INTRACEREBRAL INFLAMMATION AFTER HUMAN BRAIN CONTUSION

OBJECTIVE: This study was undertaken to analyze the inflammatory compo nents in contused human brain tissue to compare the findings with prev ious experimental data regarding the pathogenesis of brain contusions. METHODS: Contused brain tissue biopsies were obtained from 12 consecu tive patients undergoing surgery for brain contusions 3 hours to 5 day s after trauma. Inflammatory and immunological components were analyze d by immunohistochemistry. RESULTS: In patients undergoing surgery les s than 24 hours after trauma, the inflammatory response was limited to vascular margination of polymorphonuclear cells. In patients undergoi ng surgery 3 to 5 days after trauma, however, a massive inflammatory r esponse consisting of monocytes/macrophages, reactive microglia, polym erphonuclear cells, and CD4- and CD8-positive T lymphocytes was detect ed. Human lymphocyte antigen-DO was expressed on reactive microglia an d infiltrating leukocytes in the late patient group. In addition, CD1a , which is a marker for antigen-presenting dendritic cells, was detect ed in a subgroup of microglial cells. CONCLUSION: The results corrobor ated hypotheses derived from experimental data. In the early phase aft er contusional trauma, inflammation is mainly intravascular and domina ted by polymorphonuclear cells. The inflammation was parenchymal in pa tients undergoing surgery 3 to 5 days after trauma. The brain swelling seemed to be biphasic, the delayed phase correlating with a parenchym al inflammation. The inflammatory cells may produce several potentiall y harmful effects, such as acute cellular degeneration; they may also lead to degenerative long-term effects.