Lymphocyte stimulation with muscle homogenate in polymyositis and other muscle-wasting disorders.

Polymyositis is a non-hereditary disorder chiefly affecting the musculature of the limb girdles, neck, and pharynx (Walton and Adams, 1959; Barwick and Walton, 1963); it has features suggesting an immunological pathogenesis-notably the histology, the association with collagen disorders and malignancy, and the responsiveness to steroids and immunosuppressive agents (Walton and Adams, 1959; Barwick and Walton, 1963; Rose and Walton, 1966; Logan, Bandera, Mikkelsen, and Duff, 1966; Winkelmann, Mulder, Lambert, Howard, and Diessner, 1968; Malaviya, Many, and Schwartz, 1968). Direct evidence is scanty and conflicting as to whether the immunological processes involved are of the direct humoral or the delayed hypersensitivity type. Tests of skin sensitivity in cases of dermatomyositis associated with malignancy and the passive transfer of this sensitivity by sera (Grace and Dao, 1959; Curtis, Heckaman, and Wheeler, 1961) suggest a humoral mechanism, while the frequency of circulating antibodies is not higher in cases of polymyositis than in control cases (Caspary, Gubbay, and Stern, 1964). A delayed hypersensitivity mechanism is implied for human polymyositis if the myositis induced by injections of muscle and adjuvant Dawkins, 1965)-and possibly mediated by lymphocytes (Kakulas, 1966a; Kakulas, 1966b)-is taken as an experimental analogue of the disease. On the other hand, polymyositis has occurred in association with Hodgkin's disease (Deep, Fraumeni, Tashima, and McDivitt, 1964), in whichthere is an early depression of delayed hypersensitivity (Aisenberg, 1966) and impaired lymphocyte transformation with phytohaemagglutinin (Hersh and Oppenheim, 1965). 'Specific' antigens, many of which cause delayed hypersensitivity reactions, may transform from 2 to 40% of lymphocytes from previously sensitized subjects (Oppenheim, 1968), and this is a means of detecting lymphocyte sensitization to a particular antigen. In this paper we report the results of lymphocyte stimulation with homogenized muscle antigen in patients with polymyositis, with other muscle-wasting disorders, and unaffected controls.