Definition of the Immune Parameters Related to COVID-19 Severity

Lymphocyte and neutrophil count combined with intestinal bacteria abundance predict the severity of COVID-19

IMPORTANCE

The 2019 coronavirus disease (COVID-19) patients had a unique profile of gut bacteria. In this study, we characterized the intestinal bacteria in our COVID-19 cohorts and found that there was an increased incidence of severe cases in COVID-19 patients with decreased lymphocytes and increased neutrophils. Levels of lymphocytes and neutrophils and abundances of intestinal bacteria correlated with the severity of COVID-19.

Peripheral blood parameters for predicting PICU admission and mechanical ventilation in pediatric inpatients with human parainfluenza virus-induced pneumonia

Human parainfluenza viruses (hPIVs)-induced pneumonia is an important cause of pediatric hospitalization, and some develop severe pneumonias requiring pediatric intensive care unit (PICU) admission and mechanical ventilation (MV). The aim of this study is to investigate the value of peripheral blood (PB) parameters available on admission in predicting the need for PICU admission and MV due to pneumonia caused by hPIVs. A total of 331 cases including 277 (83.69%) on the general ward (GW) and 54 (16.31%) on the PICU were enrolled between January 2016 and June 2021. Of 54 patients admitted to the PICU, 24 patients (7.25%) received MV, whereas 30 (9.06%) did not. For both the PICU and GW groups, infants accounted for the highest proportion while school children had the lowest. Compared with the GW group, the PICU group had significantly higher rates of premature birth, fatigue, sore throat, headache, chest pain, tachypnea, dyspnea, and underlying diseases including congenital tracheal stenosis, congenital heart disease (CHD), metabolic disorder, and neurological disorder (ND), but significant lower proportion of exclusive breastfeeding and Z-scores for weight-for-height, weight-for-age, height-for-age, and body-mass-index (BMI)-for-age (BMIZ). Higher levels of some leukocyte differential counts (LDC)-related parameters including counts of neutrophil (N), ratios of neutrophil-to-lymphocyte ratio (NLR), derived neutrophils/(leukocytes minus neutrophils) ratio (dNLR), and platelet-to-lymphocyte ratio (PLR), lower levels of some other LDC-related parameters including lymphocyte (L) and monocyte (M) counts, ratios of lymphocyte-to-monocyte ratio (LMR), lymphocyte-to-C-reactive protein ratio, and prognostic nutritional index (PNI), and lower levels of PB protein (PBP)-related parameters including red blood cell (RBC), hemoglobin, total protein (TP), and serum albumin were observed in the PB of patients in the PICU compared with those in the GW. Notably, higher PLR level and two comorbidities including CHD and ND were identified as independent risk factors for PICU admission, while lower PNI level as well as smaller numbers of RBC and L as good predictors. Low levels of TP might be a useful predictor of the need for MV. Overall, the relative contributions of LDC- and PBP-related factors for accurate identification of patients required PICU admission accounted for 53.69% and 46.31%, respectively. Thus, determination of whether a patient with hPIVs-induced pneumonia is admitted to PICU involves consideration of both the LDC- and PBP-related parameters.

T Cells Immunophenotyping and CD38 Overexpression as Hallmarks of the Severity of COVID-19 and Predictors of Patients' Outcomes

BACKGROUND

By the end of 2019, the COVID-19 pandemic spread all around the world with a wide spectrum of clinical presentations ranging from mild to moderate to severe or critical cases. T cell subtype dysregulation is mostly involved in the immunopathogenic mechanism. The present study aimed to highlight the role of monitoring T cell subtypes and their activation (expression of CD38) in COVID-19 patients compared to healthy subjects and their role in predicting severity and patients' outcomes.

MATERIALS

The study involved 70 adult COVID-19 confirmed cases stratified into three groups: a mild/asymptomatic group, a clinically moderate group, and a clinically severe/critical group. Flow cytometry analysis was used for the assessment of CD3⁺ cells for total T cell count, CD4⁺ cells for helper T cells (Th), CD8⁺ cells for cytotoxic T cells (Tc), CD4⁺CD25⁺ cells for regulatory T cells (T reg), and CD38 expression in CD4⁺ T cells and CD8⁺ T cells for T cell activation.

RESULTS

A statistically significant difference was found between COVID-19 cases and healthy controls as regards low counts of all the targeted T cell subtypes, with the lowest counts detected among patients of the severe/critical group. Furthermore, CD38 overexpression was observed in both CD4⁺ and CD8⁺ T cells.

CONCLUSION

Decreased T cell count, specifically CD8⁺ T cell (Tc), with T cell overactivation which was indicated by CD38 overexpression on CD4⁺ and CD8⁺ T cells had a substantial prognostic role in predicting severity and mortality among COVID-19 patients. These findings can provide a preliminary tool for clinicians to identify high-risk patients requiring vigilant monitoring, customized supportive therapy, or ICU admission. Studies on larger patient groups are needed.