Limbic encephalitis and type 1 diabetes with glutamic acid decarboxylase 65 (GAD65) autoimmunity: Improvement with high-dose intravenous immunoglobulin therapy

Recurrent seizures of autoimmune origin: emerging phenotypes

OBJECTIVE

Recurrent seizures of autoimmune origin (AEp) are one of the most frequent causes of recurrent seizures or suspected epilepsy of unknown cause. The aim of this study was to identify specific phenotypes corresponding to AEp.

METHODS

We retrospectively reviewed features of patients with recurrent seizures of unknown cause and investigated for suspected AEp (January 2015-May 2018). Patients were separated in: (1) AEpAb+: AEp with positive autoantibodies; (2) AEpAb-: suspected AEp (inflammatory central nervous system (CNS) profile) without autoantibodies; (3) NAEp: epilepsy without CNS inflammation.

RESULTS

Eighty-nine epileptic patients underwent a CSF antibody detection. From the remaining 57 epileptic patients (32 excluded for a differential diagnosis), 61.4% were considered as AEp. 21% were AEpAb+ (4 NMDAR, 2 GABAbR, 3 GAD-Ab, 2 LGi1, 1 CASPR2), 40.4% AEpAb-, and 38.6% NAE. AE (AEpAb+ and AEpAb-) was significantly associated with antibody prevalence in epilepsy (APE) score ≥ 4 (80%), encephalitic phase (71.4%), psychiatric involvement (64.7%), cognitive impairment (50%), and status epilepticus (41.2%). Within the group of 29 patients without encephalitic phase and with chronic epilepsy (NEPp), 34.5% were defined as AEp. 10.4% were AEpAb+ (2 GAD, 1 CASPR2) and 24.1% were AEpAb-. NEP AEp was associated with non-cerebral autoimmune disorders, short epileptic disease duration, and cognitive impairment.

CONCLUSIONS

Autoimmune cause (AEp) should be assessed in patient suffering from recurrent seizures of unknown cause. Acute encephalitis is clearly the main AEp phenotype. AEp was also defined in more than one-third of chronic epilepsy patients (NEP) of unknown cause. Then, AEp may be combined with other autoimmune comorbidities, a shorter evolution of recurrent seizures, and cognitive impairment.

Psychiatric symptoms in anti glutamic acid decarboxylase associated limbic encephalitis in adults: a systematic review

Autoimmune Limbic Encephalitis (LE) is a relatively new category of immune-mediated diseases with a wide range of neuropsychiatric symptoms. LE associated with Glutamic Acid Decarboxylase (GAD) antibodies is difficult to diagnose due to its possible atypical presentation with neuropsychiatric and behavioral features. We performed a systematic review of literature and retrieved 21 cases of anti GAD-associated LE with neuropsychiatric signs. Median age at onset was 27 years with a female predominance (81.0 %) and median diagnostic delay of 6 months. Clinical presentation included typical LE symptoms such as anterograde amnesia (95.2 %) and temporal lobe or tonico-clonic seizures (95.2 %). Psychiatric symptoms were described in 61.9 % of patients, presenting as anxiety, depressive symptoms, apathy and behavioral changes. Extra-limbic symptoms were present in 14.3 % of patients. No neoplasia associated was found. Some patients had poor epileptic, cognitive and psychiatric outcomes requiring prolonged immunosuppressive treatment. The description of the neuropsychiatric spectrum of anti-GAD LE and its specificities aims to improve our understanding of this entity, and may lead to earlier diagnosis as well as better outcome.

Type 1 diabetes and GAD65 limbic encephalitis: a case report of a 10-year-old girl

Limbic encephalitis is a rare neurological disorder that may be difficult to recognize. Clinical features include memory impairment, temporal lobe seizures and affective disturbance. We report the case of a 10-year-old girl with type 1 diabetes mellitus that presented with seizures, depressed mood and memory changes. The diagnosis of glutamic acid decarboxylase 65 (GAD65) mediated limbic encephalitis relied on cerebral magnetic resonance imaging lesions and high serological and cerebrospinal fluid GAD65-antibodies titers. High-dose steroidal therapy was started with clinical improvement. Relapse led to a second high-dose steroid treatment followed by rituximab with remission. A correlation between serum GAD65-antibodies levels and symptoms was found, demonstrating GAD65-antibodies titers may be useful for clinical follow-up and immunotherapy guidance. This report raises awareness of this serious neurological condition that may be associated with type 1 diabetes, underlining the importance of an early diagnosis and prompt treatment for a better prognosis.

