Altered chemokine receptor expression in the peripheral blood lymphocytes in polymyositis and dermatomyositis.

OBJECTIVE

To examine the expression of chemokine receptors in different peripheral blood T-cell subsets in patients with polymyositis (PM) and dermatomyositis (DM).

METHODS

We used flow cytometry to measure the frequencies of chemokinereceptors CXCR3 and CCR4 expression in the CD4 or CD8 lymphocytes. Enzyme linked immunosorbent assays were also used to measure the concentrations of C-X-C motif chemokine 10 (CXCL10), thymus and activation regulated chemokine (TARC) and macrophage derived chemokine (MDC).

RESULTS

Comparing to 20 healthy controls, %CD4CXCR3 and %CD8CXCR3 T cells significantly decreased in 33DM patients, and %CD8CXCR3 cells decreased in 24PM patients, but %CD4CCR4 and %CD8CCR4 cells did not significantly change in both the PM and DM patients. Accordingly, the Th1/Th2 polarization, analyzed as the balance obtained after dividing %CD4CXCR3 cells by %CD4CCR4 cells, showed a significant reduction in DM. The serum concentration of CXCR3 ligand, CXCL10, significantly increased and negatively correlated with circulating %CD4CXCR3 cells in DM patients. There was no significant change of TARC and MDC in PM and DM patients. Furthermore, %CD4CXCR3 cells decreased more severely in the patients with interstitial lung disease.

CONCLUSIONS

The present results indicate that the distributions of circulating CXCR3 T-cells differ among the PM and DM cases. Our findings suggest a pathogenic difference between PM and DM.