Neutrophil CD64 expression in cirrhotic patients with infected ascites

Background The early recognition of spontaneous bacterial peritonitis (SBP) is very important to avoid a bad prognosis. However, microbial cultures are time-consuming therefore, recent research focuses on the noninvasive and rapid markers for SBP diagnosis. The neutrophil CD64 (nCD64) expression has been studied as a biomarker of many infections and sepsis. Objectives This study was to evaluate the diagnostic value of peripheral blood nCD64 as a noninvasive biomarker in the diagnosis of ascitic fluid (AF) infection in cirrhotic patients. Patients and methods The study was conducted on 100 patients with cirrhosis and ascites. The total leukocytic count, procalcitonin, and C-reactive protein were performed on the blood sample in addition to AF parameters and culture. Peripheral blood nCD64 was done using flow cytometry and CD64 index was calculated. Results The nCD64% and index were significantly higher in patients with SBP and cirrhosis than in those without SBP. A positive correlation was found between the CD64 index and both AF-total leukocytic count and absolute neutrophil count. At cut-off value greater than 0.70, the optimal one, for nCD64 index with the area under the curve of 0.950 gave a sensitivity of 94% and specificity of 72% for discriminating SBP from noninfected ascites. Conclusion The nCD64 index could be used as a noninvasive marker which is sensitive, specific, and rapid for early prediction and the diagnosis of SBP in cirrhotic patients. Largo scale study is recommended to confirm the role of nCD64 (% and index) as a promising marker for therapeutic monitoring in SBP cases.