Increased myeloperoxidase activity as an indicator of neutrophil-induced inflammation and sepsis in neonates

Background: MPO is an enzyme that contains heme secreted by phagocytic cells after the respiratory burst system activation. MPO is expressed mainly by neutrophils and monocytes in small quantities and it is very important to determine further process of hydrogen peroxide. Objective: to evaluate neutrophils activation and the MPO enzyme activity in plasma as an indicator of sepsis as well as sepsis severity in neonates with sepsis with correlation to their clinical and laboratory findings. Methods: were classified into 2 groups: sepsis group: included 45 neonates with gestational ages 28-40 weeks with sepsis, 15 of them had been subjected to follow up samples, control group: included 30 neonates proved to be free of sepsis. All neonates were subjected to history taking, clinical examination and measurement of plasma MPO enzyme. Results: this study revealed that MPO activity and neutrophil cell count are increased in sepsis group compared to the non-septic neonates. The ROC curve showed that the best cut off for MPO in prediction of septic patients and mortality was found >54 mu/ml and >83 mu/ml respectively. There was positive correlation between MPO enzyme activity and the total leukocyte count and neutrophil count. By following up some of sepsis group neonates there was significant decrease in MPO activity goes along with improvement in clinical state of neonates with sepsis. MPO enzyme activity was found to be low in septic shock patients who also have pancytopenia compared to septic patients without shock. Conclusion: plasma MPO enzyme proved to be a good marker of sepsis in neonates, with a good prognostic value in severe cases. Keywords: MPO, inflammatory response, neonates, sepsis