Pure red cell aplasia and thymoma: demonstration of persisting inhibition of erythropoiesis after thymectomy and resolution after immune suppressive treatment.

A 61 year-old woman presented with general malaise, hair loss, pure red cell aplasia (PRCA) and thymoma: no growth of erythropoietic colonies in vitro (BFU-E) was observed in the presence of her own serum. The thymoma was removed: after the operation no improvement of her anaemic condition was observed and colony growth was very poor, although T-depleted narrow preparations showed a modest BFU-E formation in autologous serum. Following treatment with azathioprine, a complete recovery was seen, associated with normal BFU-E formation in vitro. This observation suggests that a complex inhibition of erythropoiesis may operate in PRCA involving both humoral and cellular factors; thymectomy alone may not be sufficient to restore haemopoiesis, but has to be followed by immune suppressive treatment.