Cell-mediated immunity to myoglobin in polymyositis.

Using the leucocyte migration inhibition (LIF) test we looked for evidence of cell-mediated hypersensitivity against myoglobin in 8 patients with polymyositis (PM) or dermatomyositis (DM). The migration index for PM-DM patients was 47.5 +/- 17%, while in the controls the index was 86 +/- 12% (p less than 0.001). The presence of serum antibodies against myoglobin was also investigated by passive haemagglutination (PH) and counterimmunoelectrophoresis (CIE). By PH the reciprocal titre of antimyoglobin antibodies was 150 +/- 28 in PM-DM compared with 16.2 +/- 15.9 and 8.7 +/- 7.7 in control patients with diseases (p less than 0.01) and negative in normal persons. CIE showed antimyoglobin antibodies in 3 PM-DM patients and in none of controls. Cell-mediated immunity against myoglobin may be implicated in the pathogenesis of PM. The pathological significance of antimyoglobin antibodies remains to be determined.