Cytokines and sepsis

Introduction

Being sepsis a clinical syndrome with a very high mortality rate, this led us to the effort of monitoring some cytokines as potential diagnostic and prognostic serum markers.

Methods

In 1998 a prospective study was initiated, consisting at the moment in 24 patients, with diagnostic criteria for SIRS (Systemic Inflammatory Response Syndrome), sepsis and/or MODS (Multiple Organ Dysfunction Syndrome). The soluble serum cytokines – TNFα, IL-1β, IL-6, IL-8 and TGF-1β – were measured by a solid phase immunoassay method (RD Systems – CITOMED PORTUGAL) based on a previously established protocol. The blood samples were immediately separated in aliquots (3/cytokine) and frozen in sterile tubes at minus 70°C. Every sample of all the patients were simultaneously analysed for each cytokine, duplicated and performed by the same technician, having as references the maximum values of a healthy population.

Results

Amongst the 24 patients studied, 16 presented IL-6 >300 pg/ml. High concentrations of IL-8 and TNFα were also observed, but these were not uniformly coincident with the former. Two of these patients survived, being those in whom we were able to interfere with the cytokine profile. The 7 patients with SIRS, presented relatively low concentrations of cytokines, having one of them died. TNFα and IL-8, sometimes in very high concentrations, do not correlate with any particular organic dysfunction. IL-1β and TGF-1β always presented low values, close to the detection limits, in all of the patients.

Discussion

The high concentrations of IL-6 (the ‘black smoke’?), revealed a homogenous correlation with the clinical severity, thus making it a useful diagnostic and prognostic serum marker. The rapid knowledge of the cytokine profile is important for intervention in the mechanisms, which lead to multiple organ failure. The relation of some cytokines with particular organ dysfunction, such as ARDS and cardiac failure, as well as the influence of presently known and future anti-cytokine strategies, remains to be evaluated.