Cytokines and sepsis - just black smoke?

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Introduction

Sepsis is a clinical syndrome resulting from an inflammatory response of the host to infection, mediated by the production of cytokines in circulation. The need to understand better the mechanisms that lead to multiple organ failure, the authors (AA) began a study of cytokines in these patients.

Material and methods

In 1998 the AA began a prospective study of soluble cytokines, consisting at the moment of 54 patients, 36 with criteria of Sepsis/MODS (Multiple organ dysfunction syndrome) and 18 with SIRS (Systemic inflammatory response syndrome). The soluble cytokines (TNFα, IL-6, IL-8 and IL-10) were measured in serum samples by the quantitative sandwich enzyme immunoassay (solid phase) — RD systems, Inc. Minneapolis (CITOMED, PORTUGAL) — with a previously established protocol.

Results

In the sepsis/MODS group, 7 patients with IL-6 <300 pg/ml survived; among the ones with IL-6 >300 pg/ml, only the five patients submitted to pulses of methyl-prednisolone and/or emergent surgery survived. The patients with SIRS always presented low concentrations of cytokines, and 14 of them survived.

Conclusion

In the patients with Sepsis/MODS, the clinical severity was always related to high serum levels of IL-6, and/or its increase. Serum values of IL-6 >300 pg/ml were predictive of death. Although TNFα and IL-8 values were high in some patients, these showed a non-uniform behaviour, and the correlation of these values with clinical severity or outcome was not statistically significant as was IL-6. In those patients who survived, the clinical improvement was always followed by a remarkable decline in the serum values of IL-6. IL-6 is an important severity serum marker in equal or superior value to others described and accepted world-wide for patients with sepsis.