TREX-1 related Aicardi-Goutières syndrome improved by Janus kinase inhibitor

Aicardi-Goutières syndrome (AGS) is a genetic interferonopathy classically characterized by early onset of severe neurologic injury with basal ganglia calcifications, white matter abnormalities, and progressive cerebral atrophy, along with lymphocytosis and raised interferon alpha (INFα) in the cerebrospinal fluid (CSF). Here, we report a 31/2 year-old patient born with prenatal onset AGS, first manifesting as intra-uterine growth retardation. Cranial ultrasonography and cerebral MRI revealed ventriculomegaly and periventricular and basal ganglia calcifications, along with cerebral atrophy. Perinatal infections and known metabolic disorders were excluded. Both CSF lymphocytosis and raised INFα were present. Molecular analysis disclosed two already described compound heterozygous pathogenic variants in TREX1 (c. 309dup, p.(Thr104Hisfs*53) and c. 506G > A, p.(Arg169His)). The evolution was marked by severe global developmental delay with progressive microcephaly. Promptly, the patient developed irritability, quadri-paretic dyskinetic movements, and subsequently tonic seizures. Sensorineural hearing loss was detected as well as glaucoma. Initially, he was symptomatically treated with trihexyphenidyl followed by levetiracetam and topiramate. At age 22 months, baricitinib (0.4 mg/kg/day) was introduced, leading to normal serum INFα levels. Clinically, dyskinetic movements significantly decreased as well as irritability and sleep disturbance. We confirmed that baricitinib was a useful treatment with no major side effect.

B-cell targeted therapies in autoimmune encephalitis: mechanisms, clinical applications, and therapeutic potential

Autoimmune encephalitis (AE) broadly refers to inflammation of the brain parenchyma mediated by autoimmune mechanisms. In most patients with AE, autoantibodies against neuronal cell surface antigens are produced by B-cells and induce neuronal dysfunction through various mechanisms, ultimately leading to disease progression. In recent years, B-cell targeted therapies, including monoclonal antibody (mAb) therapy and chimeric antigen receptor T-cell (CAR-T) therapy, have been widely used in autoimmune diseases. These therapies decrease autoantibody levels in patients and have shown favorable results. This review summarizes the mechanisms underlying these two B-cell targeted therapies and discusses their clinical applications and therapeutic potential in AE. Our research provides clinicians with more treatment options for AE patients whose conventional treatments are not effective.

Neuropathologic Impacts of JAK Inhibitor Treatment in Aicardi-Goutières Syndrome

Aicardi-Goutières syndrome (AGS) is a genetic interferonopathy characterized by upregulation of type I interferon response. It is associated with increased mortality and severe disabilities. Janus Kinase (JAK) inhibitors have shown effectiveness in treatment of AGS through blocking the downstream effects of interferon activation. We illustrate post-mortem histopathologic findings in a patient with AGS who received baricitinib treatment for a duration of over 4 years, initiating at a remarkably young age of 2 months. We observed global cerebral atrophy, markedly diminished white matter, abundant calcifications involving supratentorial white matter, basal ganglia, dentate nuclei, and brainstem. This study showed profound central nervous system (CNS) sequelae despite early initiation of treatment. Our findings highlight the potential necessity for therapeutic options with enhanced CNS bioavailability.

Anticonvulsive treatment in autoimmune encephalitis: a systematic literature review

BACKGROUND

Epileptic seizures are a common manifestation of autoimmune encephalitis (AIE). Immunosuppression (IT) is an efficient therapeutic approach, particularly in AIE associated with antibodies against extracellular structures. The role of antiseizure medication (ASM) is less clear. However, it may be beneficial in disease refractory to IT or in chronic post-AIE epilepsy.

METHODS

We conducted a systematic review assessing the PubMed and Cochrane databases to identify all reports on patients with epileptic seizures due to AIE in whom ASM was used and report it according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. We included case series (minimum 3 eligible patients), retrospective and prospective observational studies, and randomized controlled trials. The main outcome assessed was therapeutic efficacy of ASM. Secondary outcomes comprise number, type, and adverse effects of ASM. Descriptive statistics were used. The level of evidence was assessed according to the Centre for Evidence-Based Medicine.

RESULTS

We screened a total of 3371 studies and included 30 (7 prospective, 23 retrospective). The reports cover a total of 708 patients, the majority (72.5%) suffering from AIE with antibodies against extracellular structures. Type of AIE, seizure frequency, and number and type of ASM used were heterogenous. While most patients profited from IT and/or ASM, the effect of ASM could rarely be isolated. Nine studies report on patients who received ASM monotherapy or were on ASM for a relevant length of time before IT initiation or after IT failure. One study reports a significant association between seizure freedom and use of sodium channel inhibitors. However, levels of evidence were generally low.

CONCLUSION

Few robust data exist on the particular efficacy of ASM in autoimmune epileptic seizures. While these patients generally seem to respond less well to ASM or surgical interventions, sodium channel blockers may have an additional benefit compared to other substances. However, levels of evidence are low and early IT remains the mainstay of AIE therapy. Future trials should address optimal ASM selection and dosing in AIE.

Survival Analysis of Immunotherapy Effects on Relapse Rate in Pediatric and Adult Autoimmune Encephalitis

BACKGROUND AND OBJECTIVES

Prior observational studies for autoimmune encephalitis (AE) have mostly focused on outcomes after acute immunotherapies with better outcomes associated with earlier immunotherapy use. However, the impact of long-term immunotherapy and its association with clinical relapse is not well known.

METHODS

We conducted a retrospective study of consecutive patients meeting published clinical criteria for AE evaluated at UC San Diego and Rady Children's Hospital from January 2007 to November 2021. Survival analysis and Cox multivariable regression models were used to evaluate relapse risk using rituximab exposure as a time-dependent variable. Pooled and age-stratified analyses were performed.

