Evaluation of Serum Leptin Level as Early Marker in Early Onset Neonatal Sepsis

Background: Despite improved neonatal care over the past decades, sepsis remains a common and life-threatening condition among neonates admitted to NICU. Human leptin plays a role in the activation of the immune system and act as a mediator of inflammation. Leptin deficiency is associated with increasing frequency of infections and it is also involved in the mediation of the systemic response to sepsis. Objective: The present study was designed to evaluate the level of serum leptin in cases of early onset neonatal sepsis and its importance in early diagnosis. Methodology: This case control study included 50 full term newborns #3 days suspected clinically as having EOS (cases group) and another 30 apparently healthy, age and sex matched neonates as control group. They were recruited from NICU of Al Azhar University Hospital (New Damietta) during the period from May, 2013-June, 2015. All cases with suspected neonatal sepsis according to clinical sepsis score were submitted to laboratory investigations including Complete Blood Count (CBC) that including red blood Cell counts (RBCs), hemoglobin (Hb) Total Leukocyte Count (TLC), Absolute Neutrophils Count (ANC), immature/total count ratio (I/T), C-Reactive Protein (CRP), blood culture (for cases) and serum leptin level by ELIZA. Results: Regarding demographic data, there was non-significant difference between cases and control as regard age, sex, gestational age, birth weight and delivery mode. As regard laboratory data, there was non-significant difference between cases and control as regard RBCs (p = 0.097), Hb (p = 0.1) and platelet count (p = 0.396), while cases had significant increase of TLC, ANC, I/T ratio, CRP and leptin levels (p<0.001). There was a significant positive correlation between leptin from one side and both CRP and ANC from the other side. As regard ability of serum leptin levels to predict neonatal sepsis it had a good sensitivity as denoted by the area under curve (0.89), the best cut-off value was selected to be 2.5 ng dLG1 (according to simultaneous best sensitivity and specificity). At this cut-off value, sensitivity was 98% and specificity was 74%. Conclusion: Study revealed that serum leptin level was elevated early in cases of EOS and it seems that it may have a role in its early diagnosis at cut-off point 2.5 ng dLG1 with sensitivity 98% and specificity 74%. Recommend measurement of serum leptin level early on suspicion of EOS which may aid in confirming the diagnosis. However, large, prospective multi-centre studies should be done to confirm the association between early high serum leptin level and EOS.