Absolute immature platelet count dynamics in diagnosing and monitoring the clinical course of thrombotic thrombocytopenic purpura

作者:Hong Hong; Xiao Wenbin; Stempak Lisa M; Sandhaus Linda M; Maitta Robert W*
来源:Transfusion, 2015, 55(4): 756-765.
DOI:10.1111/trf.12912

摘要

BackgroundThrombotic thrombocytopenic purpura (TTP) is a life-threatening diagnosis requiring prompt initiation of therapeutic plasma exchange (TPE). Measurement of immature platelet (PLT) fraction (%-IPF) differentiates PLT consumption or destruction from hypoproduction. Study Design and MethodOur study evaluated %-IPF changes over the course of TTP treated with TPE and as a measure of treatment efficacy. Eleven idiopathic TTP patients, two human immunodeficiency virus (HIV)-associated TTP patients, and five non-TTP patients with thrombocytopenia were enrolled into our study. All patients were treated with TPE and had ADAMTS13 activity measured. ResultsAll idiopathic TTP patients had a significantly increased %-IPF and decreased absolute immature PLT count (A-IPC) and PLT count at presentation. An A-IPC value of less than 5x10(9)/L at presentation has 84.6% sensitivity, 80% specificity, and 91.7% positive predictive value for diagnosing TTP. A concurrent steady decline in %-IPF and increased PLT counts toward normal was observed in TTP patients undergoing TPE. The A-IPC, however, showed an increase and decrease curve that was not seen in the two HIV-associated TTP patients with no response to TPE and the five non-TTP patients. More importantly, reaching an A-IPC ratio of 3 compared to baseline value during TPE can readily differentiate idiopathic TTP from the other two groups and is correlated with good clinical responses to TPE. An abrupt increase of A-IPC during TPE was also noted in a TTP patient who relapsed 3 days before PLT count decrease. A-IPC is positively correlated with ADAMTS13 activity at presentation but negatively correlated with ADAMTS13 activity during recovery. ConclusionA-IPC should be routinely analyzed for diagnosing and monitoring TTP patients.

  • 出版日期2015-4