Host Factors and Antibody Response in Haemophilus influensae Type b Meningitis and Epiglottitis

Levels of antibody in serum after infection with Haemophilus influenzae type b or challenge with polysaccharide vaccine are highly variable. Convalescent-phase serum antibody to the capsular polysaccharide of H. influenzae type b was measured in two groups of patients with pathophysiologically distinct diseases, meningitis and acute epiglottitis. Antibody response after H. influenzae meningitis was subnormal. Mean levels of antibody, the distribution of antibody levels by age, and erythrocyte and genetic marker lymphocyte antigens were studied; all results suggested that these two groups of patients were genetically and immunologically different from each other. Evidence suggested that the magnitude of the important host immunologic response was under host genetic control. Haemophilus influenzae type b is the etiologic agent for at least two diseases with distinctive clinical and epidemiologic features. Although patients with either meningitis or epiglottitis have bacteremia during the acute phase of illness, organisms localize preferentially in different anatomic sites, the meninges or epiglottal submucosa. Compared with meningitis, epiglottitis occurs in older children, has a more rapid onset, has more florid symptoms of septicemia, and occurs more often in spring and summer rather than in winter