Detection of circulating superantigens in an intensive care unit population

OBJECTIVE: Plasma concentrations of superantigens were measured in an intensive care unit (ICU) population and the relationship of superantigen positive rates with the presence of sepsis was investigated. METHODS: Plasma samples were collected at least twice a week from 78 patients whose primary diagnoses were abdominal disorders (n = 27), respiratory disorders (n = 11), trauma (n = 10), burns (n = 10), cardiovascular disorders (n = 4), neurological disorders (n = 2), and others (n = 14). Five different species of superantigens, i.e., staphylococcal enterotoxins A, B, and C (SEA, SEB, and SEC), toxic shock syndrome toxin-1 (TSST-1), and streptococcal pyrogenic exotoxin A (SPEA), were measured using an enzyme-linked immunosorbent assay. RESULTS: Significant levels of plasma superantigens were detected in 16 patients. SEA was found in seven patients, SEB in four patients, SEC in two patients, TSST-1 in six patients, and SPEA in five patients. Superantigen detection rates were 6% (1/17) in patients without systemic inflammatory response syndrome (SIRS), 0% (0/21) in SIRS patients without infection, 31% (5/16) in septic patients without shock, and 42% (10/24) in septic shock patients. CONCLUSIONS: The presence of superantigens was confirmed in part of the ICU population. The role of superantigens in the pathogenesis of sepsis remains to be determined.