RESULTS

A total of 204 pediatric and 380 adult participants were screened of which 30 pediatric and 75 adult participants were included. The most common antibody subtype in both cohorts was anti-NMDA receptor (76% in pediatric, 34% in adult). Relapses occurred in 31% of pediatric antibody-positive, 40% of adult antibody-positive, and 20% of adult antibody-negative cases. Times to first relapse (TTFR) were 10.6 ± 7.4 months (pediatric antibody-positive), 13.1 ± 24.5 months (adult antibody-positive), and 6.9 ± 3.8 months (adult antibody-negative). Rituximab was the most common second-line immunotherapy used. Combining pediatric and adult data, rituximab use was associated with a 71% lower hazard for time to first relapse (hazard ratio [HR] 0.29, 95% CI 0.09-0.85) and 51% lower hazard for recurring relapses (HR 0.49, 95% CI 0.9-1.26). The HR for TTFR with rituximab use in children was 0.30 (95% CI 0.05-1.69), 0.29 (95% CI 0.07-1.29) in adults, 0.32 in non-NMDA antibody-positive encephalitis (95% CI 0.07-1.39), and 0.42 (95% CI 0.07-2.67) for anti-NMDAR.

DISCUSSION

Relapses are common in pediatric and adult patients with AE, although less frequently in anti-NMDARE. Using a rigorous survival model, we demonstrate a substantial benefit of rituximab use for reducing relapse rates in AE, especially for the adult population.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that rituximab is associated with a lower hazard to relapse in patients with AE.

Mechanisms and Emerging Therapies for Treatment of Seizures in Pediatric Autoimmune Encephalitis and Autoinflammatory/Autoimmune-Associated Epilepsy

There has been increasing understanding of the role of inflammation in seizures and epilepsy, as well as targeted immunomodulatory treatments. In children, immune-mediated seizures often present acutely in the setting of autoimmune encephalitis and are very responsive to immunotherapy with low rates of subsequent epilepsy. Conversely, seizures in autoimmune-associated epilepsies, such as Rasmussen syndrome, can remain refractory to multimodal therapy, including immunomodulation. In this review, the authors discuss the presentations of immune-mediated seizures in children, underlying mechanisms, and emerging therapies.

Tocilizumab reduces the unmanageable inflammatory reaction of a patient with Aicardi-Goutières syndrome type 7 during treatment with ruxolitinib

BACKGROUND

Aicardi-Goutières syndrome (AGS) is a rare hereditary early-onset encephalopathy characterized by upregulation of the type I interferon pathway, poorly responsive to conventional immunosuppression.

CASE PRESENTATION

We describe a 7-year-old Chinese boy who developed symptoms at the age of 6 months. He presented with a chilblain-like rash, leukopenia, neutropenia, elevated liver enzymesgrowth retardation, microcephaly, elevated acute phase reactants, intracranial calcification and leukodystrophy. At the age of 3 years old, whole-exome sequencing confirmed a de novo heterozygous gain-of-function mutation, c.1016 C > A (p.Ala339Asp), in the IFIH1 gene, and he was diagnosed with AGS7. He was treated with ruxolitinib accompanied by steroids and thalidomide for about four years. The rash, hematological manifestations, and the liver function were all improved, but the erythrocyte sedimentation rate remained consistently elevated until the addition of tocilizumab, a monoclonal antibody against interleukin 6.

CONCLUSIONS

Ruxolitinib was not successful in suppressing the inflammatory process, and tocilizumab produced highly encouraging results in reducing the inflammatory reaction of AGS. The study makes a significant contribution to the literature because we may found a potential alternative therapeutic option for AGS.

Case Report: High-dose steroid and IVIG successful treatment in a case of COVID-19-associated autoimmune encephalitis: a literature review

Autoimmune encephalitis is a rare but critical complication of COVID-19. The management of COVID-19-associated autoimmune encephalitis includes the use of steroids, intravenous immunoglobulin (IVIG), plasmapheresis, and monoclonal antibody therapy. This study presented a patient with critical COVID-19 autoimmune encephalitis who rapidly recovered after the initiation of corticosteroids and IVIG therapy. This study reviewed the current literature on the pathophysiological mechanisms, diagnosis, and management of COVID-19-associated autoimmune encephalitis.

Infection risk in a real-world cohort of patients treated with long-term B-cell depletion for autoimmune neurologic disease

BACKGROUND

B-cell depleting medications are effective disease-modifying therapies for multiple sclerosis. Prior studies have demonstrated that use of these medication is associated with infections and immunologic changes. Limited data suggest that infectious adverse effects may be more common with long-term use. We aimed to investigate rates of infections and laboratory abnormalities in a real-world cohort of patients treated with long term B-cell depletion and identify clinical factors associated with these outcomes.

METHODS

In this retrospective, single-center observational study, patients with MS and other autoimmune neurologic disorders treated with rituximab or ocrelizumab for ≥2 years were identified. Linear regression analyses identified factors associated with increased risk of minor and severe infections. Rates of total and severe infections were compared between the first two years of treatment and years three and beyond.

RESULTS

291 patients, treated with rituximab or ocrelizumab for an average of 46 months, were included. Total infections and infections requiring hospitalization occurred at rates of 25.0 and 3.03 per 100 person-years, respectively. Female gender and current or former smoking status were associated with a higher rate of total infections. Hypogammaglobulinemia and higher BMI were associated with increased risk of hospitalization. Rates of total and serious infections were higher in years three and beyond compared to the first two years.

CONCLUSIONS

Infections in patients with MS treated with long-term B-cell depletion may be more common with longer duration of therapy. This study provides additional information to help personalize care.

