Immunohistochemical study of microglia in the Creutzfeldt-Jakob diseased brain

Area of Science:

• Neuroscience
• Immunology
• Neuropathology

Background:

• Creutzfeldt-Jakob disease (CJD) is a fatal neurodegenerative prion disease.
• Microglial activation is a hallmark of neuroinflammation in various brain disorders.

Purpose of the Study:

• To investigate microglial reactions in CJD brains using immunohistochemical techniques.
• To determine the stage and extent of microglial involvement in CJD pathogenesis.

Main Methods:

• Autopsy brain tissues from six CJD patients and age-matched controls were analyzed.
• Immunohistochemistry was performed using antibodies for MHC class II antigen, LCA, CDw75, CD68, and glial fibrillary acidic protein.
• Microglial reactivity was assessed in different CJD subtypes and disease stages.

Main Results:

• Increased numbers of reactive microglia (MHC class II Ag+, LCA+) were observed in the cerebral cortex of CJD patients with subacute spongiform encephalopathic type and short survival.
• In advanced panencephalopathic CJD cases with significant atrophy and astrocytosis, the increase in reactive microglia was minimal.
• Vacuoles in the neuropil were often surrounded by MHC class II Ag- or LCA-immunoreactive microglia.
• The number of ramified microglia decreased in affected lesions but remained unchanged in the hippocampus.

Conclusions:

• Microglia are frequently involved in the pathological process of CJD.
• Microglial activation appears to occur at the early stages of CJD, particularly in the subacute spongiform encephalopathic type.
• These findings highlight the dynamic role of microglia in CJD neuropathology.