Frequency of C-peptide and antibody levels (anti GAD, Islet cell antibodies, insulin auto antibodies) in children of Pakistan with Type-1 diabetes.

Background and Objective: The autoimmune mechanism in T1DM causes gradual loss of pancreatic ß-cell, which progresses to hyperglycemia and ultimate reliance on consistent insulin therapy. T1DM has been the commonest type of diabetes in children and this study will help in refining indulgent towards the problem and its pathophysiology in our people. The objective was to find out the prevalence of C-peptide and antibody levels (anti GAD, ICA, IAA and IA2) in children and adolescents of Pakistan with T1DM. Methods: We conducted this cross-sectional study at Department of Pediatric Endocrinology, National Institute of Child Health, Karachi between August 2019 to February 2020 and included 98 children who had T1DM for more than one month. Subjects whose GFR was <30ml/min were omitted from the study. Among those registered subjects, C-peptide, human islet cell antibody (ICA), insulin auto antibodies (IAA) and anti-glutamic acid decarboxylase were assessed. Demographical and laboratorial facts were noted on a pre-constructed proforma. Results: There were 77(78.3%) cases who had level of C-peptide <0.8 and anti-GAD was found in 47(48%) subjects. 35(35.7%) cases found positive for IA2 .and 7(7.1%) patients had insulin auto antibodies positive while ICA was negative in total 98(100%) subjects. Conclusion: Children with T1 DM possessed increased levels of anti-GAD antibodies, insulin autoantibodies and anti (IA2) but islet cells antibodies were negligible in our population when checked at a point of time. C-peptide may be normal in some, but its level declines with long duration of diabetes in children.

Analytical evaluation of a GAD65 antibodies chemiluminescence immunoassay for CSF in neurological syndromes.

OBJECTIVES: Antibodies against glutamic acid decarboxylase isoform 65 (GAD-Ab) have been found in different severe neurological conditions associated with altered synthesis of γ-aminobutyric acid (GABA). Serum GAD-Ab can be found in up to 90 % of patients with type 1 diabetes mellitus (T1DM), mostly at relatively low concentrations, while high concentrations of GAD-ab are thought to be more frequently associate to a neurological condition, with levels 100-folds higher than those found in T1DM. Although CSF testing is recommended when suspecting a GAD-associated neurological syndrome, no commercial immunoassay is validated for this use and no cut-off is internationally recognized to support the diagnosis. METHODS: In this study we validated CSF testing of GAD-Ab on an automated chemiluminescence (CLIA) immunoassay that had previously shown good agreement with ELISA on serum. RESULTS: We tested 43 CSF from patients with typical GAD-associated neurological disorders and patients with other neurological conditions, identifying a clinical cut-off of 18 kIU/L that discriminated GAD-disease with an area under the curve (AUC) of 0.921. CLIA showed good analytical performances on repeatability and recovery tests in CSF and confirmed an excellent agreement with ELISA. CONCLUSIONS: GAD-Ab associated neurological disorders are rare but CSF testing for GAD-Ab is a common request for neurologists when suspecting an insidious autoimmune central nervous system disease. CLIA platforms are expected to be increasingly adopted in clinical laboratories due to their flexibility and reliability, therefore studies on decisional levels should be implemented for improving the interpretation and utilization of laboratory data.

Is Non-Stimulated C-Peptide at Diagnosis a Good Predictive Value for Insulin Use at Two Years after Diagnosis in Pediatric Diabetic Patients?

Background and Objectives: Insulin treatment may be initially required to stabilize patients presenting with metabolic crisis at type 1 and 2 diabetes mellitus (DM) onset. Some patients with type 2 DM may need persistent insulin treatment. This study aimed to examine the predictive performance of non-stimulated C-peptide level at the time of diagnosis for future insulin use in pediatric diabetic patients. Materials and Methods: We reviewed the medical charts of diabetic patients aged 18 years or younger in a medical center in southern Taiwan from January 2000 to December 2019. Clinical and individual data were collected at the time of DM diagnosis. Outcomes were persistent insulin use at the time of diagnosis, as well as at one and two years after diagnosis. Results: The final analysis included a total of 250 patients. The best cut-off point of non-stimulated C-peptide was 0.95 ng/mL, and the predictive indices for the insulin use were 0.84 for sensitivity and 0.94 for specificity at two years after DM diagnosis. Incorporating age at onset and presence of GAD antibodies can further increase the predictive power of non-stimulated C-peptide. Conclusions: The value of non-stimulated C-peptide at diabetic onset was feasible and effective for predicting future insulin treatment up to the time point of two years after diagnosis.

