Evaluation of platelet parameters in pediatric thrombocytopenic patients

R. Knöfler, S. Hackel, B. Arneth, J. Lohse, J. Stächele, O. Tiebel (Dresden, Germany)

Platelets - Physiology and Disorders of platelet number and function
Date: 17.02.2017,
Time: 17:15 - 18:15

Objective: The underlying reason of thrombocytopenia in children should be clarified to initiate effective or to avoid unnecessary treatment. For differential diagnostics the measurement of some relatively new platelet parameters (mean platelet volume - MPV, relative and absolute immature platelet fraction – rIPF and aIPF, plateletcrit - PCT, platelet distribution width – PDW, platelet large cell ratio - P-LCR) may be useful but only limited data are available until now. As presented on the GTH congress in 2016, we already determined reference values for these parameters in healthy children of different age groups. In the next step we now evaluated the parameters in pediatric thrombocytopenic patients.

Methods: Data were collected retrospectively in 98 children with the following diagnoses: acute ITP (n=19), chronic ITP (n=17), acute leukemia (n=33; 25 with acute lymphoblastic leukemia - ALL, 4 with ALL relapse and 4 with acute myeloid leukemia), inherited impairment of haematopoiesis (n=23; 8 with thrombocytopenia-absent radius syndrome, 6 with inherited thrombocytopenia of unknown origin, 3 with inherited macrothrombocytopenia, 3 with Wiskott-Aldrich syndrome, 2 with Fanconi anemia and 1 with May-Hegglin anomaly) and acquired impairment of haematopoiesis (n=6; 5 with myelodysplastic syndrome and 1 with severe aplastic anemia). Parameters were determined in 200 µl EDTA-anticoagulated blood using the fully automated haematology analyser Sysmex XE 5000.

Results: Patients with acute ITP showed significantly lower platelet counts and higher rIPF values compared to the groups of acute leukemia and of impaired hematopoiesis. Children with chronic ITP displayed significantly elevated rIPF values in comparison with the acute leukemia group and a significantly increased MPV compared to leukemia patients and children with impaired haematopoiesis. For aIPF and the other parameters no significant differences among the groups were detected.

Conclusion: In the context of the patient’s individual history and a careful clinical examination, the determination of rIPF might be helpful in the thrombocytopenic child to distinguish acute ITP from acute leukemia and a disorder with impaired haematopoiesis. This hypothesis should be investigated in a prospective setting. The relevance of other platelet parameters remains unclear yet.