In a study of serum levels of tumor necrosis factor (TNF alpha) and interleukin-1 beta (IL-1 beta) in patients developing sepsis in the ICU, high TNF alpha levels were found in patients with septic shock. Normal values are 75 +/- 15 pg/ml; in these patients, TNF alpha serum level ranged from 100 to 5000 pg/ml with a mean of 701 +/- 339 pg/ml and a median of 250 pg/ml. There was a correlation between TNF alpha level and sepsis severity score as well as with mortality. In contrast, IL-1 beta serum levels were only slightly increased and were not correlated with severity or mortality.