Autoimmune Peripheral Neuropathies and Contribution of Antiganglioside/Sulphatide Autoantibody Testing

Inter-laboratory comparison of routine autoantibody detection methods for autoimmune neuropathies and myasthenia gravis

Serological tests are important to detect autoantibodies (autoAbs) in patients with autoimmune neuropathies (AN) and myasthenia gravis (MG) as they are biomarkers for diagnosis, stratification, treatment selection, and monitoring. However, tests to detect autoAbs frequently lack proper standardization and results differ across diagnostic laboratories. We compared results for tests routinely performed in Spanish diagnostic laboratories to detect AN and MG autoAbs. In the Spanish Society of Immunology Autoimmunity Group national workshop, serum samples from 13 patients with AN or MG were tested for anti-ganglioside, anti-myelin-associated glycoprotein (MAG), anti-nicotinic acetylcholine receptor (AChR), and anti-muscle-specific kinase (MuSK) autoAbs using reference methods and were distributed for analysis to 27 participating laboratories using their routine methods. Overserved were inter-laboratory variability and worryingly low sensitivity, especially for anti-ganglioside immunoglobulin G and anti-MAG autoAb detection. This pilot study reflects autoAbs detection state of the art in AN and MG testing in leading diagnostic laboratories in Spain, highlighting the need for standardization prior to clinical use.

Yellow fever vaccine-associated neurologic and viscerotropic disease: a 10-year case series of the French National Reference Center for Arboviruses with clinical and immunological insights

BACKGROUND

Immunization against the Yellow fever virus (YFV) with the 17D live-attenuated vaccine is the most effective way to prevent the disease. However, unexpected severe adverse events can occur. They consist in a neurological impairment - neurological disease (YEL-AND), a YF-like illness - viscerotropic disease (YEL-AVD) or anaphylaxis. In this article, we describe the epidemiology, clinical and biological features of YEL-AND and YEL-AVD cases reported to the French National Reference Center for Arboviruses (NRCA) in the past 10 years.

METHODS

We conducted a national, retrospective study using the database of the NRCA from June 2012 to June 2022. All patients whose biological samples were sent to the NRCA for detection of YFV by serology and/or RT-qPCR for a suspected vaccine-associated adverse event were included. We collected data by reading medical records and conducted complementary neuro-immunological analysis, followed by a search for autoimmunity against type-1-interferon when samples were available at the NRCA.

RESULTS

There were 10 cases of YEL-AND and 2 cases of YEL-AVD reported to the NRCA in the past 10 years, which represented an overall incidence of 0.6 for 100 000 doses. A total of 6/12 cases were previously healthy patients (50%, mean age 31 years), and 4/12 cases had cardiovascular co-morbidities (42%, mean age 56 years). The majority of YEL-AND had a favourable outcome at 6 months of follow up. One YEL-AVD patient passed. In secondary analyses, we evidenced a significant blood cerebrospinal fluid (CSF) barrier dysfunction, without intrathecal synthesis of immunoglobulin and without argument for a neuron damage. We further detected a significant rate of anti-type-1alpha interferon antibodies in 3/10 tested patients (2 YEL-AND and 1 YEL-AVD).

CONCLUSION

YEL-AND and YEL-AVD are rare events that can underlie defect in the innate immunity of apparently healthy or mild co-morbid subjects. Outcome was generally favourable in the YEL-AND cases of our series, but still life-threatening or even fatal in the YEL-AVD cases.

Molecular, Electrophysiological, and Ultrasonographic Differences in Selected Immune-Mediated Neuropathies with Therapeutic Implications

