Similar low frequency of anti-MOG IgG and IgM in MS patients and healthy subjects

The authors used a liquid-phase radiobinding assay to measure serum anti-myelin oligodendrocyte protein (MOG) immunoglobulin (Ig) G in 87 patients with multiple sclerosis (MS), in 12 patients with encephalomyelitis, and in 47 healthy subjects. Anti-MOG IgM was determined in samples obtained at onset from 40 of 87 patients with MS and in control subjects. The frequency of positive samples with low titers of anti-MOG IgG (≤5.7%) and IgM (≤8.3%) was similar in all the groups and subgroups. Binding competition experiments showed that these antibodies had low affinity. Anti-MOG antibodies are not disease specific. Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies induce extensive demyelination in T-cell-mediated experimental autoimmune encephalomyelitis (EAE)1 and bind to disintegrating myelin in acute multiple sclerosis (MS) and in the marmoset model of EAE.2 These observations motivate the search for anti-MOG antibodies in MS, in which increased MOG-specific T- and B-cell responses are reported.3 The reported data have had a negligible impact on patient care, but Berger et al.4 showed that serum anti-MOG immunoglobulin (Ig) M strongly predicted the early conversion of first demyelinating events to clinically definite MS. We devised a radiobinding assay (RBA) to measure anti-MOG IgG and IgM in patients with MS, in patients with encephalomyelitis, and in healthy subjects.