Acute flaccid myelitis: cause, diagnosis, and management.

Acute flaccid myelitis (AFM) is a disabling, polio-like illness mainly affecting children. Outbreaks of AFM have occurred across multiple global regions since 2012, and the disease appears to be caused by non-polio enterovirus infection, posing a major public health challenge. The clinical presentation of flaccid and often profound muscle weakness (which can invoke respiratory failure and other critical complications) can mimic several other acute neurological illnesses. There is no single sensitive and specific test for AFM, and the diagnosis relies on identification of several important clinical, neuroimaging, and cerebrospinal fluid characteristics. Following the acute phase of AFM, patients typically have substantial residual disability and unique long-term rehabilitation needs. In this Review we describe the epidemiology, clinical features, course, and outcomes of AFM to help to guide diagnosis, management, and rehabilitation. Future research directions include further studies evaluating host and pathogen factors, including investigations into genetic, viral, and immunological features of affected patients, host-virus interactions, and investigations of targeted therapeutic approaches to improve the long-term outcomes in this population.

Laboratory validation of a clinical metagenomic sequencing assay for pathogen detection in cerebrospinal fluid.

Metagenomic next-generation sequencing (mNGS) for pan-pathogen detection has been successfully tested in proof-of-concept case studies in patients with acute illness of unknown etiology but to date has been largely confined to research settings. Here, we developed and validated a clinical mNGS assay for diagnosis of infectious causes of meningitis and encephalitis from cerebrospinal fluid (CSF) in a licensed microbiology laboratory. A customized bioinformatics pipeline, SURPI+, was developed to rapidly analyze mNGS data, generate an automated summary of detected pathogens, and provide a graphical user interface for evaluating and interpreting results. We established quality metrics, threshold values, and limits of detection of 0.2-313 genomic copies or colony forming units per milliliter for each representative organism type. Gross hemolysis and excess host nucleic acid reduced assay sensitivity; however, spiked phages used as internal controls were reliable indicators of sensitivity loss. Diagnostic test accuracy was evaluated by blinded mNGS testing of 95 patient samples, revealing 73% sensitivity and 99% specificity compared to original clinical test results, and 81% positive percent agreement and 99% negative percent agreement after discrepancy analysis. Subsequent mNGS challenge testing of 20 positive CSF samples prospectively collected from a cohort of pediatric patients hospitalized with meningitis, encephalitis, and/or myelitis showed 92% sensitivity and 96% specificity relative to conventional microbiological testing of CSF in identifying the causative pathogen. These results demonstrate the analytic performance of a laboratory-validated mNGS assay for pan-pathogen detection, to be used clinically for diagnosis of neurological infections from CSF.

Lack of evidence for Toxocara infection in Italian myelitis patients.

Acute myelitis is a common neurological manifestation due to different causes, but in about 15-30% of cases its etiology remains unknown (idiopathic myelitis). Myelitis represents the most common manifestation of neurotoxocariasis, the infection of the human nervous system by larvae of the nematode Toxocara spp.; however, despite the high seroprevalence worldwide, its contribution to the burden of disease has not been assessed. We evaluated the presence of antibodies against Toxocara spp. in cerebrospinal fluid (CSF) from a sample of 28 patients with a diagnosis of idiopathic myelitis (N = 20) or encephalomyelitis (N = 8) who attended the Neurological Unit of the University Hospital of Catania, Sicily. Antibodies against Toxocara spp. were measured using a multiplex bead-based assay and Toxocara immunoblot using Toxocara canis excretory secretory antigens. All samples tested negative for the presence of anti-T. canis IgG antibodies. In this series, we found no evidence of a contribution of neurotoxocariasis to the burden of myelitis.

Molecular detection of human herpesvirus 7 DNA in cerebrospinal fluid from adult patients with neurological disorders.

