Human leukocyte antigen-DR expression on peripheral monocytes may be an early marker for secondary infection in severe acute pancreatitis.

Background/Aims: To investigate whether the human leukocyte antigen-DR (HLA-DR) expression on peripheral monocytes can be utilized as a precursor to a secondary infection of severe acute pancreatitis (SAP). Methodology: Patients diagnosed with SAP who were admitted into West China Hospital within 48 h after symptom onset from July 1, 2010 to December 31, 2010 (n = 40) were included. HLD-DR expression on peripheral monocytes on the 1st, 3rd, 5th and 7,th day of hospitalization was detected with flow cytometry analysis to determine whether a prediction could be made in regards to development of a secondary infection. Results: There were 11 patients with secondary infection complications, 4 of which died during hospitalization. On the 1st, 3rd, 5th and 7th day, HLA-DR expression on monocytes in the infected patients was lower than those in the noninfected patients (P <0.05). There was no statistical significance in the serum CRP and APACHE II between the groups on the first day (P >0.05). Upon initial admission HLA-DR expression showed a negative correlation with longer-term admission APACHE II (r = -0.790, P = 0.000) and serum CRP (r = -0.642, P = 0.000). The area under the ROC curve (AUC) was 0.837 (95%CI: 0.685-0.989, P = 0.001) for admission HLA-DR, 0.809 (95% CI: 0.667-0.951; P = 0.003) for APACHE II score and 0.781 for serum CRP (95% CI: 0.627-0.934; P = 0.007) to predict secondary infection. The cut-off value of prediction of secondary infection was 35.8% in HLA-DR expression with a sensitivity of 81.8% and a specificity of 82.8%, 10.5 in APACHE II on admission with a sensitivity of 90.9% and a specificity of 48.3%, 155 mg/L in serum CRP on admission with a sensitivity of 90.9% and a specificity of 44.8%. Conclusions: The HLA-DR expression on monocytes may be an ideal marker for an early prediction of secondary infection in SAP.