Myasthenia gravis: stimulation of antireceptor autoantibodies by autoreactive T cell lines.

We studied autoreactive acetylcholine receptor (AChR)-specific T cell lines from two patients with myasthenia gravis. Anti-AChR autoantibody production by peripheral blood mononuclear cells (PBM) from the donors of the T cell lines was measured with an enzyme-linked immunoadsorbent assay, using purified human AChR as antigen. Freshly isolated PBM produced barely detectable amounts of anti-AChR autoantibodies. If, however, autologous AChR-specific T cells were added to the cultures, the production of anti-AChR autoantibodies, and of total IgM and IgG, was markedly stimulated, depending on the number of T line cells and on the amount of AChR present in the cultures. AChR-specific functional helper T-lymphocytes may have a role in the immunoregulation of myasthenia gravis.