The neurological syndromes associated with glutamic acid decarboxylase antibodies.

A number of neurological syndromes have been described in patients with positive serum antibodies (Abs) against the enzyme glutamic acid decarboxylase (GAD), the rate limiting step in the synthesis of GABA (γ-aminobutyric acid). These disorders include: classical stiff-person syndrome and variants, cerebellar ataxia, limbic and extra-limbic encephalitis, nystagmus/oculomotor dysfunction, drug-resistant epilepsy, paraneoplastic stiff-person syndrome and progressive encephalopathy with rigidity and myoclonus (PERM), the latter two are mainly related to amphiphysin and the glycine receptor Abs respectively; but patients may also have positive GAD-Abs. Although observations are consistent with an autoimmune response in these patients and there is evidence of GABAergic dysfunction in some cases; the pathogenic role of GAD-Abs in the nervous system has not been clarified and it is a matter of debate. The diagnosis of these syndromes is based on clinical grounds plus the presence of GAD-Abs in serum and CSF with demonstration of intrathecal secretion. Although some presentations may be negative for GAD-Abs, such as stiff-person syndrome; positive GAD-Abs are required for the diagnosis in patients with cerebellar ataxia, encephalitis, and epilepsy. Immunotherapy is required for most patients. Intravenous immunoglobulins, oral or IV steroids and plasma exchange are considered the first line options, aimed to induce remission, but chronic immunosuppression is usually required. Symptomatic therapy should also be provided, aimed to control muscle spasms, seizures, delirium, etc. Prognosis varies among patients; but it is considered intermediate between that of patients with neurological syndromes associated with neural Abs against membrane antigens and those with onconeural Abs.

Stiff Person Syndrome and Type 1 Diabetes Mellitus: a Case of the Chicken or the Egg?

Anti-glutamic acid decarboxylase (anti-GAD) antibodies are linked with both autoimmune diabetes and the rare neurological disorder stiff person syndrome (SPS). SPS is an uncommon autoimmune-mediated condition characterized by painful episodic spasms and progressive muscle rigidity. We present the case of a 23-year-old non-diabetic, insulin-naïve woman with known SPS who was hospitalized for SPS-related symptomatology. The patient quickly developed type 1 diabetes mellitus (T1DM) with unexpectedly large insulin requirements. To our knowledge, there are no other reports describing rapid T1DM development during an acute hospitalization for SPS and fewer than 5 case reports describing the association of SPS with extreme insulin resistance. Our case highlights the key clinical features, pathology, and pathogenesis of both SPS and T1DM and explores the relationship between the two disease processes.

Characterisation of rapid progressors to type 1 diabetes among children with HLA-conferred disease susceptibility.

