CHRONOLOGICAL CHANGES IN THE COMPLEMENT-SYSTEM IN SEPSIS

The time courses of serum complement levels and the severity of sepsis were compared in two groups of septic patients, one in which the pati ents survived (surviving group) and one in which they did not (nonsurv iving group), The components of the complement system, namely, C3a, C4 a, C5a, CH50, C3, C4, and C5, were measured at several points in time after the diagnosis of sepsis had been established, A 2-antibody radio immunoassay was used to measure C3a, C4a, and C5a; the latex agglutina tion test was used to measure C3 and C4; nephelometry was used to meas ure C5; and Meyer's 50% hemolysis method was used to measure CH50. Fol lowing the diagnosis of sepsis, the levels of CH50, C3, and C4 were si gnificantly lower in the nonsurviving than the surviving group, while the levels of C3a and C4a were significantly higher in the nonsurvivin g than the surviving group. The C5a levels were significantly higher i n the nonsurviving than the surviving group, although no significant i ntergroup differences were subsequently noted. These results suggest t hat the serum levels of C3a, C4a, C5a, CH50, C3, and C4 could serve as indices of the severity of sepsis. Thus, monitoring the complement sy stem may be useful for predicting the outcome of patients with sepsis.