Myasthenia gravis after allogeneic bone marrow transplantation treated with mycophenolate mofetil monitored by peripheral blood OX40+ CD4+ T cells

A patient who developed myasthenia gravis (MG) 25 months after allogeneic bone marrow transplant was immunologically analyzed. OX40(+) CD4(+) T cells in the peripheral blood prominently increased one month before the onset of MG. CD4/CD8 ratios, usually abnormally inverted in patients with chronic graft-vs.-host disease (cGVHD), showed pseudonormalization during the course of MG. We succeeded in uneventful rapid tapering of prednisolone (PSL) using mycophenolate mofetil (MMF). Monitoring of OX40(+) CD4(+) T cells supported the tapering of PSL and MMF as a marker of cGVHD activity. This case suggested the utility of MMF and monitoring of OX40(+) CD4(+) T cells in the management of cGVHD-associated autoimmune diseases.