Sampling of per- and polyfluoroalkyl substances in drainage water from a waste management facility.

Per- and polyfluoroalkyl substances (PFAS) have been used for decades in a broad range of consumer products and industrial applications. A variety of waste and products containing PFAS inevitably end up at waste management facilities when they are no longer considered useful. Drainage water samples (n = 157) were collected from eight subsections at a waste management facility in Sweden and analyzed for 23 PFAS and extractable organofluorine (EOF). Two different sampling methods were used, grab sampling (n = 32, without filtration) and composite sampling (n = 8, produced by pooling 16 filtered samples taken at the same subsection). Although PFAS have been studied at waste sites, the information is scarce regarding how the concentrations and homologue profiles could differ within the sites. In this study, we investigated if composite sampling could be an alternative to grab sampling for PFAS monitoring purposes. Herein, the PFAS concentrations ranged from <1 to 22 µg/L; the grab samples showed systematic higher concentrations than their corresponding composite sample. Short-chain perfluoroalkyl sulfonic acids (C4 and C5) were the largest contributing sub-class, followed by short-chain perfluoroalkyl carboxylic acids (C4 to C6). EOF was measured up to approximately 140 µg/L F with 99% being unexplained by the fluorine mass balance analysis. The results from this study showed that both sampling methods were comparable for target analysis and that 11 compounds represented most of the PFAS concentrations. However, the discrepancy between the sampling methods was greater for EOF analysis and may be due to the preparation of composite samples and/or due to fluctuating discharges during the sampling period. Composite sampling was observed to be comparable to grab sampling for target analysis.

High levels of neurofilament light and YKL-40 in cerebrospinal fluid are related to poor outcome in ALS.

Amyotrophic lateral sclerosis (ALS) is a neurological disease without effective treatment. No pathognomonic test can diagnose ALS in sporadic cases. Routine investigation in suspected cases includes neurological examination, imaging of the brain and spine and electromyography supported by blood and cerebrospinal fluid (CSF) analyses. The ALS diagnosis is made by clinical judgement and results from examinations. We aimed to study if the CSF biomarkers neurofilament light protein (NFL), glial fibrillary acidic protein (GFAP), YKL-40, soluble amyloid precursor protein (sAPP) α and ß, and soluble triggering receptor expressed on myeloid cells 2 (sTREM2) were associated with ALS diagnosis and could predict disease progression. Eighty-one patients with suspected ALS were included after referral to the neurological clinic at Sahlgrenska University Hospital. Fifty-nine patients were diagnosed having ALS, while 22 patients were given alternative diagnoses and labeled ALS mimics. Finally, 25 age-matched neurologically intact individuals were used as controls. ALS patients had significantly higher CSF levels of NFL than controls and mimics. Levels of YKL-40 and GFAP were significantly higher in ALS patients compared with controls. No difference was found between study groups when comparing levels of sAPPα, sAPPß and sTREM2. Further, elevated levels of NFL and YKL-40 were associated with an increased hazard of death and the annual decline in ALSFRS-R. We also found that patients with elevated levels of both NFL and YKL-40 had a particularly poor prognosis. The results demonstrate the usefulness of CSF biomarkers in the diagnosis and prognostication of ALS.

CSF biomarkers of neurotoxicity in childhood cancer survivors after cranial radiotherapy or surgery.

OBJECTIVE: Treatment of pediatric brain tumors is associated with potential long-term cognitive sequelae. Patients treated with craniospinal irradiation for posterior fossa tumors are at high risk. New biomarkers that could help to differentiate treatment effects from other causes of cognitive dysfunction would be valuable in tailoring optimal survivorship care. Biomarkers that reflect biological mechanisms behind treatment-associated cognitive decline would also be important in the evaluation of future treatment regimens for pediatric brain or skull base tumors. METHODS: In this biomarker-finding study, 10 adult survivors of pediatric medulloblastoma, skull base tumors, and posterior fossa low-grade glioma underwent study specific lumbar puncture at a minimum of 17 years following treatment. We analyzed cerebrospinal fluid biomarkers reflecting neuron and astrocyte integrity, amyloid metabolism, inflammation, extracellular matrix, synaptic integrity, and blood-brain barrier function. The values were compared with biomarker levels in healthy controls of comparable age. RESULTS: Biomarkers reflecting neuronal injury (neurofilament light chain protein), astrocyte injury or activation (glial fibrillary acidic protein) as well as inflammation (YKL-40) were significantly elevated in cancer survivors compared to controls. Biomarkers reflecting amyloid metabolism showed a pattern of decrease in patients treated for medulloblastoma. INTERPRETATION: The results suggest a potential chronic low-grade neurodegeneration and astrocyte activation in patients treated for pediatric brain or skull base tumors. Protein biomarkers of CNS disease could potentially be used to increase our understanding of the contribution from different tumor treatments with regard to long-term symptoms in cancer patients.

