Journal of Clinical and Diagnostic Research (Dec 2021)
CD64 Expression by Neutrophils as a Diagnostic Marker for Sepsis: A Critical Evaluation
Abstract
Introduction: The increasing incidence of sepsis and its associated mortality has urged the search for rapid and reliable diagnostic test. Flow cytometry offers rapid assessment of change in antigen expression by neutrophils in blood in suspected sepsis cases. An increased expression of CD64, a high affinity opsonic surface receptor, by neutrophils is seen in sepsis. Aim: To critically analyse the role of neutrophilic CD64 expression by different possible flow cytometric parameters in sepsis. Materials and Methods: This case-control study was conducted in Department of Pathology of a Sri Guru Ram Rai Institute of Medical and Health Sciences, Dehradun, Uttarakhand, India from February 2017 to July 2019. It included peripheral blood samples from 43 cases of sepsis and their corresponding age matched controls. Flow cytometric analysis of blood samples for CD64 expression by neutrophils was done. The statistical analysis was performed with Statistical Package for Social Sciences (SPSS) version 18.0, Chicago, IL. Results: Flow cytometric analysis revealed a statistically significant increased expression of CD64 by neutrophils in sepsis patients, in terms of all four parameters analysedincreased expression of CD64 as compared to controls, in terms of percentage of neutrophils expressing CD64 (63.88±34.12 in cases), mean Fluorescent Intensity (FI) (2137.19±2319.71), Median Fluorescent Intensity (MFI), (2011.28±2261.89) as well as Neutrophil:Lymphocyte (N:L) CD64 index (7.29±9.66). Sensitivity and specificity of each parameter evaluated in present study varied from 60.4-67.4% and 81.4-83.7%, respectively. Conclusion: Quantitative expression of neutrophil CD64 (nCD64), by flow cytometry, in terms of percentage expression, MFI, mean fluorescent intensity and Neutrophils:Lymphocytes CD64 index is helpful in diagnosing sepsis patients even after 72 hours of onset. This is a rapid, reliable and cost-effective investigation. Hence, enabling prompt and judicious treatment of sepsis.
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