Serial procalcitonin responses in infection of children with secondary immunodeficiency.

Purpose: Procalcitonin has proven to be a sensitive inflammatory marker in non-neutropenic patients. The aim of this study was to determine and compare Procalcitonin with other inflammatory markers in the serum of immunosuppressed children with haematological malignancies; and to assess the predictive value of these mediators in distinguishing between bacterial and non-bacterial infection.

Methods & Results: The study included 37 children with acute lymphoblastic leukaemia undergoing intensive chemotherapy. They were divided into 3 groups, A, B and C. Group A consisted of 29 neutropenic children with 94 febrile episodes, group B of 20 neutropenic children with 56 afebrile episodes and group C of 13 non-neutropenic children with 58 afebrile episodes. Serial serum levels of PCT, C-Reactive Protein, Neopterin, Interleukin-6 and NO2/NO3 were all determined on a day-to-day basis for 7 consecutive days. In serum the concentrations of CRP was determined by nephelometry, of PCT by immunoluminescence and of Neopterin, IL-6 and NO2/NO3 by ELISA method.

Conclusions: According to our results the Procalcitonin concentration increased rapidly in patients with microbial infection; the response was detectable within 24 hs of the onset of fever due to microbial infections. Procalcitonin is a specific and sensitive marker of microbial infection in patients with neutropenic fever. The markers, C-Reactive Protein, Interleukin-6 and NO2/NO3 may not help to identify infections and distinguish the etiology of infection in neutropenic febrile children with acute lymphoblastic leukaemia.