Elderly-onset neuromyelitis optica which developed after the diagnosis of prostate adenocarcinoma and relapsed after a 23-valent pneumococcal polysaccharide vaccination.

We report a case of elderly-onset neuromyelitis optica (NMO) positive for the anti-aquaporin-4 (AQP-4) antibody; symptoms developed after the diagnosis of prostate adenocarcinoma and relapsed after a 23-valent pneumococcal polysaccharide vaccination. We suggest that activation of CD4-positive T cells and secretion of interferon-gamma induced by adenocarcinoma and complement activation induced by vaccination are responsible for the onset and relapse of NMO, even if a patient is positive for the anti-AQP-4 antibody. This case supports the previous experimental finding that the anti-AQP-4 antibody does not cause NMO-like lesions when injected alone, but does so after the induction of T cell-mediated experimental autoimmune encephalomyelitis or when co-injected with human complement.