Clinical and Laboratory Features in Anti-NF155 Autoimmune Nodopathy

BACKGROUND AND OBJECTIVES

To study the clinical and laboratory features of antineurofascin-155 (NF155)-positive autoimmune nodopathy (AN).

METHODS

Patients with anti-NF155 antibodies detected on routine immunologic testing were included. Clinical characteristics, treatment response, and functional scales (modified Rankin Scale [mRS] and Inflammatory Rasch-built Overall Disability Scale [I-RODS]) were retrospectively collected at baseline and at the follow-up. Autoantibody and neurofilament light (NfL) chain levels were analyzed at baseline and at the follow-up.

RESULTS

Forty NF155+ patients with AN were included. Mean age at onset was 42.4 years. Patients presented with a progressive (75%), sensory motor (87.5%), and symmetric distal-predominant weakness in upper (97.2%) and lower extremities (94.5%), with tremor and ataxia (75%). Patients received a median of 3 (2-4) different treatments in 46 months of median follow-up. Response to IV immunoglobulin (86.8%) or steroids (72.2%) was poor in most patients, whereas 77.3% responded to rituximab. HLA-DRB1*15 was detected in 91.3% of patients. IgG4 anti-NF155 antibodies were predominant in all patients; anti-NF155 titers correlated with mRS within the same patient (r = 0.41, p = 0.004). Serum NfL (sNfL) levels were higher in anti-NF155+ AN than in healthy controls (36.47 vs 7.56 pg/mL, p < 0.001) and correlated with anti-NF155 titers (r = 0.43, p = 0.001), with I-RODS at baseline (r = -0.88, p < 0.001) and with maximum I-RODS achieved (r = -0.58, p = 0.01). Anti-NF155 titers and sNfL levels decreased in all rituximab-treated patients.

DISCUSSION

Anti-NF155 AN presents a distinct clinical profile and good response to rituximab. Autoantibody titers and sNfL are useful to monitor disease status in these patients. The use of untagged-NF155 plasmids minimizes the detection of false anti-NF155+ cases.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that anti-NF155 antibodies associate with a specific phenotype and response to rituximab.

Clinical, neuroradiological, diagnostic and prognostic profile of autoimmune glial fibrillary acidic protein astrocytopathy: A pooled analysis of 324 cases from published data and a single-center retrospective study

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a recently defined autoimmune meningoencephalomyelitis, associated with GFAP-IgG antibody. A pooled analysis of 324 cases from published literature and a retrospective single-center study were performed, firstly reveals the possibility that patients with myelitic lesions respond better to initial immunotherapy, but are prone to relapse, suggesting a more aggressive and long-term immunosuppressive medication for them. Moreover, our results showed using tacrolimus at maintenance stage exhibited a less tendency to relapse, providing a possibly new choice to future clinical treatments.

Rituximab Treatment and Long-term Outcome of Patients With Autoimmune Encephalitis: Real-world Evidence From the GENERATE Registry

BACKGROUND AND OBJECTIVES

To determine the real-world use of rituximab in autoimmune encephalitis (AE) and to correlate rituximab treatment with the long-term outcome.

METHODS

Patients with NMDA receptor (NMDAR)-AE, leucine-rich glioma-inactivated-1 (LGI1)- AE, contactin-associated protein-like-2 (CASPR2)-AE, or glutamic acid decarboxylase 65 (GAD65) disease from the GErman Network for Research on AuToimmune Encephalitis who had received at least 1 rituximab dose and a control cohort of non-rituximab-treated patients were analyzed retrospectively.

RESULTS

Of the 358 patients, 163 (46%) received rituximab (NMDAR-AE: 57%, CASPR2-AE: 44%, LGI1-AE: 43%, and GAD65 disease: 37%). Rituximab treatment was initiated significantly earlier in NMDAR- and LGI1-AE (median: 54 and 155 days from disease onset) compared with CASPR2-AE or GAD65 disease (median: 632 and 1,209 days). Modified Rankin Scale (mRS) scores improved significantly in patients with NMDAR-AE, both with and without rituximab treatment. Although being more severely affected at baseline, rituximab-treated patients with NMDAR-AE more frequently reached independent living (mRS score ≤2) (94% vs 88%). In LGI1-AE, rituximab-treated and nontreated patients improved, whereas in CASPR2-AE, only rituximab-treated patients improved significantly. No improvement was observed in patients with GAD65 disease. A significant reduction of the relapse rate was observed in rituximab-treated patients (5% vs 13%). Detection of NMDAR antibodies was significantly associated with mRS score improvement. A favorable outcome was also observed with early treatment initiation.

DISCUSSION

We provide real-world data on immunosuppressive treatments with a focus on rituximab treatment for patients with AE in Germany. We suggest that early and short-term rituximab therapy might be an effective and safe treatment option in most patients with NMDAR-, LGI1-, and CASPR2-AE.

CLASS OF EVIDENCE

This study provides Class IV evidence that rituximab is an effective treatment for some types of AE.

Therapeutic Attributes of Endocannabinoid System against Neuro-Inflammatory Autoimmune Disorders

In humans, various sites like cannabinoid receptors (CBR) having a binding affinity with cannabinoids are distributed on the surface of different cell types, where endocannabinoids (ECs) and derivatives of fatty acid can bind. The binding of these substance(s) triggers the activation of specific receptors required for various physiological functions, including pain sensation, memory, and appetite. The ECs and CBR perform multiple functions via the cannabinoid receptor 1 (CB1); cannabinoid receptor 2 (CB2), having a key effect in restraining neurotransmitters and the arrangement of cytokines. The role of cannabinoids in the immune system is illustrated because of their immunosuppressive characteristics. These characteristics include inhibition of leucocyte proliferation, T cells apoptosis, and induction of macrophages along with reduced pro-inflammatory cytokines secretion. The review seeks to discuss the functional relationship between the endocannabinoid system (ECS) and anti-tumor characteristics of cannabinoids in various cancers. The therapeutic potential of cannabinoids for cancer-both in vivo and in vitro clinical trials-has also been highlighted and reported to be effective in mice models in arthritis for the inflammation reduction, neuropathic pain, positive effect in multiple sclerosis and type-1 diabetes mellitus, and found beneficial for treating in various cancers. In human models, such studies are limited; thereby, further research is indispensable in this field to get a conclusive outcome. Therefore, in autoimmune disorders, therapeutic cannabinoids can serve as promising immunosuppressive and anti-fibrotic agents.

