Bactericidal antibody response to Neisseria meningitidis serogroup B in patients with bacterial meningitis: effect of immunization with an outer membrane protein vaccine.

We evaluated the bactericidal antibody response to Neisseria meningitidis serogroup B in convalescent patients (n=65) from bacterial meningitis. Patients infected with B meningococci were stratified according to their vaccination status (Cuban BC vaccine) into group 1 (immunized) (n=12) and group 2 (non-immunized) (n=15). The results suggested that antibody titers > or =2 (log(2)) indicate a specific immune response to N. meningitidis. In group 1, 64% of patients had a significant antibody titer (> or =2) in their acute sera against a B:4:P1.15 strain, compared to only 21% of group 2 patients. All patients from group 1 without bactericidal antibodies in their acute sera had a significant increase (at least 2-fold increase in log(2) titers) in antibody titers in their convalescent sera, in contrast, to only 27% of patients from group 2 (P=0.06). Using mutant strains lacking OMP1 or OMP5, it was shown that OMP1 was an important antigen recognized by immunized patients but not by non-immunized patients.

Classification trees and logistic regression applied to prognostic studies: a comparison using meningococcal disease as an example.

The authors used logistic regression and classification trees to develop prediction models for fatal outcomes in meningococcal disease in a cohort of 829 children hospitalized for meningococcal disease during 1989-1990 in Rio de Janeiro. The area under the receiver operator characteristic (ROC) curve was 92 per cent for logistic regression and 88 per cent for classification trees. Logistic regression may be preferred when the main objective is to obtain explicit measures for statistical inference and measures of the force of the association between each variable and the outcome. However, estimation of the probability of dying for each patient involves manipulation of the logistic regression formula, which would not easily be done in an emergency room. Classification trees provided comparable discrimination between fatal and non-fatal outcomes, and yielded a graphical display of the results that is easier to understand and is straightforward to apply in clinical settings.

[Meningococcal disease: epidemiology and control of secondary cases]. / Doença meningocócica: epidemiologia e controle dos casos secundários.

Epidemiological features of meningococcal disease described as from the second half of the 80's inclusive, have motivated a revision of current guidelines for sporadic disease and outbreak control. The increase of disease among teenagers and linked cases involving schools are the two most significant aspects that have prompted the revision of control measures. Vaccination routines and advice for the disease management of clusters are also relevant features recently revised. This present paper describes the management and some epidemiological features of secondary cases.

Human immune response to epitopes on the meningococcal outer membrane class 5 protein following natural infection.

Two monoclonal antibodies (mAbs) were produced against a serogroup B Neisseria meningitidis strain. These mAbs recognized two epitopes in the class 5 outer membrane proteins (OMP), designated P5.7 and P5.Bm, and were able to kill the homologous strain through complement activation. Both epitopes were surface exposed and 68% of group B meningococcal clinical isolates had one or both epitopes present in their class 5 OMP. Antibodies to one or both epitopes were demonstrated in 17 patients with meningococcal meningitis using an ELISA inhibition assay. Of the 17 paired sera, 41% and 29% of the acute-phase sera had antibodies to the P5.7 and P5.Bm epitopes, respectively. Immunoglobulin G to P5.Bm were found in all 17 convalescent-phase sera while specific antibodies against P5.7 were only found in 6 of these sera. These results demonstrate the potential importance of the P5.Bm and P5.7 epitopes on the class 5 OMP as candidates for vaccine composition.