Blood-brain barrier damage in children with central nervous system infections

The blood-brain barrier (BBB) function in childhood central nervous system (CNS) infections was evaluated, using cerebrospinal fluid (CSF) and paired serum samples from 30 controls and 74 patients aged from 1 to 15 years with various CNS infections. The 74 patients included 34 cases of aseptic meningitis, 24 of encephalitis and 16 of purulent meningitis. The degree of BBB damage was graded by CSF/serum albumin ratio, and IgG production by IgG index (IgG ratio/albumin ratio of CSF to serum). In the acute stage, patients with purulent meningitis had greater elevation of the albumin ratio than other study groups. The patients with encephalitis, especially chronic encephalitis, had a selectively elevated IgG index compared to other groups. Most patients with aseptic meningitis showed little or no elevation of albumin ratio and IgG index. This study demonstrated the nature of various degrees of BBB damage and intra-BBB IgG production in different infectious CNS diseases in children. BBB damage is most severe in cases of purulent meningitis, while the intrathecal IgG production is greatest in chronic encephalitis. These abnormalities disappear as the inflammatory processes subside.