Neutropenia in Preterm Infants.

Background: The non-specific and antigen-specific components of host defense mechanisms are subject to the adaptation process in the neonate; however, the neutrophil quantitative and qualitative deficiency is one of the most significant causative factors of neonatal-increased vulnerability to infection.

Objective: To review the incidence and outcome of neutropenia of unknown cause in preterm infants.

Results: The incidence of early and late-onset idiopathic neutropenia of prematurity is significant.

Conclusion: The low neutrophil counts respond quickly to G-CSF treatment; however, due to the low probability of septic complications, particularly in the late-onset neutropenia, a deep diagnostic approach and the potential hematopoietic growth factor treatment should be limited to the severe cases, such as a neutrophil count <500/μL, lasting for more than 2 days.