Oligoclonal Band Number Correlates with Relapses and Progression in Multiple Sclerosis

Background: Oligoclonal bands (OCBs) in the cerebrospinal fluid (CSF) are a reliable laboratory abnormality in multiple sclerosis (MS), found in greater than 90% of patients. Their presence has been shown to have predictive value with respect to clinically-isolated syndrome evolving into clinically-definite MS as well as worse prognosis if noted early in the disease course. OCBs have been incorporated into the latest version of McDonald Criteria for MS diagnosis. The predictive value of OCBs has, to date, been incompletely explored. While most studies examine the presence or absence of OCBs with regard to prognosis, only a few small studies have investigated correlations between the number of OCBs on single disease metrics.

Objectives: The goal of this study was to examine relationships between the number of OCBs and markers of relapses as well as progression, both clinical and radiographic, in two-year follow-up.

Methods: In this retrospective study, 1270 patients on MS disease-modifying therapies (DMTs) were screened for OCB testing. Further selection criteria included a diagnosis of relapse-remitting MS and adherence to a DMT with two years of follow-up clinical visits and imaging, yielding 128 patients. The primary outcome measures were clinical relapses (number of steroid prescriptions) and radiographic relapses (number of new lesions on MRI) at two-year follow-up. Secondary outcome measures were clinical progression (categorized as independent, cane, walker, or wheelchair) and radiographic progression (net changes in third ventricular width, lateral ventricular width, and cortical width). Unpaired, two-­tailed t­-tests were used for comparative analyses. Significance was determined with p<0.05.

Results: In two years, clinical relapses were significantly greater in patients with ≥10 OCBs (μ=0.70) compared to patients with <10 OCBs (μ=0.27), p=0.006. Similarly, patients with ≥10 OCBs were more likely to have radiographic relapses with nearly twice the number of new lesions on MRI at two years compared to patients with <10 OCBs (μ=1.98 and μ=1.04, respectively), p=0.018. Furthermore, with no significant difference between groups at baseline with regard to an assistive device, within-subjects analysis demonstrated that use of a new assistive device was higher for patients with ≥10 OCBs, p=0.007. While lateral ventricular width increased to a greater extent in patients with ≥10 OCBs  (p=0.015), changes in third ventricular width and cortical width were not significantly different between groups.

Conclusions: This study reveals significantly greater relapses, both clinical and radiographic, as well as clinical progression in patients with high levels (≥10) of OCBs in short-term follow-up. As OCBs may have greater diagnostic weight going forward, the quantity may be important in guiding selection of DMTs.