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 chemokine receptors 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, %CD4+CXCR3+ and %CD8+CXCR3+ T cells significantly decreased in 33 DM patients, and %CD8+CXCR3+ cells decreased in 24 PM patients, but %CD4+CCR4+ and %CD8+CCR4+ cells did not significantly change in both the PM and DM patients. Accordingly, the Th1/Th2 polarization, analyzed as the balance obtained after dividing %CD4+CXCR3+ cells by %CD4+CCR4+ cells, showed a significant reduction in DM. The serum concentration of CXCR3+ ligand, CXCL10, significantly increased and negatively correlated with circulating %CD4+CXCR3+ cells in DM patients. There was no significant change of TARC and MDC in PM and DM patients. Furthermore, %CD4+CXCR3+ 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.