Blood cell morphology and COVID-19 clinical course, severity, and outcome

MDS-Type Morphologic Abnormalities of Peripheral Blood Granulocytes in Symptomatic COVID-19 Patients

Background: Hematological abnormalities in COVID-19 infection included quantitative and qualitative changes and should be further characterized. Evaluation for myelodysplastic syndromes (MDS) is usually prompted by abnormal hematologic findings and the presence of dysplastic morphologies. Viral infections are considered to be the cause of dysplastic morphologies and should be considered by morphologists. There are few reports of dysplastic abnormal morphologies in patients with COVID-19 infection. However, such correlations still have to be clarified. Materials and Methods: In the present study, we examined the granulocyte lineage morphological abnormalities in symptomatic RT-PCR-confirmed COVID patients. Peripheral blood samples were collected from 82 patients with symptomatic COVID-19. Blood smears were prepared according to the standard Wright-Giemsa staining procedure. The morphological examination was carried out by two laboratory experts. Results: Blood smear examination revealed common myelodysplastic syndrome (MDS) type abnormalities including but not limited to pseudo-pelger nuclear lobulation (4.8%), hypogranulation (7.3%), Howell-Jolly-like bodies or detached nuclear segments (6.0%) and elongated and thin nuclear filaments (6.0%). One case of abnormal immature granulocyte and ring form nucleus is also evident. Conclusion: Our results accounted for the possibility of active COVID-19 infection in all subjects with granulocyte dysplasia. These results are of practical importance for patients suspected of having myelodysplastic syndromes or disease processes associated with myeloid malignancies.

It's in the blood: a review of the hematological system in SARS-CoV-2-associated COVID-19

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an unprecedented global healthcare crisis. While SARS-CoV-2-associated COVID-19 affects primarily the respiratory system, patients with COVID-19 frequently develop extrapulmonary manifestations. Notably, changes in the hematological system, including lymphocytopenia, neutrophilia and significant abnormalities of hemostatic markers, were observed early in the pandemic. Hematological manifestations have since been recognized as important parameters in the pathophysiology of SARS-CoV-2 and in the management of patients with COVID-19. In this narrative review, we summarize the state-of-the-art regarding the hematological and hemostatic abnormalities observed in patients with SARS-CoV-2-associated COVID-19, as well as the current understanding of the hematological system in the pathophysiology of acute and chronic SARS-CoV-2-associated COVID-19.

Analysis of the Morphology of Monocytes and Lymphocytes from COVID-19 Patients Using Low-Voltage Scanning Electronic Microscopy

Severe course of COVID-19 is largely determined by hyperactivation of the immune system, or cytokine storm, in which immune cells (lymphocytes, monocytes, etc.) play a major role. Using low-voltage scanning electron microscopy, we studied the morphology of lymphocytes and monocytes during cytokine storm. Monocytes and lymphocytes were isolated by fluorescence sorting from the blood of healthy volunteers (n=6) and patients with COVID-19 (n=5) during cytokine storm (IL-6>23 ng/ml, smear positive for SARS-CoV-2). For each patient, 11-32 individual cells were analyzed at magnification of 18-32,000 times. Measurements showed that monocyte size was increased during cytokine storm (p=0.0001).

Systematic Evaluation of Hematologic Parameters and Blood Smear Findings in Patients With SARS-CoV-2 vs Other Viral Respiratory Infections

OBJECTIVES

We evaluated and compared the peripheral blood findings in patients with acute COVID-19 vs other viral respiratory infections.

METHODS

We retrospectively reviewed peripheral blood counts and smear morphology in patients with a positive viral respiratory panel (VRP) or SARS-CoV-2 test.

RESULTS

A total of 97 peripheral blood samples (COVID-19 infection, 53; VRP positive, 44) from 50 patients (mean [SD] age, 45.8 [20.8] years; females 52%) were reviewed. There were no statistically significant differences in the demographic characteristics between the 2 groups. The most common peripheral blood abnormalities were anemia, thrombocytopenia, absolute lymphopenia, and reactive lymphocytes. The following peripheral blood findings were significantly associated with other viral respiratory infections compared with COVID-19 infection: low red blood cell count, low hematocrit, high mean corpuscular volume, thrombocytopenia, low mean platelet volume, high red cell distribution width, band neutrophilia, and toxic granulation in neutrophils.

