Recovery from neutropenia can be predicted by the immature reticulocyte fraction several days before neutrophil recovery in autologous stem cell transplant recipients.

ABSTRACT

The duration of neutropenia (absolute neutrophil count (ANC) < or = 100/microl) identifies cancer patients at risk for infection. A test that precedes ANC > or = 100/microl would be of clinical value. The immature reticulocyte fraction (IRF) reflects erythroid engraftment and hence a recovering marrow. We evaluated the IRF as predictor of marrow recovery among 90 myeloma patients undergoing their first and second (75 patients) melphalan-based autologous stem cell transplantation (Mel-ASCT). The time to IRF doubling (IRF-D) preceded ANC > or = 100/microl in 99% of patients after the first Mel-ASCT by (mean+/-s.d.) 4.23+/-1.96 days and in 97% of the patients after the second Mel-ASCT by 4.11+/-1.95 days. We validated these findings in a group of 117 myeloma patients and 99 patients with various disorders undergoing ASCT with different conditioning regimens. We also compared the time to hypophosphatemia and to absolute monocyte count > or = 100/microl to the time to ANC > or = 100/microl. These markers were reached prior to this ANC end point in 55 and 25% of patients but were almost always preceded by IRF-D. We conclude that the IRF-D is a simple, inexpensive and widely available test that can predict marrow recovery several days before ANC> or = 100/microl.