An early warning indicator of mortality risk in patients with COVID-19: the neutrophil extracellular traps/neutrophilic segmented granulocyte ratio

Background

Neutrophil extracellular traps (NETs) play a key role in thrombus formation in patients with coronavirus disease 2019 (COVID-19). However, the existing detection and observation methods for NETs are limited in their ability to provide quantitative, convenient, and accurate descriptions of in situ NETs. Therefore, establishing a quantitative description of the relationship between NETs and thrombosis remains a challenge.

Objective

We employed morphological observations of blood cells and statistical analyses to investigate the correlation between the NETs/neutrophilic segmented granulocyte ratio and mortality risk in patients with COVID-19.

Methods

Peripheral blood samples were collected from 117 hospitalized patients with COVID-19 between November 2022 and February 2023, and various blood cell parameters were measured. Two types of smudge cells were observed in the blood and counted: lymphatic and neutral smudge cells. Statistical data analysis was used to establish COVID-19 mortality risk assessment indicators.

Results

Morphological observations of neutrophilic smudge cells revealed swelling, eruption, and NETs formation in the neutrophil nuclei. Subsequently, the NETs/neutrophilic segmented granulocyte ratio (NNSR) was calculated. A high concentration of NETs poses a fatal risk for thrombus formation in patients. Statistical analysis indicated that a high NNSR was more suitable for evaluating the risk of death in patients with COVID-19 compared to elevated fibrinogen (FIB) and D-dimer (DD) levels.

Conclusion

Observing blood cell morphology is an effective method for the detection of NETs, NNSR are important markers for revealing the mortality risk of patients with COVID-19.

Smudge Cells in Chronic Lymphocytic Leukemia: Pathophysiology, Laboratory Considerations, and Clinical Significance

Chronic lymphocytic leukemia (CLL) is the most commonly encountered leukemia in the clinical laboratory. Cytoskeletal defects in CLL lymphocytes can result in the formation of up to 75% smudge cells (SCs) during blood film preparation. Failure to account for these damaged lymphocytes in the white blood cell (WBC) differential diminishes the accuracy and reproducibility of the results. Lacking clear practice standards on handling SCs in CLL, different laboratories may employ different methods to mitigate SC-induced errors. This review explores the pathophysiology of SCs, their effect on WBC differentials in CLL, and how these results can impact clinical decisions. The pros and cons of various SC corrective methods are described to assist laboratories in developing an optimized protocol to reduce errors and inconsistencies in WBC differentials. Finally, the potential utility of SC enumeration as an indicator of CLL prognosis is discussed in terms of laboratories with differing access to technology.

Clinical Significance of Smudge Cells in Peripheral Blood Smears in Hematological Malignancies and Other Diseases

BACKGROUND

It is reported that the percentage of smudge cells in the blood smear could be a prognostic indicator in chronic lymphocytic leukemia. However, the clinical significance of smudge cells in other hematological malignancies, solid tumors or non-malignant diseases is less clear. Hence, this study was conducted to survey the clinical significance of smudge cells in hematological cancers and other disorders.

MATERIALS AND METHODS

From January to November, 2015, the clinical data of patients who received blood examination with differential counts for clinical purpose and were found to have smudge cells in the peripheral blood film in Far Eastern Memorial Hospital were selected. The percentage of smudge cells and patient outcomes were evaluated for further univariate and survival analyses.

RESULTS

A total of 102 patients with smudge cells in their blood smears were included. Smudge cells were frequently presented in out-of-hospital cardiac arrest (OHCA; n=30), infections (n=23), hematological cancers (n=23) and solid cancers (n=10). There was no relationship between the percentage of smudge cells and the patient mortality in all diseases (OR: 1.08, 95% CI: 0.47-2.48, P=1.000) as well as the OHCA group (OR: 1.91, 95% CI: 0.38-9.60, P=0.694). It was observed that in patients with all cancers with the percentage of smudge cells less than 50% had a lower mortality rate in comparison with those who had the percentage of smudge cells of 50% or more (OR: 22.29, 95% CI: 2.38-208.80, <0.001). Additionally, it was seemingly that patients with smudge cells of 50% or more had a lower survival rate than those with smudge cells less than 50% in all cancers with follow-up at 2-month intervals, but without statistical significance (P=0.064).

CONCLUSIONS

Our survey indicated that in all cancers, those who had higher percentage of smudge cells were prone to have poor outcomes when compared with the subjects with lower percentage of smudge cells. This finding was quite different from the results of previous studies in which the race-ethnicity of most study populations was non-Asian; hence, further investigations are required. Besides, there was no apparent association of the percentage of smudge cells with patient outcomes in all diseases, including OHCA.