Intrathecal IgM synthesis predicts the onset of new relapses and a worse disease course in MS
Villar LM, Masjuan J, González-Porqué P, Plaza J, Sádaba MC, Roldán E, Bootello A and Alvarez-Cermeño JC;
Commented by , 25 Sep 2002
Background
In multiple sclerosis (MS), the search for potential paraclinical markers of disease course is of great interest in relation to counseling and selection for therapeutic intervention. It has been shown in a cross-sectional study that intrathecal IgM synthesis (ITMS) correlates with higher disability in MS, which give reason to believe that ITMS may predict worse disease course in MS.
Aim
To study MS patients in the initial stage of the disease to evaluate if the presence of ITMS correlates with worse disease course.
Methods
The study was prospective and included 22 patients with recently diagnosed MS. Specimens were obtained for routine detection of oligoclonal IgG bands in CSF, and the authors then analyzed the samples for IgM bands as well. Lumbar puncture was performed one month later and every six months until the end of the study (6 to 36 months).
Disability score (EDSS) and relapse rate was assessed (21 with relapsing remitting course and one with primary progressive course). All patients started b-interferon treatment and converted to clinically definite MS (CDMS) during the study.
Results
The authors divided patients in two groups according to the presence (group 1, 10 patients) or absence (group 2, 12 patients) of ITMS. There was no clinical difference between the two groups at the beginning of the study. At follow-up, the group with ITMS had
- higher risk of converting to CDMS (90% in group 1 after eight months, and 51% in group 2 after 36 months)
- more relapses (mean 2.0 in group 1 and mean 0,58 in group 2)
- higher disability (mean EDSS 1,70 in group 1 and 0,79 in group 2) at the end of the study
Discussion
Prognostic paraclinical markers in MS are few and practically restricted to MRI. It is therefore helpful when the authors show results that have the potential of predicting disease severity, with the use of a simple and well known technique.
The current study shows that the group of patients with ITMS had a worse disease course, which resulted in a higher probability of converting to CDMS, and had a higher number of relapses, although most of the ITMS group received b-interferon before those without ITMS.
Furthermore, the patients with ITMS had a higher risk of increased disability. The authors conclude that ITMS seems to be a prognostic factor in the initial stage of MS although the results should be confirmed in larger series of patients.