Age-related immune responses after burn and inhalation injury are associated with altered clinical outcomes.

This prospective study aimed to address changes in inflammatory response between different aged populations of patients who sustained burn and inhalation injury. Plasma and bronchoalveolar lavage (BAL) samples were collected from 104 patients within 15h of their estimated time of burn injury. Clinical variables, laboratory parameters, and immune mediator profiles were examined in association with clinical outcomes. Older patients were at higher odds for death after burn injury (odds ratio (OR)=7.37 per 10years, p=0.004). In plasma collected within 15h after burn injury, significant increases in the concentrations of interleukin 1 receptor antagonist (IL-1RA), interleukin 2 (IL-2), interleukin 4 (IL-4), interleukin 6 (IL-6), granulocyte colony-stimulating factor (G-CSF), interferon-gamma-induced protein 10 (IP-10) and monocyte chemoattractant protein 1 (MCP-1) (p<0.05 for all) were observed in the ≥65 group. In the BAL fluid, MCP-1 was increased three-fold in the ≥65 group. This study suggests that changes in certain immune mediators were present in the older cohort, in association with in-hospital mortality.