Abstract:
Objective : To investigate the causes of early COVID-19 complicated with platelets(PLT) abnormality, and to analyze the possible mechanisms.
Methods: The case datum of early COVID-19 complicated with PLT increase or decrease was collected. (125-350) ×109/L defined as the normal level of PLT(Group C), <125×109/L was defined as the PLT decrease group (Group A), >350×109/L defined as the PLT increase group (Group B) . The data were analyzed after collected.
Results: Our statistical results showed that the incidence of COVID-19 combined PLT decreased was about 11.94% and the incidence of combined PLT increased was about 9.33% at admission. Compared with Group B and C, Group A showed a significant decrease in white blood cell, neutrophil and CD4 (P<0.05). The lymphocyte in Group A and C decreased significantly, but not find in Group B (P<0.05). Compared with Group A and C, IL-4 was increased in Group B, but lymphocyte decline was not significant (P>0.05).
Conclusion: PLT abnormalities occur in all patients with different types of COVID-19. It may be related to the severity of inflammation and infection, immune regulation and megakaryocyte function, etc.
Keywords: COVID-19, PLT, Megakaryocyte
The interaction between PLT and endothelial cells has been shown to play a role in the formation of acute lung injury caused by influenza virus(Rommel et al.,2019). Study have reported that PLT reduction in COVID-19 patient(Huang et al.,2020). We found that PLT was not only decreased, but also increased in many COVID-19 patients. In this paper, COVID-19 complicated with PLT abnormality cases at admission were collected and analyzed.
1. Research objects and test methods
Retrospective study COVID-19 patients are admitted to the Tumor Center affiliated to Tongji Medical College of Huazhong University of Science and Technology. PLT abnormality case datum was gathered. Indicators including WBC, RBC, hemoglobin, neutrophils, lymphocytes and T lymphocyte subsets, cytokines (IL2, 4, 6, 8, 10, TNF -α, IFN -γ), CRP and PCT. and according to the PLT clinical reference range divide 3 groups, (125-350) ×109/L defined as the normal level of PLT(Group C), <125×109/L was defined as the PLT decrease group (Group A), >350×109/L defined as the PLT increase group (Group B). Comparing the above indicators between each group. Exclusion criteria: prior to COVID-19, there were underlying diseases or drugs that caused PLT abnormalities, pregnant women,and so on.
COVID-19 diagnostic criteria: Refer to the COVID-19 Diagnosis and Treatment Protocol (Trial version 6). Novel Coronavirus nucleic acid positive(test by real-time FLUORESCENCE RT-PCR). Clinical classification: critical, severe and normal (including light in article)type. All patients were treated in the same way after admission, including regular CT, nucleic acid test, oral antiviral, anti-inflammatory,etc.
2. Statistical methods
Data were analyzed by SPSS22.0 software and checked by T-test, chi-square test or Fisher’s exact probability test. P<0.05 was considered statistically significant.
3.Results
3.1 In our study, we had investigated 268 COVID-19 patients and found 32 cases (11.94%) PLT decreased patients at admission, including 22 males and 10 females. The age ranged from 29 to 84 years old. most of them were≥60 years old. the PLT value were between (15-124 )×109/L, but only 8 cases were lower than 100 ×109/L. Among them, 2 case were critically severe type, 16 were heavy type, and 14 were normal type. 25 patients ( 9.33% )  PLT increased been found at admission, including 16 males and 9 females. The age ranged from 23 to 83 years old, and the PLT value were between (351-541) ×109/L, of which only 1 case was critical heavy type, 13 cases were heavy type, and 11 cases were normal type.
3.2 There was no statistically significant difference between the three groups in terms of RBC and hemoglobin at admission (P>0.05), as shown in table 1. Compared with Group B and C, there was a decrease in WBC in Group A (P<0.05). The lymphocyte in Group A and C decreased significantly compared with Group B (P<0.05). The absolute value/percentage of neutrophils and the percentage of lymphocytes were not significantly different (P>0.05), as shown in table 1-2.
3.3 Among the 57 patients with abnormal PLT, except for one in group A, the values of PCT of the other 56 patients were in the normal range; IFN-γ was normal too; Only one case patient,s NF-α was elevated in each group. There was no significant difference in the comparison of CD3, IL2, IL4, and IL10 among patients in the three groups at admission (P> 0.05), but CD4 in Group A was lower than that in Group B and C(P<0.05), as shown Table 3-4. IL-6 was increased in all patients, but the range of IL-6 values fluctuated widely. There were more cases of IL-6 value ≥ 50 pg / ml in Group A, while B and C Group have no significant difference(P> 0.05); CRP was not statistically significant in the number of cases (P> 0.05), but values ≥50mg / L, Group A was more than Group B (P <0.05). IL-4 value in Group B was significantly higher than that in Group C(P <0.05), but there was no significant difference between Group A and C.