The mechanism of post-vaccination
acute disseminated encephalomyelitis (ADEM) has been hypothesized as resulting from vaccination-injected
antigens cross-reacting with myelin components, however, a precise etiology has been uncertain. In this report, we describe the case of a 6-year-old Japanese boy who had multiphasic disseminated
encephalomyelitis (MDEM), and was positive for both anti-
myelin oligodendrocyte glycoprotein (MOG)
antibodies and Chlamydophila pneumoniae
antibodies. After vaccinations that were the second one for
measles and
rubella, and the booster immunization for
Japanese encephalitis, the patient presented with
fever,
headache,
vomiting, and a change in personality. He was treated with a high-dose of intravenous
methylprednisolone in the diagnosis of ADEM. However, these symptoms recurred with different magnetic resonance imaging lesion, and he was diagnosed as MDEM. Retrospective testing for pathogens revealed C. pneumoniae
IgM and
IgG antibodies, and it was considered that he was infected with C. pneumoniae subclinically. The patient's serum indicated a positive response for the anti-MOG antibody from the onset of the ADEM diagnosis and in all recurrent episodes. Chlamydia species
infection has been known to play a role in
demyelinating diseases. It is also known that the anti-MOG antibody may be present but not exhibit its pathogenesis in the absence of a cell-mediated inflammatory response; however, the precise mechanism of action of the anti-MOG
antibodies is not yet determined. We propose the possibility that post-vaccination
demyelinating disease may result from the synergistic effects of a preceding anti-MOG antibody, possibly produced in response to a subclinical Chlamydia species
infection.