The spectrum of immune-mediated neuropathies is broad and the different subtypes are still being researched. With the numerous subtypes of immune-mediated neuropathies, establishing the appropriate diagnosis in normal clinical practice is challenging. The treatment of these disorders is also troublesome. The authors have undertaken a literature review of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), Guillain-Barre syndrome (GBS) and multifocal motor neuropathy (MMN). The molecular, electrophysiological and ultrasound features of these autoimmune polyneuropathies are analyzed, highlighting the differences in diagnosis and ultimately treatment. The immune dysfunction can lead to damage to the peripheral nervous system. In practice, it is suspected that these disorders are caused by autoimmunity to proteins located in the node of Ranvier or myelin components of peripheral nerves, although disease-associated autoantibodies have not been identified for all disorders. The electrophysiological presence of conduction blocks is another important factor characterizing separate subgroups of treatment-naive motor neuropathies, including multifocal CIDP (synonyms: multifocal demyelinating neuropathy with persistent conduction block), which differs from multifocal motor neuropathy with conduction block (MMN) in both responses to treatment modalities and electrophysiological features. Ultrasound is a reliable method for diagnosing immune-mediated neuropathies, particularly when alternative diagnostic examinations yield inconclusive results. In overall terms, the management of these disorders includes immunotherapy such as corticosteroids, intravenous immunoglobulin or plasma exchange. Improvements in clinical criteria and the development of more disease-specific immunotherapies should expand the therapeutic possibilities for these debilitating diseases.

Anti-ganglioside antibody positive neuromyelitis optica spectrum disorders with peripheral neuropathy: a case report

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is a group of autoimmune-mediated disorders of the central nervous system primarily involving the optic nerve and spinal cord. There are limited reports of NMOSD associated with peripheral nerve damage.

CASE PRESENTATION

We report a 57-year-old female patient who met the diagnostic criteria for aquaporin 4 (AQP4)-IgG positive NMOSD with undifferentiated connective tissue disease and multiple peripheral neuropathy. In addition, the patient was positive for multiple anti-ganglioside antibodies (anti-GD1a IgG antibodies and anti-GD3 IgM antibodies) and anti-sulfatide IgG antibodies in serum and cerebrospinal fluid. After treatment with methylprednisolone, gamma globulin, plasma exchange, and rituximab, the patient's status improved and was subsequently discharged from our hospital.

CONCLUSIONS

The neurologist should be aware of the unusual association between NMOSD and immune-mediated peripheral neuropathy undifferentiated connective tissue disease and nerve damage mediated by multiple antibodies may have combined to cause peripheral nerve damage in this patient.

Clinical and antibodies analysis of anti-GQ1b antibody syndrome: a case series of 15 patients

Objectives

To investigate the clinical manifestations, immunity, laboratory test, treatment and prognosis of patients with anti-GQ1b antibody syndrome in Chongqing, China.

Methods

We reviewed 15 patients with positive anti-ganglioside antibodies in the First Affiliated Hospital of Chongqing Medical University from 2016 to 2019.

Results

Fifteen patients were included in the study (mean age, 54.4 years; age range, 27 to 80 years; 9 men (60%)). Ten patients presented with a history of preinfection, including flu-like syndrome (n = 6, 60%), upper respiratory tract infection (URTI) (n = 3, 30%), and digestive tract infection (GI) (n = 1, 10%). The most common manifestation was ophthalmoplegia (n = 13, 86.67%), followed by weakness (n = 12, 80%), ataxia (n = 11, 73.3%), paresthesia (n = 8, 53.33%) and hypersomnolence (n = 5, 33.33%). All 15 patients underwent antibody testing. Eight patients (53.33%, 7 men (87.5%)) of whom only have positive immunoglobulin G (IgG) against anti-GQ1b antibody while seven (46.67%, 2 men (28.57%)) were positive for multiple anti-ganglioside antibodies apart from anti-GQ1b antibodies. Nine patients (60%) received intravenous immunoglobulin (IVIG) therapy, four (26.67%) received plasma exchange (PE) and two (13.33%) received steroid therapy. Three patients were lost to follow-up at 6 months, 1 patient (6.67%) had persistent back numbness, and the other 11 patients (73.33%) had fully recovered.

Conclusion

The clinical subtype of anti-GQ1b antibody syndrome correlates with the type of anti-ganglioside antibody. Patients who test positive for only anti-GQ1b antibody are more likely to be men. Most patients exhibit a unidirectional course with a good prognosis, but anti-GQ1b antibody syndrome is also associated with a risk of recurrence.