Fascin-expressing dendritic cells dominate in polymyositis and dermatomyositis.

OBJECTIVE

Dendritic cells (DC) have been reported among inflammatory infiltrating cells in muscle tissue in idiopathic inflammatory myopathies (IIM), but to our knowledge no studies concerning the expression of langerin (CD207) or fascin (markers of immature and mature DC, respectively) in IIM have been published.

METHODS

Immunohistochemical analyses of langerin and fascin expression were performed on specimens from normal muscles, as well as those affected by polymyositis (PM) and dermatomyositis (DM). The results were analyzed by Mann-Whitney U test.

RESULTS

In PM and DM, fascin-positive cells were numerous in the majority of the studied samples in perimysial, endomysial, and perivascular cellular infiltrates. Sporadic langerin-positive cells were detected.

CONCLUSION

Fascin-positive DC predominance in inflammatory infiltrates in myositic muscles confirms the prevalence of mature forms and indicates that there are conditions stimulating DC maturation in both PM and DM. The induction of immunological tolerance by inhibiting DC maturation may be a promising direction for studies of myositis treatment.