Serial measurement of anti-interleukin-8 IgG autoantibody in cerebrospinal fluid of infants with bacterial meningitis

We serially measured concentrations of interleukin (IL)-8 and anti-IL-8 IgG autoantibody in cerebrospinal fluid of infants with bacterial meningitis, and also measured these concentrations in cerebrospinal fluid obtained from infants without meningitis on admission. We have reported that the IL-8 concentration in cerebrospinal fluid of infants with purulent meningitis rapidly decreases after the initiation of therapy. Thus, in the present study, the IL-8 concentration in infants with purulent meningitis only before the initiation of therapy was significantly higher compared with that in infants without meningitis. However, the concentration of anti-IL-8 IgG autoantibody was still high after the initiation of therapy. The concentration of anti-IL-8 IgG autoantibody was significantly higher compared with that in infants without meningitis until the 15th day after the initiation of therapy. The time lag between the decrease of IL-8 and anti-IL-8 IgG autoantibody demonstrated in the present study could be used to indicate the past presence of a large amount of IL-8, even if the IL-8 concentration was already low.