Background: Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine (CSA) is standard therapy in patients with severe aplastic anemia (SAA) who do not have an available HLA-matched sibling donor.
Methods and patients: The current study aimed to determine the predictive factors for response to IST in patients with SAA and to identify prognostic factors following IST. A total of 62 patients diagnosed with SAA who received IST with either rabbit ATG (n = 33) or horse ATG (n = 29) plus CSA between October 1994 and December 2007 were included.
Results: With a median follow-up duration of 60.5 months, complete response and overall response were estimated to be 31% and 53%, respectively. The 4 yr overall survival rate was 75 + or - 6%. In terms of predicting the response to IST, neutrophil counts above 0.3 x 10(9)/L prior to IST were the only significant predictive factor (P = 0.02). Survival following IST was significantly different in favor of both the group showing high absolute reticulocyte counts (ARC) above 10.9 x 10(9)/L prior to IST (P = 0.004) and the group achieving any response following IST (P = 0.002).
Conclusions: Pre-IST neutrophil counts might predict the response to IST, while absolute ARCs prior to IST and response status after IST could be prognostic factors following IST.