Standard versus High Cardiopulmonary Bypass Flow Rate: A Randomized Controlled Subtrial Comparing Brain Injury Biomarker Release.

OBJECTIVES: To compare brain injury biomarker release levels between two different cardiopulmonary bypass (CPB) flow rates in elective cardiac surgery and to explore differences in postoperative delirium between groups and associations between age, sex, CPB time, oxygen levels, and near-infrared spectroscopy, and biomarker levels. DESIGN: A randomized controlled substudy trial SETTING: Sahlgrenska University Hospital, Sweden PARTICIPANTS: Forty patients undergoing elective cardiac surgery with CPB INTERVENTION: Patients were assigned at random to either a standard (2.4 L/min/m2) or a high (2.9 L/min/m2) CPB flow rate. MEASUREMENTS AND MAIN RESULTS: Glial fibrillary acidic protein, neurofilament light chain, total-tau, and phosphorylated-tau217 were sampled in plasma before anesthesia induction, after 60 minutes on CPB, and at 30 minutes, 24 hours, and 72 hours post-CPB. Mixed models for repeated measures were used to analyze differences in biomarker levels between groups and to assess relationships, which showed no differences between the 2 flow rate groups. There also was no difference in the occurrence of delirium between the 2 groups. Associations were found between age and increased neurofilament light chain levels. Female sex, oxygen delivery >330 mL/min/m2, and near-infrared spectroscopy level >60% were associated with lower biomarker levels. CONCLUSIONS: An increased flow rate did not have any significant effects on biomarker levels compared to a standard flow rate. Several associations were identified between treatment characteristics and biomarker levels. No difference in delirium was seen.

Association of serum glial fibrillary acidic protein with progression independent of relapse activity in multiple sclerosis.

OBJECTIVE: Insidious disability worsening is a common feature in relapsing-remitting multiple sclerosis (RRMS). Many patients experience progression independent of relapse activity (PIRA) despite being treated with high efficacy disease-modifying therapies. We prospectively investigated associations of body-fluid and imaging biomarkers with PIRA. METHODS: Patients with early RRMS (n = 104) were prospectively included and followed up for 60 months. All patients were newly diagnosed and previously untreated. PIRA was defined using a composite score including the expanded disability status scale, 9-hole peg test, timed 25 foot walk test, and the symbol digit modalities test. Eleven body fluid and imaging biomarkers were determined at baseline and levels of serum neurofilament light (sNfL) and glial fibrillary acidic protein (sGFAP) were also measured annually thereafter. Association of baseline biomarkers with PIRA was investigated in multivariable logistic regression models adjusting for clinical and demographic confounding factors. Longitudinal serum biomarker dynamics were investigated in mixed effects models. RESULTS: Only sGFAP was significantly higher in PIRA at baseline (median [IQR] 73.9 [60.9-110.1] vs. 60.3 [45.2-79.9], p = 0.01). A cut-off of sGFAP > 65 pg/mL resulted in a sensitivity of 68% and specificity of 61%, to detect patients at higher risk of PIRA. In a multivariable logistic regression, sGFAP > 65 pg/mL was associated with higher odds of developing PIRA (odds ratio 4.3, 95% CI 1.44-12.86, p = 0.009). Repeated measures of sGFAP levels showed that patients with PIRA during follow-up had higher levels of sGFAP along the whole follow-up compared to stable patients (p < 0.001). CONCLUSION: Determination of sGFAP at baseline and follow-up may be useful in capturing disability accrual independent of relapse activity in early RRMS.

Medically unexplained symptoms are common in women in tertiary neurological healthcare center: A survey cohort study of persons investigated for suspected multiple sclerosis.