Neurological manifestations associated with HHV-7 have been described in primary infection in children, and very occasionally in immunocompromised adult patients. However, the role of HHV-7 reactivation as a cause of central nervous system (CNS) diseases in immunocompetent adults has not yet been defined. We retrospectively analyzed clinical and microbiological features of adults with neurological symptoms who underwent lumbar puncture and a multiplex polymerase chain reaction (PCR) for herpesviruses (HHV-1-8) and enteroviruses performed in cerebrospinal fluid (CSF), during a 4-year period. A total of 251 subjects were included. Mean age was 55 years, ranging 15-89. Globally, HHV-7 DNA was detected in CSF in 14 patients (5.6%). It was detected in 1 of 36 patients with microbiologically confirmed CNS infections, and in 7 of 172 patients with diagnoses of non-infectious neurological disorders (Specificity 0.96, 95% confidence interval 0.93-0.99). Additionally, HHV-7 DNA was detected in 6 of 21 patients (28.6%) with probable CNS infections (compatible clinical syndrome and CSF changes) in the absence of other causative agent: four meningitis, one myelitis, and one encephalitis. Treatment with foscarnet was effective in achieving improvement of symptoms and clearance of HHV-7 DNA in CSF in the cases of encephalitis and myelitis, while ganciclovir was ineffective in the case of encephalitis. Our results show that HHV-7 reactivation may cause CNS disease in immunocompetent adults and that detection of HHV-7 DNA in CSF as a false-positive result or as asymptomatic reactivation in adult patients with neurological diseases is uncommon. Foscarnet seems the first-line treatment for HHV-7 CNS disease.

Angiostrongylus cantonensis Meningitis and Myelitis, Texas, USA.

Infection with Angiostrongylus cantonensis roundworms is endemic in Southeast Asia and the Pacific Basin. A. cantonensis meningitis and myelitis occurred in summer 2013 in a child with no history of travel outside of Texas, USA. Angiostrongyliasis is an emerging neurotropic helminthic disease in Texas and warrants increased awareness among healthcare providers.

Acute Flaccid Myelitis in the United States, August-December 2014: Results of Nationwide Surveillance.

BACKGROUND: During late summer/fall 2014, pediatric cases of acute flaccid myelitis (AFM) occurred in the United States, coincident with a national outbreak of enterovirus D68 (EV-D68)-associated severe respiratory illness. METHODS: Clinicians and health departments reported standardized clinical, epidemiologic, and radiologic information on AFM cases to the Centers for Disease Control and Prevention (CDC), and submitted biological samples for testing. Cases were ≤21 years old, with acute onset of limb weakness 1 August-31 December 2014 and spinal magnetic resonance imaging (MRI) showing lesions predominantly restricted to gray matter. RESULTS: From August through December 2014, 120 AFM cases were reported from 34 states. Median age was 7.1 years (interquartile range, 4.8-12.1 years); 59% were male. Most experienced respiratory (81%) or febrile (64%) illness before limb weakness onset. MRI abnormalities were predominantly in the cervical spinal cord (103/118). All but 1 case was hospitalized; none died. Cerebrospinal fluid (CSF) pleocytosis (>5 white blood cells/µL) was common (81%). At CDC, 1 CSF specimen was positive for EV-D68 and Epstein-Barr virus by real-time polymerase chain reaction, although the specimen had >3000 red blood cells/µL. The most common virus detected in upper respiratory tract specimens was EV-D68 (from 20%, and 47% with specimen collected ≤7 days from respiratory illness/fever onset). Continued surveillance in 2015 identified 16 AFM cases reported from 13 states. CONCLUSIONS: Epidemiologic data suggest this AFM cluster was likely associated with the large outbreak of EV-D68-associated respiratory illness, although direct laboratory evidence linking AFM with EV-D68 remains inconclusive. Continued surveillance will help define the incidence, epidemiology, and etiology of AFM.

Viral load and ganciclovir (GCV) concentration in cerebrospinal fluid of patients successfully treated with GCV or valGCV for human herpesvirus 6 encephalitis/myelitis following umbilical cord blood transplantation.

