Group-Specific Polysaccharide Antigen and Humoral Antibody Response in Disease due to Neisseria meningitidis

Abstract

In 87 patients with disease due to Neisseria meningitidis of group C, group-specific polysaccharide antigen in serum and spinal fluid was measured and the specific immune response was assessed. Sera drawn at time of admission from 29% of the patients contained concentrations of antigen ranging from 0.02 to 1.25 µg/ml. The level of antigen in serum before treatment correlated inversely with amounts of platelets, fibrinogen, and white blood cells in blood at admission. In five patients with severe fulminant meningococcemia, antigen increased fourfold within 18 hr after penicillin was administered. Platelet counts after 36 hr of treatment with antibiotic correlated inversely to amount and duration of antigen in serum before that time. The induction phase of the group-specific antibody was shorter in those without detectable antigen in serum than in persons with antigen in their sera (median, 24 vs. 60 hr). The clearance of antigen from the serum appeared to relate to the formation of bactericidal antibody. Cerebrospinal fluid from 70% of those with bacteriologic evidence of meningitis contained detectable levels of antigen ranging from 0.02 to 20 µg/rnl. High concentrations of antigen were found in the cerebrospinal fluid of patients with meningitis and coma.