BACKGROUND: A significant proportion of individuals with suspicious onset of multiple sclerosis (MS) does not fulfill the diagnostic criteria. Although some receive other diagnoses, many remain undiagnosed and lack healthcare follow-up. This study aimed to characterize persons with undetermined diagnosis (PwUD) through a questionnaire. METHODS: Incident cases with suspected MS were consecutively admitted to a tertiary neurological healthcare center in a prospective cohort study. Those who remained undiagnosed after 40 months (mean, range 31-52) were considered PwUD. They completed a modified questionnaire, previously used in a population-based case-control study of incident MS cases. Their responses were compared with two control cohorts, persons with MS (PwMS) and healthy controls, randomly selected from national registries, matched by age, gender, and area of residence. RESULTS: Out of 271 patients with suspected MS onset, 72 (20.3%) were PwUD with a female majority (79%). The response rate was 83% and 39% reported persisting MS-like symptoms. Compared to controls (n = 548) and PwMS (n = 277), fewer PwUD were currently smoking (p = .4 and p = .03), consumed less alcohol (p = .04 and p = .01), and had children (p = .02 and p = .002). PwUD reported occurrence of other autoimmune disease in 29%, higher compared to PwMS and controls (p < .001 and p < .001). CONCLUSIONS: UD is common among persons investigated for suspected MS, in particular among female parents. Our data suggest that PwUD can be characterized as nonsmokers with low alcohol consumption and a higher prevalence of autoimmune disease, in particular thyroid disease.

High temperature requirement A1 and macrophage migration inhibitory factor in the cerebrospinal fluid; a potential marker of conversion from relapsing-remitting to secondary progressive multiple sclerosis.

BACKGROUND: Predictive and prognostic biomarkers for multiple sclerosis (MS) remain a significant gap in MS diagnosis and treatment monitoring. Currently, there are no timely markers to diagnose the transition to secondary progressive MS (SPMS). OBJECTIVE: This study aims to evaluate the discriminatory potential of the High temperature requirement serine protease (HTRA1)/Macrophage migration inhibitory factor (MIF) cerebrospinal fluid (CSF) ratio in distinguishing relapsing-remitting (RRMS) patients from SPMS patients. METHODS: The MIF and HTRA1 CSF levels were determined using ELISA in healthy controls (n = 23), RRMS patients before (n = 22) and after 1 year of dimethyl fumarate treatment (n = 11), as well as in SPMS patients before (n = 11) and after 2 years of mitoxantrone treatment (n = 7). The ability of the HTRA1/MIF ratio to discriminate the different groups was determined using receiver operating curve (ROC) analyses. RESULTS: The ratio was significantly increased in treatment naïve RRMS patients while decreased again in SPMS patients at baseline. Systemic administrated disease modifying treatment (DMT) only significantly affected the ratio in RRMS patients. ROC analysis demonstrated that the ratio could discriminate treatment naïve RRMS patients from SPMS patients with 91% sensitivity and 100% specificity. CONCLUSION: The HTRA1/MIF ratio is a strong candidate as a MS biomarker for SPMS conversion.

A prospective feasibility trial exploring novel biomarkers for neurotoxicity after isolated limb perfusion.

BACKGROUND: Isolated limb perfusion (ILP) is a regional cancer treatment in which high-dose chemotherapy is administered in an isolated extremity. The main side effect is regional toxicity, which occasionally leads to nerve damage. Measuring neuroaxonal biomarkers, might be a method predicting such complications. Therefore, the primary aim of the study is to investigate if neuronal biomarkers are measurable and alters in an isolated extremity during ILP. Secondly, if postoperative regional toxicity, alterations in sensitivity, and/or muscle strength are correlated to the biomarker levels. METHODS: Eighteen scheduled ILP-patients were included in the study. Glial fibrillary acidic protein (GFAP), neurofilament light (NfL), and tau concentrations were measured in plasma sampled preoperatively, at the start and end of the ILP, on days 3 and 30, using ultrasensitive Single molecule array (Simoa) technology. The patients were assessed by a physiotherapist pre- and postoperatively. RESULTS: At ILP end, significantly higher NfL and tau levels were measured in the extremity than in the corresponding systemic circulation (NfL; 17 vs 6 ng/L, p < .01, tau; 1.8 vs 0.6 ng/L, p < .01), and the extremity levels were significantly increased at ILP end (NfL; 66 ± 37%, p < .001, tau; 75 ± 45%, p = .001). On days 3 and 30, significantly increased NfL and GFAP levels were measured systemically (NfL day 3: 69 ± 30%, p < .001; day 30: 76 ± 26%, p < .001; GFAP day 3: 33 ± 22%, p < .002; day 30: 33 ± 23%, p ≤ .004). Finally, no significant correlations were found between regional toxicity or between postoperative muscle or sensitivity decrease and biomarker release. CONCLUSION: During ILP, NfL and tau levels increased significantly. No obvious correlations were observed between biomarker release and regional toxicity or decreased muscle strength or sensitivity, although large-scale studies are warranted.