Limbic Encephalitis Associated With GAD65 Antibodies: Brief Review of the Relevant literature

Recently, many cases of autoimmune limbic encephalitis with positive GAD65 (glutamic acid decarboxylase) antibodies have been described in the scientific literature. However, it remains an understudied topic of great relevance to practicing neurologists. Thus, we report here a review of published cases, in English, of autoimmune limbic encephalitis with this type of antibodies, focusing on presenting symptoms and signs, associated conditions, and findings upon investigation. We also report treatment responses. We aim to offer a better description of the clinical spectrum of autoimmune limbic encephalitis associated with GAD65 antibodies as well as to expose its paraclinical features and outcome.

The Production Processes and Biological Effects of Intravenous Immunoglobulin

Immunoglobulin is a highly diverse autologous molecule able to influence immunity in different physiological and diseased situations. Its effect may be visible both in terms of development and function of B and T lymphocytes. Polyclonal immunoglobulin may be used as therapy in many diseases in different circumstances such as primary and secondary hypogammaglobulinemia, recurrent infections, polyneuropathies, cancer, after allogeneic transplantation in the presence of infections and/or GVHD. However, recent studies have broadened the possible uses of polyclonal immunoglobulin showing that it can stimulate certain sub-populations of T cells with effects on T cell proliferation, survival and function in situations of lymphopenia. These results present a novel and considerable impact of intravenous immunoglobulin (IVIg) treatment in situations of severe lymphopenia, a situation that can occur in cancer patients after chemo and radiotherapy treatments. In this review paper the established and experimental role of polyclonal immunoglobulin will be presented and discussed as well as the manufacturing processes involved in their production.

Screening Autoimmune Anti-neuronal Antibodies in Pediatric Patients with Suspected Autoimmune Encephalitis

Background and Purpose:

The aim of this study was to identify and describe the pediatric autoimmune encephalitis cases positive for anti-neuronal antibody tests.

Methods:

Screening of six anti-neuronal antibodies in 23 children with suspected autoimmune encephalitis was performed by cell-based indirect immunofluorescence test with patients’ serum or cerebrospinal fluid.

Results:

Among the 23 cases enrolled here, eight patients (35%) were positive for the anti-N-methyl-d-aspartate (NMDA) receptor antibody and one patient (4%) was positive for the anti-contactin-associated protein-like 2 (CASPR2) antibody. In the anti-NMDA receptor antibody-positive group, seizure and movement disorders were the most prominent features and were present in all patients. A tumor was present in only one patient. Three patients with infant- and toddler-onset disease did not exhibit a classic multistage illness. In addition to seizure and dyskinesia, aphasia or mutism without severe consciousness impairment was present in all three patients. These atypical clinical presentations may suggest different pathomechanism of anti-NMDA receptor encephalitis among these age groups. The patient who was positive for the anti-CASPR2 antibody was an 8-year-old girl who presented with fever, encephalopathy, and seizure. Neuromyotonia or other dyskinesia was not present.

Conclusions:

Eight anti-NMDA receptor antibody positive patients and one CASPR2 positive patient were identified from the screening of six anti-neuronal antibodies in pediatric patients suspected with autoimmune encephalitis. Developmental regression specifically for language skills was suggested as one of the atypical clinical features in infants and toddler onset anti-NMDA receptor antibody positive patients.

Novel sexual dimorphisms of sleep apnea syndrome in diabetes

BACKGROUND

OSAS, a frequently neglected, yet frequent comorbidity in T2DM, is associated with obesity, metabolic syndrome and central fat. OSAS is better documented in males, and this study explored novel gender dimorphisms in T2DM.

METHODS

Cross-sectional study: 815 T2DM (541 males; 274 females) classified into OSAS[-] and OSAS[+] were assessed for cardiometabolic risk factors, glucose homeostasis, micro/macroangiopathies, CV risk, autoimmune thyroid disease (AITD); and GAD65 antibodies.

RESULTS

There was a gender dimorphism in glucose control (worse in females), apolipoprotein B100 (higher in females), with apoB100/apoA1 and log(TG)/HDL-C sexually dimorphic. There was also a marked gender dimorphism in GAD65 positivity, higher (+793%) in OSAS[+] females vs. males. There were clear sexual dimorphisms in macro-/microangioathies, regarding stroke, retinopathy and polyneuropathy. OSAS was not sexually dimorphic regarding age; education; and diabetes duration. There was a significant dimorphism in ethnicity. There were no gender-specific dimorphisms related to OSAS in anthropometrics, nor in hypertension, insulin sensitivity, or hyperbolic product loss rate.

CONCLUSION

We report a series of novel OSAS-related sexual dimorphisms, concerning GAD65 auto-antibodies; polyneuropathy; atherogenic dyslipidemia [all increased in females]; diabetic retinopathy; North-Caucasian ethnicity; metabolic control; and TIA/stroke prevalence [all lower in females]. These findings raise challenging questions regarding the reciprocal pathophysiology between obstructive sleep disorders and cardiometabolic risk in T2DM.