MEASUREMENT OF THE LEVELS OF RETICULATED PLATELETS AFTER PLATELETPHERESIS TO MONITOR ACTIVITY OF THROMBOPOIESIS

BACKGROUND: Little is known about the effects of long-term plateletphe resis on the donors' health. The aim of this study was to examine the effect of plateletpheresis on the time course of reticulated platelet counts as an estimate for thrombopoiesis. STUDY DESIGN AND METHODS: Th e effect of moderate platelet depletion on the thrombopoietic capacity was evaluated prospectively by the measurement of reticulated platele ts before and after plateletpheresis and on the following 4 days. Dono rs undergoing plateletpheresis for the first time were compared to tho se donating platelets every other week for more than 18 months. RESULT S: The median levels of reticulated platelets were significantly lower in frequent donors than in new donors. In new donors, there was a tra nsient increase in the median levels of reticulated platelets on Day 3 after apheresis, and baseline values were reached again on Day 4. On the contrary, in repeat donors, there was a sustained rise in the perc entage of reticulated platelets from Days 1 through 4. However, this i ncrease in reticulated platelet counts was still less than that seen i n new donors. There was no difference in the peripheral blood platelet counts in the two groups at any time point. CONCLUSION: These finding s suggest that repeat platelet donation might lead to a relative exhau stion of thrombopoiesis, as evidenced by the low levels of reticulated platelets exhibited by repeat donors. The reticulated platelet count can be used to monitor the thrombopoietic capacity of long-term platel et donors.