Radiologically isolated syndrome: from biological bases to practical management

A Scoping Review on Body Fluid Biomarkers for Prognosis and Disease Activity in Patients with Multiple Sclerosis

Multiple sclerosis (MS) is a complex demyelinating disease of the central nervous system, presenting with different clinical forms, including clinically isolated syndrome (CIS), which is a first clinical episode suggestive of demyelination. Several molecules have been proposed as prognostic biomarkers in MS. We aimed to perform a scoping review of the potential use of prognostic biomarkers in MS clinical practice. We searched MEDLINE up to 25 November 2021 for review articles assessing body fluid biomarkers for prognostic purposes, including any type of biomarkers, cell types and tissues. Original articles were obtained to confirm and detail the data reported by the review authors. We evaluated the reliability of the biomarkers based on the sample size used by various studies. Fifty-two review articles were included. We identified 110 molecules proposed as prognostic biomarkers. Only six studies had an adequate sample size to explore the risk of conversion from CIS to MS. These confirm the role of oligoclonal bands, immunoglobulin free light chain and chitinase CHI3L1 in CSF and of serum vitamin D in the prediction of conversion from CIS to clinically definite MS. Other prognostic markers are not yet explored in adequately powered samples. Serum and CSF levels of neurofilaments represent a promising biomarker.

Secondary Prevention in Radiologically Isolated Syndromes and Prodromal Stages of Multiple Sclerosis

Following the extraordinary progress in the treatment of multiple sclerosis (MS), two major unmet needs remain: understanding the etiology of the disease and, hence, designing definitive cures (this perspective is neither at hand, nor it can be taken for granted that the etiologic targets will be readily treatable); the prevention of an overt and disabling disease, which seems to be a more realistic and pragmatic perspective, as the integration of genetic data with endophenotypes, MRI, and other biomarkers ameliorates our ability to identify early neuroinflammation. Radiologically isolated syndrome (RIS; diagnosed when the unanticipated MRI finding of brain spatial dissemination of focal white matter lesions highly suggestive of MS occurs in subjects without symptoms of MS, and with normal neurological examinations) and the recently focused “prodromal MS” are conditions at risk of conversion toward overt disease. Here, we explore the possibility of secondary prevention approaches in these early stages of neuroinflammation. RIS and prodromal MS are rare conditions, which suggest the importance of Study Groups and Disease Registry to implement informative clinical trials. We summarize ongoing preventive approaches in the early stages of the demyelinating process, especially in RIS conditions. Moreover, we highlight the importance of the biomarkers and the predictors of evolution to overt disease, which may be useful to select the individuals at risk of conversion to clinically isolated syndrome (CIS) and/or clinically definite MS. Finally, we illustrate the importance of the endophenotypes to test the frontline immunomodulatory approach for preventive strategies. Future investigations, especially in relatives of patients, based on MRI techniques and biological studies (better with integrated approaches) may provide opportunities to understand the MS early causal cascade and may help to identify a “therapeutic window” to potentially reverse early disease processes.

Accumulative risk of clinical event in high-risk radiologically isolated syndrome in Argentina: data from the nationwide registry RelevarEM

INTRODUCTION

We aimed to analyze the accumulative risk of MRI and OB factors for evolution from RIS to MS in subjects included in the Argentinean MS registry (NCT03375177).

METHODS

RIS subjects were identified according to RIS diagnosis criteria. Subjects were longitudinally followed with clinical and MRI at intervals of 6 months. Time from RIS identification to the first clinical event was estimated using Kaplan-Meier. Multivariable Cox regression models were created to assess the independent predictive value of demographic characteristics, as well as clinical, OB and MRI data on time to the first clinical event. The single and increased risk factor of evolution of RIS was quantified.

RESULTS

A total of 88 RIS subjects, mean follow-up time 42 ± 4 months were included. 39 (44.3%) and 23 (26.1%) had a new MRI lesion or a clinical event, respectively, during the follow-up. OB (HR 5.9, 95% CI 1.29-10.1, p = 0.004), infratentorial lesions (HR 3.7, 95% CI 1.09-7.5) and spinal cord lesions (HR 5.3, 95% CI 1.4-8.2, p = 0.01) at RIS identification were independent predictors associated with a subsequent clinical event. The accumulative risk showed that when two of the three factors (OB, infratentorial or spinal cord lesions) were present the HR was 10.4, 95% CI 4.4-22, p < 0.001, and when three factors were present, it was HR 15.6, 95% CI 5.7-28, p < 0.001 for a relapse.

CONCLUSION

The presence of three factors significantly increased the risk of clinical event; high-risk subjects should probably be managed by a different approach than those used for individuals without high-risk factors.