Interleukin 1 activity in the synovial fluid of patients with rheumatoid arthritis

Abstract

The synovial fluids (SF) of patients with rheumatoid arthritis (RA) were investigated for their effects on thymocytes of C3H/HeJ mice. Of the 20 SF tested, 17 (85%) showed an augmentation of the phytohaemagglutinin (PHA) induced thymocyte stimulation. Out of 16 SF of patients with osteoarthrosis, such an activity was detected in only one (6.25%). Further characterisation of the amplification factor revealed that (1) the SF of RA patients augmented both the PHA and the Concanavalin A response of the thymocytes (2) in the absence of mitogens, SF-treated thymocytes showed an increased uptake of 3H-thymidine, (3) the SF did not propagate the growth of an interleukin 2 dependent ovalbumin specific T cell clone, but (4) the SF were found to be required for optimal interleukin 2 release by spleen cells stimulated with suboptimal doses of lectin. Based on these biological effects the factor in the SF of RA patients is suggested to represent an interleukin 1 (IL-1). IL-1 produced in cultures by activated macrophages has been shown to stimulate T and B cell functions and to induce the production of collagenase and prostaglandins by cultured synovial cells. Both properties of IL-1 could be relevant in the pathogenesis of RA.

Isolation of an interleukin‐1‐like factor from human joint effusions

“…Our results differ from those of Fontana et a1 (24) and from those of other investigators studying lymphocyte stimulating activities in inflamed joints (6)(7)(8)26) in that the others have found the activity only in fluids from rheumatoid joints and not from osteoarthritic joints. There are at least two explanations for the discrepancy.…”

Expression of monocyte chemotactic and activating factor in rheumatoid arthritis. regulation of its production in synovial cells by interleukin‐1 and tumor necrosis factor

“…This may correlate with the higher levels of MCAF in RA SF. Various cytokines, including IL-1, IL-6, IL-8, and GM-CSF, have been also shown to be present at higher levels in RA SF than in OA SF (20,22,23,25). We have also shown that freshly isolated SF cells and synovial tissue from patients with RA express MCAF mRNA.…”

“…To quantify the amplified transcripts, PCR was conducted by incorporation at 14-34 cycles using cDNA samples from FLS. The amounts of amplified products of MCAF and &m were exponential at [14][15][16][17][18][19][20][21][22][23][24][25][26] cycles and then decreased slowly (data not shown); PCR amplification of cDNA for MCAF and &m was consequently carried out for 20 cycles in this study. As shown in Figure 5 , 188 bp of MCAF transcripts were detected in FLS incubated with the medium alone.…”

Interleukin‐1β induces synthesis and secretion of interleukin‐6 in human chondrocytes

“…It has been shown that IL-1 (a potent inducer of IL-6 synthesis) is found in high concentrations in the synovial fluid of patients with inflammatory joint diseases [31,32]. Chondrocytes respond to IL-1 by the release of hydrolases [33] and in turn an increase of proteoglycan degradation [13,14].…”