OBJECTIVETo testify whether absolute neutrophil count (ANC) response to preimmunosuppressive-therapy (pre-IST) granulocyte-stimulating factor (G-CSF) treatment could predict early response to IST in severe aplastic anemia (SAA).

METHODSClinical data and hematologic response of 125 SAA patients treated with antithymocyte globulin (r-ATG) combined with cyclosporine were retrospectively analyzed. Correlation of ANC response to pre-IST G-CSF treatment and early response to IST were statistically analyzed, and receiver operating characteristic (ROC) curve was used to estimate the value of increased ANC (∆ANC) in predicting early IST response.

RESULTSThe hematologic response (HR) rate to IST in ANC reponded patients was significantly higher than non-responded group (3-month HR 49.0% vs 28.9%, P=0.023; 6-month HR 61.2% vs 40.8%, P=0.026). With ∆ANC≥0.5×10⁹/L as cutoff level, the best point to predict early IST response was 10 days after G-CSF (d 10). Response of ANC to pre-IST G-CSF treatment at d 10 was among the independent factors of predicting 3-month (P=0.004), but not for 6-month response to IST. The overall 5-year survival rate was 92.8% and 69.5% in ANC responded and non-responed groups, respectively (P=0.025).

CONCLUSIONResponding to pre-IST G-CSF treatment reflected the residual bone marrow hematopoiesis, and could act as a convenient and practical predictor to early IST response as well as long-term survival in SAA.