Intravenous immunoglobulin (IVIG) is an established treatment of immune-mediated 
demyelinating neuropathy. Since IVIG possesses multiple immunomodulatory and 
anti-inflammatory properties, IVIG therapy may represent a way of interfering 
with the disease process in multiple sclerosis (MS). In the MS animal model 
experimental autoimmune encephalomyelitis (EAE), infusions of IVIG significantly 
reduced disease symptoms as well as the underlying CNS pathology. IVIG was only 
effective in EAE when administered in a prophylactic treatment protocol, since 
IVIG infusions during the established phase of EAE did not alter the disease 
course or the degree of inflammation found in the central nervous system. IVIG 
also has the potential to act through myelin repair mechanisms as evidenced by 
work done in the Theilers murine encephalomyelitis virus model of demyelination. 
Together these observations have led to certain expectations for IVIG as a 
treatment for MS, and have resulted in various clinical trials. Several 
controlled trials report beneficial effects of IVIG on relapse rate, new MRI 
lesions, and disease progression in relapsing-remitting MS, while a 
remyelinating effect of IVIG has not been documented. IVIG is, therefore, 
presently regarded as a second-line therapy of MS.