[Peripheral blood macrophages in diagnosis of acute infected pancreatic necrosis]

To establish a laboratory marker of infection in destructive pancreatitis based on peripheral blood macrophage response.

A prospective study (2019-2024) enrolled 78 patients with phase IB and II acute pancreatitis. Macrophage response was assessed three times (on days 1-2, 7-8, and 18-20) using native blood smears stained with methylene blue and examined under microscopy in six fields of view. Quantitative parameters (leukocytosis, leukocyte intoxication index, qSOFA, Dzhanelidze, Ranson, and Balthazar scores) were analyzed with correlation coefficients (Pearson and Spearman tests).

In patients with infected necrosis, there was a significant increase in macrophage count (from 0.5±0.5 to 1.5±1.0 cells per six fields; p<0.001), whereas macrophage count remained unchanged in the aseptic group (0.1±0.3). Macrophage count moderately correlated with leukocytosis (r=0.48), leukocyte intoxication index (r=0.50), severity scores (ρ=0.34-0.49), and necrosis area (r≈0.50; p<0.001).

Original method enables detection of infected necrosis as early as phase II of acute pancreatitis and may serve as a guide for timely surgical intervention.