Spontaneous remission of aplastic anemia: a retrospective analysis

Although acquired aplastic anemia is usually a chronic disorder, a small proportion of patients with aplastic anemia was reported to recover spontaneously without specific therapy such as allogeneic bone marrow transplantation or immunosuppressive treatment. We attempted to determine the rate of spontaneous remission in the patients with AA.

We reviewed the medical records of adult patients (n=136) who were diagnosed as aplastic anemia at the Asan Medical Center from 1990 to 2000. The hematologic criteria of spontaneous remission were defined according to the proposed remission criteria of the SAA Working Party of the EBMT.

Eighteen (13%) of 136 patients satisfied the criteria for spontaneous remission at median 14 days (range, 4-332) from the diagnosis of aplastic anemia. In fifteen (83%) of 18 patients, spontaneous remission occurred within 50 days. Spontaneous remission was complete in fourteen patients (78%). Only two patients relapsed at 208 and 1,857 days after spontaneous remission, respectively. Multivariate logistic regression analysis showed that presence of infection at diagnosis (p = 0.017), drug as an etiology of aplastic anemia (p = 0.028), and serum albumin level less than 3.4 g/dL (p = 0.005) were independent predictive factors for spontaneous remission.

Our study confirmed that a minority of patients with AA recovered spontaneously. Spontaneous remission was rapid and complete in most patients, and relapses were rarely observed. In most cases with spontaneous remission, aplastic anemia might be associated with external factors such as drug or infection.