Thymic lymphocyte function in myasthenia gravis

Mitogen and muscle extract induced in vitro proliferative responses in myasthenia gravis, dermatomyositis, and polymyositis.

“…Using this technique, significant inhibition of migration of leucocytes from patients with myasthenia or polymyositis induced by several fractions of muscle extract has been reported (Alpert et al, 1972;Goust et al, 1974). Armstrong et al (1973) have demonstrated a similar inhibition by muscle extract of the migration of thymic cells obtained from myasthenics at thymectomy.…”

“…Using such techniques, studies have been published suggesting that cell-mediated hypersensitivity to muscle is a concomitant and perhaps causative mechanism of both myasthenia gravis (Alpert et al, 1972;Goust et al, 1974) and polymyositis Johnson et al, 1972;Dawkins and Mastaglia, 1973;Esiri et al, 1973;Goust et al, 1974;Haas and Arnason, 1974). Evidence has likewise been presented, using lymphocyte mediated cytotoxicity and inhibition of thymic cell migration, suggesting that there are cells within the myas-thenic thymus sensitized to muscle (Armstrong et al, 1973). We sought to investigate the in vitro proliferative response to muscle extract in the peripheral blood of patients with myasthenia gravis as well as in patients with polymyositis and dermatomyositis and to compare these with the responses in blood lymphocytes of controls.…”

Phenotypic and functional analysis of lymphocytes in myasthenia gravis

“…Thymic lymphocytes from patient specimens in general did not show enhanced proliferative responses in the presence of muscle extract [63]. However, thymic cells were found to enhance PHA-induced cytotoxicity to muscle cells in culture [7], an effect not seen with thymic cells from non-myasthenic controls. The exact target specificity of these muscle-directed responses is unknown.…”

Genetic associations between myasthenia gravis and the HL-A system.

“…Several findings support the concept of alterations in the cell-mediated immunity, the well-known thymus pathology in about 80% of patients, the frequent presence of muscle lymphorrhages, the increased cytotoxicity of myasthenic lymphocytes both in vivo (Namba et al, 1969a, b) and in vitro (Armstrong et al, 1973), and the migration inhibition of myasthenic lymphocytes in the presence of muscle antigen (Alpert et al, 1972;Kott et al, 1973) and thymus antigen (Vejjajiva et al, 1974).…”