AIMS/HYPOTHESIS: In this study, we aimed to characterise rapid progressors to type 1 diabetes among children recruited from the general population, on the basis of HLA-conferred disease susceptibility. METHODS: We monitored 7410 HLA-predisposed children participating in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study for the development of beta cell autoimmunity and type 1 diabetes from birth over a median follow-up time of 16.2 years (range 0.9-21.1 years). Islet cell antibodies (ICA) and autoantibodies to insulin (IAA), GAD (GADA) and islet antigen 2 (IA-2A) were assessed as markers of beta cell autoimmunity. Rapid progression was defined as progression to clinical type 1 diabetes within 1.5 years of autoantibody seroconversion. We analysed the association between rapid progression and demographic and autoantibody characteristics as well as genetic markers, including 25 non-HLA SNPs predisposing to type 1 diabetes. RESULTS: Altogether, 1550 children (21%) tested positive for at least one diabetes-associated autoantibody in at least two samples, and 248 (16%) of seroconverters progressed to type 1 diabetes by the end of 2015. The median time from seroconversion to diagnosis was 0.51 years in rapid progressors (n = 42, 17%) and 5.4 years in slower progressors. Rapid progression was observed both among young (<5 years) and early pubertal children (>7 years), resulting in a double-peak distribution of seroconversion age. Compared with slower progressors, rapid progressors had a higher frequency of positivity for multiple (≥2) autoantibodies and had higher titres of ICA, IAA and IA-2A at seroconversion, and there was a higher prevalence of the secretor genotype in the FUT2 gene among those carrying the high-risk HLA genotype. Compared with autoantibody-positive non-progressors, rapid progressors were younger, were more likely to carry the high-risk HLA genotype and a predisposing SNP in the PTPN22 gene, had higher frequency of ICA, IAA, GADA and IA-2A positivity and multipositivity, and had higher titres of all four autoantibodies at seroconversion. CONCLUSIONS/INTERPRETATION: At seroconversion, individuals with rapid progression to type 1 diabetes were characterised by a younger age, higher autoantibody titres, positivity for multiple autoantibodies and higher prevalence of a FUT2 SNP. The double-peak profile for seroconversion age among the rapid progressors demonstrates for the first time that rapid progression may take place not only in young children but also in children in early puberty. Rapid progressors might benefit from careful clinical follow-up and early preventive measures.

Post-ganglionic autonomic neuropathy associated with anti-glutamic acid decarboxylase antibodies.

PURPOSE: Antibodies to glutamic acid decarboxylase (GAD-Abs) have been associated with several conditions, rarely involving the autonomic nervous system. Here, we describe two patients complaining of autonomic symptoms in whom a post-ganglionic autonomic neuropathy has been demonstrated in association with significantly elevated serum and CSF GAD-Abs levels. METHODS: Patients underwent nerve conduction studies, sympathetic skin response testing, evaluation of autonomic control of the cardiovascular system and skin biopsy. Also, serum screening to exclude predisposing causes of peripheral neuropathy was performed. Anti-GAD65 antibodies were evaluated in serum and CSF. RESULTS: GAD-Abs titer was increased in both serum and CSF in both patients. Sympathetic skin response was absent and skin biopsy revealed a non-length-dependent small-fiber neuropathy with sympathetic cholinergic and adrenergic post-ganglionic damage in both patients. Nerve conduction studies and evaluation of autonomic control of the cardiovascular system were normal in both patients. Both patients were treated with steroids with good, but partial, (patient 2) recovery of the autonomic dysfunctions. CONCLUSIONS: Although the pathophysiological mechanisms involved are not fully defined, GAD-abs positivity in serum and CSF should be searched in patients with autonomic neuropathy when no other acquired causes are evident. This positivity may help to clarify autoimmune etiology and, subsequently, to consider immunomodulatory treatment.

Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias.

In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia associated with anti-GAD antibodies, the cerebellar type of Hashimoto's encephalopathy, primary autoimmune cerebellar ataxia, gluten ataxia, Miller Fisher syndrome, ataxia associated with systemic lupus erythematosus, and paraneoplastic cerebellar degeneration. Humoral mechanisms, cell-mediated immunity, inflammation, and vascular injuries contribute to the cerebellar deficits in immune-mediated cerebellar ataxias.

The Effect of Corticosteroid Withdrawal on Glucose Metabolism and Anti-GAD Antibodies in Simultaneous Pancreas-Kidney Transplant Patients.

CONTEXT: Corticosteroid withdrawal may reduce insulin resistance; however, it could also influence pancreatic autoantibody profile in simultaneous pancreas-kidney (SPK) transplant patients. OBJECTIVE: To evaluate the effect of corticosteroid withdrawal on glucose metabolism and anti-glutamic acid decarboxylase (GAD) antibody titers in SPK patients with type 1 diabetes after 12 months of follow-up. DESIGN: In this retrospective study, fasting glucose and glycated hemoglobin (A1c) were compared before and after 3, 6, and 12 months of corticosteroid withdrawal in 80 SPK patients. In addition, weight, anti-GAD, and C-peptide levels were compared before and after withdrawal. Finally, fasting and postglucose, insulin, and C-peptide levels were compared before and after withdrawal in 25 patients undergoing oral glucose tolerance test (OGTT). RESULTS: Fasting glucose levels did not change during corticosteroid discontinuation. After 12 months, A1c slightly increased from 4.6% (0.4%) to 4.8% (0.6%) (P < .01) and C-peptide decreased from 2.8 (1.1) ng/mL to 2.4 (1.3) ng/mL (P <. 01). In patients submitted to OGTT, glucose, insulin, and C-peptide levels did not change. There was no alteration in the proportion of anti-GAD positive tests (41% vs 45%). Anti-GAD titers remained stable or decreased in 70% of positive patients. CONCLUSION: Corticosteroid withdrawal has no significant effect on glucose metabolism and on anti-GAD profile among SPK patients.

