Use and monitoring of low dose rituximab in myasthenia gravis

BACKGROUND

Myasthenia gravis is an autoimmune disorder of the neuromuscular junction. Rituximab (RTX), a monoclonal antibody to CD20, leads to B lymphocyte depletion and has been used in some autoimmune disorders, including small case series of myasthenia gravis patients.

METHODS

A retrospective analysis was performed of all patients with acetylcholine receptor (AChR) (11 subjects) or muscle specific kinase antibody (MuSK) positive myasthenia gravis (three subjects), who had been treated with RTX in Brisbane, Australia. In most patients 1 g of RTX, in two divided doses, was given. Patients were monitored by serial clinical assessments, flow cytometry of peripheral blood B lymphocytes and antibody testing.

RESULTS

RTX led to a significant improvement in symptoms in 11 of 14 patients. Doses of immunosuppressive medications were able to be reduced in 12 of 14 patients but medications could be completely ceased in only one patient. A demonstrable reduction of autoantibody levels was found in only three AChR positive patients and one MuSK positive patient, independent of clinical improvement. Peripheral blood B lymphocyte depletion was achieved in 13 out of 14 patients. B lymphocyte recovery occurred between 9 and 30 months post RTX (median 12.3 months) and was consistently associated with worsening of clinical symptoms.

CONCLUSION

Rituximab at a dose of 1 g appears to be beneficial in the treatment of patients with severe myasthenia gravis. Serial monitoring of peripheral blood B lymphocytes appears to be useful in guiding the need for further RTX therapy.

AQP4 Antibody Assay Sensitivity Comparison in the Era of the 2015 Diagnostic Criteria for NMOSD

We have compared five different assays for antibodies to aquaporin-4 in 181 cases of suspected Neuromyelitis optica spectrum disorders (NMOSD) and 253 controls to assess their relative utility. As part of a clinically-based survey of NMOSD in Australia and New Zealand, cases of suspected NMOSD were referred from 23 centers. Clinical details and magnetic imaging were reviewed and used to apply the 2015 IPND diagnostic criteria. In addition, 101 age- and sex-matched patients with multiple sclerosis were referred. Other inflammatory disease (n = 49) and healthy controls (n = 103) were also recruited. Samples from all participants were tested using tissue-based indirect immunofluorescence assays and a subset were tested using four additional ELISA and cell-based assays. Antibodies to myelin oligodendrocyte glycoprotein (MOG) were also assayed. All aquaporin-4 antibody assays proved to be highly specific. Sensitivities ranged from 60 to 94%, with cell-based assays having the highest sensitivity. Antibodies to MOG were detected in 8/79 (10%) of the residual suspected cases of NMOSD. Under the 2015 IPND diagnostic criteria for NMOSD, cell-based assays for aquaporin-4 are sensitive and highly specific, performing better than tissue-based and ELISA assays. A fixed cell-based assay showed near-identical results to a live-cell based assay. Antibodies to MOG account for only a small number of suspected cases.

The prevalence and treatment outcomes of antineuronal antibody-positive patients admitted with first episode of psychosis

BACKGROUND

Antineuronal antibodies are associated with psychosis, although their clinical significance in first episode of psychosis (FEP) is undetermined.

AIMS

To examine all patients admitted for treatment of FEP for antineuronal antibodies and describe clinical presentations and treatment outcomes in those who were antibody positive.

METHOD

Individuals admitted for FEP to six mental health units in Queensland, Australia, were prospectively tested for serum antineuronal antibodies. Antibody-positive patients were referred for neurological and immunological assessment and therapy.

RESULTS

Of 113 consenting participants, six had antineuronal antibodies (anti-N-methyl-D-aspartate receptor antibodies [n = 4], voltage-gated potassium channel antibodies [n = 1] and antibodies against uncharacterised antigen [n = 1]). Five received immunotherapy, which prompted resolution of psychosis in four.

CONCLUSIONS

A small subgroup of patients admitted to hospital with FEP have antineuronal antibodies detectable in serum and are responsive to immunotherapy. Early diagnosis and treatment is critical to optimise recovery.

DECLARATION OF INTEREST

None.

