Abstract Number: PB1003
Meeting: ISTH 2021 Congress
Theme: Platelets and Megakaryocytes » Platelet Function and Interactions
Background: PTEM whole mount (WM) is a standard method for evaluating platelet dense granules (pDG). However, a pediatric/adolescent pDG reference range (RR) and prevalence of pDG deficiency in symptomatic patients has not been well-established.
Aims: This study aimed to establish a pediatric/adolescent RR for mean pDG and determine the prevalence of pDG deficiency in a cohort of patients who had clinical suspicion for platelet disorders (PD).
Methods: First, WM-PTEM was performed on healthy donors. A mean pDG RR was calculated by averaging DG of 100 plt per patient as previously described (PMID: 29863946). Next, patients undergoing laboratory evaluation of suspected PD were recruited to this study. In addition to routine laboratory testing, their ISTH BAT score (normal <3; abnormal >3) was correlated with mean pDG.
Results: Healthy donors (n=77, 41.6% female), ages 3-18 years, had a mean pDG 2.7 (+/- 0.5) ranging from 1.9 to 3.8. The mean pDG did not correlate with age or gender. The tentative RR was calculated to be 1.9 to 3.8 DG/platelet. Nineteen patients over the age of three (25.3%, n=19/75) had <1.9 mean pDG. Of the 75 symptomatic patients (age 3-18 years, 69.3% female), 42 and 33 patients had BAT scores >3 and <3 (range 0-11), respectively. DG/plt in pt with bleeding scores >3 (mean=2.3 +/- 0.83, n = 42) vs. those with bleeding scores < 3 (mean=2.3+/-0.66, n = 32) (p=.206) were similar. There was no difference in the number of patients with normal or abnormal bleeding scores in groups with normal vs decreased mean DG/plt (p=.595).
Conclusions: In this study, we established a tentative pediatric RR for platelet DG at 1.9 – 3.8 DG/plt. Approximately 25% of patients were found to have DG deficiency. However, pDG did not not correlate with the ISTH BAT.
To cite this abstract in AMA style:
Greenmyer J, Warad D, Howell K, Fischer K, Stromback L, Gibbons T, Charlesworth J, Barness R, Gossman S, Gamez J, Pruthi R, Chen D. Evaluation of Platelet Dense Granules by Transmission Electron Microscopy (PTEM) in Pediatric Patients and Healthy Pediatric Donors [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/evaluation-of-platelet-dense-granules-by-transmission-electron-microscopy-ptem-in-pediatric-patients-and-healthy-pediatric-donors/. Accessed June 25, 2022.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/evaluation-of-platelet-dense-granules-by-transmission-electron-microscopy-ptem-in-pediatric-patients-and-healthy-pediatric-donors/