Evaluation of Immature Platelet Fraction as a Marker of Platelet Recovery in Prophylactic Platelet Transfusion

Kim, Hyunjung; Kim, Myungshin; Lim, Jihyang; Han, Kyungja; Cho, Byung Sik; Cho, Seok Goo; Lee, Jong Wook; Min, Woo Sung; Kim, Yonggoo

Abstract

BACKGROUND: It has been known that the increase of reticulated platelets indicates the increase of thrombopoiesis in platelet consumptive diseases or the impending platelet recovery in patients with thrombocytopenic conditions. A new rapid automated method to assess reticulated platelets, the immature platelet fraction (IPF), was recently introduced. We evaluated the usefulness of the IPF for the prediction of platelet recovery in patients after hematopoietic stem cell transplantation (HSCT) and cytotoxic chemotherapy.
METHODS
Thirty one healthy volunteers and 59 patients formed 3 groups: the allogenic HSCT group (n=23, an ABO major-mismatch 6 of 23), the autologous HSCT group (n=8) and the cytotoxic chemotherapy group (n=28). The platelet count, % of IPF and the % of reticulocytes were checked every day by using a Sysmex XE-2100.
RESULTS
The IPF in the healthy volunteers was a mean of 2.2+/-1.6% (range: 0.3~6.7%), and the maximum level of the IPF in the patient group was 6.1+/-1.7% (range: 3.3~13.5%). The ideal cut-off value of the IPF increase to discriminate the platelet recovery group was 5.1%. When this cut-off value is used, the positive predictive value is 90.9% in the HSCT groups and 87.5% for the total patients. The 4 patients who showed an IPF higher than 5.1% without platelet recovery were in platelet consumptive conditions. It took 8.0+/-8.3 days to show platelet recovery after elevation of the IPF over 5.1% and an ABO major mismatch HSCT doesnt affect platelet recovery.
CONCLUSION
The IPF is thought to be a useful parameter for the prediction of platelet recovery after HSCT and cytotoxic chemotherapy, but the problem of the patient' conditions affects the accuracy of the IPF, and the variable intervals between the increase of the IPF and platelet recovery is thought to be improved.