Pretreatment Neurofilament Light Chain Serum Levels, Early Disease Severity, and Treatment Response in Pediatric Multiple Sclerosis

BACKGROUND AND OBJECTIVES

High disease activity and frequent therapy failure in pediatric multiple sclerosis (MS) make prognostic biomarkers urgently needed. We investigated whether serum neurofilament light chain (sNfL) levels in treatment-naive pediatric patients with MS are associated with early disease severity and indicate treatment outcomes.

METHODS

A retrospective cohort study of patients seen in the Göttingen Center for MS in Childhood and Adolescence, Germany. Inclusion criteria were MS diagnosis according to the McDonald criteria, MS onset <18 years, and available pretreatment serum sample. sNfL levels were analyzed using a single-molecule array assay. Associations with clinical and MRI evidence of disease severity at sampling were evaluated using the Spearman correlations and nonparametric tests for group comparisons. Correlations between pretreatment sNfL and annualized relapse and new T2 lesion rate on first-line therapy, and odd ratios for switch to high-efficacy therapy were assessed.

RESULTS

A total of 178 patients (116 women [65%]) with a mean sampling age of 14.3 years were included in the study. Pretreatment sNfL levels were above the ≥90th percentile reported for healthy controls in 80% of patients (median 21.1 pg/mL) and correlated negatively with age, but no correlation was seen with sex, oligoclonal band status, or body mass index. High pretreatment sNfL levels correlated significantly with a high number of preceding relapses, a shorter first interattack interval, a high T2 lesion count, and recent gadolinium-enhancing lesions. Of interest, sNfL levels reflected more strongly MRI activity rather than clinical activity. Pretreatment sNfL levels also correlated significantly with the relapse rate and occurrence of new/enlarging T2 lesions while on first-line injectable therapy. Odds of future therapy escalation increased from 0.14 for sNfL below 7.5 pg/mL to 6.38 for sNfL above 15 pg/mL. In patients with a recent relapse, higher sNfL levels were associated with poorer recovery 3 months after attack.

DISCUSSION

The results of this study have 3 important implications: First, pretreatment sNfL levels are a valuable biomarker for underlying disease activity in pediatric patients with MS. Second, pretreatment sNfL levels in pediatric patients with MS have a predictive value for the response to first-line therapy and the necessity of future therapy escalation. Third, high sNfL levels during a relapse are associated with poor recovery in this age group.

Evaluation of Novel Enhancer Compounds in Gentamicin-Mediated Readthrough of Nonsense Mutations in Rett Syndrome

Rett syndrome (RTT), a severe X-linked neurodevelopmental disorder, is primarily caused by mutations in the methyl CpG binding protein 2 gene (MECP2). Over 35% RTT patients carry nonsense mutation in MECP2, making it a suitable candidate disease for nonsense suppression therapy. In our previous study, gentamicin was found to induce readthrough of MECP2 nonsense mutations with modest efficiency. Given the recent discovery of readthrough enhancers, CDX compounds, we herein evaluated the potentiation effect of CDX5-1, CDX5-288, and CDX6-180 on gentamicin-mediated readthrough efficiency in transfected HeLa cell lines bearing the four most common MECP2 nonsense mutations. We showed that all three CDX compounds potentiated gentamicin-mediated readthrough and increased full-length MeCP2 protein levels in cells expressing the R168X, R255X, R270X, and R294X nonsense mutations. Among all three CDX compounds, CDX5-288 was the most potent enhancer and enabled the use of reduced doses of gentamicin, thus mitigating the toxicity. Furthermore, we successfully demonstrated the upregulation of full-length Mecp2 protein expression in fibroblasts derived from Mecp2^R255X/Y mice through combinatorial treatment. Taken together, findings demonstrate the feasibility of this combinatorial approach to nonsense suppression therapy for a subset of RTT patients.