A five-year observational prospective mono-center study of the efficacy of alemtuzumab in a real-world cohort of patients with multiple sclerosis.

Background: Alemtuzumab (ALZ) is a pulsed immune reconstitution therapy for multiple sclerosis (MS). Objective: To assess basic characteristics, therapeutic effects, and prognostic biomarkers on clinical and imaging parameters of disease activity for relapsing-remitting MS (RRMS) patients selected for ALZ, in a real-world long-term setting. Methods: Fifty-one RRMS patients [female = 31; mean age 36 (standard deviation 7.1) years; median expanded disability status scale (EDSS) 2 (interquartile range (IQR) 1.5)] initiating ALZ treatment, were consecutively included. Patients were assessed at baseline and thereafter annually for 5 years with clinical measures, symbol digit modality test (SDMT), and magnetic resonance imaging (MRI). Concentrations of glial fibrillary acidic protein (GFAP), reflecting astrogliosis, and neurofilament light (NfL), reflecting axonal damage, were measured in cerebrospinal fluid (CSF) and serum samples collected at baseline and after 2 years in CSF, and annually in serum. Control subjects were symptomatic controls (SCs, n = 27), who were examined at baseline and after 5 years without evidence of neurological disease. Results: While the mean annualized relapse rate was significantly reduced from baseline at each year of follow-up, disability was essentially maintained at a median EDSS of 1.5 and IQR between 1.13 and 2.25. New MRI activity was recorded in 26 patients (53%) over 5 years. The proportion of patients who achieved no evidence of disease activity (NEDA-3), 6-months confirmed disability worsening (CDW), and 6-months confirmed disability improvement (CDI) at 5 years were 33, 31, and 31%, respectively. The SDMT score was reduced for patients (p < 0.001), but unchanged for SCs. ALZ treatment did not change GFAP levels, whereas there was a significant decrease for RRMS patients in median CSF and serum NfL levels at follow-up [CSF month 24: 456 pg./mL (IQR 285.4) (p = 0.05); serum month 24: 6.7 pg/mL (IQR 4.7) (p < 0.01); serum month 60: 7.2 pg/mL (IQR 4.7) (p < 0.01)], compared to baseline [CSF: 1014 pg/mL (IQR 2832.5); serum 8.6 pg/mL (IQR 17.4)]. Conclusion: In this real-world mono-center population, we observed a progression-free survival of 69%, cumulative NEDA-3 of 33%, and reduced NfL levels, over a five-year follow-up. This confirms ALZ as an effective pulsed immune reconstitution therapy that significantly reduces neuro axonal loss, and therefore has the potential to reduce long-term neurological disability. ALZ did not appear to affect astrogliosis.

Neurofilament light, glial fibrillary acidic protein, and tau in a regional epilepsy cohort: High plasma levels are rare but related to seizures.

OBJECTIVE: Higher levels of biochemical blood markers of brain injury have been described immediately after tonic-clonic seizures and in drug-resistant epilepsy, but the levels of such markers in epilepsy in general have not been well characterized. We analyzed neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and tau in a regional hospital-based epilepsy cohort and investigated what proportion of patients have levels suggesting brain injury, and whether certain epilepsy features are associated with high levels. METHODS: Biomarker levels were measured in 204 patients with an epilepsy diagnosis participating in a prospective regional biobank study, with age and sex distribution correlating closely to that of all patients seen for epilepsy in the health care region. Absolute biomarker levels were assessed between two patient groups: patients reporting seizures within the 2 months preceding inclusion and patients who did not have seizures for more than 1 year. We also assessed the proportion of patients with above-normal levels of NfL. RESULTS: NfL and GFAP, but not tau, increased with age. Twenty-seven patients had abnormally high levels of NfL. Factors associated with such levels were recent seizures (p = .010) and epileptogenic lesion on radiology (p = .001). Levels of NfL (p = .006) and GFAP (p = .032) were significantly higher in young patients (<65 years) with seizures ≤2 months before inclusion compared to those who reported no seizures for >1 year. NfL and GFAP correlated weakly with the number of days since last seizure (NfL: rs = -.228, p = .007; GFAP: rs = -.167, p = .048) in young patients. NfL also correlated weakly with seizure frequency in the last 2 months (rs = .162, p = .047). SIGNIFICANCE: Most patients with epilepsy do not have biochemical evidence of brain injury. The association with seizures merits further study; future studies should aim for longitudinal sampling and examine whether individual variations in NfL or GFAP levels could reflect seizure activity.

