Macrophage subsets in mechanical brain injury (MBI)--a contribution to timing of MBI based on immunohistochemical methods: a pilot study
Legal Medicine
M OehmichenC Meissner
Abstract
Cortical hemorrhages as a consequence of closed mechanical brain injury (MBI) trigger an inflammatory response including a distinct increase of macrophages. According to published data this reactive macrophage population is heterogenous as to their immunological properties. The expression of certain immunohistochemically detectable epitopes of macrophages, however, may correlate with the posttraumatic interval (PTI). In a pilot study, 50 selected cases of cortical hemorrhages with 1 min to 1.5 years PTI were examined by light microscopy and macrophages were labeled with CD68-, HLA-D-, HAM-56-, LN-5-, and 25F9-antibodies, while hemosiderin was detected by a Prussian-blue reaction. Qualitative and semiquantitative investigations were performed. The semiquantitative study included 5 different classes. The results of the study revealed a distinct timetable of the appearance of macrophages labeled with certain antibodies. While HLA-D immunoreactivity was detected after a PTI of 6h in the cortex and white matter bordering the traumatic hemorrhage, CD68 immunopositive macrophages were present after 12h, LN-5 and HAM-56 after 48h, and 25F9 within 10d. Hemosiderin-containing macrophages were detectable within 100h in the same region. Wi...Continue Reading