A study of leukocyte surface antigen CD64, as a marker of early-onset and late-onset sepsis in preterm and full-term neonates

Background
Neonatal sepsis is an important cause of morbidity and mortality among newborns. Its diagnosis depends mainly on blood culture that takes at least 48 h to give results. Therefore, searching for biomarkers for early diagnosis is of value. We aimed to assess neutrophil CD64 as an early diagnostic biomarker in early-onset and late-onset neonatal sepsis in full-term and preterm neonates and to compare it with other diagnostic markers, blood culture, and neonatal scores of sepsis.


Patients and methods
A case–control study was conducted on 60 neonates with clinical sepsis and 30 neonates as control aged from 1 to 28 days of life admitted to NICU in Damanhour Teaching Hospital during the period from 1/8/2018 to 1/4/2019. Studied neonates were evaluated using clinical and laboratory indicators for sepsis, and neutrophil CD64 was measured by flow cytometry.


Results
There was a statistically significant increase in CD64 of early-onset sepsis and late-onset sepsis groups than control group (P>0.001), either in full-term and preterm neonates, whereas there was no statistically significant difference between early-onset sepsis group and late-onset sepsis group regarding CD64. CD64 at a cutoff point more than 30% had sensitivity of 100%, specificity of 100%, positive predictive value of 100, negative predictive value 100, and area under a curve=1, which means CD64 is the gold standard test. However, C-reactive protein (CRP) at a cutoff point more than 6 mg/l had sensitivity of 71.67%, specificity of 83.33%, and area under a curve=0.78, which means CRP is a good test.


Conclusion
The level of CD64 was equally increased in neonates with early-onset and late-onset neonatal sepsis and not affected by age or sex and was highly sensitive and specific in diagnosis of neonatal sepsis. There were positive significant correlations between CD64 and both CRP and neonatal score of sepsis, whereas there was an insignificant relation between mean values of CD64 and blood cultures results.