Prognostic performance of neutrophil CD64 expression in patients with complicated intra-abdominal infections - a prospective study

No study yet analyzed the prognostic abilities of neutrophil CD64 expression (nCD64) in complicated intra-abdominal infections (cIAIs), therefore our aim was to evaluate the possible association between this biomarker and outcome in such patients. This single-center prospective study was conducted in the Department of Surgical Diseases at a University Hospital 'Prof. Dr. Stoyan Kirkovich' Stara Zagora for the period November 2018 - August 2021. We used flow cytometry to measure the percentage of nCD64 preoperatively and on the 3(rd) postoperative day (POD) in 62 patients with cIAIs and 31 healthy controls. Of the 62 enrolled patients, nine (14.5%) died during hospitalization. The perioperative expression of nCD64 was significantly higher in non-survivors compared to survivors (p = 0.02 before surgery and p = 0.024 after surgery). ROC Curve analysis revealed the good prognostic value of pre- and postoperative nCD64 levels as mortality predictors (AUROC = 0.744 and 0.765, respectively). Preoperatively, the identified sensitivity and specificity for nCD64 cut-off = 94.8% were 66.7% and 84.6%, respectively and on the 3(rd) POD for nCD64 cut-off = 84.85% we observed a sensitivity of 71.4% and a specificity of 78.8%. Neutrophil CD64 shows good prognostic value in patients with cIAIs both preoperatively and on the 3(rd) POD.