Serum chemokine IL-8 acts as a biomarker for identifying COVID-19-associated persistent severe acute kidney injury.

OBJECTIVES: Persistent severe acute kidney injury (PS-AKI) is associated with poor clinical outcomes. Our study attempted to evaluate the diagnostic value of chemokines for early-stage PS-AKI prediction. METHODS: According to the KDIGO criteria, 115 COVID-19 patients diagnosed with stage 2/3 AKI were recruited from the intensive care unit between December 2022 and February 2023. Primary clinical outcomes included detecting PS-AKI in the first week (≥ KDIGO stage 2 ≥ 72 h). Cytometric Bead Array was used to detect patient plasma levels (interleukin-8 (IL-8), C-C chemokine ligand 5 (CCL5), chemokine (C-X-C Motif) ligand 9 (CXCL9), and interferon-inducible protein 10 (IP-10)) of chemokines within 24 h of enrollment. RESULTS: Of the 115 COVID-19 patients with stage 2/3 AKI, 27 were diagnosed with PS-AKI. Among the four measured chemokines, only the IL-8 level was significantly elevated in the PS-AKI group than in the Non-PS-AKI group. IL-8 was more effective as a biomarker while predicting PS-AKI with an area under the curve of 0.769 (0.675-0.863). This was superior to other biomarkers related to AKI, including serum creatinine. Moreover, plasma IL-8 levels of >32.2 pg/ml on admission could predict PS-AKI risk (sensitivity = 92.6%, specificity = 51.1%). Additionally, the IL-8 level was associated with total protein and IL-6 levels. CONCLUSION: Plasma IL-8 is a promising marker for the early identification of PS-AKI among COVID-19 patients. These findings should be validated in further studies with a larger sample size.

Analysis of mitochondrial function in lymphocytes obtained from COVID-19 patients.

OBJECTIVES: There is a significant decline in the lymphocyte subset counts in the peripheral blood of COVID-19 patients. However, the mitochondrial function of lymphocytes obtained from COVID-19 patients has rarely been studied. METHODS: A case-control study was conducted in 115 COVID-19 patients and 50 healthy controls from December 2022 to February 2023. The extent of lymphocytic mitochondrial damage in these patients using mitochondrial fluorescence staining and flow cytometry. Clinical symptoms were evaluated using the SOFA and APACHE II scores. RESULTS: The mitochondrial function of lymphocytes was severely impaired in the peripheral blood of COVID-19 patients, compared to healthy controls, and was characterized by an increased single-cell mitochondrial mass (SCMM) and increased percentage of low mitochondrial membrane potential. The increase in the SCMM of T cells was more notable in patients with severe COVID-19 and was positively correlated with the SOFA and APACHE II scores. When the SCMM-CD8 cutoff value was 38.775, the AUC for distinguishing between severe and mild COVID-19 was 0.740, and the sensitivity, specificity, and Youden index were 65.8%, 82.1%, and 0.478, respectively. CONCLUSION: SCMM-CD8 could act as a diagnostic biomarker of COVID-19 progression. However, this needs to be verified in other multi-center studies with a larger sample size.

Diagnostic Utility of CD64 and CD38 Biomarkers for the Differential Diagnosis of Infections.

Purpose: Identification of infection type in patients with fever is particularly important in the emergency departments (EDs) of hospitals. This study was designed to evaluate the performance of two biomarkers, the modified neutrophil CD64 (nCD64) index and CD38 presence on T cells, using flow cytometry. Methods: A total of 305 potentially infected patients with fever were admitted to the ED of Zhongda Hospital (Nanjing, China) between March 2021 and August 2021. This study included three groups of patients: bacterial (N = 180), viral (N = 30) , and uninfected (N = 65) based on their final diagnostic outcomes and clinical records. Results: The expression level of traditional/modified nCD64 was significantly increased in the bacterial infection group, especially in case of patients infected with Gram-negative bacteria. The most prevalent species were Staphylococcus spp. and Escherichia coli. In contrast, CD3+CD38+ cell percentages were elevated in patients with viral infections, which were mostly caused by Epstein-Barr virus and cytomegalovirus. CD38 expression is age dependent, and higher percentages of CD3+CD38+ cells were observed in children with viral infections. For the prediction of bacterial infections, the area under the curve (AUC) of modified nCD64 (AUC: 0.800) was significantly higher than that of C-reactive protein and heparin-binding protein but slightly lower than that of traditional nCD64 (AUC: 0.831). The AUC, specificity, and sensitivity values for the prediction of viral infections using CD3+CD38+ cells percentages in children were 0.899 (0.785-1.000), 96.2%, and 85.9%, respectively. Conclusion: nCD64 levels and CD3+CD38+ cell percentage are potential biomarkers that facilitate identification of patients with bacterial and viral infections.