Soluble Triggering Receptor Expressed on Myeloid Cells 1 and the Diagnosis of Ventilator-Associated Pneumonia

Abstract

To the Editor: We read with interest the report of Marin Kollef and coworkers1Anand NJ Zuick S Klesney-Tait J et al.Diagnostic implications of soluble triggering receptor expressed on myeloid cells-1 in BAL fluid of patients with pulmonary infiltrates in the ICU.Chest. 2009; 135: 641-647Abstract Full Text Full Text PDF PubMed Scopus (70) Google Scholar on the usefulness of BAL soluble triggering receptor expressed on myeloid cells 1 (TREM-1) determination in diagnosing ventilator-associated pneumonia. We would like to warn the readers against an important methodologic aspect of the presented work: the authors used a commercially available assay, namely the TREM-1 Quantikine assay (R&D Systems; Minneapolis, MN), to measure soluble TREM-1 concentrations. It happens that this assay was recalled by R&D Systems during the early 2008 summer, and researchers informed (and even reimbursed) due to its inability to accurately measure soluble TREM-1 concentration. A new assay has just been lunched by this company. We therefore recommend to readers and researchers interested in this field to be very careful in interpreting data, positive or negative, obtained by the use of this very assay, and we would encourage the authors to perform new measurements with a different technique. We also wanted to underline two fundamental methodologic differences that exist between our study2Gibot S Cravoisy A Levy B et al.Rapid detection of the soluble form of triggering receptor expressed on myeloid cells-1 (TREM-1) in the diagnosis of pneumonia.N Engl J Med. 2004; 350: 451-458Crossref PubMed Scopus (471) Google Scholar and this one: first, we used an original antibody (clone 21C7) developed by Bouchon et al3Bouchon A Facchetti F Weigand MA et al.TREM-1 amplifies inflammation and is a crucial mediator of septic shock.Nature. 2001; 230: 1103-1107Crossref Scopus (841) Google Scholar different from the one used here; second, and more importantly, our measurements were obtained against a reference curve constructed by using the naturally occurring soluble form of TREM-1 (derived from a cell-free Escherichia coli production system) and not a human Ig Fc-containing chimera. This is clearly not a “battle of experts” but crucial differences readers must keep in mind when interpreting data from different works.