The impact of hybrid immunity on immune responses after SARS-CoV-2 vaccination in persons with multiple sclerosis treated with disease-modifying therapies.

BACKGROUND AND PURPOSE: Hybrid immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) develops from a combination of natural infection and vaccine-generated immunity. Multiple sclerosis (MS) disease-modifying therapies (DMTs) have the potential to impact humoral and cellular immunity induced by SARS-CoV-2 vaccination and infection. The aims were to compare antibody and T-cell responses after SARS-CoV-2 mRNA vaccination in persons with MS (pwMS) treated with different DMTs and to assess differences between naïvely vaccinated pwMS and pwMS with hybrid immunity vaccinated following a previous SARS-CoV-2 infection. METHODS: Antibody and T-cell responses were determined in pwMS at baseline and 4 and 12 weeks after the second dose of SARS-CoV-2 vaccination in 143 pwMS with or without previous SARS-CoV-2 infection and 40 healthy controls (HCs). The MS cohort comprised natalizumab (n = 22), dimethylfumarate (n = 23), fingolimod (n = 38), cladribine (n = 30), alemtuzumab (n = 17) and teriflunomide (n = 13) treated pwMS. Immunoglobulin G antibody responses to SARS-CoV-2 antigens were measured using a multiplex bead assay and FluoroSpot was used to assess T-cell responses (interferon γ and interleukin 13). RESULTS: Humoral and T-cell responses to vaccination were comparable between naïvely vaccinated HCs and pwMS treated with natalizumab, dimethylfumarate, cladribine, alemtuzumab and teriflunomide, but were suppressed in fingolimod-treated pwMS. Both fingolimod-treated pwMS and HCs vaccinated following a previous SARS-CoV-2 infection had higher antibody levels 4 weeks after vaccination compared to naïvely vaccinated individuals. Antibody and interferon γ levels 12 weeks after vaccination were positively correlated with time from last treatment course of cladribine. CONCLUSION: These findings are of relevance for infection risk mitigation and for vaccination strategies amongst pwMS undergoing DMT.

Paraneoplastic or not? Sirtuin 2 in anti-N-methyl-d-aspartate receptor encephalitis.

BACKGROUND AND PURPOSE: N-methyl-d-aspartate receptor (NMDAR) and leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis are important types of autoimmune encephalitis (AE) with significant morbidity. In this study, we used a proteomic approach in search of novel clinically relevant biomarkers in these types of encephalitides. METHODS: Swedish and Czech tertiary neuroimmunology centers collaborated in this retrospective exploratory study. Fifty-eight cerebrospinal fluid (CSF) samples of 28 patients with AE (14 definite NMDAR, 14 with definite LGI1 encephalitis) and 30 controls were included. CSF samples were analyzed using proximity extension assay technology (Olink Target 96 Inflammation panel). For each CSF sample, 92 proteins were measured. Clinical variables were retrospectively collected, and correlations with protein levels were statistically analyzed. RESULTS: Patients and controls differed significantly in the following 18 biomarkers: TNFRSF9, TNFRSF12, TNFRSF14, TNFß, TNFα, IL7, IL10, IL12B, IFNγ, CD5, CD6, CASP8, MMP1, CXCL8, CXCL10, CXCL11, IL20RA, and sirtuin 2 (SIRT2). In LGI1 encephalitis, no clinically useful association was found between biomarkers and clinical variables. In the NMDAR encephalitis group, SIRT2, TNFß, and CD5 were significantly associated with ovarian teratoma. For SIRT2, this was true even for the first patients' CSF sample (SIRT2 without vs. with tumor, mean ± SD = 2.2 ± 0.29 vs. 2.88 ± 0.48; p = 0.007, 95% confidence interval = -1.15 to -0.22; r statistic in point-biserial correlation (rpb) = 0.66, p = 0.011). SIRT2 was positively correlated with age (rpb = 0.39, p = 0.018) and total hospital days (r = 0.55, p = <0.001). CONCLUSIONS: SIRT2 should be investigated as a biomarker of paraneoplastic etiology in NMDAR encephalitis.

