Association of Serum Soluble Triggering Receptor Expressed on Myeloid Cells Levels in Malignant Febrile Neutropenic Patients with Bacteremia and Fungemia

OBJECTIVE: Infections are the major cause of morbidity and mortality in febrile neutropenic patients with malignancy. Rapid diagnostic tests are needed for prompt diagnosis and early treatment which is crucial for optimal management. We assessed the utility of soluble triggering receptor expressed on myeloid cells (sTREM-1) in the diagnosis of bacteremia and fungemia in febrile neutropenic patients. METHODS: Sixty-five febrile neutropenic children with malignancy hospitalized in Mofid Children's Hospital during a period of one year from January 2007 were recruited for this cross sectional study (mean age 66.2± 37 months; 35 females and 30 males). Thirty patients (46.2%) had acute lymphoblastic leukemia, 2 (3.1%) acute myeloid leukemia, one (1.5%) lymphoma and 32 (49.2%) were under treatment for solid tumors. Simultaneous blood samples were collected for measurement of serum sTREM-1 levels and for blood cultures which were grown in BACTEC media. Gold standard for the presence of infection was a positive BACTEC culture as a more sensitive method compared to current blood culture techniques. FINDINGS: Blood cultures with BACTEC system were positive in 13(20%) patients (12 bacterial and one fungal culture). The mean serum sTREM-1 level in BACTEC positive patients was 948.2±592.9 pg/ml but in BACTEC negative cases it was 76.3±118.8 pg/ml (P<0.001). The optimal cut-off point of sTREM-1 for detecting patients with positive result of BACTEC was 525 pg/ml with sensitivity and specificity of 84.6% and 100%, respectively. CONCLUSION: Our study revealed a significant association between serum sTREM-1 level and bacteremia and fungemia in febrile neutropenic patients suffering malignancy with acceptable sensitivity and specificity.