Molecular pathogenesis of neuromyelitis optica

Neuromyelitis optica (NMO) is a rare autoimmune disorder, distinct from multiple sclerosis, causing inflammatory lesions in the optic nerves and spinal cord. An autoantibody (NMO IgG) against aquaporin-4 (AQP4), a water channel expressed on astrocytes is thought to be causative. Peripheral production of the antibody is triggered by an unknown process in genetically susceptible individuals. Anti-AQP4 antibody enters the central nervous system (CNS) when the blood brain barrier is made permeable and has high affinity for orthogonal array particles of AQP4. Like other autoimmune diseases, Th17 cells and their effector cytokines (such as interleukin 6) have been implicated in pathogenesis. AQP4 expressing peripheral organs are not affected by NMO IgG, but the antibody causes extensive astrocytic loss in specific regions of the CNS through complement mediated cytotoxicity. Demyelination occurs during the inflammatory process and is probably secondary to oligodendrocyte apoptosis subsequent to loss of trophic support from astrocytes. Ultimately, extensive axonal injury leads to severe disability. Despite rapid advances in the understanding of NMO pathogenesis, unanswered questions remain, particularly with regards to disease mechanisms in NMO IgG seronegative cases. Increasing knowledge of the molecular pathology is leading to improved treatment strategies.

An Australian State-Based Cohort Study of Autoimmune Encephalitis Cases Detailing Clinical Presentation, Investigation Results, and Response to Therapy

Introduction: Autoimmune encephalitis is a disorder associated with antibodies directed against central nervous system proteins with variable clinical features. This study aims to add to knowledge of the disease by reporting the details of a cohort of patients with autoimmune encephalitis in Queensland, Australia.

Methodology: We surveyed patients with autoimmune encephalitis diagnosed and managed through public hospitals in Queensland, Australia between 2010 and the end of 2019. Cases were identified via case detection through a centralized diagnostic neuroimmunology laboratory (Division of Immunology, HSQ Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia) and a survey of neurologists. Data including demographic details, clinical presentation, investigation results, treatments including immune therapy and outcomes was collected.

Results: Sixty cases of antibody positive autoimmune encephalitis were identified. Twenty-eight were of anti-NMDA-receptor encephalitis with other cases associated with antibodies against LGi1, Caspr2, glycine receptor, DPPX, GABA_B receptor, IgLON5, GFAP, and SOX1. The number of diagnosed cases, especially of anti-NMDA-receptor encephalitis has markedly increased over the period 2017 to 2019. Clinical presentations were marked by heterogeneous symptom complexes and prolonged hospital admissions. Imaging studies were largely normal or non-specific. There was a response to immune therapy and a low mortality rate. Most cases affected by this disorder were left with ongoing symptoms associated with mild disability.

Conclusion: Autoimmune encephalitis in Queensland, Australia is an increasingly common but complex clinical entity marked by heterogeneous presentations, response to immune therapy and outcome results marked by low mortality and incomplete recovery.

Serum and CSF Anti-NMDAR Antibody Testing in Psychiatry

OBJECTIVE

The authors examined and compared the clinical presentation of CSF positive and negative N-methyl-d-aspartate receptor (NMDAR) antibody.

METHODS

The investigators performed a retrospective chart review of NMDAR-antibody-positive cases (serum or CSF) involving patients presenting to psychiatric services from 2010 to 2018 in Queensland, Australia. Presentation, progress, investigations, and efficacy of treatment are detailed.

RESULTS

There were 24 serum or CSF NMDAR-antibody-positive cases and three equivocal serum results. High rates of prodromal cognitive deficits, catatonia, speech disturbance, and antipsychotic sensitivity were observed in the 16 CSF NMDAR-antibody-positive case patients and two CSF NMDAR-antibody-negative case patients, all evident before neurological deterioration with seizures, movement disorder, and autonomic disturbance occurring in the weeks following admission. The majority of these patients (N=17) were treated successfully with immunomodulatory therapy. The nine remaining patients, who were CSF NMDAR antibody negative or equivocal, did not demonstrate any of these features and improved with psychiatric care alone.

CONCLUSIONS

These findings suggest that traditional psychiatric care may be appropriate for patients with isolated psychiatric symptoms who have positive serum NMDAR testing when CSF is negative and there are no key clinical features such as cognitive deficits, catatonia, speech disturbance, and antipsychotic sensitivity. However, if these key features are present, a trial of immunomodulatory treatment should be considered with repeated examination of CSF for neuronal antibodies.

PRES-like presentation in MOG antibody-related demyelination (MARD)

A 33-year-old male presented with a progressive four-week history of frontal headache and left visual field impairment. MRI brain confirmed bilateral, asymmetric, occipital vasogenic oedema, suggestive of posterior reversible encephalopathy syndrome (PRES). Serum testing for MOG antibodies was positive, confirming a diagnosis of MOG antibody-related demyelination (MARD). A similar PRES-like pattern of white matter inflammation has been reported previously in neuromyelitis optica spectrum disorder but has not previously been reported in MARD.

