Meningococcal immunology

Basal Ganglia Injury With Extrapyramidal Presentation: A Complication of Meningococcal Meningitis

Basal ganglia injury, accompanied by extrapyramidal signs, has been described in the setting of chronic tuberculous meningitis; however, such injury rarely occurs in acute bacterial meningitis and has never been reported with meningococcal meningitis. We report the case of a boy who developed tongue bradykinesia and dysarthria 1 week following presentation with meningococcal meningitis. Magnetic resonance imaging revealed bilateral basal ganglia lesions, suspected to result from cytotoxic edema secondary to infection. The patient subsequently developed general bradykinesia, choreoathetosis, and ataxia, which had improved but not completely subsided by the time of discharge, 8 weeks following initial presentation. The purpose of this report is to present basal ganglia injury with extrapyramidal signs as a possible complication of meningococcal meningitis. Furthermore, we emphasize the importance of suspecting parkinsonian signs as early indicators of basal ganglia involvement in the setting of meningitis, which may later develop into a full-blown movement disorder.

Consensus building and recommendations based on the available epidemiology of meningococcal disease in Gulf Cooperation Council States

The Gulf Cooperation Council (GCC) States share concerns about meningococcal disease, particularly in association with the Hajj and Umrah pilgrimages, which have been connected with outbreaks within the Kingdom of Saudi Arabia and among contacts of the pilgrims in their countries of origin. Currently, the most prevalent meningococcal serogroup in the GCC States is W-135. Although vaccination with polysaccharide vaccines has protected pilgrims and their close contacts from invasive disease, the potential availability of novel conjugate vaccines, such as the one currently used for vaccination of military personnel in the Kingdom of Saudi Arabia, prompted an evaluation of disease epidemiology in the region. For several countries, published data on recent epidemiology are not available. We report findings from a meeting of the GCC States Meningitis Study Group, which comprised experts from the Kingdom of Saudi Arabia, the Kingdom of Bahrain, Kuwait, Qatar, the Sultanate of Oman, and the United Arab Emirates. These experts provided an update on epidemiology and current vaccination practices in the GCC States, and discussed new approaches to more effective disease prevention.

Prevention of meningococcal disease

Neisseria meningitidis is the most common cause of meningitis in children aged 2-18 with a mortality rate ranging from 4-40% and substantial morbidity in 11-19% of survivors. Of the four serogroups ofNeisseria meningitidis, serogroups B and C are the most common causes in the United States, with serogroup C causing most disease among adolescents, a population at risk for invasive meningococcal disease. The meningococcal polysaccharide vaccine was developed in response to increasing rates of bacterial meningitis among military recruits. With widespread use of the vaccine in the military, there was a dramatic decreased incidence in invasive meningococcal disease. However, there may be limitations to the polysaccharide vaccine including lack of durable protection, lack of induction of T-cell-dependent immune response, and lack of immunogenicity in children less than 2 years of age. Based on the success of other conjugate vaccines in pediatrics, a new conjugate polysaccharide vaccine, Menactra, has been approved by the Food and Drug Administration and recommended for routine vaccination in adolescents by the Advisory Committee on Immunization Practices.

Mucosal vaccination against serogroup B meningococci: induction of bactericidal antibodies and cellular immunity following intranasal immunization with NadA of Neisseria meningitidis and mutants of Escherichia coli heat-labile enterotoxin

Conjugated polysaccharide vaccines protect against serogroup C meningococci. However, this approach cannot be applied to serogroup B, which is still a major cause of meningitis. We evaluated the immunogenicity of three surface-exposed proteins from serogroup B Neisseria meningitidis (App, NhhA, and NadA) identified during whole-genome sequencing. Mice were immunized intranasally with individual proteins in the presence of wild-type Escherichia coli heat-labile enterotoxin (LTwt), LTR72, a partially inactivated mutant, or LTK63, a completely nontoxic mutant, as the adjuvant. Each of the meningococcal proteins induced significant cellular responses; NhhA and NadA induced strong antibody responses, but only NadA induced bactericidal antibody when administered intranasally with mucosal adjuvants. In addition, immunoglobulin A and bactericidal antibodies were detected in the respiratory tract following intranasal delivery of NadA. Analysis of antigen-specific cytokine production by T cells from immunized mice revealed that intranasal immunization with NadA alone failed to generate detectable cellular immune responses. In contrast, LTK63, LTR72, and LTwt significantly augmented NadA-specific gamma interferon, interleukin-4 (IL-4), IL-5, and IL-10 production by spleen and lymph node cells, suggesting that both Th1 and Th2 cells were induced in vivo. The strongest cellular responses and highest bactericidal antibody titers were generated with LTR72 as the adjuvant. These findings demonstrate that the quality and magnitude of the immune responses generated by mucosal vaccines are influenced by the antigen as well as the adjuvant and suggest that nasal delivery of NadA with mucosal adjuvants has considerable potential in the development of a mucosal vaccine against serogroup B meningococci.