Elevated plasma levels of antimicrobial polypeptides in patients with severe sepsis.

We wanted to investigate if plasma levels of antimicrobial polypeptides (AMPs) are increased in severe sepsis and if they correlate with severity and mortality. Samples were collected from 31 sepsis patients at the intensive care unit. The Sequential Organ Failure Assessment (SOFA) score and 90-day mortality were registered, and inflammatory markers and AMP levels were measured by ELISA. A median SOFA score (13) and cardiovascular SOFA score (3) indicated multiorgan failure with severe circulatory derangement, and elevated cytokine levels indicated inflammatory activation. Levels of bactericidal/permeability-increasing protein, heparin-binding protein, alpha-defensins and lactoferrin but not LL-37 were elevated in sepsis patients compared with controls. Bactericidal/permeability-increasing protein levels correlated with mortality, with lower levels in survivors. Levels of all AMPs, except LL-37, positively correlated with the cardiovascular SOFA score. In conclusion, levels of several AMPs are increased in sepsis and correlate with circulatory derangement. This probably reflects neutrophil activation as part of an innate immune response.