We describe successful treatment of 3 cases of human herpesvirus 6 (HHV-6) encephalitis/myelitis following cord blood transplantation (CBT). Ganciclovir (GCV) (10 mg/kg/day) reduced HHV-6 load to undetectable levels in cerebrospinal fluid (CSF). Early dose reduction in the presence of HHV-6 detectable in CSF resulted in an increased HHV-6 load. GCV was capably shifted to valganciclovir (VGCV) with an almost equivalent concentration. GCV/VGCV may be effective for HHV-6 encephalitis/myelitis after CBT, although HHV-6 load in CSF should be monitored.

Acute Flaccid Myelitis of Unknown Etiology in California, 2012-2015.

IMPORTANCE: There has been limited surveillance for acute flaccid paralysis in North America since the regional eradication of poliovirus. In 2012, the California Department of Public Health received several reports of acute flaccid paralysis cases of unknown etiology. OBJECTIVE: To quantify disease incidence and identify potential etiologies of acute flaccid paralysis cases with evidence of spinal motor neuron injury. DESIGN, SETTING, AND PARTICIPANTS: Case series of acute flaccid paralysis in patients with radiological or neurophysiological findings suggestive of spinal motor neuron involvement reported to the California Department of Public Health with symptom onset between June 2012 and July 2015. Patients meeting diagnostic criteria for other acute flaccid paralysis etiologies were excluded. Cerebrospinal fluid, serum samples, nasopharyngeal swab specimens, and stool specimens were submitted to the state laboratory for infectious agent testing. MAIN OUTCOMES AND MEASURES: Case incidence and infectious agent association. RESULTS: Fifty-nine cases were identified. Median age was 9 years (interquartile range [IQR], 4-14 years; 50 of the cases were younger than 21 years). Symptoms that preceded or were concurrent included respiratory or gastrointestinal illness (n = 54), fever (n = 47), and limb myalgia (n = 41). Fifty-six patients had T2 hyperintensity of spinal gray matter on magnetic resonance imaging and 43 patients had cerebrospinal fluid pleocytosis. During the course of the initial hospitalization, 42 patients received intravenous steroids; 43, intravenous immunoglobulin; and 13, plasma exchange; or a combination of these treatments. Among 45 patients with follow-up data, 38 had persistent weakness at a median follow-up of 9 months (IQR, 3-12 months). Two patients, both immunocompromised adults, died within 60 days of symptom onset. Enteroviruses were the most frequently detected pathogen in either nasopharynx swab specimens, stool specimens, serum samples (15 of 45 patients tested). No pathogens were isolated from the cerebrospinal fluid. The incidence of reported cases was significantly higher during a national enterovirus D68 outbreak occurring from August 2014 through January 2015 (0.16 cases per 100,000 person-years) compared with other monitoring periods (0.028 cases per 100,000 person-years; P <.001). CONCLUSIONS AND RELEVANCE: In this series of patients identified in California from June 2012 through July 2015, clinical manifestations indicated a rare but distinct syndrome of acute flaccid paralysis with evidence of spinal motor neuron involvement. The etiology remains undetermined, most patients were children and young adults, and motor weakness was prolonged.

Magnetic Resonance Imaging/cerebrospinal Fluid-negative Myelitis Following COVID-19 with a Dramatic Response to Early Aggressive Immunosuppressive Therapy.

A 57-year-old man presented with subacute-onset paraparesis, bilateral dysesthesia in his lower extremities, and bladder/bowel disturbance six weeks after being infected with severe acute respiratory syndrome coronavirus 2 infection [coronavirus disease 2019 (COVID-19)]. A neurological examination suggested transverse myelitis at the level of the lower thoracic spinal cord. However, repeated spinal magnetic resonance imaging (MRI) showed no abnormalities in the spinal cord. Laboratory and cerebrospinal fluid (CSF) tests ruled out other etiologies of myelitis, eventually suggesting COVID-19-associated myelitis. Aggressive immunosuppressive therapy, started soon after hospitalization, dramatically improved his symptoms. Early aggressive immunosuppressive therapy should therefore be considered in cases of MRI/CSF-negative myelitis associated with COVID-19.

