Human Genetics May Regulate Meningitis Severity

Bacterial meningitis is caused by an infection of the fluid that surrounds the brain and spinal cord. Neisseria meningitides is the most common form of bacteria that produces such an infection. The Centers for Disease Control (CDC) report that approximately 10% of individuals with this type of meningitis do not survive and that pre-teens, college freshman, and travelers to regions of the world where meningitis rates are high, are the most likely to be afflicted.

The infection causes inflammation and eventual neurological damage, which can eventually progress severely enough to cause death. Various studies in the literature have suggested that meningitis severity is linked with the degree of inflammation exhibited by the host. A new study published in the journal Lancet Infectious Disease looked to pool this data and look for trends that would implicate specific genes in meningitis severity using a meta analysis strategy.

The authors examined data from 28 separate studies that met their inclusion criteria and included a total of 7,301 patients. Inclusion criteria being: studies about Neisseria meningitides meningitis that had a genetic component and included parameters of severity, mortality, and clinical phenotype.

Using the 28 studies, the authors noted a statistically significant influence on meningitis severity and mortality by variation in three separate host genes. The genes were SERPINE1, IL1RN, and IL1B; each of which has a role in the course of an inflammatory response. SERPINE1 influences clotting, while the other two have a more direct role in amping up inflammation. The greatest link between mortality and genetic variation was found with the SERPINE1 gene, in which the authors calculated an odds ratio of 2.23.

The data suggests that individuals with the polymorphisms listed above may require a tailored treatment strategy for optimal results in curbing morbidity and mortality. That is, placing an emphasis on anti-inflammation may have a beneficial role in treating Neisseria meningitides induced meningitis. Although the data is promising for shaping treatment in the manner described above, the authors point out that the data generated is retrospective, so prospective clinical trials will need to be conducted before any such assertion can be made.

References:

Brouwer MC, Read RC, van de Beek D. Host genetics and outcome in meningococcal disease: a systematic review and meta-analysis. Lancet Infect Dis. 2010: 10(4):262-74.

Meningitis Homepage: People at Risk. http://www.cdc.gov/meningitis/high-risk/index.html. Accessed 3/27/2010.