AIM To evaluate the numbers of different subsets of monocytes and their associations with the values of clinical measures in mild acute pancreatitis(MAP) patients.METHODS The study included one group of 13 healthy controls and another group of 24 patients with new-onset MAP. The numbers of different subsets of monocytes were examined in these two groups of subjects by flow cytometry. The concentrations of plasma interleukin(IL)-10 and IL-12 were determined by cytometric bead array. The acute physiology and chronic health evaluation(APACHE) II scores of individual patients were evaluated, and the levels of plasma C-reactive protein(CRP) as well as the activities of amylase and lipase were measured. RESULTS In comparison with that in the controls, significantly increased numbers of CD14+CD163-, CD14+CD163-MAC387+ M1 monocytes, but significantly reduced numbers of CD14+CD163+IL-10+ M2 monocytes were detected in the MAP patients(P < 0.01 or P < 0.05). Furthermore, significantly higher levels of plasma IL-10 and IL-12 were observed in the MAP patients(P < 0.01 for all). More importantly, the levels of plasma CRP were positively correlated with the numbers of CD14+CD163-(R = 0.5009, P = 0.0127) and CD14+CD163-MAC387+(R = 0.5079, P = 0.0113) M1 monocytes and CD14+CD163+CD115+ M2 monocytes(R = 0.4565, P = 0.0249) in the patients. The APACHE II scores correlated with the numbers of CD14+CD163+CD115+(R = 0.4581, P = 0.0244) monocytes and the levels of plasma IL-10(R = 0.4178, P = 0.0422) in the MAP patients. However, there was no significant association among other measures tested in this population. CONCLUSION Increased numbers of CD14+CD163- and CD14+ CD163-MAC387+ monocytes may contribute to the pathogenesis of MAP, and increased numbers of CD14+CD163+CD115+ monocytes may be a biomarker for evaluating the severity of MAP. AIM To evaluate the numbers of different subsets of monocytes and their associations with the values ​​of clinical measures in mild acute pancreatitis (MAP) patients. METHODS The study included one group of 13 healthy controls and another group of 24 patients with new-onset MAP. The numbers of different subsets of monocytes were examined in these two groups of subjects by flow cytometry. The concentrations of plasma interleukin (IL) -10 and IL-12 were determined by cytometric bead array. The acute physiology and chronic health evaluation (APACHE) II scores of individual patients were evaluated, and the levels of plasma C-reactive protein (CRP) as well as the activities of amylase and lipase were measured. RESULTS In contrast with that in the controls, significantly increased numbers of CD14 + CD163-, CD14 + CD163-MAC387 + M1 monocytes, but significantly reduced numbers of CD14 + CD163 + IL-10 + M2 monocytes were detected in the MAP patients (P <0.01 or P <0.05). More importantly, the levels of plasma CRP were positively correlated with the numbers of CD14 + CD163- (R = 0.5009, P = 0.0127) and CD14 + CD163-MAC387 + (R = 0.5079, P = 0.0113) M1 monocytes and CD14 + CD163 + CD115 + M2 monocytes (R = 0.4565, P = 0.0249) in the patients. The APACHE II scores correlated with the numbers of CD14 However, there was no significant association among other measures tested in this population. (R = 0.4581, P = 0.0244) monocytes and the levels of plasma IL- 10 (R = 0.4178, P = 0.0422) . CONCLUSION Increased numbers of CD14 + CD163- and CD14 + CD163-MAC387 + monocytes may contribute to the pathogenesis of MAP, and increased numbers of CD14 + CD163 + CD115 + monocytes may be a biomarker for evaluating the severity of MAP.