CONCLUSIONS

Our study showed that there are several peripheral blood count and morphologic abnormalities seen in patients with COVID-19, but most of these findings lack specificity as they are also seen in the other viral respiratory infections.

Preliminary Study of sCD14 and sCD163 as Predictors of Disease Severity and ICU Admission in COVID-19: Relation to Hematological Parameters, Blood Morphological Changes and Inflammatory Biomarkers

Background and Objectives

Research supports the role of monocyte/macrophage activation in COVID-19 immunopathology. This study aimed to evaluate sCD14 and sCD163 - the monocyte activation markers - and to investigate their relation to hematological parameters and blood morphology in COVID-19 infection.

Methods

This is a case-control study that included 70 COVID-19 patients. Patients were subdivided into two groups: 23 severely diseased ICU-admitted patients and another group of 47 non-ICU-admitted patients. sCD163 and sCD14 levels were determined using ELISA.

Results

sCD163 and sCD14 showed significantly higher levels in sera of patients compared to the control group, with significantly higher levels of sCD163 in ICU-admitted patients than non-ICU admitted patients. Receiver operating characteristic curve analysis demonstrated the usefulness of sCD163 with a cut-off value of 734 ng/mL as a potential marker to discriminate between ICU and non-ICU admitted COVID-19 patients (sensitivity of 81.16%; specificity of 96.67% and positive predictive value of 98% with area under the curve of 0.930). sCD163 levels showed a positive correlation with total white blood cells, absolute neutrophilic count, Neutrophil/Lymphocyte ratio, and a negative correlation with platelet count. sCD14 levels positively correlated with D-dimer values associated with a shift to the left and neutrophilic toxic granulations in blood morphology.

Conclusion

High sCD163 and sCD14 levels, hematological parameters, and blood morphology reflect monocyte activation in COVID-19 infection. sCD163 is a potential marker of disease severity. These findings support further study of therapeutics targeting macrophage activity in COVID-19 patients with high sCD163 levels.

Increased red blood cell deformation in children and adolescents after SARS-CoV-2 infection

Severe coronavirus disease 2019 (COVID-19) is associated with hyperinflammation, hypercoagulability and hypoxia. Red blood cells (RBCs) play a key role in microcirculation and hypoxemia and are therefore of special interest in COVID-19 pathophysiology. While this novel disease has claimed the lives of many older patients, it often goes unnoticed or with mild symptoms in children. This study aimed to investigate morphological and mechanical characteristics of RBCs after SARS-CoV-2 infection in children and adolescents by real-time deformability-cytometry (RT-DC), to investigate the relationship between alterations of RBCs and clinical course of COVID-19. Full blood of 121 students from secondary schools in Saxony, Germany, was analyzed. SARS-CoV-2-serostatus was acquired at the same time. Median RBC deformation was significantly increased in SARS-CoV-2-seropositive compared to seronegative children and adolescents, but no difference could be detected when the infection dated back more than 6 months. Median RBC area was the same in seropositive and seronegative adolescents. Our findings of increased median RBC deformation in SARS-CoV-2 seropositive children and adolescents until 6 months post COVID-19 could potentially serve as a progression parameter in the clinical course of the disease with an increased RBC deformation pointing towards a mild course of COVID-19.

Hematopathology of SARS-CoV-2 infection and COVID-19 disease

Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 and is associated with pronounced hematopathologic findings. Peripheral blood features are heterogeneous and very often include neutrophilia, lymphopenia, myeloid left shift, abnormally segmented neutrophils, atypical lymphocytes/plasmacytoid lymphocytes, and atypical monocytes. Bone marrow biopsies and aspirates are often notable for histiocytosis and hemophagocytosis, whereas secondary lymphoid organs may exhibit lymphocyte depletion, pronounced plasmacytoid infiltrates, and hemophagocytosis. These changes are reflective of profound innate and adaptive immune dysregulation, and ongoing research efforts continue to identify clinically applicable biomarkers of disease severity and outcome.