Ruxolitinib in Aicardi-Goutières syndrome

Aicardi-Goutières Syndrome (AGS) is a monogenic leukodystrophy with pediatric onset, clinically characterized by a variable degree of neurologic impairment. It belongs to a group of condition called type I interferonopathies that are characterized by abnormal overproduction of interferon alpha, an inflammatory cytokine which action is mediated by the activation of two of the four human Janus Kinases. Thanks to an ever-increasing knowledge of the molecular basis and pathogenetic mechanisms of the disease, Janus Kinase inhibitors (JAKIs) have been proposed as a treatment option for selected interferonopathies. Here we reported the 24 months follow-up of the fifth AGS patient treated with ruxolitinib described so far in literature. The treatment was globally well tolerated; clinical examinations and radiological images demonstrated a progressively improving course. It is however to note that patients presenting with mild and spontaneously improving course have been reported. Large natural history studies on AGS spectrum are strongly required in order to get a better understanding of the results emerging from ongoing therapeutic trials on such rare disease.

[High Dose Intravenous Immunoglobulin Therapy for Autoimmune Diseases of the Central Nervous System]

High-dose intravenous immunoglobulin (IVIg) therapy has pharmacological suppressive actions against phagocytosis, complement system, pathogenic autoantibodies, and inflammatory cytokines, making it an effective treatment for autoimmune diseases. Unfortunately, there is no established evidence of the efficacy of IVIg therapy for autoimmune diseases of the central nervous system. Patients who are resistant to steroids and other immunosuppressive therapies or have complications that preclude the use of strong immunosuppressive therapies are considered eligible for IVIg therapy. The advantages of IVIg therapy include safety and ease of use. However, further evidence of the efficacy of IVIg treatment for autoimmune diseases of the central nervous system is warranted.

Association of Rituximab Use With Adverse Events in Children, Adolescents, and Young Adults

IMPORTANCE

Rituximab is among the most frequently used immunotherapies in pediatrics. Few studies have reported long-term adverse events associated with its use for children.

OBJECTIVE

To describe the use of rituximab and to assess whether its use is associated with short- or long-term adverse events, infections, or time to immune reconstitution in a diverse group of young people.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 468 patients aged younger than 21 years who received rituximab for diverse indications between October 1, 2010, and December 31, 2017, at Texas Children's Hospital, a large pediatric referral hospital. Patterns of adverse events, infections, and immune recovery are described. Data analyses were conducted from December 2019 to June 2020.

EXPOSURE

One or more doses of rituximab.

MAIN OUTCOMES AND MEASURES

Adverse drug events (eg, anaphylaxis), incidence of mild and severe infections, and time to recovery of B lymphocyte subset counts and immunoglobulin levels. Survival models and logistic regression analyses and were used to identify associated risk factors of infectious and noninfectious adverse drug events.

RESULTS

We identified 468 patients receiving at least 1 dose of rituximab. The total follow-up time was 11 713 person-months. Of the 468 patients, 293 (62.6%) were female, the median (interquartile range) age at receipt of dose was 14.3 (9.9-16.8) years, and 209 (44.7%) were self-reported White Hispanic. Adverse events associated with rituximab infusion occurred in 72 patients (15.4%), and anaphylaxis occurred in 17 patients (3.6%). Long-term adverse events, such as prolonged neutropenia and leukoencephalopathy, were absent. Infections occurred in 224 patients (47.9%); 84 patients (17.9%) had severe infections, and 3 patients (0.6%) had lethal infections. Concurrent use of intravenous chemotherapy, treatment of systemic lupus erythematosus, neutropenia, and use of intravenous immunoglobulin were associated with increased risk of infection. Among 135 patients (28.8%) followed up to B cell count recovery, CD19+ or CD20+ cell numbers normalized in a median of 9.0 months (interquartile range, 5.9-14.4 months) following rituximab use; 48 of 95 patients (51%) evaluated beyond a year had low-for-age B cell counts. Recovery of CD27+ memory B cell number occurred in a median of 15.7 months (interquartile range, 6.0-22.7 months). Among patients with normal baseline values, low immunoglobulin G (IgG) levels developed in 67 of 289 patients (23.2%) and low IgM levels in 118 of 255 patients (40.8%); of these patients evaluated beyond 12 months from rituximab, 16 of 117 (13.7%) had persistently low IgG and 37 (33.9%) of 109 had persistently low IgM.

CONCLUSIONS AND RELEVANCE

Rituximab is well tolerated among young people and is associated with few serious adverse events, but infections are common, corresponding to a prolonged period of B cell count recovery often lasting for longer than a year. Further examination of strategies to prevent infections following rituximab should be pursued.

Anti-IgLON5 disease with distinctive brain MRI findings responding to immunotherapy: A case report

RATIONALE

Anti-IgLON5 disease was first described as a progressive antibody-associated encephalopathy, with multiple non-specific clinical symptoms including sleep dysfunction, bulbar symptoms, progressive supranuclear palsy-like syndrome, cognitive impairment, and a variety of movement disorders. This newly discovered disease presents with unremarkable or unspecific brain magnetic resonance imagings (MRI), and have poor responsiveness to immunotherapy.

