surface IL-10R expression between SLE, rheumatoid arthritis and normal subjects. Deficient or excessive circulating leukocyte surface IL-10R expression therefore does not seem to play a role in the pathogenesis of SLE or rheumatoid arthritis. Functional IL-10R studies would be of interest.     

Molecular analysis of rheumatoid factors derived from rheumatoid synovium suggests an antigen-driven response in inflamed joints

Objective. Understanding the molecular genetic basis for rheumatoid factor (RF) production is necessary to a better understanding of the etiology and pathogenesis of rheumatoid arthritis (RA). We sought to define the genetic basis of RF in RA. Methods. The heavy and light chain variable region genes encoding 4 human monoclonal RF were cloned and sequenced using the polymerase chain reaction and the dideoxynucleotide chain-termination method. Results. The heavy and light chains of the C6 RF and the light chain of the G9 RF were encoded by 3 new RF-related Ig V-region genes. The heavy and light chains of D5 and G4 RFs were identical; most of their mutations caused amino acid substitutions. Conclusions. The RF-related Ig V-region gene repertoire is large and is still expanding. The data from D5 and G4 strongly suggest that these 2 RFs arise in an antigen-driven response in rheumatoid synovium. The presumed germline V genes for C6 may represent disease-specific RF-related V genes.