PB1319 - Observation of neutrophil extracellular traps (NET-s) in pediatric group of patients with chronic myeloproliferative disease.

Tuesday, June 25, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

EA

Ekaterina Adamanskaya

Junior researcher
Center for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia
Moscow, Moskva, Russia
EY

Eugenia Yushkova

Junior researcher
Center for Theoretical Problems of Physico-Сhemical Pharmacology
Moscow, Moskva, Russia
NP

Nadezhda Podoplelova

Senior Researcher
Center for Theoretical Problems of Physico-Сhemical Pharmacology
Moscow, Moskva, Russia
AP

Alexey Pshonkin

Hematologist, Head of day hospital department, P.h.D.
Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
NS

Natalia S. Smetanina

Professor
Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia

Presenting Author(s)

Ekaterina V. Shamova, PhD

Head of Laboratory of Medical Biophysics
Institute of biophysics and cell engineering NAS of Belarus, Minsk, Belarus
Minsk, Minskaya Voblasts', Belarus

Co-Author(s)

AS

Anastasia N. Sveshnikova

Head of Laboratory
Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
Moscow, Moskva, Russia

Background: Neutrophils’ ability to release DNA into extracellular space and form nets those capture and destroy various pathogens is well known. However, there is a lack of reliable methods for assessing the propensity of neutrophils to produce NET-s. In chronic myeloproliferative disease (CMP) platelet count is several fold increased leading to thrombosis risk.

Aims: Assessment of granulocytes state in pediatric patients with CMP.

Methods: 50 CMP pediatric patients, 3 patients with various types of leukemia, and 10 healthy donors (12-25 years) were recruited into the study. PFA-fixed smears of EDTA-anticoagulated leukocyte rich plasma were stained with Hoechst 33342, anti-myeloperoxidase (MPO) and anti-neutrophil elastase (Ela) antibodies, and analyzed with Nikon Ti2 AX confocal microscope. Raw tiff images of cells could be found at https://osf.io/yvj2c/?view_only=5903fc6574424131a731cc612dabfc3d.

Results: At least 100 neutrophils were examined for each patient. The nucleated cells observed in all samples could be divided into eight groups: suicidal NET (sNET, Fig. 1A), vital NET (vNET, Fig. 1B), whole neutrophil (WN), eosinophil (E), smudge cell (Scell, Fig. 1C), monocyte (M), lymphocyte (L), or other nucleated cell (Ocell). The amount of Ocells did not exceed 1%. The level of NETosis was calculated as (sNET + vNET)/ (sNET + vNET + WN). The level of NETosis in healthy donors did not exceed 12%, being 3-4% in most donors. For CMP patients the level of NETosis was 40-68%. In CMP patients a significant portion of neutrophils shifted to sNETs. In patients with leukemia many Scells were observed instead of sNETs, while some vNETs were detected.

Conclusion(s): The level of NETosis is significantly increased in patients with CMP.
The study was supported by Russian Science Foundation grant 23-45-10039, and B23-RSF162.