Brain atrophy and lesion load are related to CSF lipid-specific IgM oligoclonal bands in clinically isolated syndromes. 
The objective of this work is to study the relationship between the presence of lipid-specific oligoclonal IgM bands (LS-OCMB) in CSF, with both T2 lesion volume (T2LV) accumulation and brain atrophy (percentage change of brain volume-PCBV-and brain parenchyma fraction-BPF) in patients with clinically isolated syndromes (CIS) suggestive of demyelination.  Twenty-four CIS patients were included in this prospective study.  IgG oligoclonal bands (OCGB) and LS-OCMB were determined in paired serum and CSF samples within 3 months since clinical onset.  Brain MRI studies were scheduled at baseline, 3 months, first and second years after CIS onset.  Differences in T2LV, PCBV and BPF between CIS patients according to the type of OCB were studied.  Nine patients had no OCB; 15 had only OCGB, and seven had OCGB + LS-OCMB present in the CSF.  LS-OCMB were associated with greater T2LV in all scheduled MRI studies.  At the end of follow-up (year 2), it was threefold higher in patients with these antibodies than in those without LS-OCMB (3.95 cm(3) vs. 1.36 cm(3), p = 0.001).  At that point, brain atrophy was also higher in patients with LS-OCMB (BPF, 0.73 in LS-OCMB+ patients vs. 0.76 in negative ones, p = 0.03).  The rate in brain atrophy was higher in the first group of patients as well.  Considering only patients with OCGB, the presence of LS-OCMB was also related to greater T2LV, T2LV increase and a trend towards higher atrophy rate.  The presence of LS-OCMB in the first event suggestive of demyelination is related to an early increase in lesion load and brain atrophy.  These data are in line with prospective studies showing the clinical prognostic value of LS-OCMB.