[Erythroblastopenia during recurrence of a thymoma associated with myasthenia gravis. Apropos of a new case].

A new case of thymoma, myasthenia gravis and pure red cell aplasia is presented. Pure red cell aplasia came out 10 years after the diagnosis of the two other diseases in one of several relapses of metastatic thymoma with clinical signs of myasthenia. Surgery, chemotherapy and radiotherapy besides pyridostigmine treatment were used in the clinical course of the patient. A phenotypical change of medullary T lymphocytes (CD4 to CD8) was observed at the same time of pure red cell aplasia diagnosis. A dual role of medullary CD2+ T cell lymphocytes, stimulant and suppressive, over erythroid progenitor cells (BFU-E and CFU-E) was suggested by in vitro cultures.