ObjectivesTo determine the pattern of the soluble interleukin (IL)-6 receptor during acute meningococcal infections and recovery phase, and to measure the effect of plasma or whole blood exchange on the plasma concentrations of these mediators.DesignProspective, descriptive patient study.SettingUniversity hospital intensive care unit.PatientsPatients with bacteriologically proven meningococcal infections were entered in the study. Three group were formed: a) patients with meningitis without shock (group A); b) patients with meningitis and shock (group B); and c) patients with shock only (group C).InterventionsPart (n = 9) of the patients with shock underwent plasma or whole blood exchange.Measurements and Main ResultsSerum concentrations of interleukin-6 and soluble IL-6 receptors were determined sequentially during the acute and recovery phases. Peak concentrations of IL-6 were highest in group C, followed by group B and group A. Soluble IL-6 receptor concentrations showed an opposite pattern and were all below normal. Soluble IL-6 receptor concentrations were negatively correlated with the IL-6 concentrations. During recovery, IL-6 rapidly decreased and soluble IL-6 receptors increased to supranormal concentrations, after which concentrations returned to normal. Plasma or whole blood exchange did not significantly influence IL-6 concentrations but did increase the soluble IL-6 receptor concentration directly after an exchange session followed by a rapid decrease.ConclusionsSoluble IL-6 receptor concentrations are low in acute meningococcal infections. Plasma or whole blood exchange temporarily increases these concentrations. It needs to be determined whether the effect of this therapy is beneficial to the patient.(Crit Care Med 1996; 24:1801-1805)