A novel remitting leukodystrophy associated with a variant in FBP2

Leukodystrophies are genetic disorders of cerebral white matter that almost exclusively have a progressive disease course. We became aware of three members of a family with a disorder characterized by a sudden loss of all previously acquired abilities around 1 year of age followed by almost complete recovery within 2 years. Cerebral MRI and myelin sensitive imaging showed a pronounced demyelination that progressed for several months despite signs of clinical improvement and was followed by remyelination. Exome sequencing did not-identify any mutations in known leukodystrophy genes but revealed a heterozygous variant in the FBP2 gene, c.343G>A, p. Val115Met, shared by the affected family members. Cerebral MRI of other family members demonstrated similar white matter abnormalities in all carriers of the variant in FBP2. The FBP2 gene codes for muscle fructose 1,6-bisphosphatase, an enzyme involved in gluconeogenesis that is highly expressed in brain tissue. Biochemical analysis showed that the variant has a dominant negative effect on enzymatic activity, substrate affinity, cooperativity and thermal stability. Moreover, it also affects the non-canonical functions of muscle fructose 1,6-bisphosphatase involved in mitochondrial protection and regulation of several nuclear processes. In patients’ fibroblasts, muscle fructose 1,6-bisphosphatase shows no colocalization with mitochondria and nuclei leading to increased reactive oxygen species production and a disturbed mitochondrial network. In conclusion, the results of this study indicate that the variant in FBP2 disturbs cerebral energy metabolism and is associated with a novel remitting leukodystrophy.

Association of Obesity With Multiple Sclerosis Risk and Response to First-line Disease Modifying Drugs in Children

Importance

Obesity reportedly increases the risk of pediatric multiple sclerosis (MS), but little is known about its association with disease course.

Objective

To investigate the association of obesity with pediatric MS risk and with first-line therapy response among children with MS.

Design, Setting, and Participants

This single-center retrospective study used the medical records and database at the Center for MS in Childhood and Adolescence, Göttingen, Germany. The study included 453 patients with relapsing-remitting pediatric MS and body mass index (BMI) measurement taken within 6 months of diagnosis. Onset of the disease occurred between April 28, 1990, and June 26, 2016, and the mean disease duration was 38.4 months. Data were collected from July 14, 2016, to December 18, 2017.

Main Outcomes and Measures

Data on BMIs were stratified by sex and age using German BMI references and compared with the BMI data of 14 747 controls from a nationwide child health survey for odds ratio (OR) estimates. Baseline magnetic resonance imaging findings, intervals between first and second MS attacks, annualized relapse rates before and during treatment with interferon beta-1a or -1b and glatiramer acetate, frequency of second-line treatment, and Expanded Disability Status Scale (EDSS) scores were compared between nonoverweight (BMI≤90th percentile), overweight (BMI>90th-97th percentile), and obese (BMI>97th percentile) patients.

Results

In total, 453 patients with pediatric MS were included, of whom 306 (67.5%) were female, and the mean (SD) age at diagnosis was 13.7 (2.7) years. At diagnosis, 126 patients (27.8%) were overweight or obese, with obesity associated with statistically significant twofold odds of MS in both sexes (girls OR, 2.19; 95% CI, 1.5-3.1; P < .001 vs boys OR, 2.14; 95% CI, 1.3-3.5; P = .003). Obese patients, compared with nonoverweight patients, had statistically significantly more relapses on first-line treatment with interferon beta and glatiramer acetate (ARR, 1.29 vs 0.72; P < .001) and a higher rate of second-line treatment (21 [56.8%] of 37 vs 48 [38.7%] of 124; P = .06). Baseline neuroimaging, interval between first and second MS attacks, pretreatment relapses, and EDSS progression scores were not correlated with BMI.

Conclusions and Relevance

In this study, increased pediatric MS risk appeared to be associated with obesity, and obese patients did not respond well to first-line medications; altered pharmacokinetics appeared to be most likely factors in treatment response, suggesting that achieving healthy weight or adjusting the dose according to BMI could improve therapy response.

