title: Defective mitogenic responses in myasthenia gravis and multiple sclerosis.
abstract: Using in vitro lymphocyte proliferation induced by the phytomitogen concanavalin A (Con A), we investigated immune function and regulation in patients with myasthenia gravis (MG) and multiple sclerosis (MS). Unfractionated peripheral blood mononuclear cells of normal individuals responded to a wide range of ConA concentrations; the T cell fraction responded to a lesser degree and only to high concentrations. These findings suggest the presence of two receptors for ConA, one of high affinity present on a non-T cell accessory cell and the other of low affinity present on T cells. Contrasting defects in the level of response of unfractionated lymphocytes and T cells were found in patients with MG and MS. The peak response of T cells in the MG patients was 22.6 +/- 9.6 X 10(3) cpm (mean +/- SEM) compared with 54.6 +/- 6.5 X 10(3) for controls (p less than 0.05), while the response of unfractionated lymphocytes did not differ from that in controls. For MS patients, the unfractionated lymphocyte response was diminished: 56.3 +/-2.8 X 10(3) cpm versus 70.5 +/- 4.5 X 10(3) for controls (p less than 0.05), while the T cell response was normal. These results indicate a defect in the direct T cell response in MG; in contract, in MS the response requiring T cell-accessory cell interaction is abnormal.
mesh_terms: D000328:Adult; D000368:Aged; D003208:Concanavalin A / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D009103:Multiple Sclerosis / Q000276:immunology*; D009157:Myasthenia Gravis / Q000276:immunology*; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D003208:Concanavalin A