Performance of myositis-specific antibodies detected on myositis line immunoassay to diagnose and sub-classify patients with suspected idiopathic inflammatory myopathy, a retrospective records-based review

AIM

To evaluate myositis line immunoassay (LIA) for diagnosis and sub-classification of suspected idiopathic inflammatory myopathy (IIM). To investigate if test performance is improved by increasing signal strength cut-off for myositis-specific antibody (MSA) or combining MSA with indirect immunofluorescence (IIF).

METHODS

A retrospective, consecutive case series of patients investigated for MSAs from June 2013 to June 2020 for suspected IIM. Specificity, sensitivity, positive predictive value, and negative predictive value were calculated with 95% confidence intervals for diagnosis of IIM. Association of IIM diagnosis with increased signal strength and presence of an expected IIF pattern on Hep-2 cells was assessed by Fisher's exact test in MSA-positive patients.

RESULTS

A total of 195 patients were evaluated. IIM was diagnosed in 32/195 (16.4%) patients. MSAs were detected in 41/195 (21%) patients, 18/41 (43.9%) patients with an MSA had a diagnosis of IIM. The probability of an IIM diagnosis was increased in MSA-positive patients with high compared with low signal strength (83.3% vs 43.5%; P = 0.01) and an expected compared with unexpected IIF pattern (61.5% vs 23.8%; P = 0.04). Specificity for IIM was not significantly improved by increasing signal strength cut-off (85.9% vs 93.8%). Positive predictive value of myositis LIA was only modest and not significantly improved by either increasing signal strength cut-off or requiring an expected IIF pattern for determination of MSA positivity (43.9% vs 60% vs 61.5%). Sub-classification of IIM correlated closely for respective MSAs (88.9%).

CONCLUSION

Increased MSA signal strength on myositis LIA and the presence of an expected IIF pattern were associated with IIM diagnosis. Test performance was non-significantly improved by these methods. Prevalence of IIM in this patient cohort was low; it is not excluded that LIA performance could be improved by these methods in a higher prevalence cohort.

Analysing Triggers for Anti-NMDA-Receptor Encephalitis Including Herpes Simplex Virus Encephalitis and Ovarian Teratoma: Results from the Queensland Autoimmune Encephalitis Cohort

INTRODUCTION

Anti-N-methyl-D-Aspartate-Receptor (anti-NMDA-R) encephalitis is a complex autoimmune neuropsychiatric syndrome. Although initially associated with ovarian teratoma, subsequent studies have demonstrated that anti-NMDA-R encephalitis may occur without an identifiable cause or be triggered by viral infection of the central nervous system such as herpes simplex virus encephalitis (HSVE). This study will present details from a Queensland cohort analysing triggering events in patients with anti-NMDA-R encephalitis in an Australian context.

METHODOLOGY

The authors identified patients with anti-NMDA-R encephalitis diagnosed and managed through public hospitals in Queensland, Australia between 2010 and the end of 2019. Data collected included demographics, clinical presentation, investigation results, management and outcome measurements.

RESULTS

Thirty-one cases of anti-NMDA-R encephalitis were included in the study. Three cases of anti-NMDA-R encephalitis were triggered by prior HSVE, five cases were associated with ovarian teratoma and twenty-three cases had no identifiable trigger. There were an additional three cases in which anti-NMDA receptor antibodies were present in the context of other disease states but where the patient didn't develop anti-NMDA-R encephalitis. Cases triggered by HSVE or associated with ovarian teratoma experienced a more severe disease course compared to cases with no identifiable trigger. All groups responded to immunosuppressive or immunomodulatory therapy. Analysis of clinical characteristics revealed a complex heterogeneous syndrome with some variability between groups.

CONCLUSION

In this cohort, the number of cases of anti-NMDA-R encephalitis triggered by HSVE is comparable to those triggered by ovarian teratoma. However, the majority of cases of anti-NMDA-R encephalitis had no identifiable trigger or associated disease process. This article is protected by copyright. All rights reserved.

059 Teratoma with glycine, NMDA & VGKC antibodies presenting with severe weakness, respiratory failure & corticospinal tract dysfunction

Introduction

Glycine antibodies are associated with progressive encephalomyelitis with rigidity and myoclonus (PERM) but have been rarely reported to cause myasthenic-like symptoms.1 We present a single patient seen at a tertiary neurology centre with fatigable muscle weakness and corticospinal tract dysfunction with positive glycine, VGKC and NMDA receptor antibodies, associated with an ovarian teratoma expressing neural tissue.

