Pathogenetic significance of large forms of platelets in complication of COVID-19 

Nadezhda I. Mikulyak, Doctor of medical sciences, associate professor, head of the sub-department of human physiology, Medical Institute, Penza State University (40 Krasnaya street, Penza, Russia),  normphys@mail.ru
Il'ya A. Sorokin, Student, Medical Institute, Penza State University (40 Krasnaya street, Penza, Russia),  iluh30072001@yandex.ru
Larisa A. Sorokina, Candidate of medical sciences, head of the Clinical and Diagnostic Laboratory, K.R. Evgrafov Regional Psychiatric Hospital (28 Lermontova street, Penza, Russia), sorlora@mail.ru
Aleksandr S. Kinzirskiy, Doctor of medical sciences, professor of the sub-department of human physiology, Medical Institute, Penza State University (40 Krasnaya street, Penza, Russia), akinz@inbox.ru
Ekaterina D. Kostrigina, Senior lecturer of the sub-department of maxillofacial surgery, Medical Institute, Penza State University (40 Krasnaya street, Penza, Russia),  kostriginaed1987@yandex.ru

Background. The presence of large platelets in the pulmonary vessels was first reported by Aschoff as early as 1893. Somewhat later it was discovered that up to half of the entire blood platelet pool could be formed by thrombopoietic cells deposited in the pulmonary capillaries. Because of the nature of the cytokine storm in COVID-19, pulmonary platelets may play a significant role in the development of fatal thromboembolic complications. In addition, there are a large number of clinical conditions in which large platelets are also found. Young large platelets contain a large number of granules with cytokines such as RANTES, IL-1β, etc., which contribute to the release of other pro-inflammatory cytokines that stimulate even more platelet synthesis. The purpose of the study is to compare changes in platelet indices in patients who died and died from coronavirus infection. Materials and methods. 149 results of platelet indices of the general blood count were analysed in 94 patients with identified coronavirus infection. The results were divided into 3 groups: those who died of COVID-19, those who did not die of COVID-19 of the same, older age and those who did not die of COVID-19 of younger age. The following platelet indices were considered: PLT, MPV, PDW, P-LCR. Results and conclusions. The deceased patients (70,6 ± 11,4 years old) had lower platelet count (p<0,01) and higher PDW, P-LCR indices (p<0,05) compared to the patients who didn't die from COVID-19, which indicates both percentage and absolute increase of the large platelet fraction. In the study, we looked at changes in several platelet indices: PLT, MPV, PDW, P-LCR in patients with COVID- 19. Deceased patients (70.6 ± 11.4 years) showed decreased platelet count (p<0.01) and increased PDW, P-LCR indices, compared to patients who did not die from COVID-19. Conclusions. The presence of macrothrombocytes in deceased patients indicates their increase over time, providing an opportunity for its timely screening and predicting the development of thromboembolic complications pro COVID-19.

macrothrombocytes, COVID-19, thrombosis, P-LCR, PDW, PLT, MPV

Mikulyak N.I., Sorokin I.A., Sorokina L.A., Kinzirskiy A.S., Kostrigina E.D. Pathogenetic significance of large forms of platelets in complication of COVID-19. Izvestiya vysshikh uchebnykh zavedeniy. Povolzhskiy region. Meditsinskie nauki = University proceedings. Volga region. Medical sciences. 2023;(3):232–241. (In Russ.). doi: 10.21685/2072-3032-2023-3-21