At low serum glucan concentrations there is an inverse correlation between serum glucan and serum cytokine levels in ICU patients with infections

Abstract

Glucans are fungal cell wall glucose polymers that are released into the blood of infected patients. The role of glucans in infection is unknown. We examined serum glucan and cytokine levels in intensive care unit (ICU) patients with infections. There was an inverse correlation ( p<0.001) between serum glucan levels and interleukin (IL)-2), IL-4, tumor necrosis factorα (TNFα) and granulocyte macrophage-colony stimulating factor (GM-CSF) levels in infected ICU patients. The correlation between serum cytokines and serum glucan was only observed at glucan concentrations <40 pg/ml. No change was observed at serum glucan levels of >40 pg/ml. There was no correlation between serum glucan levels and systemic levels of IL-1β, IL-5, IL-6, IL-8, IL-10 or IFNγ. Interestingly, blood borne glucans did not suppress systemic cytokine levels in infected ICU patients, instead they were maintained at control levels. We conclude that circulating glucans may prevent cytokine upregulation in response to infection. This may represent an adaptive response to septic injury.