Phenotypic features and subset composition of monocytes in acute pancreatitis

The aim of our research was to study the features of activation receptor expression on various subsets of blood monocytes in patients with acute pancreatitis (AP). 69 patients aged 37-62 years with moderateand severe-grade AP were examined. The diagnosis of AP was based on the results of clinical, laboratory and instrumental examination. Phenotype and subpopulation composition of monocytes were studied by flow cytometry. Alterations in blood monocytes phenotypes and increased expression of activation receptors were noted in patients during the initial period of AP. Thus, an increased proportion of monocytes in the blood of patients with AP with co-expression of CD45RO and CD62L was detected, along with increased number of cells expressing CD25 receptor. An increased level of migratory monocyte activity in AP could be linked with CXCR4 and CCR5 receptors. Altered subset composition during the acute period of AP was linked with 2-fold increased levels of “non-classical” monocytes. The proportion of cells with expression of chemokine receptors in the subset composition of monocytes changed in AP. Thus, the number of “classical” and “nonclassical” monocytes with CXCR4 was increased within total monocyte subset in the patients. Meanwhile, the content of cell subsets with CCR5 receptor expression was almost uniformly increased. The changed expression levels of activation receptors also characterized the activation features of various monocyte subsets in patients during the initial period of AP. Elevated CCR5 was detected in AP only on “classical” monocytes, whereas increased CD64 was found only on “non-classical” monocytes. Elevated HLA-DR expression was detected on “classical” and “intermediate” monocytes of patients with AP but a high level of CXCR4 expression was found on all monocytes subsets. The registered changes in phenotype and subset composition of monocytes in patients during the initial period of the disease seem to characterize the mode of monocyte involvement into the inflammatory process in AP thus revealing not only pro-inflammatory reaction of monocytes, along with increased activity of monocyte subset with anti-inflammatory function.