Chemotactic activity and IL-8 levels in the cerebrospinal fluid in canine steroid responsive meningitis-arteriitis.

Steroid responsive meningitis-arteriitis (SRMA) is a systemic immune disorder, characterized by inflammatory-stenosing lesions of the meningeal arteries and meningitis. The predilection of the disease for the central nervous system (CNS) remains unexplained. In this study, chemotactic activity and chemotactic factors were measured in the cerebrospinal fluid (CSF) of dogs with SRMA. CSF of dogs with SRMA exerted a marked chemotactic activity for leukocytes. Neutrophils were attracted to a similar degree as by CSF from animals with bacterial encephalitis. Chemotactic activity was also noted for mononuclear cells, however, by far weaker than in CSF from animals with viral encephalitis. While the inflammatory process could be suppressed with glucocorticoid treatment, the chemotactic activity of CSF persisted. We could identify IL-8-like activities using a desensitization assay in the CSF of animals with SRMA and also found increased IgA levels. Increased chemotactic activity for polymorphonuclear leukocytes correlated positively with the levels of IL-8-like activity in CSF. Our observations clearly suggest that in SRMA chemotactic factors are generated in the CNS. These include IL-8, but probably also others. The intensity of this production appears to correlate with IgA levels in the CSF suggesting either a causal link or reflecting the severity of the inflammation.