CSF high-mobility group box 1 is associated with intrathecal inflammation and astrocytic damage in neuromyelitis optica.

OBJECTIVE: High-mobility group box 1 (HMGB1) acts as a proinflammatory mediator when released by cells. Recent studies implicate extracellular HMGB1 in the pathogenesis of various autoimmune diseases. Our main aim of this study is to determine whether HMGB1 is involved in the neuromyelitis optica (NMO) inflammatory process. METHODS: Cerebrospinal fluid (CSF) and serum HMGB1 levels in 42 NMO patients were compared with those in 30 multiple sclerosis (MS) patients, and 30 patients with other noninflammatory neurological disorders (ONNDs). We also tested the possible correlation between CSF HMGB1 levels and the clinical and laboratory variables in NMO patients. RESULTS: CSF HMGB1 levels in NMO patients were higher than those in MS and ONNDs patients (p<0.001), and these levels in MS patients were higher than those in ONNDs patients (p<0.001). After treatment, the CSF HMGB1 levels in NMO patients decreased to normal. In addition, CSF HMGB1 levels correlated with CSF cell counts, CSF protein levels, CSF interleukin-6 levels, CSF glial fibrillary acidic protein levels, and CSF/serum albumin ratio (p≤0.001). Serum HMGB1 levels in MS patients were significantly higher than those in ONNDs patients (p=0.002). CONCLUSIONS: HMGB1 could play a key role in central nervous system inflammation in NMO patients.

Angiostrongylosis meningomyelitis without blood eosinophilia.

Angiostrongylus cantonensis and Gnathostoma spinigerum usually cause eosinophilic meningitis with associated peripheral blood eosinophilia. A 44-year-old man developed acute paraplegia with bowel and bladder dysfunction. Spinal magnetic resonance images showed a long T2W hyperintensity signal from the 1st to 8th spinal thoracic level. Cerebrospinal fluid analysis revealed eosinophilia and elevated cerebrospinal fluid protein, whereas differential leucocytes count in peripheral blood was unremarkable. Positive immunoblot tests for A. cantonensis antibody in serum and cerebrospinal fluid were reported. The patient had neither history of recent traveling to the high endemic areas of the parasite in Thailand, nor consumption the parasitic hosts. Immediate treatment with intravenous pulse methylprednisolone and oral albendazole resulted in complete recovery. Despite an unremarkable differential leucocytes count, absence a history of parasitic hosts consumption, and a less common presentation with meningomyelitis, A. cantonensis should be considered when cerebrospinal fluid eosinophilia presents.

Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy in Children: A Retrospective Analysis of 35 Cases.

