Figure 2.

Possible pathways to post-vaccination demyelinating disease mediated by hypersensitivity reactions. (a) After vaccination with antigenic substances, antigen-antibody immune complexes are synthesized in the bloodstream, triggering activation of the complement system and inflammatory cells such as neutrophils. (b) Neutrophils release inflammatory mediators, lysosomal enzymes, and complement, which increase vascular permeability, leading to tissue damage and vascular inflammation. (c) This process can compromise the blood-brain barrier, potentially resulting in demyelinating diseases.