Stiff-person syndrome in association with Hashimoto's thyroiditis: a case report.

Stiff-person syndrome (SPS) is a rare neurological disorder characterized by chronic and progressive axial muscle rigidity and paroxysmal painful muscle spasms. The present case study described an SPS patient (increased anti-GAD65 antibody in serum and cerebrospinal fluid) with co-occurring Hashimoto's thyroiditis and decreased C3 complement levels. The clinical presentation, diagnostic approach, and treatment employed for this unique case were comprehensively described in detail. In this case, we comprehensively presented a case of SPS with co-occurring Hashimoto's thyroiditis and an associated decrease in serum C3 complement, as well as a discussion on the current data on this topic.

Elevated IL-6 plasma levels are associated with GAD antibodies-associated autoimmune epilepsy.

Background: Antibodies against glutamic acid decarboxylase (GADA) are present in multiple neurological manifestations, such as stiff-person syndrome, cerebellar ataxia, limbic encephalitis, and epilepsy. Increasing data support the clinical significance of GADA as an autoimmune etiology of epilepsy, however, there is not yet definitive evidence to confirm the pathogenic link between GADA and epilepsy. Objective: Interleukin-6 (IL-6), a pro-convulsive and neurotoxic cytokine, and interleukin-10 (IL-10), an anti-inflammatory and neuroprotective cytokine, are crucial inflammatory mediators in the brain. Increased production of IL-6 and its association with epileptic disease profiles are well established, suggesting the presence of chronic systemic inflammation in epilepsy. Therefore, in this study, we investigated the association of plasma cytokine concentrations of IL-6 and IL-10 and their ratio with GADA in patients with drug-resistant epilepsy. Methods: Interleukin-6 and IL-10 concentrations were measured by ELISA in plasma, and the IL-6/IL-10 ratio was calculated in a cross-sectional cohort of 247 patients with epilepsy who had their GADA titers measured previously for their clinical significance in epilepsy. Based on GADA titers, patients were grouped as GADA negative (n = 238), GADA low positive (antibody titers < 1,000 RU/mL, n = 5), and GADA high positive (antibody titers ≥ 1,000 RU/mL, n = 4). Results: Median IL-6 concentrations were significantly higher in patients with high GADA positivity [2.86 pg/mL, interquartile range (IQR) = 1.90-5.34 pg/mL] than in GADA-negative patients [1.18 pg/mL, interquartile range (IQR) = 0.54-2.32 pg/mL; p = 0.039]. Similarly, IL-10 concentrations were also higher in GADA high-positive patients [1.45 pg/mL, interquartile range (IQR) = 0.53-14.32 pg/mL] than in GADA-negative patients [0.50 pg/mL, interquartile range (IQR) = 0.24-1.00 pg/mL], however, the difference was not statistically significant (p = 0.110). Neither IL-6 nor IL-10 concentrations were different between GADA-negative and GADA low-positive patients (p > 0.05) or between GADA low-positive or GADA high-positive patients (p > 0.05). The IL-6/IL-10 ratio was also similar among all the study groups. Conclusion: Increased circulatory concentrations of IL-6 are associated with high GADA titers in patients with epilepsy. These data provide additional pathophysiological significance of IL-6 and help to further describe the immune mechanisms involved in the pathogenesis of GADA-associated autoimmune epilepsy.

Late-onset stiff-person syndrome: challenges in diagnosis and management.