Objective: To analyze the clinical manifestations, imaging, electroencephalography, treatment, and prognosis of 35 cases of autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A) in children. Methods: Children hospitalized in the Department of Neurology, Hunan Children's Hospital, China, between January 2015 and June 2021, owing to autoimmune diseases of the central nervous system were subjected to a cell-based assay (CBA). The assay identified 40 children positive for GFAP-immunoglobulin (Ig)G antibodies in the serum and/or the cerebrospinal fluid. Based on clinical manifestations and imaging characteristics, five children who were only positive for GFAP-IgG antibodies in serum were excluded, and the remaining 35 children were diagnosed with autoimmune GFAP-A. The clinical data derived from the 35 children were retrospectively analyzed. Results: A total of 35 children, including 23 males and 12 females with a mean age of 6.3 ± 0.6 years, manifested clinical symptoms of fever (62.9%), headache (42.9%), convulsions (42.9%), abnormal mental behavior (51.4%), disorders of consciousness (54.3%), visual disturbance (22.9%), ataxia (11.4%), paralysis (40%), and autonomic dysfunction (25.7%). One child exhibited only the clinical symptom of peripheral facial nerve palsy. Eleven out of 35 children were also positive for other antibodies. In addition to the common overlapping autoimmune syndromes, one case of autoimmune GFAP-A also manifested as Bickerstaff's brainstem encephalitis. Linear periventricular enhancement upon MRI was significantly less frequent in children (8.5%) than in adults. In pediatric patients, MRI contrast enhancement was principally seen in the meninges and brain lobes. Although repeated relapse (17.1%) and sequelae symptoms (20%) occurred in some cases, most children showed a favorable prognosis. Spearman's rank correlation showed that the antibody titer was not significantly associated with the severity of the initial disease conditions. Conclusions: The disease diagnosis in children seropositive for GFAP antibodies only should receive a comprehensive diagnosis based on their clinical symptoms, imaging, electroencephalographic characteristics, and treatment responses. Some patients with relapses should receive repeated gamma globulin and corticosteroid therapy or the addition of immunosuppressants to their therapeutic regimen, and slow-dose tapering of corticosteroids and extended treatment are recommended for patients with overlapping autoimmune syndromes.

Free light chains kappa can differentiate between myelitis and noninflammatory myelopathy.

OBJECTIVE: To test the hypothesis that the intrathecal synthesis of free light chain kappa (FLC-k) can be used as a CSF biomarker to differentiate patients with myelitis due to multiple sclerosis (MS), myelitis due to neuromyelitis optica spectrum disease (NMOSD), and noninflammatory myelopathy, we analyzed FLC-k in 26 patients with MS myelitis, 9 patients with NMOSD myelitis, and 14 patients with myelopathy. METHODS: This is a retrospective monocentric cohort study. FLC-k were analyzed using the nephelometric Siemens FLC-k kit in paired samples of CSF and sera. Intrathecal fraction (IF) of FLC-k was plotted in a FLC-k quotient diagram. RESULTS: Ninety-six percent of patients with MS myelitis had an intrathecal synthesis of FLC-k in comparison with 55.6% for NMOSD and 14.3% of patients with noninflammatory myelopathy. The locally synthesized absolute amount of FLC-k was significantly higher in patients with myelitis due to MS than in patients with NMOSD (p = 0.038) or noninflammatory myelopathy (p < 0.0001). The sensitivity of FLC-k synthesis to detect inflammation in patients with myelitis is 85.7%. Using a receiver operating characteristic analysis, FLC-k IF >78% can discriminate patients with myelitis due to MS and NMOSD with a sensitivity of 88.5% and a specificity of 88.9% CONCLUSIONS: With the hyperbolic reference range in quotient diagrams for FLC-k, it is possible to distinguish inflammatory myelitis from noninflammatory myelopathies. An FLC-k IF >78% can be a hint to suspect myelitis due to MS rather than NMOSD.

Cytokine biomarkers associated with clinical cases of acute flaccid myelitis.

Acute flaccid myelitis (AFM) is a serious neurological illness first recognized in the United States in 2014, with subsequent outbreaks every two years. Following extensive etiologic testing by multiple laboratories of hundreds of specimens collected from patients diagnosed with AFM, no consistent cause of AFM has been identified. However, viruses, including enteroviruses, have been implicated through detection in non-sterile site specimens and antibody studies. Cytokines and chemokines play important roles in the modulation of the innate and adaptive immune response to pathogens. In the current study, we measured levels of cytokines and chemokines in serum and CSF collected from confirmed AFM patients and non-AFM control patients, to identify unique biomarkers as potential hallmarks of AFM pathogenesis. Analysis of ratios of cytokines and chemokines in the CSF compared to the serum indicate that the pro-inflammatory cytokines/chemokines IP-10 and IL-6 were significantly elevated in AFM patients compared to non-AFM patients. These results may provide additional insight into potential etiologies, pathogenic mechanisms, and treatments for AFM.