Parameters and Morphological Changes of Erythrocytes and Platelets of COVID-19 Subjects: A Longitudinal Cohort Study

Purpose

Information about dynamic changes occurring in the parameters and morphology of erythrocytes and platelets during the coronavirus disease 2019 (COVID-19) infection and convalescence is scarce. To explore potential associations between dynamic erythrocyte and platelet parameters, morphological changes, and the course or severity of the disease is essential.

Patients and Methods

From January 17th, 2020, to February 20th, 2022, we followed up on 35 patients with non-severe and 11 patients with severe COVID-19 following their discharge. We collected clinical features, dynamic complete blood count (CBC), and peripheral blood smears (PBS) and analyzed parameter and morphological changes of erythrocytes and platelets depending on the course or severity of the disease. The course of the disease included four periods, namely onset (T1), discharge (T2), 1-year follow-up (T3), and 2-year follow-up (T4).

Results

Red blood cell (RBC) counts and hemoglobin were the lowest in T2, followed by T1, and lower in T1 and T2 than in T3 and T4. Inversely, the red blood cell distribution width (RDW) was the highest in T2, followed by T1, and higher than in T3 and T4. Compared to non-severe patients, the platelet of severe patients was lower in T1 and T2. In contrast, the mean platelet volume (MPV) and platelet distribution width (PDW) tended to be higher in severe patients. Similarly, anisocytosis was more common in peripheral blood smears at early stages and in severe patients. Finally, large platelets were more common in severe patients.

Conclusion

Anisocytosis of erythrocytes and large platelets are found in patients with severe COVID-19, these changes may help primary hospitals to identify patients with a high risk of severe COVID-19 at an early stage.

Detection of abnormal lymphocytes in the peripheral blood of COVID-19 cancer patients: diagnostic and prognostic possibility

BACKGROUND

Peripheral morphological abnormalities play important roles in the early diagnosis and prognosis of the COVID-19 infection. The aim of the present study was to assess the morphological alterations in the peripheral blood (PB) cells in patients with COVID-19 infection, with special attention to a different group of atypical lymphocytes that had been observed in the PB of COVID-19 cancer and non-cancer patients.

METHODS

The PB cells were examined in 84 COVID-19 positive cancer patients, and 20 COVID-19 positive non-cancer patients, compared to 30 healthy normal controls. The data were correlated to the disease severity, patients' clinicopathological features, and outcomes.

RESULTS

There was an increased incidence of giant platelets, neutrophils shifting left, and abnormal monocytes in the COVID-19 positive cancer and non-cancer patients compared to the control group (P < .001, P < .001 and P = .014; respectively). Neutrophils with abnormal toxic granulations, Pseudo Pelger-Heut abnormality, and reactive lymphocytes were significantly increased in COVID-19 cancer patients compared to COVID-19 non-cancer patients and the control group (P = .001, P < .001, and P < .001; respectively). An abnormal form of lymphocytes' morphological changes (Covicytes) was significantly detected in COVID-19 cancer patients [60.7% (51/84)], and in COVID-19 non-cancer patients [55% (11/20)], while it was absent in the normal controls [0.0% (0/30), P < 0.001]. The presence of the Covicytes is associated significantly with a better prognosis in cancer and non-cancer COVID-19 patients.

CONCLUSION

Covicytes could be a useful marker supporting the diagnosis of SARS-COV-2 infection, and it is associated with a favorable prognosis.

Coronavirus disease 2019 (COVID-19): Focus on peripheral blood cell morphology

Numerous studies have shown peculiar morphological anomalies in COVID-19 patients' smears. We searched all the peer-reviewed scientific publications that explicitly reference the cytomorphological alterations on peripheral blood smears of patients with COVID-19. We extracted data from sixty-five publications (case reports, patient group studies, reviews, and erythrocyte morphology studies). The results show that frequent alterations concern the morphology of lymphocytes (large lymphocytes with weakly basophilic cytoplasm, plasmacytoid lymphocytes, large granular lymphocytes). Neutrophils display abnormal nuclei and cytoplasm in a distinctive cytomorphological picture. Besides a left shift in maturation, granulations can be increased (toxic type) or decreased with areas of basophilia. Nuclei are often hyposegmented (pseudo-Pelger-Huёt anomaly). Apoptotic or pycnotic cells are not uncommon. Monocytes typically have a large cytoplasm loaded with heterogeneous and coalescing vacuoles. Platelets show large and giant shapes. The presence of erythrocyte fragments and schistocytes is especially evident in the forms of COVID-19 that are associated with thrombotic microangiopathies. Such atypia of blood cells reflects the generalized activation in severe COVID-19, which has been demonstrated with immunophenotypic, molecular, genetic, and functional methods. Neutrophils, in particular, are involved in the pathophysiology of hyperinflammation with cytokine storm, which characterizes the most unfavorable evolution.

