Leukemia inhibitory factor during sepsis in adults and neonates

Introduction

Leukemia inhibitory factor (LIF), a glycosylated single chain polypeptide, induces differentiation in and suppression of leukemia cell lines. It switches signalling of autonomic nerves from adrenergic to cholinergic mode. stimulates the acute phase response and has profound effects on fat metabolism, calcium homeostasis and participates in hematopoiesis. Depending on priming or its concentration. LIF influences neutrophil chemotaxis and activation. This pleiotrophic cytokine is secreted by different nucleated cells after stimulation with LPS or other cytokines. LIF participates in the pathophysiology of several diseases and the protein is found to be increased in urine during urinary tract infection. The aim of this preliminary study was to evaluate the presence of LIF in urine and serum in an ICU population.

Materials and methods

Blood and urine was drawn from patients responding to the sepsis criteria with detected site of infection (group SEPS, n = 17). Pro-operative patients without signs of infection and negative microbiologic assays served as control (group CONT, n = 37). Weekly, serial urine samples were drawn from neonates which had no evidence of infection (group NCONT, n = 23) or with infection during one of the samplings (group NINF, n = 7). LIF was determined by ELISA with detection limit of 10 pg/ml.

Results

In group CONT urinary LIF was low (mean ± SEM: 17.5 ± 5 pg/ml) and serum LIF was only detectable in five patients (< 23 pg/ml). Compared to group CONT, urinary LIF in group SEPS was significantly higher (105 ± 50 pg/ml). Serum LIF was significantly more detected in group SEPS (n = 6, range up to 274 pg/ml). No correlation was found between urinary and serum LIF concentrations; No detectable LIF was found in urine of group NCONT. Two patients of group NINF (5 samples) with MRSE sepsis had increased urinary LIF.

Discussion

Serum or urinary LIF levels may increase during sepsis, but LIF cannot be used as diagnostic marker for the diagnosis of urinary tract infection or sepsis. The wide range of LIF concentrations in urine or serum indicate the magnitude of regulatoy factors of LIF secretion.