Background: Stiff person syndrome (SPS) is a rare slowly progressive autoimmune neuronal hyperexcitability disease with very-high GAD-65 antibody titers that most commonly presents above the age of 20, with muscle stiffness, painful muscle spasms, slow gait, and falls leading to disability. In other autoimmune disorders, late-onset disease has different symptom-spectrum and outcomes, but there is no information regarding late-onset SPS (LOSPS). Objective: Highlight delayed diagnosis and poor tolerance or incomplete response to therapies of patients with LOSPS and outline how best to increase disease awareness early at onset. Design A retrospective chart reviewMethods: We reviewed GAD-positive SPS patients with symptom onset above age 60, identified among 54 SPS patients, examined, treated and followed-up by the same clinicians, focused on clinical presentation, misdiagnoses, response and tolerance to therapies, and evolved disability. Results: Nine patients had LOSPS with symptom onset at median age of 61 years (range 60-78), and current median age of 73. The median time from symptom onset to SPS diagnosis was 3 years; prior to diagnosis, five patients were treated for lumbosacral radiculopathies (one with laminectomy), two for Parkinson's disease, one for multiple sclerosis, and another for cerebellar degeneration. Progressive decline occurred rapidly in all patients; at time of diagnosis, six patients were already using a cane or walker and two were wheelchair-bound. Tolerance and response to treatment were limited; two patients did not respond to IVIg, two discontinued IVIg despite early response due to comorbidities (cardiac disease, thrombosis), four others partially responded to IVIg and one to rituximab; several could not tolerate high doses of oral antispasmodics due to somnolence; and two patients died. Conclusions: LOSPS is almost always misdiagnosed for other similar conditions commonly seen in the elderly. Patients with LOSPS decline quickly to clinically severe disease due to delayed treatment initiation, poor response or tolerance, other comorbidities, and possibly immunosenescence. Increased awareness that SPS can occur in the elderly mimicking other disorders is important for early diagnosis and treatment, even necessitating earlier immunotherapy initiation, compared to their younger counterparts, to prevent faster-evolving severe disability.

Celiac And Autoimmune Thyroid Disease In Patients With Anti-Gad Positive Type-1 Diabetes Mellitus.

BACKGROUND: Type-1 diabetes mellitus (T1DM) and autoimmune thyroid disease can occur concomitantly and patients with TIDM have a high risk of other autoimmune conditions like thyroid disease and celiac disease. This study aimed to analyze the association of anti-GAD positive T1DM with anti-thyroid antibodies and celiac disease. METHODS: This cross-sectional study was conducted at the Department of Paediatric Endocrinology & Diabetes, National Institute of Child Health, Karachi Pakistan from July 2022 to December 2022. A total of 115 children of both genders aged between 1-18 years having known T1DM were analyzed. Children with chronic kidney disease or chronic liver disease were excluded. Those children were also not included whose parents/caregivers did not wish their children to be part of this research. The blood sample of each child was taken in a sterilized container and sent to an institutional laboratory for biochemical investigations. RESULTS: In a total of 115 patients, 67 (58.3%) were female and 48 (41.7%) males. The mean age was 8.87±3.43 (ranging between 1.5-17 years). The mean HbA1c was 11.86±7.31%. It was found that anti-GAD IgG was having signification association with celiac disease (p<0.001). Significant correlation of anti-GAD positive antibodies with Ttg-IgG antibodies (correlation coefficient=0.303, p=0.001), thyroid peroxidase antibodies (correlation coefficient=0.228, p=0.001). CONCLUSIONS: High proportions of children with anti-GAD positive T1DM patients were found to have thyroid disorders and celiac disease. A significant correlation was found between anti-GAD positive antibodies, celiac disease and anti-thyroglobulin antibodies.

Autoimmune Encephalitis With Autoimmune Diabetes: A Case of Horror Autotoxicus.

Diagnosing autoimmune encephalitis relies on clinical, radiological, and serological studies. Several autoantibodies have been implicated and recognized, with dozens of potential targets identified in the past 20 years. Despite that progress, some patients with encephalitis present a diagnostic dilemma with a seronegative status. The presence of other autoimmune diseases in a patient with encephalitis should provide a clue to the autoimmune nature of a developing neurological syndrome (cognitive, psychiatric, behavioral, and catatonia). In this report, we describe the case of a young man with type 1 diabetes mellitus who was diagnosed with seronegative autoimmune encephalitis after presenting with catatonia. We describe the lengthy clinical course, the various therapeutic trials, and his clinical outcome and response to B-cell depleting agent. This study also discusses the potential pathophysiologic pathways, providing a rationale for the diagnostic workup and therapeutic options for autoimmune encephalopathy in this case presentation.