Case

A 32 year old female presented with fatigable muscle weakness. Physical examination was atypical for a disease of the neuromuscular junction with features of exaggerated reflexes and clonus. The weakness progressed over 1–2 weeks leading to respiratory failure. Investigations including MRI brain, repetitive stimulation and acetylcholine-receptor antibody studies were all within the normal limits. Studies for neuronal antibodies against intracellular targets were negative. Further investigation revealed positive autoantibodies against Glycine receptor, NMDA (N-Methyl-d-aspartate) receptor and VGKC (voltage-gated potassium channel) with an underlying ovarian teratoma. Complete clinical resolution was achieved with teratoma resection and 2 g/kg course of intravenous immunoglobulin. Histopathological examination of the tumour revealed a mature cystic teratoma with dystrophic calcification. The teratoma included skin, adipose tissue, intestinal type mucosa, and neuroglial tissue in which nerve fibres and ganglion cells are present. A lymphoid infiltrate was concentrated in areas of neural tissue within the teratoma.

Conclusion

Muscle weakness, corticospinal tract dysfunction and respiratory failure have previously been reported in the context of anti-glycine antibodies. This is the first case where anti-glycine, anti-NMDA and anti-VGKC antibodies have been found in the context of an ovarian teratoma. The autoimmune nature of this condition is emphasised by the lymphoid infiltrate around the neural tissue expressed within the teratoma.

Reference

1. Carvajal-Gonzalez A, Leite MI, Waters P, Woodhall M, Coutinho E, Balint B, … Vincent A. Glycine receptor antibodies in PERM and related syndromes: characteristics, clinical features and outcomes. Brain2014;137(Pt 8):2178–2192.

Long-term outcomes of ADEM-like and tumefactive presentations of CNS demyelination: a case-comparison analysis

A minority of initial multiple sclerosis (MS) presentations clinically or radiologically resemble other central nervous system (CNS) pathologies, acute disseminated encephalomyelitis (ADEM) or tumefactive demyelination (atypical demyelination presentations). With the aim of better defining the long-term outcomes of this group we have performed a retrospective cohort comparison of atypical demyelination versus 'typical' MS presentations. Twenty-seven cases with atypical presentations (both first and subsequent demyelinating events) were identified and compared with typical MS cases. Disease features analysed included relapse rates, disability severity, whole brain and lesion volumes, lesion number and distribution. Atypical cases represented 3.9% of all MS cases. There was considerable overlap in the magnetic resonance imaging (MRI) features of ADEM-like and tumefactive demyelination cases. ADEM-like cases tended to be younger but not significantly so. Atypical cases showed a trend towards higher peak expanded disability severity score (EDSS) score at the time of their atypical presentation. Motor, cranial nerve, cerebellar, cerebral and multifocal presentations were all more common in atypical cases, and less likely to present with optic neuritis. Cerebrospinal fluid (CSF) white cell counts were higher in atypical cases (p = 0.002). One atypical case was associated with peripheral blood myelin oligodendrocyte glycoprotein (MOG) antibodies, but subsequent clinical and radiological course was in keeping with MS. There was no difference in long-term clinical outcomes including annualised relapse rates (ARR), brain volume, lesion numbers or lesion distributions. Atypical demyelination cases were more likely to receive high potency disease modifying therapy early in the course of their illness. Despite the severity of initial illness, our cohort analysis suggests that atypical demyelination presentations do not confer a higher risk of long-term adverse outcomes.

058 ANTI-CASPR2-ANTIBODY associated encephalitis in a 63-year old male with chronic lymphocytic leukaemia

Introduction

This case from a tertiary neurology centre reports a novel association between the emerging clinical entity of anti-contactin associated protein-2 (CASPR-2) antibody encephalitis and chronic lymphocytic leukaemia (CLL).

Case

We describe a 63 year old Maori male truck-driver who presented with progressive altered personality, speech, cognition and perception over 9 months. The patient also developed choreiform movements, broad-based gait, incontinence, sleep apnoea with type 2 respiratory failure and episodic loss of consciousness. 12 months prior, he had been diagnosed with low-risk CLL, for which he remained untreated. MRI of the brain revealed mid-sagittal bilateral mid-temporal T2/FLAIR hyperintensities. Cerebrospinal fluid examination showed a mononuclear pleocytosis (WCC 270×10^6/L) with 15% of these CD5/CD19/CD23 positive and 92% CD3/CD5 positive CD 19 negative on flow cytometry, protein was also elevated at 2600 mg/L. The interplay between CLL and inflammation is uncertain. Anti-Caspr2-antibody was identified in CSF and serum. The patient was treated with a combination of fludarabine, cyclophosphamide, rituximab, dexamethasone and intravenous immunoglobulin (IVIG). Clinical status improved and antibody titre decreased from 580 to 241 pM in three weeks and to 55pM (negative <85 pM) at five months. Symptoms worsened when IVIG doses were missed. He returned home after inpatient rehabilitation, showed striking clinical improvement at 12 month follow-up and continues on maintenance IVIG therapy.

