TREM-1 was initially proposed as an early marker of infection because its expression is high in peritoneal neutrophils of septic shock patients [11]; a soluble form of TREM-1 is present in high concentrations in bronchoalveolar lavage of patients with pneumonia [15]; and soluble TREM-1 concentration is high in the serum of septic patients [16]. Here, TREM1 is linked to pneumonia.