A ten-year retrospective evaluation of acute flaccid myelitis at 5 pediatric centers in the United States, 2005-2014.

BACKGROUND: Acute flaccid myelitis (AFM) is a severe illness similar to paralytic poliomyelitis. It is unclear how frequently AFM occurred in U.S. children after poliovirus elimination. In 2014, an AFM cluster was identified in Colorado, prompting passive US surveillance that yielded 120 AFM cases of unconfirmed etiology. Subsequently, increased reports were received in 2016 and 2018. To help inform investigations on causality of the recent AFM outbreaks, our objective was to determine how frequently AFM had occurred before 2014, and if 2014 cases had different characteristics. METHODS: We conducted a retrospective study covering 2005-2014 at 5 pediatric centers in 3 U.S. regions. Possible AFM cases aged ≤18 years were identified by searching discharge ICD-9 codes and spinal cord MRI reports (>37,000). Neuroradiologists assessed MR images, and medical charts were reviewed; possible cases were classified as AFM, not AFM, or indeterminate. RESULTS: At 5 sites combined, 26 AFM cases were identified from 2005-2013 (average annual number, 3 [2.4 cases/100,000 pediatric hospitalizations]) and 18 from 2014 (12.6 cases/100,000 hospitalizations; Poisson exact p<0.0001). A cluster of 13 cases was identified in September-October 2014 (temporal scan p = 0.0001). No other temporal or seasonal trend was observed. Compared with cases from January 2005-July 2014 (n = 29), cases from August-December 2014 (n = 15) were younger (p = 0.002), more frequently had a preceding respiratory/febrile illness (p = 0.03), had only upper extremities involved (p = 0.008), and had upper extremity monoplegia (p = 0.03). The cases had higher WBC counts in cerebrospinal fluid (p = 0.013). CONCLUSION: Our data support emergence of AFM in 2014 in the United States, and those cases demonstrated distinctive features compared with preceding sporadic cases.

Clinical and MRI phenotypes of sarcoidosis-associated myelopathy.

OBJECTIVE: To determine the characteristic clinical and spinal MRI phenotypes of sarcoidosis-associated myelopathy (SAM), we analyzed a large cohort of patients with this disorder. METHODS: Patients diagnosed with SAM at a single center between 2000 and 2018 who met the established criteria for definite and probable neurosarcoidosis were included in a retrospective analysis to identify clinical profiles, CSF characteristics, and MRI lesion morphology. RESULTS: Of 62 included patients, 33 (53%) were male, and 30 (48%) were African American. SAM was the first clinical presentation of sarcoidosis in 49 patients (79%). Temporal profile of symptom evolution was chronic in 81%, with sensory symptoms most frequently reported (87%). CSF studies showed pleocytosis in 79% and CSF-restricted oligoclonal bands in 23% of samples tested. Four discrete patterns of lesion morphology were identified on spine MRI: longitudinally extensive myelitis (n = 28, 45%), short tumefactive myelitis (n = 14, 23%), spinal meningitis/meningoradiculitis (n = 14, 23%), and anterior myelitis associated with areas of disc degeneration (n = 6, 10%). Postgadolinium enhancement was seen in all but 1 patient during the acute phase. The most frequent enhancement pattern was dorsal subpial enhancement (n = 40), followed by meningeal/radicular enhancement (n = 23) and ventral subpial enhancement (n = 12). In 26 cases (42%), enhancement occurred at locations with coexisting structural changes (e.g., spondylosis). CONCLUSIONS: Recognition of the clinical features (chronically evolving myelopathy) and distinct MRI phenotypes (with enhancement in a subpial and/or meningeal pattern) seen in SAM can aid diagnosis of this disorder. Enhancement patterns suggest that SAM may have a predilection for areas of the spinal cord susceptible to mechanical stress.

Acute urinary retention due to HSV-1: a case report.

