[The interconnection between the severity of meningococcal infection and the endotoxicity levels and patient's blood complement].

Seventy-eight patients with severe systemic meningococcal disease admitted to the Intensive Care Unit of the Second Moscow Hospital for Infectious Diseases were divided into four groups by complications of their disease: patients with refractory septic shock (RSS)--group 1; patients with early septic shock (ESS)--group 2; patients without shock but with severe mental disorders--group 3; patients without any of these complications--group 4. The LPS concentration in plasma was assessed by chromogenic method. Initial LPS levels in plasma of group 3 or group 4 patients (170 ng/l, median value and 360 ng/l, respectively) were greater than those of healthy donors (LPS < 15 ng/l). LPS concentration was significantly greater in group 2 (920 ng/l) or group 1 (12,400 ng/l). LPS levels declined exponentially in all the patients. The half-life was calculated to be 1.4 (+) -0.3 h. In group 2 and 1, respectively, the classical pathway complement activity in patients' serum was 50 and 10% of normal control values. To estimate significant prognostic factors for fatality in our patients, specificity and factor fatality difference of various clinical and laboratory factors were calculated. The cut-off LPS value for development of ESS was 600 ng/l and that for development of RSS and death was 8000 ng/l. For the prediction of fatality using the former cut-off value of LPS, sensitivity was 84% and specificity 100%. Using plasma complement activity (cut-off--15% of normal value) for prediction, sensitivity was 75% and specificity was 100%. Other factors (platelet and WBC count, blood pH, BP, etc.) had lower predictive power. Thus to date plasma endotoxin level and complement activity are the best prognostic factors in meningococcal disease.