Figure 1.

Pathological features of lesions in autoimmune demyelination. Demyelinating lesions commonly consist of immune cell infiltrates predominated by activated macrophages and microglia, lymphocytes, and varying degrees of immunoglobulin and complement deposition. CD4⁺ T cells outnumber CD8⁺ T cells in MOGAD and NMOSD while CD8⁺ T cells predominate in MS. Granulocytic infiltration is seen in MOGAD and NMOSD while not frequently observed in MS lesions. Axon and astrocyte loss is profound in NMOSD while astrocytes and axons are largely preserved in MS and MOGAD. AQP4 downregulation is observed in NMOSD while conflicting reports of MOG internalisation have been seen in MOGAD. Ab, antibody; AQP4, aquaporin‐4 water channel; Ig, immunoglobulin; MOG, myelin oligodendrocyte glycoprotein; MOGAD, MOG Ab‐associated disease; MS, multiple sclerosis; NMOSD, neuromyelitis optica spectrum disorders.