Proliferative response of peripheral blood mononuclear cells to autologous and allogeneic muscle in patients with polymyositis/dermatomyositis

Abstract
We examined the proliferative responses of peripheral blood mononuclear cells (PBMC) to autologous and homologous muscle homogenates in 21 patients with early, active, untreated polymyositis/dermatomyositis (PM/DM), 8 patients with chronic PM/DM, 10 patients with myopathies other than PM/DM, 7 patients with connective tissue diseases without myositis, and 12 healthy individuals. PBMC from patients with PM/DM and from control subjects were incubated with various dilutions of autologous and homologous muscle homogenates. PBMC from patients with active PM/DM underwent significant proliferation on exposure to both the autologous muscle and the homologous muscle homogenates. In contrast, PBMC from patients with chronic PM/DM, other myopathies, connective tissue diseases without myositis, and from healthy individuals did not respond to either autologous or homologous muscle. Our findings demonstrate that the PBMC of patients with PM/DM are sensitized to muscle.