Conclusion

Whilst paraneoplastic VGKC encephalitis has been described associated with a number of malignancies, this is the first reported case of CASPR-2 antibody present in association with CLL.

References

. Van Sonderen A, Petit-Pedrol M, Dalmau J, Titulaer MJ. The value of LGI1, Caspr2 and voltage-gated potassium channel antibodies in encephalitis. Nature Reviews Neurology2017;13(5):290–301.

. Nogai H, Israel-Willner H, Zschenderlein R, Pezzutto A. Improvement in Paraneoplastic Limbic Encephalitis after Systemic Treatment with Rituximab in a Patient with B-Cell Chronic Lymphocytic Leukaemia. Case Reports in Haematology2013;2013:Article ID958704.

. Van Sonderen A, Ariño H, Petit-Pedrol M, et al. The Clinical Spectrum of Caspr2 antibody-associated disease. Neurology2016;87:521–528.

. Gultekin SH, Rosenfeld MR, Voltz R, Eichen J, et al. Paraneoplastic limbic encephalitis: Neurological symptoms, immunological findings and tumour association in 50 patients. Brain2000;123:1481–1494.

084 Treating yourself: a glucocorticoid secreting tumour suppressing myasthenia gravis

Introduction

We aimed to report a single patient seen at a tertiary neurology centre with a rarely described phenomenon of interaction between myasthenia gravis and a glucocorticoid secreting tumour.

Case

A 70 year old, otherwise healthy male underwent a CT imaging of his chest after being trampled by a cow. Apart from several rib fractures, this revealed a slightly lobulated but well-defined right adrenal mass. Further studies revealed elevated morning cortisol levels of 847 nmol/L (reference range 140–640 nmol/L). The mass was excised and was found to be a 60 mm by 30 mm by 25 mm lesion, which was well circumscribed. It comprised of clear cells with foamy cytoplasm and a lesser component of eosinophilic cells, consistent with a functional adrenal adenoma producing glucocorticoid. Within days of the resection the patient described becoming weaker with fatigable proximal weakness of both upper and lower limbs. Acetylcholine receptor antibodies were positive and a diagnosis of myasthenia gravis was made. Upon commencement of pyridostigmine at 60 mg TDS and prednisolone 10 mg OD the symptoms improved and the patient was able to resume his previous active lifestyle.

Conclusion

The phenomenon of myasthenia gravis being suppressed by a functional adrenal adenoma has only previously been reported twice.1 2 This case report adds to the literature and can be distinguished from the other two cases by the rapidity of onset of symptoms of myasthenia over days after tumour resection. It tells a cautionary tale of medical therapy disrupting the brittle balance of nature.

References

. Petramala L, Marinelli C, Giallonardo AT, Concistre A, Lucia P, Venuta F, … Letizia C. A case report of subclinical hypercortisolism due to adrenal incidentaloma complicated by myasthenia gravis after adrenalectomy. Tumori2016;102(Suppl.2).

. Topham L, Chapman A, Gibbs C, Saha M. A patient with pemphigus foliaceus and myasthenia gravis treated by a cortisol-secreting adrenal adenoma. Br J Dermatol2015;172(1):280–282.

Pulmonary involvement in Anti-Neutrophil Cytoplasmic Antibody Associated Vasculitis: A single centre case series

Anti-Neutrophil Cytoplasmic Antibody associated Vasculitides (AAV) comprise a rare group of disorders in which respiratory tract involvement is variable and often severe. The rarity and heterogeneity of AAV makes this a challenging condition to diagnose and manage. In this single-centre case series of 44 patients with AAV-associated respiratory disease, we provide an overview of disease manifestations, management aspects and treatment outcomes. Data from this case series highlight the real-world diagnostic and therapeutic challenges of the AAV respiratory disease spectrum; including uncertainties in the management of fibrosing interstitial lung disease, tracheobronchial stenosis and diffuse alveolar haemorrhage.