IMMUNODEFICIENCY IN PATIENTS WITH MYASTHENIA GRAVIS AND A THYMOMA

Introduction Thymomas are a well-described concurrence in patients with Myasthenia Gravis. We describe two adult patients with Myasthenia Gravis and a thymoma who have undergone a total thymectomy and were found to have immune dysregulation. Case Description Two patients with years of recurrent infections were subsequently diagnosed with Myasthenia Gravis and a thymoma. Years after their thymectomies, they were found to have divergent immune aberrations. Patient 1 had decreased CD19+B cells (2%), and increased CD8+T cells (52%), associated with hyper gammaglobulinemia, MGUS, and poor antibody responses to polysaccharide antigens. Patient 2 was hypo gammaglobulinemic (IgG, IgM) with markedly increased CD19+ B cells (32%), low switched memory B cells-8% (normal 19-53%), decreased CD8+ T cells (2%) with normal naive, memory CD4+, CD8+, and TEMRA T cells. She also had poor antibody responses to polysaccharide antigens. Genetics for TACI and CTLA-4 were negative. Both patients were studied years post-thymectomy with no known immune studies pre-thymectomy. Discussion We describe two patients with a history of recurrent, poorly controlled infections and Myasthenia Gravis. Both patients presented with divergent immune abnormalities. These patients are different in their presentation from Good's syndrome, a separate immune deficiency with a thymoma often associated with Myasthenia Gravis. In general, thymectomy even in infants is not involved in marked immune aberrations except for precocious mild immune senescence with low memory CD3+CD8+CD57+ T cells. It is therefore unlikely that the immune aberrations in our patients are related to the thymectomy, but rather represent two new divergent immune aberrations leading to Myasthenia Gravis.