Complications in urinary tract nervous routes due to herpes viruses as VZV and HSV-2 are well known. Acute urinary retention and chronic neuropathic pain are not rare when sacral dermatomes are involved by these viruses. However, an analogous condition has not yet been clearly ascribed to HSV-1 infection. We present a 32-year-old immunocompetent patient with fever, lumbar pain and acute urinary retention who had never had herpetic clinical manifestations. Urodynamic studies diagnosed a neurologic bladder with an absent filling sensation. Cystoscopic assessment revealed the presence of reddened and isolated small mucosal areas in the bladder walls. The search for herpes viruses in plasma and CSF by PCR assay were positive for HSV-1. After treatment with antiviral therapy the disease resolved. Intermittent catheterization was necessary and voiding dysfunction resolved after three weeks by its appearance. Neurological damage to the central nervous system (CNS) and/or PNS due to HSV-1 seems to be the most likely reason. The course of disease was benign and self-remitting.

Viral Sequences Detection by High-Throughput Sequencing in Cerebrospinal Fluid of Individuals with and without Central Nervous System Disease.

: Meningitis, encephalitis, and myelitis are various forms of acute central nervous system (CNS) inflammation, which can coexist and lead to serious sequelae. Known aetiologies include infections and immune-mediated processes. Despite advances in clinical microbiology over the past decades, the cause of acute CNS inflammation remains unknown in approximately 50% of cases. High-throughput sequencing was performed to search for viral sequences in cerebrospinal fluid (CSF) samples collected from 26 patients considered to have acute CNS inflammation of unknown origin, and 10 patients with defined causes of CNS diseases. In order to better grasp the clinical significance of viral sequence data obtained in CSF, 30 patients without CNS disease who had a lumbar puncture performed during elective spinal anaesthesia were also analysed. One case of human astrovirus (HAstV)-MLB2-related meningitis and disseminated infection was identified. No other viral sequences that can easily be linked to CNS inflammation were detected. Viral sequences obtained in all patient groups are discussed. While some of them reflect harmless viral infections, others result from reagent or sample contamination, as well as index hopping. Altogether, this study highlights the potential of high-throughput sequencing in identifying previously unknown viral neuropathogens, as well as the interpretation issues related to its application in clinical microbiology.

Antibodies to Enteroviruses in Cerebrospinal Fluid of Patients with Acute Flaccid Myelitis.

Acute flaccid myelitis (AFM) has caused motor paralysis in >560 children in the United States since 2014. The temporal association of enterovirus (EV) outbreaks with increases in AFM cases and reports of fever, respiratory, or gastrointestinal illness prior to AFM in >90% of cases suggest a role for infectious agents. Cerebrospinal fluid (CSF) from 14 AFM and 5 non-AFM patients with central nervous system (CNS) diseases in 2018 were investigated by viral-capture high-throughput sequencing (VirCapSeq-VERT system). These CSF and serum samples, as well as multiple controls, were tested for antibodies to human EVs using peptide microarrays. EV RNA was confirmed in CSF from only 1 adult AFM case and 1 non-AFM case. In contrast, antibodies to EV peptides were present in CSF of 11 of 14 AFM patients (79%), significantly higher than controls, including non-AFM patients (1/5 [20%]), children with Kawasaki disease (0/10), and adults with non-AFM CNS diseases (2/11 [18%]) (P = 0.023, 0.0001, and 0.0028, respectively). Six of 14 CSF samples (43%) and 8 of 11 sera (73%) from AFM patients were immunoreactive to an EV-D68-specific peptide, whereas the three control groups were not immunoreactive in either CSF (0/5, 0/10, and 0/11; P = 0.008, 0.0003, and 0.035, respectively) or sera (0/2, 0/8, and 0/5; P = 0.139, 0.002, and 0.009, respectively).IMPORTANCE The presence in cerebrospinal fluid of antibodies to EV peptides at higher levels than non-AFM controls supports the plausibility of a link between EV infection and AFM that warrants further investigation and has the potential to lead to strategies for diagnosis and prevention of disease.