Intrathecal kappa free light chain synthesis is associated with worse prognosis in relapsing-remitting multiple sclerosis.

BACKGROUND: While kappa free light chain (KFLC) index has become a useful diagnostic biomarker in multiple sclerosis (MS), its prognostic properties are less explored. B cells play a crucial role in MS pathogenesis, but the impact from increased intrathecal production of immunoglobulins and KFLC remains to be determined. Recently, it has become evident that insidious worsening is not confined to progressive MS but is also common in relapsing-remitting MS (RRMS), a feature known as progression independent of relapse activity (PIRA). METHODS: We retrospectively identified 131 patients with clinically isolated syndrome or early RRMS who had determined KFLC index as part of their diagnostic workup. Demographic and clinical data were extracted from the Swedish MS registry. Associations of baseline KFLC index with evidence of disease activity (EDA) and PIRA were investigated in multivariable cox proportional hazards regression models. RESULTS: KFLC index was significantly higher in PIRA (median 148.5, interquartile range [IQR] 106.9-253.5) compared with non-PIRA (78.26, IQR 28.93-186.5, p = 0.009). In a multivariable cox regression model adjusted for confounders, KFLC index emerged as an independent risk factor for PIRA (adjusted hazard ratio [aHR] 1.005, 95% confidence interval [CI] 1.002-1.008, p = 0.002). Dichotomized by the cut-off value KFLC index > 100, patients with KFLC index > 100 had an almost fourfold increase in the risk for developing PIRA. KFLC index was also predictive of evidence of disease activity during follow-up. CONCLUSIONS: Our data indicate that high KFLC index at baseline is predictive of PIRA, EDA-3, and overall worse prognosis in MS.

Presence of neural surface and onconeural autoantibodies in cerebrospinal fluid and serum in neurological diseases presents a potential risk for misdiagnosis.

BACKGROUND AND PURPOSE: Autoantibodies have been found to contribute to pathology and are used in the diagnosis of some neurological diseases. We examined the prevalence of autoantibodies in patients with various neurological diseases and whether patients who had autoantibodies differed in age, sex, or disability from those who did not. METHODS: We examined the prevalence of neural surface and onconeural autoantibodies in cerebrospinal fluid (CSF) and serum from patients with multiple sclerosis (n = 64), Parkinson disease plus atypical parkinsonism (n = 150), amyotrophic lateral sclerosis (n = 43), or autoimmune encephalitis (positive control; n = 7) and a healthy control group (n = 37). A total of 12 onconeural autoantibodies and six neural surface autoantibodies were tested in all participants. RESULTS: Autoantibodies were present in all cohorts. The prevalence of autoantibodies was high (>80%) in the autoimmune encephalitis cohort but low (<20%) in all other cohorts. When comparing patients within cohorts who were positive for autoantibodies to patients who were not, there was no difference in age, sex, and disability. This was apart from the multiple sclerosis and Parkinson disease plus atypical parkinsonism cohorts, where those with positivity for autoantibodies in the CSF were significantly older. CONCLUSIONS: The presence of the autoantibodies examined does not appear to have a substantial clinical impact within the diseases examined in this study. The presence of autoantibodies in all cohorts presents a risk for misdiagnosis when the method is used incorrectly on patients with atypical clinical presentation.

CYBA allelic variants are associated with severity and recovery in Guillain-Barré syndrome.

BACKGROUND AND AIMS: Guillain-Barré syndrome (GBS) is a rare, acute neuropathy characterized by ascending muscle weakness. Age, axonal GBS variants, and antecedent Campylobacter jejuni infection are associated with severe GBS, but the detailed mechanisms of nerve damage are only partly explored. Pro-inflammatory myeloid cells express NADPH oxidases (NOX) that generate tissue-toxic reactive oxygen species (ROS) that are implicated in neurodegenerative diseases. This study analyzed the impact of variants of the gene encoding the functional NOX subunit CYBA (p22phox ) on acute severity, axonal damage, and recovery in adult GBS patients. METHODS: Extracted DNA from 121 patients was genotyped for allelic variation at rs1049254 and rs4673 within CYBA using real-time quantitative polymerase chain reaction. Serum neurofilament light chain was quantified by single molecule array. Patients were followed for severity and motor function recovery for up to 13 years. RESULTS: CYBA genotypes linked to reduced formation of ROS, i.e. rs1049254/G and rs4673/A, were significantly associated with unassisted ventilation, shorter time to normalization of serum neurofilament light chain and shorter time to regained motor function. Residual disability at follow-up was confined to patients carrying CYBA alleles associated with high formation of ROS. INTERPRETATION: These findings implicate NOX-derived ROS in GBS pathophysiology and CYBA alleles as biomarkers of severity.

