Polymyositis

To the Editor: In his excellent review (Nov. 21 issue),¹ Dr. Dalakas referred to a case of polymyositis that we described² as one that was “mediated by T cells expressing the γ/δ receptor, which have cytotoxic activity restricted to the MHC-I [major-histocompatibility-complex class I] antigen.” We wish to emphasize that the mere colocalization of MHC-I antigen and γ/δ T cells does not necessarily imply that the antigen functions as the restrictive element of γ/δ T cells. Although the existence of γ/δ T cells recognizing MHC-I antigen has been formally demonstrated,³ the majority of such cells apparently recognize antigens either independently.