Expression of CD64 and CD69 as biomarkers for late-onset sepsis diagnosis in infants born prematurely

Background

The incidence of Late-Onset Sepsis (LOS) increases as gestational age decreases in newborns. The clinical signs of neonatal sepsis are not specific for diagnosis in preterm infants. The gold standard for its diagnosis is the blood culture test, which requires more than 24 h to obtain results, with positive results obtained in 10–3 % of cases analysed. As the molecular markers on the lymphocyte surface CD64 and CD69 are involved in early innate immune activation, they may be helpful for faster diagnosis.

Aim

Measure the expression of CD64 and CD69 on lymphocytes in clinical and confirmed sepsis patients and compared to that in infants without sepsis.

Methodology

We used peripheral blood samples from three groups of preterm babies with suspected sepsis (n = 31), confirmed sepsis (n = 10) and without sepsis (n = 47). Using flow cytometry, we measure the expression of CD64 on neutrophils and CD69 on NK cells.

Results

Expression of CD64 on neutrophils and CD69 on NK cells did not increase in the clinical or confirmed sepsis groups compared to the without sepsis group.

Conclusions

Leukocytes from infants born prematurely may have tightly regulated mechanisms that control their activation phenotype, rendering them unsuitable for diagnosing sepsis.