PATIENT CONCERNS

In this case, a 37-year-old man presented with 4-day history of gait instability, dysarthria, and oculomotor abnormalities. The initial neurologic examination revealed mild unsteady gait, subtle dysarthria, and left abducent paralysis.

DIAGNOSIS

The patient was diagnosed with anti-IgLON5 disease, based on clinical features and positive anti-IgLON5 antibodies in serum.

INTERVENTIONS

Initially, the patient was treated with high dosages of methylprednisolone and immunoglobulins.Outcomes: The symptoms of patient rapidly improved after high-dose intravenous methylprednisolone and immunoglobulins.

CONCLUSIONS

In this paper, we report a new case of anti-IgLON5 disease with major symptoms of gait instability, dysarthria, and oculomotor abnormalities, with distinctive brain MRI findings, and responsive to immunotherapy.

Neurologic syndromes related to anti-GAD65: Clinical and serologic response to treatment

OBJECTIVE

Antibodies against glutamic acid decarboxylase 65 (anti-GAD65) are associated with a number of neurologic syndromes. However, their pathogenic role is controversial. Our objective was to describe clinical and paraclinical characteristics of anti-GAD65 patients and analyze their response to immunotherapy.

METHODS

Retrospectively, we studied patients (n = 56) with positive anti-GAD65 and any neurologic symptom. We tested serum and CSF with ELISA, immunohistochemistry, and cell-based assay. Accordingly, we set a cutoff value of 10,000 IU/mL in serum by ELISA to group patients into high-concentration (n = 36) and low-concentration (n = 20) groups. We compared clinical and immunologic features and analyzed response to immunotherapy.

RESULTS

Classical anti-GAD65-associated syndromes were seen in 34/36 patients with high concentration (94%): stiff-person syndrome (7), cerebellar ataxia (3), chronic epilepsy (9), limbic encephalitis (9), or an overlap of 2 or more of the former (6). Patients with low concentrations had a broad, heterogeneous symptom spectrum. Immunotherapy was effective in 19/27 treated patients (70%), although none of them completely recovered. Antibody concentration reduction occurred in 15/17 patients with available pre- and post-treatment samples (median reduction 69%; range 27%-99%), of which 14 improved clinically. The 2 patients with unchanged concentrations showed no clinical improvement. No differences in treatment responses were observed between specific syndromes.

CONCLUSION

Most patients with high anti-GAD65 concentrations (>10,000 IU/mL) showed some improvement after immunotherapy, unfortunately without complete recovery. Serum antibody concentrations' course might be useful to monitor response. In patients with low anti-GAD65 concentrations, especially in those without typical clinical phenotypes, diagnostic alternatives are more likely.

Treatment of Movement Disorder Emergencies in Autoimmune Encephalitis in the Neurosciences ICU

Immune response against neuronal and glial cell surface and cytosolic antigens is an important cause of encephalitis. It may be triggered by activation of the immune system in response to an infection (para-infectious), cancer (paraneoplastic), or due to a patient's tendency toward autoimmunity. Antibodies directed toward neuronal cell surface antigens are directly pathogenic, whereas antibodies with intracellular targets may become pathogenic if the antigen is transiently exposed to the cell surface or via activation of cytotoxic T cells. Immune-mediated encephalitis is well recognized and may require intensive care due to status epilepticus, need for invasive ventilation, or dysautonomia. Patients with immune-mediated encephalitis may become critically ill and display clinically complex and challenging to treat movement disorders in over 80% of the cases (Zhang et al. in Neurocrit Care 29(2):264-272, 2018). Treatment options include immunotherapy and symptomatic agents affecting dopamine or acetylcholine neurotransmission. There has been no prior published guidance for management of these movement disorders for the intensivist. Herein, we discuss the immune-mediated encephalitis most likely to cause critical illness, clinical features and mechanisms of movement disorders and propose a management algorithm.

Daratumumab treatment for therapy-refractory anti-CASPR2 encephalitis

The anti-CD38 antibody daratumumab is approved for treatment of refractory multiple myeloma and acts by depletion of plasma cells and modification of various T-cell functions. Its safety, immunological effects and therapeutic potential was evaluated in a 60-year old patient with life-threatening and treatment-refractory anti-CASPR2 encephalitis requiring medical care and artificial ventilation in an intensive care unit. His autoimmune dysfunction was driven by exceptional high anti-CASPR2 autoantibody titers combined with an abnormally increased T-cell activation. As he remained unresponsive to standard and escalation immunotherapies (methylprednisolone, plasma exchange, immunoadsorption, immunoglobulins, rituximab and bortezomib), therapy was escalated to 13 cycles of 16 mg/kg daratumumab. During the treatment period, clinical, radiological, histological and laboratory findings, including quantification of autoreactive and protective antibody levels and FACS-based immune phenotyping, were analyzed. Daratumumab treatment was associated with significant clinical improvement, substantial reduction of anti-CASPR2 antibody titers, especially in CSF, decrease of immunoglobulin levels and protective vaccine titers, as well as normalization of initially increased T-cell activation markers. However, the patient died of Gram-negative septicemia in a neurorehabilitation center. In conclusion, our findings suggest that daratumumab induces not only depletion of autoreactive long-lived plasma cells associated with improvements of neurological sequelae, but also severe side effects requiring clinical studies investigating efficacy and safety of anti-CD38 therapy in antibody-driven autoimmune encephalitis.

