Kappa Free Light Chains, Soluble Interleukin-2 Receptor, and Interleukin-6 Help Explore Patients Presenting With Brain White Matter Hyperintensities.

Introduction: Many patients are referred to multiple sclerosis (MS) tertiary centers to manage brain white matter hyperintensities (WMH). Multiple diagnoses can match in such situations, and we lack proper tools to diagnose complex cases. Objective: This study aimed to prospectively analyze and correlate with the final diagnosis, cerebrospinal fluid (CSF) interleukin (IL)-1ß, soluble IL-2 receptor (CD25), IL-6, IL-10, and kappa free light chains (KFLC) concentrations in patients presenting with brain WMH. Methods: All patients over 18 years addressed to our MS tertiary center for the diagnostic workup of brain WMH were included from June 1, 2020, to June 1, 2021. Patients were separated into three groups-MS and related disorder (MSARD), other inflammatory neurological disorder (OIND), and non-inflammatory neurological disorder (NIND) groups-according to clinical presentation, MRI characteristics, and biological workup. Results: A total of 176 patients (129 women, mean age 45.8 ± 14.7 years) were included. The diagnosis was MSARD (n = 88), OIND (n = 35), and NIND (n = 53). Median CSF KFLC index and KFLC intrathecal fraction (IF) were higher in MSARD than in the OIND and NIND groups; p < 0.001 for all comparisons. CSF CD25 and IL-6 concentrations were higher in the OIND group than in both the MSARD and NIND groups; p < 0.001 for all comparisons. KFLC index could rule in MSARD when compared to NIND (sensitivity, 0.76; specificity, 0.91) or OIND (sensitivity, 0.73; specificity, 0.76). These results were similar to those with oligoclonal bands (sensitivity, 0.59; specificity, 0.98 compared to NIND; sensitivity, 0.59; specificity, 0.88 compared to OIND). In contrast, elevated CSF CD25 and IL-6 could rule out MSARD when compared to OIND (sensitivity, 0.58 and 0.88; specificity, 0.95 and 0.74, respectively). Discussion: Our results show that, as OCBs, KFLC biomarkers are helpful tools to rule in MSARD, whereas elevated CSF CD25 and IL-6 rule out MSARD. Interestingly, CSF IL-6 concentration could help identify neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody-associated disease, and central nervous system (CNS) vasculitis. These results need to be confirmed within more extensive and multicentric studies. Still, they sustain that KFLC, CSF CD25, and CSF IL-6 could be reliable biomarkers in brain WMH diagnostic workup for differentiating MSARD from other brain inflammatory MS mimickers.

Should we still only rely on EDSS to evaluate disability in multiple sclerosis patients? A study of inter and intra rater reliability.

BACKGROUND: Few studies assessed reliability and inter-rater variability of EDSS and functional parameters (FP) rating. OBJECTIVE: To evaluate inter-rater variability and errors in EDSS and FP rating in junior (JN) and MS Neurologists (MSN). METHOD: Patients with MS were examined by a JN and a MSN on the same day. Each assessor rated FP and EDSS, then used a smartphone app to get an automated calculation for each FP ("smartphone" FP, sFP) and for EDSS ("smartphone" EDSS, sEDSS) from the description of the neurological exam. Inter-rater variability was assessed comparing JN and MSN ratings for each method. Intra-rater variability was assessed comparing traditional and digital rating for a given assessor. RESULT: 103 patients were included. Perfect agreement between JN and MSN was met for 67% and 70% of patients regarding EDSS and sEDSS. Disagreement that could lead to a significant difference in terms of level of disability occurred in 17% for EDSS and 12% for sEDSS (p=0.07). Regarding intra-rater reliability, we found 38 rating discrepancies for JN and 14 for MSN (p=0.04). CONCLUSION: We found a significant inter-rater variability as well as a substantial frequency of rating errors in JN. The use of less subjective, easier-to-rate scales should be encouraged.

Digital biomarkers can highlight subtle clinical differences in radiologically isolated syndrome compared to healthy controls.

OBJECTIVE: To explore the use of digital biomarkers to distinguish healthy controls (HC) from subjects with a radiologically isolated syndrome (RIS). METHODS: We developed a smartphone application called MS Screen Test (MSST) to explore several dimensions of the neurological exam such as finger tapping speed, agility, hand synchronization, low contrast vision and cognition during a short evaluation. This app was tested on a cohort of healthy volunteers including a subset of subjects who underwent two evaluations on the same day to assess reproducibility. In a second step, the app was tested on a cohort of RIS subjects. Performances of RIS subjects were compared with age and genre-matched HC. RESULTS: HC underwent two consecutive evaluations on MSST. The analysis showed good reproducibility for all measures. Then 21 RIS subjects were compared to 32 matched HC. Compared to HC, we found that RIS subjects had a lower finger tapping speed on the dominant hand (5.6 versus 6.5 taps per second; p = 0.005), a longer inter hand interval during the hand synchronization task (14.4 versus 11.3 ms; p = 0.03) and significantly poorer scores on the low contrast vision and cognition tests. CONCLUSION: MSST only requires a smartphone to obtain digital biomarkers relative to several dimensions of the neurological examination. Our results highlighted subtle differences between HC and RIS subjects. We plan to evaluate this tool in MS patients, which will allow us to get a much larger sample of subjects, to determine whether digital biomarkers can predict disease course.