Activating de novo mutations in NFE2L2 encoding NRF2 cause a multisystem disorder

Transcription factor NRF2, encoded by NFE2L2, is the master regulator of defense against stress in mammalian cells. Somatic mutations of NFE2L2 leading to NRF2 accumulation promote cell survival and drug resistance in cancer cells. Here we show that the same mutations as inborn de novo mutations cause an early onset multisystem disorder with failure to thrive, immunodeficiency and neurological symptoms. NRF2 accumulation leads to widespread misregulation of gene expression and an imbalance in cytosolic redox balance. The unique combination of white matter lesions, hypohomocysteinaemia and increased G-6-P-dehydrogenase activity will facilitate early diagnosis and therapeutic intervention of this novel disorder.

The NRF2 transcription factor regulates the response to stress in mammalian cells. Here, the authors show that activating mutations in NRF2, commonly found in cancer cells, are found in four patients with a multisystem disorder characterized by immunodeficiency and neurological symptoms.

Therapy of highly active pediatric multiple sclerosis

Objective:

Study aims were to determine the frequency of highly active disease in pediatric multiple sclerosis (MS), the response to natalizumab (NTZ) and fingolimod (FTY) treatment, and the impact of current treatment modalities on the clinical course.

Methods:

Retrospective single-center study in the German Center for MS in Childhood and Adolescence.

Results:

Of 144 patients with first MS manifestation between 2011 and 2015, 41.6% fulfilled the criteria for highly active MS. In total, 55 patients treated with NTZ and 23 with FTY demonstrated a significant reduction in relapse rate (NTZ: 95.2%, FTY: 75%), new T2 lesions (NTZ: 97%, FTY: 81%), and contrast-enhancing lesions (NTZ: 97%, FTY: 93%). However, seven patients switched from NTZ to FTY experienced an increase in disease activity. Comparing pediatric MS patients treated in 2005 with those treated in 2015 showed a 46% reduction in relapse rate and a 44% reduction in mean Expanded Disability Status Scale (EDSS).

Conclusion:

The rate of highly active disease among pediatric MS patients is high; more than 40% in our cohort. Response to NTZ and FTY treatment is similar if not better than observed in adults. Current treatment modalities including earlier treatment initiation and the introduction of NTZ and FTY have significantly improved the clinical course of pediatric MS.

JC virus antibody status in a pediatric multiple sclerosis cohort: prevalence, conversion rate and influence on disease severity

BACKGROUND

Because of the emergence of novel therapies for multiple sclerosis (MS) and the associated increased risk of progressive multifocal leukoencephalopathy, John Cunningham (JC) virus infection has become a focus of interest for neurologists. However, little is known about JC virus infection in pediatric MS to date.

OBJECTIVE

We aimed to analyze the prevalence of anti-JC virus antibodies, the conversion rate and the influence of the anti-JC virus antibody status on the clinical course in a large pediatric MS cohort.

METHODS

Anti-JC virus antibodies were analyzed in serum samples within six months of disease onset and during the course of the disease. Clinical data were extracted from a pediatric MS databank.

RESULTS

A total of 51.6% of 256 patients were found to be positive for anti-JC virus antibodies at onset of disease. No correlation between antibody status and clinical course was seen. Analyzing 693 follow-up serum samples revealed high titer stability, and an annual conversion rate of 4.37% was seen.

CONCLUSION

No evidence was found that seropositivity for anti-JC virus antibodies influences the clinical course. Surprisingly, seroprevalence for anti-JC virus antibodies was more than twice as high as anticipated in this age group, raising the question of whether the infection increases the risk of MS development.

Acute disseminated encephalomyelitis followed by recurrent or monophasic optic neuritis in pediatric patients

BACKGROUND

Some pediatric patients with inflammatory demyelinating central nervous system disorders cannot be classified under any of the established disease entities, making their treatment and prognosis difficult.

