Rheumatoid arthritis: current concepts

Change in cellular localization of a rheumatoid arthritis-related antigen (RA-A47) with downregulation upon stimulation by inflammatory cytokines in chondrocytes

We previously isolated a rheumatoid arthritis-related antigen (RA-A47) protein that had reactivity with RA sera from a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8. Sequencing analysis of ra-a47 cDNA revealed RA-A47 as a product of the colligin-2 gene, which is also known as the human heat shock protein (HSP) 47 gene. Expression of hsp47 has been shown to be cooperatively altered with that of collagen genes upon stimulation. In this study, it was confirmed that the mRNA expression of ra-a47 and COL2A1, a type II collagen gene, was upregulated on stimulation with transforming growth factor (TGF) beta in chondrocytes. However, in contrast, inflammatory cytokines such as tumor necrosis factor (TNF) alpha, interferon (IFN) beta, and interleukin (IL)-6 downregulated the expression of ra-a47 mRNA, whereas the expression of COL2A1 mRNA was not repressed, or even upregulated, in HCS-2/8 cells. Of note, inducible NO synthase (iNOS) and matrix metalloproteinase (MMP)-9 mRNAs were strongly stimulated by TNFalpha. We also found that cell-surface type II collagen disappeared upon such a stimulation, suggesting that decrement of RA-A47 may inhibit the secretion of type II collagen and lead to its accumulation inside the cells. RA-A47 was detected in the cultured medium of TNFalpha-treated HCS-2/8 cells and of IL-1-treated rabbit chondrocytes by Western blot analysis. Under the same conditions, RA-A47 was detected on the cell surface by immunofluorescence staining. These findings demonstrate that the RA-A47 chaperone protein is specifically downregulated, causing the intracellular accumulation of unsecretable type II collagen, while the extracellular matrix (ECM) is degraded by MMPs and iNOS through the stimulation of chondrocytes by TNFalpha. The altered localization of RA-A47 to the surface or outside of cells may represent the mechanism for the recognition of RA-A47 as an autoantigen during rheumatoid arthritis.

The efficacy of dexamethasone iontophoresis for the treatment of rheumatoid arthritic knees: a pilot study

OBJECTIVE

To examine the efficacy of dexamethasone sodium phosphate (DEX) iontophoresis for the treatment of rheumatoid arthritis (RA) of the knee, and to obtain statistical information for a future randomized controlled trial (RCT).

METHODS

Ten subjects with RA, ranging in age from 34-75, were randomly assigned to either the experimental or placebo group. Iontophoresis treatments were given to both groups on days 1, 3, and 5. Five subjects in the experimental group received a mixture of 1 ml of DEX (4 mg/ml) and 1 ml of injectable sterile water; those in the placebo group received 2 ml of saline solution. Pain on movement, at rest, and on pressure, active joint count, and active range of motion, were evaluated on days 1, 5, and 20. The patient's global assessment of treatment efficacy was also assessed on days 5 and 20. Mann-Whitney U tests and Friedman two-way analyses of variance were performed for statistical analyses.

RESULTS

Pain at rest was found to be statistically different between the two groups (P = 0.0317). Statistical significance was also found over time for pain on movement within the experimental group (P = 0.0224).

CONCLUSION

The results suggest that DEX iontophoresis is more effective than placebo in relieving pain at rest and on movement in the RA knee. Based on the study data, a total of 40 subjects will be required for an RCT of a similar nature.