Detection of erythroid progenitors and erythrocytopathies in patients with severe COVID-19 disease

OBJECTIVES

To assess the effect of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection on erythropoiesis and red blood cells (RBC) surface markers by evaluating erythroid progenitor cells (CD [cluster of differentiation]71⁺/CD235a⁺) and RBC surface markers (CD235a and CD36), together with various hematological parameters.

METHODS

This case-control study includes 47 participants recruited in the study: 30 patients with coronavirus disease 2019 (COVID-19) and 17 healthy individuals. The COVID-19 patients were recruited from the intensive care unit (ICU) of various hospitals in Makkah, Saudi Arabia. Blood samples were collected during July and September 2021. Red blood cells indices were measured using a CBC analyzer. The expression of CD235a, CD71, and CD36 was obtained using flow cytometry technique. The unpaired t-test was conducted to evaluate the differences in these markers in COVID-19 patients and healthy individuals.

RESULTS

The data showed that more than half of the COVID-19 patients were anemic (64%). Expansion of erythroid progenitors (CD71⁺/CD235a⁺) was detected in the COVID-19 patients. Analysis of the expression of RBC surface markers, such as CD235a and CD36, showed that SARS-CoV-2 was associated with significantly higher expression of these markers in COVID-19 patients.

CONCLUSION

Severe acute respiratory syndrome coronavirus-2 promoted the expansion of erythroid progenitors in the peripheral blood of COVID-19 patients. In addition, the expression of RBC surface markers was higher in COVID-19 patients. The expansion of erythroid progenitors and alteration of RBC surface markers can contribute to erythrocytopathies observed in severe COVID-19 patients and can therefore be used as prognostic factors.

Platelets in Viral Infections - Brave Soldiers or Trojan Horses

Viral infections are often associated with platelet activation and haemostatic complications. In line, low platelet counts represent a hallmark for poor prognosis in many infectious diseases. The underlying cause of platelet dysfunction in viral infections is multifaceted and complex. While some viruses directly interact with platelets and/or megakaryocytes to modulate their function, also immune and inflammatory responses directly and indirectly favour platelet activation. Platelet activation results in increased platelet consumption and degradation, which contributes to thrombocytopenia in these patients. The role of platelets is often bi-phasic. Initial platelet hyper-activation is followed by a state of platelet exhaustion and/or hypo-responsiveness, which together with low platelet counts promotes bleeding events. Thereby infectious diseases not only increase the thrombotic but also the bleeding risk or both, which represents a most dreaded clinical complication. Treatment options in these patients are limited and new therapeutic strategies are urgently needed to prevent adverse outcome. This review summarizes the current literature on platelet-virus interactions and their impact on viral pathologies and discusses potential intervention strategies. As pandemics and concomitant haemostatic dysregulations will remain a recurrent threat, understanding the role of platelets in viral infections represents a timely and pivotal challenge.

Laboratory medicine in pandemic of COVID-19

After the outbreak in China in the year 2019, severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) quickly spread around the world causing a protracted pandemic. Approximately one-third of infections appear to be asymptomatic. Symptomatic disease is characterized primarily by symptoms of respiratory tract infection of varying severity. But Coronavirus Disease 2019 (COVID-19) is much more than an acute respiratory disease because SARS-CoV-2 affects many organs inducing a vast number of symptoms such as cardiovascular, neurological, gastrointestinal, dermatological, with numerous complications. Short and long-term effects of infection, severe ones, and especially mild forms of the disease which affect a huge number of patients need to be further investigated. Laboratory medicine has a crucial role in early diagnosis of the disease, recognition of the patients who need hospital care, and close monitoring of hospitalized patients to timely identify associated clinical complications as well as follow-up of patients with long-term COVID-19.