Extremely Painful Multifocal Acquired Predominant Axonal Sensorimotor Neuropathy of the Upper Limb

The differential diagnosis of upper extremity mononeuritis multiplex includes neuralgic amyotrophy, vasculitic neuropathy, and Lewis-Sumner syndrome. We describe 3 patients initially suspected of neuralgic amyotrophy, who had an extremely painful, protracted, progressive disease course, not fitting one of these established diagnoses. Nerve ultrasonography showed focal caliber changes of the roots, plexus, and limb nerves. Electromyography showed predominant multifocal axonopathy. Ongoing autoimmune neuropathy was suspected. Steroid treatment provided temporary relief, and intravenous immunoglobulin A sustained pain decrease and functional improvement. These patients appear to have extremely painful axonal inflammatory neuropathy, with a good response to immune-modulating treatment.

Clinical Problem Solving: A Tobacco Merchant Who Can't Spit

A 47 year old man presented with a combination of dry mouth and lightheadedness while standing. His medical background was unremarkable except for cigarette smoking and hyperlipidemia. Sjögren's syndrome was ruled out, and he was referred for evaluation of orthostatic hypotension, which by then included syncopal episodes and injuries. Additional symptoms included dry eyes, constipation, reduced sweating, and erectile dysfunction. After excluding medications and structural cardiac abnormalities as causes of orthostatic hypotension, a clinical autonomic evaluation was performed. The pattern of beat-to-beat blood pressure associated with performance of the Valsalva maneuver, and a low plasma norepinephrine level that did not increase in response to standing, established that the orthostatic hypotension was neurogenic. Treatment with an alpha-adrenoceptor agonist and fludrocortisone yielded partial improvement. After systemic diseases involving autonomic failure were excluded, cardiac sympathetic neuroimaging was performed by 123I-metaliodobenzylguanidine (MIBG) scanning. The normal uptake seen in the heart indicated intact post ganglionic sympathetic innervation. There were no signs of central neurodegeneration or peripheral neuropathy. Because of symptoms and signs of both parasympathetic and sympathetic failure without denervation, an autonomic ganglionopathy was considered. A high titer of antibody to the neuronal nicotinic receptor, which mediates ganglionic neurotransmission, was obtained. The diagnosis of autoimmune autonomic ganglionopathy (AAG) was made, and the management strategy shifted to first lowering the antibody burden by plasma exchanges and then instituting chronic anti-autoimmune treatment with rituximab and a low dose of cortiosteroid. The patient showed remarkable improvement.

Clinical and experimental studies of potentially pathogenic brain-directed autoantibodies: current knowledge and future directions

The field of neuronal surface-directed antibody-mediated diseases of the central nervous system has dramatically expanded in the last few years and now forms an important cluster of treatable neurological conditions. In this review, we focus on three areas. First, we review the demographics, clinical features and treatment responses of these conditions. Second, we consider their pathophysiology and compare autoantibody mechanisms and their effects to genetic or pharmacological disruptions of the target antigens. Third, we discuss areas of controversy within the field, propose possible resolutions, and explore new directions for neuronal surface antibody-mediated diseases.

Post-infectious autoimmune disorders: Sydenham's chorea, PANDAS and beyond

Infections, and the resulting immune response to these infections, have recently received increased recognition as pathogenic mechanisms for neuropsychiatric disorders. Sydenham's chorea (SC), a widely recognized post-streptococcal autoimmune disorder, represents a model for this proposed pathogenesis. In SC, a dysregulated immune response to a streptococcal infection is hypothesized to result in inflammation of neuronal networks, particularly the basal ganglia nuclei. The resulting dysfunction in the basal ganglia nuclei are hypothesized to lead to a constellation of adventitious movements and psychiatric symptoms, which investigations have shown are amenable to immunomodulatory therapies. PANDAS (Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal infections) has been proposed as a variant of SC, and is hypothesized to share a pathogenic mechanism, despite a unique symptom profile of predominantly psychiatric symptoms. In this review, we present the clinical aspects of both disorders, the data for potential shared etiopathogenesis between them, and the evidence for the therapeutic use of immunomodulatory therapies for the symptoms of SC and PANDAS. This article is part of a Special Issue entitled SI: Neuroimmunology in Health And Disease.

Anti-NMDA encephalitis: an uncommon, autoimmune mediated form of encephalitis

We report an interesting case of a 19 year old female with findings on MRI suggestive of viral encephalitis. An extensive workup was negative for infectious causes and she was subsequently diagnosed with anti-NMDA encephalitis. Anti-NMDA encephalitis is a highly lethal but treatable form of autoimmune encephalitis that has recently been characterized. It is frequently found in young women and associated with an underlying teratoma. Although rare, this diagnosis should be considered in young females for whom a rapid onset of encephalitis cannot be explained by more common causes.

[Anti-NMDA receptor encephalitis: two paediatric cases]

INTRODUCTION

Encephalitis associated to anti-N-methyl D-aspartate (NMDA) receptor antibodies is an autoimmune neurological pathology that has been reported increasingly more frequently in the paediatric population in recent years. We report two cases from our own experience with similar clinical pictures.

CASE REPORTS

Case 1: a 5-year-old girl who began with clinical signs and symptoms of convulsions and altered consciousness, associated to movement disorders and regression of previously acquired abilities that developed into autism. Case 2: a 13-year-old girl who presented left-side hemiparesis, abnormal movements, conduct disorder and dysautonomia. In both cases positive anti-NMDA receptor antibodies were obtained in cerebrospinal fluid and they were diagnosed with anti-NMDA receptor encephalitis. In the first case, treatment was established with intravenous perfusion of corticoids and immunoglobulins, and rituximab also had to be associated. In the second case, treatment consisted in corticoids and immunoglobulins. Progress was favourable in both cases, with a slight language disorder as a sequela in the first case and a relapse in the second case, with full resolution.

CONCLUSIONS

Anti-NMDA receptor encephalitis is a treatable disorder and early diagnosis and treatment are crucial, since this improves the prognosis and diminishes the chances of relapses.

