Disturbance in the serum IgG subclass distribution in patients with anti-Hu positive paraneoplastic neurological syndromes

Immune Mechanisms in Epileptogenesis: Update on Diagnosis and Treatment of Autoimmune Epilepsy Syndromes

Seizures and epilepsy can result from various aetiologies, yet the underlying cause of several epileptic syndromes remains unclear. In that regard, autoimmune-mediated pathophysiological mechanisms have been gaining attention in the past years and were included as one of the six aetiologies of seizures in the most recent classification of the International League Against Epilepsy. The increasing number of anti-neuronal antibodies identified in patients with encephalitic disorders has contributed to the establishment of an immune-mediated pathophysiology in many cases of unclear aetiology of epileptic syndromes. Yet only a small number of patients with autoimmune encephalitis develop epilepsy in the proper sense where the brain transforms into a state where it will acquire the enduring propensity to produce seizures if it is not hindered by interventions. Hence, the term autoimmune epilepsy is often wrongfully used in the context of autoimmune encephalitis since most of the seizures are acute encephalitis-associated and will abate as soon as the encephalitis is in remission. Given the overlapping clinical presentation of immune-mediated seizures originating from different aetiologies, a clear distinction among the aetiological entities is crucial when it comes to discussing pathophysiological mechanisms, therapeutic options, and long-term prognosis of patients. Moreover, a rapid and accurate identification of patients with immune-mediated epilepsy syndromes is required to ensure an early targeted treatment and, thereby, improve clinical outcome. In this article, we review our current understanding of pathogenesis and critically discuss current and potential novel treatment options for seizures and epilepsy syndromes of underlying or suspected immune-mediated origin. We further outline the challenges in proper terminology.

Blood biomarker for Parkinson disease: peptoids

Parkinson disease (PD) is the second most common neurodegenerative disease. Because dopaminergic neuronal loss begins years before motor symptoms appear, a biomarker for the early identification of the disease is critical for the study of putative neuroprotective therapies. Brain imaging of the nigrostriatal dopamine system has been used as a biomarker for early disease along with cerebrospinal fluid analysis of α-synuclein, but a less costly and relatively non-invasive biomarker would be optimal. We sought to identify an antibody biomarker in the blood of PD patients using a combinatorial peptoid library approach. We examined serum samples from 75 PD patients, 25 de novo PD patients, and 104 normal control subjects in the NINDS Parkinson’s Disease Biomarker Program. We identified a peptoid, PD2, which binds significantly higher levels of IgG3 antibody in PD versus control subjects (P<0.0001) and is 68% accurate in identifying PD. The PD2 peptoid is 84% accurate in identifying de novo PD. Also, IgG3 levels are significantly higher in PD versus control serum (P<0.001). Finally, PD2 levels are positively correlated with the United Parkinson’s Disease Rating Scale score (r=0.457, P<0001), a marker of disease severity. The PD2 peptoid may be useful for the early-stage identification of PD, and serve as an indicator of disease severity. Additional studies are needed to validate this PD biomarker.

Immunopathogenesis of paraneoplastic neurological syndromes associated with anti-Hu antibodies: A beneficial antitumor immune response going awry

Paraneoplastic neurological disorders (PNDs) are syndromes that develop in cancer patients when an efficient antitumor immune response, directed against antigens expressed by both malignant cells and healthy neurons, damages the nervous system. Herein, we analyze existing data on the mechanisms of loss of self tolerance and nervous tissue damage that underpin one of the most frequent PNDs, the anti-Hu syndrome. In addition, we discuss future directions and propose potential strategies aimed at blocking deleterious encephalitogenic immune responses while preserving the antineoplastic potential of treatment.

Autoantibody profiling for cancer detection

Despite substantial progress in the understanding of the pathogenesis of cancer, the development and implementation of strategies for early cancer detection have lagged behind. Harnessing the immune response to tumor antigens is particularly useful for early detection because the immune response occurs early during tumor development and affords signal amplification with the end product, namely reactive immunoglobulins, being released into the circulation allowing easy access through the blood. This article presents recent developments in autoantibody profiling with a focus on proteomic approaches and applications to lung cancer.

Antibodies against 9-O-acetylated sialoglycans: a potent marker to monitor clinical status in childhood acute lymphoblastic leukemia

BACKGROUND

Although childhood acute lymphoblastic leukemia (ALL) is highly responsive to chemotherapy, reliable techniques are needed to determine treatment outcome and predict impending relapse. In ALL, the cell surface over expression of 9-O-acetylated sialoglycans (9-OAcSGs) on lymphoblasts and concomitant high antibody titers in patients' sera was reported.

OBJECTIVES

The present study was aimed to evaluate whether anti-9-OAcSG titers can be harnessed to monitor the clinical outcome of ALL.

DESIGN AND METHODS

Anti-9-OAcSGs were analyzed by ELISA in children receiving either UK ALL X (n = 69, Group I) in India or UK ALL 97 (n = 47, Group II) in UK along with age-matched normal healthy controls at different time points over a period of >2 years. An attempt was also made to investigate subclass distribution of disease-specific IgG. Moreover, 17 patients having a higher sample size were longitudinally monitored.

RESULTS

Antibody levels were raised at disease presentation, decreased with remission induction, and importantly, reappeared with clinical relapse. Sera from patients with other hematological disorders and normal controls showed negligible levels of circulating anti-9-OAcSGs. In patients of both Groups I and II, the assay showed high sensitivity (98.92% and 96.77%) and specificity (92.1% and 95.91%), respectively. IgG subclass analyses during different phases of treatment revealed that 9-OAcSG-specific IgG(1) could serve as a better prognostic marker in ALL.

CONCLUSIONS

This study demonstrated the potential of this disease-specific antibody as an alternate marker in diagnosis and long-term assessment of ALL patients, suggesting its application in detection and prediction of impending relapse. Therefore, the expression of anti-9-OAcSGs, irrespective of their treatment protocol, may serve as an economical yet effective index for monitoring of childhood ALL.

Type 1 diabetes alters anti-hsp90 autoantibody isotype

The 90-kDa chaperon family includes heat shock protein (hsp) 90 and glucose-regulated protein (grp) 94. These proteins play an important role in normal cellular architecture, in the etiology of some autoimmune and infectious diseases and in antigen presentation to T cells. Owing to its role in autoimmunity, we explored anti-hsp90 autoantibody (hsp90AA) response in the sera of persons with type 1 diabetes, first-degree relatives (FDR) and in normal subjects. Significant high level of hsp90AA was found in FDR, but there was no significant difference between the normal and diabetic persons. The IgG1 and IgG3 isotypes of hsp90AA were higher in persons with type 1 diabetes and FDR than in normal subjects. We found a good correlation between hsp90AA measured by ELISA and RIA. A positive correlation between serum hsp90AA and glutamic acid decarboxylase (GAD65) autoantibody (GAA) was also observed. Hsp90AA positive sera from diabetic persons immunoblotted recombinant hsp90, GAD65 and corresponding proteins in islet lysates. Our study suggests that hsp90AA are present in normal, FDR and diabetic persons. However, there is a higher level of IgG1 and IgG3 isotypes of hsp90AA in FDR and type 1 diabetic subjects. Thus, autoimmunity leading to type 1 diabetes significantly alters the autoantibody isotype to autoantigens, such as hsp90.