Oligoclonal bands: contribution and interpretation in patients with suspected multiple sclerosis

In the latest revision of the diagnostic criteria for multiple sclerosis (MS), magnetic resonance imaging had displaced the cerebrospinal fluid (CSF) analysis. The aims of this study were to establish a cut-off value for the IgG index between patients with oligoclonal bands (OCB) (+) and OCB (-), the prevalence of OCB and evaluate the utility of IgG index, Reibergrama (R) and OCB in patients with suspected MS. In this study, 210 consecutive patients were included, IgG index, R and OCB by isoelectric focusing (IEF) was determined. Clinical data of 135 patients was accessed. An IgG index >0.58 had a sensitivity= 100% for the presence of OCB in CSF. In OCB (+) patients, the IgG index and R were sensitive but not specific for MS. In patients with OCB (+), the patterns of type 2 or 3 IEF were the only ones associated with MS and only in these patients 9 or more OCB were observed in CSF; the prevalence of OCB with these patterns was 82% for MS, 42% in clinically isolated syndrome and 11% in other neurological diseases. An IgG index <0.58 would exclude the presence of OCB in CSF with a PNV= 100%. A pattern of type 2 or 3 IEF with 9 or more OCB in CSF had a PPV= 100% for MS. The IgG index and R provide complementary information and together with OCB, they support the diagnosis of MS.