Identification of two HIV inhibitors that also inhibit human RNaseH2

A total of 140,000 compounds were screened in a targetfree cell-based high throughput assay against HIV-1 infection, and a subset of 81 promising compounds was identified. Secondary screening of these 81 compounds revealed two putative human RNaseH2 inhibitors, RHI001 and RHI002, with IC50 value of 6.8 μM and 16 μM, respectively. RHI002 showed selective activity against human RNaseH2 while RHI001 inhibited HIV-RNaseH, E. coli RNaseH, and human RNaseH1 with IC50 value of 28.5 μM, 7.9 μM, and 31.7 μM, respectively. Kinetic analysis revealed that both inhibitors had non-competitive inhibitor-like properties. Because RNaseH2 is involved in the etiology of Aicardi-Goutier syndrome and has been suggested as an anticancer drug target, small molecule inhibitors modulating its activity would be useful for investigating the cellular function of this molecule.

[Abnormalities of synaptogenesis in autism. Pathogenic and therapeutic implications]

INTRODUCTION

The social, language, and behavioural problems that occur with autism suggest that this syndrome affects a functionally diverse and widely distributed set of neural systems.

AIMS

To review the molecular pathways involved in synaptic growth, development, and stability of human synapses. We also examine the genes implicated in synaptogenesis which have been associated with autism. In particular, we highlight the role of these genes in synaptic cell adhesion, organization of presynaptic and postsynaptic specializations, growth signaling pathways, and endosomal function.

DEVELOPMENT

Proper brain function requires stringent balance of excitatory and inhibitory synapse formation during neural circuit assembly. Mutation of genes that normally sculpt and maintain this balance results in severe dysfunction, causing neurodevelopmental disorders including autism, epilepsy, Angelman syndrome, fragile X syndrome, and Rett syndrome. Such mutations may result in defective architectural structuring of synaptic connections, molecular assembly of synapses and/or functional synaptogenesis.

CONCLUSIONS

Increased knowledge of abnormal mechanisms of human synaptogenesis may lead to define different etio-pathogenic models of autism and to understand how far abnormal cell/synaptic growth and synaptic function could be reversed.

[Current indications of polyvalent immunoglobulins]

Polyvalent immunoglobulins have been used for more than 20 years in immune-mediated disorders and humoral immunodeficiency Their use has gradually increased, leading regulatory authorities to issue guidelines on the indications of these costly treatments. Neurological diseases, including autoimmune neuromuscular disorders such as acute and chronic polyradiculoneuropathies and multifocal motor neuropathy, are the main indications of intravenous immunoglobulins. Most patients with these diseases will need long-term maintenance therapy Further research is needed to optimize the use of polyvalent immunoglobulins and to find alternative treatments.

[The rational immunotherapy with intravenous immunoglobulin in neurologic diseases]

Intravenous immunoglobulins (IVIG) have been used mainly as a supplement therapy in hypogammglobulinemia patients. IVIG have been proved effective in treating TTP and recently they have been used in treating many autoimmune and inflammatory diseases. In neurologic diseases IVIG have immunomodulating features dependent on IgG Fc-fragment. Which diseases benefit from the use of IVIG was the find from controlled clinical trials in accordance with Evidence Based Medicine. IVIG have been proved effective in Guillaine-Barre syndrom, chronic inflammatory demyelinating polyradiculoneuropathy, miastenia, dermathomyositis and sclerosis multiple. The recommendations include the frequency of IVIG administering its dosage and duration of treatment.

[Beneficial effects of rituximab in a case of anti-myelin antibody-associated neuropathy]

We report here in a 61-year-old woman in whom sensory disturbance predominantly affecting the distal portion of the limbs progressed over the course of 1 year. Blood tests showed IgM monoclonal gammopathy as well as the presence of anti-myelin-associated glycoprotein (MAG) antibody. Nerve conduction studies revealed significant prolongation of distal latency, and sural nerve biopsy showed IgM deposition on the myelin sheath. She was diagnosed as suffering anti-MAG neuropathy. High-dose intravenous immunoglobulin therapy proved to be ineffective and her symptoms progressed. Therefore, rituximab was administered and the sensory disturbance improved. Although no detailed studies on rituximab therapy for anti-MAG neuropathy have been reported in Japan, the present findings suggest that rituximab may be more effective than immunoglobulin therapy and other conventional therapies that have been used for autoimmune neuropathies.

Pharmacologic agents for pediatric neuroimmune disorders

Autoimmune diseases make up a significant portion of the acute and chronic caseload of all pediatric neurologists. By comparing these diseases and their treatments side by side, common themes become evident. Therapeutic decisions follow patterns dependent on the clinical situation. Physicians must adapt therapy based on individual clinical responses. This article provides an overview of the current therapeutic options as they relate to the more common pediatric neuroimmune disorders.

Anti-N-methyl-D-aspartate receptor encephalitis: early treatment is beneficial

Anti-N-methyl-D-aspartate receptor antibody has been associated with a severe stereotypic form of subacute encephalitis, often found in women with ovarian teratoma. Reported here is the diagnosis of anti-N-methyl-D-aspartate receptor encephalitis in a 5-year-old girl who presented with subacute encephalopathy and movement disorder without evidence of malignancy. Early diagnosis and treatment with immune globulin and steroids resulted in near-complete recovery.

Molecularly targeted therapies for dysimmune neuropathies

Conventional treatment options, including corticosteroids, intravenous immunoglobulin, or plasma exchange, often fail to treat dysimmune neuropathies, such as chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and monoclonal gammopathy with its subtypes. Therefore, a significant percentage of patients require adjunctive immunosuppressive therapies. Considering that even immunosuppressive agents often are ineffective and/or associated with significant toxicities, the need for the development of safe and effective new treatment options is rising. Currently, several monoclonal antibodies (MAbs) have been tested in open-label small-sized studies or even in single cases so as to establish future directions in the therapy of diseases of the peripheral nervous system (PNS). Rituximab, an MAb targeting against the B cell surface membrane protein CD20, is the most widely used and promising MAb for the treatment of dysimmune neuropathies, especially for those in which immunoglobulin M (IgM) autoantibodies are pathogenetically involved. The efficacy of alemtuzumab, bevacizumab, and etanercept to treat various forms of dysimmune neuropathies is currently under investigation. This review looks critically at recent developments in molecularly targeted therapies for dysimmune neuropathies and also highlights areas of future research to pursue.