The role of autoimmune antibodies to predict secondary autoimmunity in patients with relapsing-remitting multiple sclerosis treated with alemtuzumab: A nationwide prospective survey.

Background: Alemtuzumab (ALZ) is an immune reconstitution therapy for treating relapsing-remitting multiple sclerosis (RRMS). However, ALZ increases the risk of secondary autoimmune diseases (SADs). Objective: We explored whether the detection of autoimmune antibodies (auto-Abs) could predict the development of SADs. Methods: We included all patients with RRMS in Sweden who initiated ALZ treatment (n = 124, 74 female subjects) from 2009 to 2019. The presence of auto-Abs was determined in plasma samples obtained at the baseline and at 6, 12, and 24 months of follow-up, as well as in a subgroup of patients (n = 51), it was determined in plasma samples obtained at the remaining 3-month intervals up to 24 months. Monthly blood tests, urine tests, and the assessment of clinical symptoms were performed for monitoring safety including that of SADs. Results: Autoimmune thyroid disease (AITD) developed in 40% of patients, within a median follow-up of 4.5 years. Thyroid auto-Abs were detected in 62% of patients with AITD. The presence of thyrotropin receptor antibodies (TRAbs) at the baseline increased the risk of AITD by 50%. At 24 months, thyroid auto-Abs were detected in 27 patients, and 93% (25/27) developed AITD. Among patients without thyroid auto-Abs, only 30% (15/51) developed AITD (p < 0.0001). In the subgroup of patients (n = 51) with more frequent sampling for auto-Abs, 27 patients developed ALZ-induced AITD, and 19 of them had detectable thyroid auto-Abs prior to the AITD onset, with a median interval of 216 days. Eight patients (6.5%) developed non-thyroid SAD, and none had detectable non-thyroid auto-Abs. Conclusion: We conclude that monitoring thyroid auto-Abs, essentially TRAbs, may improve the surveillance of AITD associated with ALZ treatment. The risk for non-thyroid SADs was low, and monitoring non-thyroid auto-Abs did not seem to provide any additional information for predicting non-thyroid SADs.

Cerebrospinal fluid sulfatide isoforms lack diagnostic utility in separating progressive from relapsing-remitting multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is an immune-mediated demyelinating disorder of the central nervous system. The glycosphingolipid sulfatide, a lipid particularly enriched in the myelin sheath, has been shown to be involved the maintenance of this specific membrane structure. Sulfatide in cerebrospinal fluid (CSF) may reflect demyelination, a dominating feature of MS. We investigated the diagnostic utility of CSF sulfatide isoform levels to separate different courses or phenotypes of MS disease. MATERIAL AND METHODS: This was a mono-center, cross-sectional study of relapsing-remitting MS (RRMS) (n = 45) and progressive MS (PMS) (n = 42) patients (consisting of primary PMS (n = 17) and secondary PMS (n = 25)) and healthy controls (n = 19). In total, 20 sulfatide isoforms were measured in CSF by liquid chromatography-mass spectrometry. RESULTS: CSF total sulfatide concentrations, as well as CSF sulfatide isoform distribution, did not differ across the study groups, and their levels were independent of disease course/phenotype, disease duration, time to conversion to secondary PMS, age, and disability in MS patients. CONCLUSION: CSF sulfatide isoforms lack diagnostic and prognostic utility as a biomarker for progressive MS.

High levels of kappa free light chain synthesis predict cognitive decline in relapsing-remitting multiple sclerosis.

