Severe Burns: Neutrophil and Complement Levels

Mortality rate in burn patients continues at a steady 5-10%, 75% of those deaths are related to sepsis (2). In order to understand why, we must elucidate the nature of the innate immune system in these patients. The innate immune system is the first line defense versus pathogens from the outside world. Burn patients receive a double hit to their first line defenses due to the nature of thermal injury to tissue. The skin barrier is breached, the inflammation begins, and though the numbers of neutrophils increases substantially in response to the elevations in compliment activation at the tissue level (1), it seems that the behavior of these neutrophils is aberrant (2). Neutrophils in burn patients were found to be impaired in their ability to adhere, phagocytose, and kill off pathogens via the oxidative burst. Additionally, they were found to have decreased migration speed with abnormal directionality in response to chemoattractants (2). One study suggested that neutrophils in burn patients became desensitized to C5a. In the rich inflammatory cytokine milieu, which develops after a severe burn, complement levels increase dramatically, but neutrophils downregulate their C5a receptors and their migratory directional speed decreases (3). This is the perfect situation for the wandering pathogen to invade and sneak past the body’s defenses in the chaos of a massive breach in security. Three studies are presented here to describe the relationship between complement and neutrophils in the severely burned patient.

Van de Goot et al. demonstrated that plasma complement levels initially decreased, then rose sharply and stayed elevated for months afterward. Complement levels correlated with the severity of the burn wound and subsequent sc...

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...enter around how to control the inflammatory response to the thermal injury such that wound healing occurs more quickly with less scarring, while preserving the patients’ ability to fight infectious agents with normal neutrophil responses.

Works Cited

1. Van de Goot et al. Acute Inflammation is Persistent Locally in Burn Wounds: A Pivotal Role for Complement and C-Reactive Protein. Journal of Burn Care and Research 2009; 30:274-280.

2. Butler KL, Ambravaneswaran V, Agrawal N, Bilodeau M, Toner M, et al. (2010) Burn Injury Reduces Neutrophil Directional Migration Speed in Microfluidic Devices. PLoS ONE 5(7): e11921. doi:10.1371/journal.pone.0011921

3. Solomkin JS, Nelson RD, Chenoweth DE, Solem LD, Simmons RL. Regulation of Neutrophil Migratory Function in Burn Injury by Complement Activation Products. Annals of Surgery 1984; Vol 200 No. 6: 742-746.