Autoimmunity in autism

Autism spectrum disorders is a heterogenous group of neurodevelopmental disorders, the etiology or etiologies of which remain unknown. Increasing evidence of autoimmune phenomena in individuals with autism could represent the presence of altered or inappropriate immune responses in this disorder, and this immune system dysfunction may represent novel targets for treatment. Furthermore, in recent studies, antibodies directed against the fetal brain have been detected in some mothers of children with autism; these antibodies have the ability to alter behavioral outcomes in the offspring of animal models. A better understanding of the involvement of the immune response in early brain development, with respect to autism, may have important therapeutic implications.

A Japanese case of autoimmune autonomic ganglionopathy (AAG) and a review of AAG cases in Japan

A 29-year-old woman presented with acute, pure autonomic (both sympathetic and parasympathetic) failure and positive antibody to ganglionic nicotinic acetylcholine receptor; the diagnosis was autoimmune autonomic ganglionopathy (AAG). She had typical symptoms of AAG, although the patient also had coughing episodes and psychiatric symptoms, which are not typical of AAG in Western countries but are common in AAG cases in Japan. In a review of the Japanese literature, 29 cases of AAG had been reported. AAG patients in Japan were younger and more male predominant than in Western countries. Of the patients in these 29 cases, 10 (34.5%) had coughing episodes and 12 (41.4%) had psychiatric symptoms.

[Encephalitis lethargica in the Netherlands; renewed interest in a mysterious disease]

In the first half of the 20th century, during the Spanish flu pandemic, more than half a million people died from a mysterious disease sleeping sickness which was named 'encephalitis lethargica'. Despite extensive research, the cause of the disease has not yet been established. In the Netherlands many doctors published cases in the Nederlands Tijdschrift voor Geneeskunde (Dutch Journal of Medicine), also when chronic forms of the disease arose. An attempt to treat patients suffering from the chronic disease with levodopa initially had spectacular results but eventually lead to a new disappointment as a result of severe side effects. The experiment was stopped prematurely. Encephalitis lethargica is still being sporadically diagnosed in the 21st century. Recent research suggests that an autoimmune response targeted at the basal ganglia, possibly caused by a streptococcal infection, plays a role in the aetiology of the disease.

Safety of liquid intravenous immunoglobulin for neuroimmunologic disorders in the home setting: a retrospective analysis of 1085 infusions

OBJECTIVE

To examine the overall safety of intravenous immunoglobulin (IVIG) administered according to a clinically defined, home-based therapeutic regimen in patients with neuroimmunologic diseases.

METHODS

A total of 1,085 infusions of a new liquid IVIG 10% preparation were administered to 70 patients diagnosed with neuroimmunologic diseases over a 9-month period. These infusions were retrospectively reviewed for safety and tolerability.

RESULTS

A very favorable adverse effect (AE) rate (4.7%) was calculated over a wide range of doses (0.9-2.14 g/kg). There were no serious AEs reported, even among patients naive to IVIG therapy. Of 51 nonserious AEs, 53% occurred in 5 patients.

CONCLUSIONS

The results of this review of 1,085 high-dose liquid IVIG infusions using a closely monitored, yet highly flexible, home-based therapeutic regimen indicate a very favorable tolerability profile in patients with neuroimmunologic disorders, even in those who were new to IVIG therapy.

[Current use of immunoglobulins in neurology]

Intravenous immunoglobulins (IVIg) have been used for treating various neuroimmunological diseases. Over the past decade their efficacy could be demonstrated in placebo-controlled, double-blinded clinical trials. Use of IVIg has become the first-line treatment for Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, and rapidly worsening myasthenia gravis. It is also a second-line treatment for dermatomyositis, polymyositis, stiff-person syndrome, and pregnancy- and postpartum-related relapses in multiple sclerosis. Intravenous immunoglobulin is easily available, its administration is uncomplicated, and it has an excellent safety profile. In Germany it has been approved only for GBS; for other indications it has to be used off-label. Here we review the clinical applications and recommendations for the use of IVIg in neurological diseases.

PDEs as drug targets for CNS immune disorders

PDEs are important second messenger systems governing a host of cellular functions involved in neural signal transduction in the CNS and inflammatory cell signaling in the immune system. The contributions of PDE family members as novel treatments that target neuroinflammation as a pathophysiological process in the neuropathogenesis of diverse neurological and psychiatric brain disorders with prominent immune system correlates are discussed.

[Neuroimmunological diseases: update]

During the past 10 to 20 years, disease modifying drugs have been introduced into clinical practice relating to neuroimmunological diseases such as multiple sclerosis, myasthenia gravis, and Guillain-Barré syndrome. Based on the mechanism of each disease, therapies are currently being developed that target crucial molecules involved in the disease process. Monoclonal antibodies, such as natalizumab against VLA-4 and alemtuzumab against CD52 antibody, have been found to be very effective for reducing relapse rates and for preventing disease progression in multiple sclerosis. However, molecular-targeted therapy may disrupt the immune balance of patients and unexpectedly induce other autoimmune diseases or opportunistic infections. Therefore, to overcome intractable neuroimmunological diseases utilizing molecular-targeted therapies, future research needs deeper insights into the mechanism of each disease along with close observations of clinical courses.