Spontaneous Downbeat Nystagmus in Anti-GAD-Antibody-Associated Paraneoplastic Syndrome.

Spontaneous downbeat nystagmus and ocular flutter are rare clinical signs. Such findings are commonly related to cerebellar pathology, predominantly ischemia. In a significant percentage of patients, the cause may not be found. If these signs are associated with ataxia, cognitive decline, and seizure, anti-glutamic acid decarboxylase-associated neurological syndrome must be suspected. Background history of tumor has to be enquired. Treatment with immune modulation helps in partial recovery of such cases.

Brachial monomelic amyotrophy as an initial manifestation of stiff person syndrome.

Stiff person syndrome (SPS) is characterized by rigidity of truncal and proximal muscles. The presence of abdominal and paraspinal rigidity is a defining clinical feature of SPS. It is rarely associated with the lower motor neuron (LMN) features. We report a patient with SPS whose initial clinical presentation was that of brachial monomelic amyotrophy (BMA). A 24-year-old gentleman presented with a history of the left upper limb wasting and weakness. In addition, he reported stiffness of the lower limbs and abdomen while walking. On examination, patient had left upper limb monomelic amyotrophy and hypertonia, exaggerated deep tendon reflexes in all four limbs. He also had abdominal and paraspinal rigidity. Serum was strongly positive for GAD 65 antibodies suggestive of SPS. Patient showed dramatic improvement to immunomodulation. Patient presented with features of BMA. Symptoms related to SPS were mild. Abdominal rigidity was the clue to the diagnosis. LMN features have been reported previously in stiff person plus syndrome with an atypical course and progressive encephalomyelitis with myoclonus and rigidity, but not in classical SPS.

Brain FDG-PET findings in glutamic acid decarboxylase antibody-associated epilepsy.

BACKGROUND AND PURPOSE: Glutamic acid decarboxylase antibodies (GAD-Ab) are sometimes associated with chronic drug-resistant focal epilepsy. Clinically, it may manifest as mesial temporal lobe epilepsy (mTLE), with GAD-Ab patients difficult to distinguish. Therefore, the aim of this study is to compare brain metabolism of patients with mTLE and high serum titers of GAD-Ab (>2000 UI/ml) to those with mTLE and hippocampal sclerosis (HS) and confirmed GAD-ab negativity. METHODS: Images from PET studies were normalized to an SPM 12 template. Voxel to voxel comparisons were made using a two-sample one-tailed t-test. RESULTS: In both patients with GAD-Ab and controls (mTLE-HS), hypometabolism in mesial temporal lobe areas was observed. When comparing the two groups, GAD-Ab patients had statistically significant reduced metabolism in both insulae and medial inferior frontal-hypothalamus area (p < 0.001). CONCLUSIONS: Hypometabolism in mesial temporal lobe areas together with hypometabolism in insulae and medial inferior frontal-hypothalamus may be characteristic of patients with epilepsy and GAD-ab. This PET pattern could be a useful diagnostic tool to identify GAD-Ab patients.

Pro- and anti-inflammatory response in neurological disorders associated to anti-glutamate decarboxylase antibodies.

Rare conditions showing psychiatric symptoms and movement disorders have been linked with the presence of anti-glutamate decarboxylase antibodies. Proinflammatory and antiinflammatory immune responses were assessed in patients with neurological disorders associated to anti-glutamic acid decarboxylase antibodies (NDGAD). Immunoregulatory and proinflammatory cell populations were quantified by flow cytometry. No polarization toward Th1, Th2, or Th17 phenotypes was observed in NDGAD patients. Immunoregulatory responses were significantly reduced for Breg, activated Treg, Tr1, and Th3 cells, suggesting a deficient regulatory response, while intermediate monocyte levels were increased. The reduced levels of regulatory T and B cells suggest an impairment in regulatory immune response, while intermediate monocytes could be playing a role in the increased proinflammatory response.