Host genetic polymorphisms affecting the susceptibility of an individual to invasive meningococcal disease have been described, such as those in complement components such as factor H [37] or C6 deficiencies known to vary depending on the racial group and described as more common in African-American in the USA [38], interleukin-1 gene cluster [39] or the plasminogen activator inhibitor 1 [40]. The gene discussed is SERPINE1; the disease is meningococcal infection.