Functional activity of neutrophilic granulocytes as an early marker of infectious inflammation in acute pancreatitis

Acute pancreatitis represents an initially aseptic inflammation of the pancreas gland. Emergency patients with acute pancreatitis have both concomitant, and/or pancreas-associated foci of infection. Granulocytes are considered immediately responding effector cells in acute inflammation, and their response to aseptic or infectious inflammation may be different. The purpose of our study was to determine some functional characteristics of granulocytes as early markers of the infectious process in acute pancreatitis. The course of the disease was followed in 95 patients (20 to 80 years old) admitted to the I. Dzhanelidze Research Institute of Emergency Care with a diagnosis of acute pancreatitis in 2022-2024, The severity of acute pancreatitis was determined according to the urgent assessment scale at the I. Dzhanelidze Research Institute of Emergency Care, distinguishing between mild, moderate and severe grades of the disease. Venous blood samples were examined on days 1, 3 and 10 of hospitalization. Granulocyte counts and the granulocyte reactivity index (Neut-RI) were estimated by means of flow cytometry. We have also determined absolute numbers of CD14+ granulocytes, contents of soluble CD14 receptors (sCD14) in blood serum, and concentrations of soluble defensin NHP1, an antimicrobial granulocyte peptide. Moreover, the contents of systemic inflammation markers (IL-6 and procalcitonin) were assayed in blood. Statistical analysis was performed using the StatTech v. 4.6.1 program. Local or systemic infections were observed in 57% of patients with acute pancreatitis (from 28% in the edematous form to 83% in the severe cases). On days 1 and 3 of hospitalization, the highest significance for detection of bacterial infection was established for Neut-RI (on days 1 and 3, respectively, p < 0.001 and p < 0.001), sCD14 (p = 0.004 and p = 0.044), and NHP1 defensin (p = 0.014 and p = 0.007). The severity of acute pancreatitis is associated with presence of focal and/or systemic bacterial infection. Indexes refllecting inflammatory activity of neutrophilic granulocytes, i.e., granulocyte reactivity (Neut-RI), levels of soluble NHP1 defensin and CD14, allow to determine the presence and/or risk of local or systemic bacterial infection in patients within several hours after their admission to hospital. Granulocyte reactivity index (Neut-RI) is a feasible rapid test for detection of infectious inflammation in acute pancreatitis.