OBJECTIVE

The objective of this study is to characterize a subgroup of pediatric patients with recurrent demyelinating central nervous system disorders.

METHODS

This study includes a case series of pediatric patients with monophasic or recurrent acute disseminated encephalomyelitis (ADEM) who later presented with either monophasic or recurrent optic neuritis (ON).

RESULTS

We describe seven patients with a median follow-up of six years (five females, two males) who presented at a median age of 6 years (range 4-8 years) with monophasic (n = 4) or recurrent ADEM (two to four attacks) followed by monophasic (n = 3) or recurrent ON (two to nine attacks). Cranial magnetic resonance imaging (MRI) was typical for ADEM (n = 6) with complete or almost complete resolution of lesions on follow-up. Cerebrospinal (CSF) studies at the time of ADEM showed a pleocytosis in six patients and were negative for oligoclonal bands (OCBs) in all. In all patients high titers for serum anti-MOG antibodies were detected.

CONCLUSION

ADEM followed by ON is a rare but distinct clinical phenotype among pediatric patients. Further studies are needed to allow recommendations on treatment or prognosis.

Neuromyelitis optica and NMO-IgG in European pediatric patients

OBJECTIVE

Neuromyelitis optica (NMO) is currently considered a severe relapsing CNS demyelinating disorder that is associated with aquaporin-4 immunoglobulin G (NMO-IgG) while in earlier reports of NMO in childhood it has been described as a benign and monophasic disorder. This study was performed to analyze the prevalence and the clinical course of NMO in a European pediatric cohort of patients with demyelinating CNS disorders.

METHODS

A cohort study was performed evaluating 118 pediatric patients presenting at the Center for Multiple Sclerosis in Childhood and Adolescents, Göttingen, Germany, with demyelinating CNS disorders between 2000 and 2009. In all patients, NMO-IgG status was determined.

RESULTS

The majority of patients (94%) were diagnosed with remitting recurrent multiple sclerosis. Six patients fulfilled the clinical criteria for NMO but only 1 was seropositive for NMO-IgG. This patient had a severe relapsing course in contrast to the seronegative patients who showed a mild and in the majority of cases monophasic course.

CONCLUSIONS

The diagnostic criteria clearly distinguished the patients with NMO from patients with other demyelinating CNS disorders. In the European pediatric population, NMO is very rare and in the majority of patients not associated with NMO-IgG. These seronegative cases have a benign and predominantly monophasic course and therefore do not need the immunosuppressant therapy that is recommended for NMO in the recent literature.

Immunoglobulin therapy in idiopathic hypothalamic dysfunction

Idiopathic hypothalamic dysfunction is a rare disorder presenting at age 3-7 years. Severe hypothalamic and brainstem dysfunction leads to death in 25% of patients. The disease is presumed to be autoimmune, or in some cases paraneoplastic. No successful treatment has been reported. Patient V. developed hyperphagia, hypersomnia, and extreme aggression at age 7 years, accompanied by episodes of hyperthermia, hypothermia, sinus bradycardia, hypernatremia, hyponatremia, persistent hyperprolactinemia, hypothyroidism, and growth-hormone deficiency. At age 9 years, a diagnosis of idiopathic hypothalamic dysfunction was rendered, and immunoglobulin therapy was commenced. Nine courses of immunoglobulins, at a dose of 2 g/kg every 4 weeks, were administered. Reproducible improvements in behavior and no further episodes of hyponatremia or hypernatremia and sinus bradycardia were evident. The endocrinologic abnormalities and poor thermoregulation remained. Administration of immunoglobulins during late stages of idiopathic hypothalamic dysfunction led to improvement in some but not all signs. Assuming an autoimmune basis for this disorder, treatment during early stages of disease should be more effective. To facilitate such early treatment, increased awareness of this disorder is necessary, to allow for early diagnosis.