Background: Evolving evidence suggests that measurement of cerebrospinal fluid (CSF) kappa free light chain (KFLC) synthesis has high diagnostic sensitivity and specificity for multiple sclerosis (MS), but its prognostic ability is less investigated. The usefulness of KFLC in predicting cognitive impairment (CI) is still unknown. Methods: In a monocentric longitudinal retrospecitve cohort study, KFLC-index ([CSF KFLC/serum KFLC]/[CSF albumin/serum albumin]) measured by latex-enhanced immunonephelometry was prospectively determined as part of the diagnostic workup in patients with early relapsing-remitting MS (RRMS, n=77). The ability of KFLC-index to predict information processing speed (IPS) worsening as assessed with the symbol digit modalities test (SDMT) was investigated in univariable and multivariable models. Results: In patients with KFLC-index>100 (n=31), 11 subjects (35.5%) showed reduced SDMT scores by ≥8 points at follow-up (mean follow-up time 7.3 ± 2.6 years), compared with their baseline scores (p=0.01). Baseline KFLC-index>100 was strongly associated with a higher hazard of SDMT score reduction at follow-up (adjusted hazard ratio 10.5, 95% confidence interval 2.2-50.8, p=0.003; median time to SDMT reduction 7 years). Conclusion: Intrathecal KFLC synthesis has become an attractive diagnostic tool for MS. We show for the first time that in a real-world setting of early RRMS, KFLC-index predicted cognitive decline. Whether this predictive ability of KFLC-index also concerns other cognitive domains than IPS, warrants further investigations.

Decreased Incidence of Guillain-Barré Syndrome during the COVID-19 Pandemic: A Retrospective Population-Based Study.

BACKGROUND: Guillain-Barré syndrome is an immune-mediated acute inflammatory polyneuropathy that is associated with various triggers, including certain infections and vaccines. It has been suggested that both SARS-CoV-2 infection and vaccination may be triggering factors for Guillain-Barré syndrome, but evidence remains equivocal. Here, we conducted a population-based incidence study of Guillain-Barré syndrome spanning the 3 years immediately prior to and the 2 years during the pandemic. METHODS: Cases were identified by searching a regional diagnostic database for the ICD-10 code for Guillain-Barré syndrome. Individuals who fulfilled the Brighton criteria for Guillain-Barré syndrome were included. Information on clinical presentation, laboratory values, and vaccination status were retrieved from medical records. We calculated the incidence immediately prior to and during the pandemic. RESULTS: The Guillain-Barré syndrome incidence rate was 1.35/100,000 person-years for the pre-pandemic period and 0.66/100,000 person-years for the pandemic period (incidence rate ratio: 0.49; p = 0.003). Three cases were temporally associated with SARS-CoV-2 infection and 1 case each to the AstraZeneca and Pfizer-BioNTech COVID-19 vaccines. CONCLUSIONS: Our results show that the incidence of Guillain-Barré syndrome decreased during the pandemic. This is most likely due to decreased prevalence of triggering infections due to social restrictions. Our findings do not support a causal relationship between Guillain-Barré syndrome and COVID-19.

Increased intrathecal neurofilament light and immunoglobulin M predict severe disability in relapsing-remitting multiple sclerosis.

Background: Emerging evidence supports that determination of intrathecal immunoglobulin M (IgM) synthesis (ITMS) and neurofilament light (NfL) concentration in cerebrospinal fluid (CSF) may be clinically useful as disease severity biomarkers in relapsing-remitting multiple sclerosis (RRMS). Methods: Monocentric observational longitudinal cohort study in which prospectively collected data were retrospectively retrieved. Included were patients with RRMS (n=457) who had a diagnostic investigation including analysis of ITMS and CSF neurofilament light (cNfL). ITMS was calculated with the linear index formula, the intrathecal fraction of IgM according to Reiber (IgMIF), and by qualitative determination of oligoclonal IgM bands (OCMB). Univariable and multivariable models were performed to predict Evidence of Disease Activity-3 (EDA-3) status within 24 months from onset, and the risk of Expanded Disability Status Score (EDSS) ≥3 and ≥6. Results: All investigated methods to calculate ITMS significantly predicted evidence of disease activity (EDA-3) within 24 months. IgMIF>0% showed the strongest association with EDA-3 status (adjusted hazard ratio [aHR] 3.7, 95%CI 2.7-5, p<0.001). Combining IgM-index>0.1 or OCMB with increased cNfL were strong predictors of EDSS≥3 (for cNfL + /IgM-index + : aHR 4.6, 95%CI 2.6-8.2, p<0.001) and EDSS≥6 (aHR 8.2, 95%CI 2.3-30, p<0.001). Conclusions: In a real-world setting, ITMS was a useful biomarker in early RRMS to predict disabling MS and its prognostic value was even stronger in combination with cNfL. Our data suggest that determination of ITMS and cNfL should be included in the diagnostic work-up of RRMS for prognostic purposes and in decisions of disease-modifying therapy.