Discontinuous distribution of IgG oligoclonal bands in cerebrospinal fluid from multiple sclerosis patients

To test the effect of sampling on the detection of immunoglobulin (Ig) cerebrospinal fluid (CSF) abnormalities, we analyzed the first and last 1 ml fraction of 10 ml obtained during a single CSF removal from 27 multiple sclerosis (MS) patients and six patients with other neurological diseases. IgG index, hyperbolic function, and IgG synthesis rate decreased between the first and the last CSF aliquot. Discordant results were found in 4/27 (15%) MS patients. In 2/27 (7.5%) clinically definite MS patients, the number of CSF oligoclonal bands (OCB) decreased between the first and the last fraction. In one of the two patients, the three OCB visualized in the first fraction were not found in the last. We conclude that fractionated sampling may partially account for the absence of OCB in the CSF of some definite MS patients.