Cytokine serum level during severe sepsis in human IL-6 as a marker of severity

Ann Surg. 1992 Apr;215(4):356-62. doi: 10.1097/00000658-199204000-00009.


Forty critically ill surgical patients with documented infections were studied during their stay in an intensive care unit. Among these patients, 19 developed septic shock and 16 died, 9 of them from septic shock. Interleukin 1 beta (IL-1 beta), tumor necrosis factor (TNF alpha), and interleukin 6 (IL-6) were measured each day and every 1 or 2 hours when septic shock occurred. Although IL-1 beta was never found, TNF alpha was most often observed in the serum at a level under 100 pg/mL except during septic shock. During these acute episodes TNF alpha level reached several hundred pg/mL, but only for a few hours. In contrast, IL-6 was always increased in the serum of acutely ill patients (peak to 500,000 pg/mL). There was a direct correlation between IL-6 peak serum level and TNF alpha peak serum level during septic shock and between IL-6 serum level and temperature or C-reactive protein serum level. Moreover, IL-6 correlated well with APACHE II score, and the mortality rate increased significantly in the group of patients who presented with IL-6 serum level above 1000 pg/mL. Thus, IL-6 appears to be a good marker of severity during bacterial infection.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Bacteremia / blood*
  • C-Reactive Protein / analysis
  • Cause of Death
  • Critical Illness*
  • Female
  • Humans
  • Interleukin-1 / analysis*
  • Interleukin-6 / analysis*
  • Male
  • Middle Aged
  • Severity of Illness Index
  • Shock / blood
  • Shock, Septic / blood*
  • Survival Rate
  • Tumor Necrosis Factor-alpha / analysis*


  • Interleukin-1
  • Interleukin-6
  • Tumor Necrosis Factor-alpha
  • C-Reactive Protein