Elevated anti-alpha-enolase antibody levels in Kawasaki disease

Antibodies and Immunity During Kawasaki Disease

The cause of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology studies support that an infectious disease is involved in at least starting the inflammatory cascade set off during KD. Clues from epidemiology support that humoral immunity can have a protective effect. However, the role of the immune system, particularly of B cells and antibodies, in pathogenesis of KD is still unclear. Intravenous immunoglobulin (IVIG) and other therapies targeted at modulating inflammation can prevent development of coronary aneurysms. A number of autoantibody responses have been reported in children with KD and antibodies have been generated from aneurysmal plasma cell infiltrates. Recent reports show that children with KD have similar plasmablast responses as other children with infectious diseases, further supporting an infectious starting point. As ongoing studies are attempting to identify the etiology of KD through study of antibody responses, we sought to review the role of humoral immunity in KD pathogenesis, treatment, and recovery.

B Cells and Antibodies in Kawasaki Disease

The etiology of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology supports a relationship of KD to an infectious disease. Several pathological mechanisms are being considered, including a superantigen response, direct invasion by an infectious etiology or an autoimmune phenomenon. Treating affected patients with intravenous immunoglobulin is effective at reducing the rates of coronary aneurysms. However, the role of B cells and antibodies in KD pathogenesis remains unclear. Murine models are not clear on the role for B cells and antibodies in pathogenesis. Studies on rare aneurysm specimens reveal plasma cell infiltrates. Antibodies generated from these aneurysmal plasma cell infiltrates showed cross-reaction to intracellular inclusions in the bronchial epithelium of a number of pathologic specimens from children with KD. These antibodies have not defined an etiology. Notably, a number of autoantibody responses have been reported in children with KD. Recent studies show acute B cell responses are similar in children with KD compared to children with infections, lending further support of an infectious disease cause of KD. Here, we will review and discuss the inconsistencies in the literature in relation to B cell responses, specific antibodies, and a potential role for humoral immunity in KD pathogenesis or diagnosis.

Epilepsy associated with systemic autoimmune disorders

Systemic autoimmune disorders affect multiple organ systems. Brain involvement commonly causes seizures, which may be the presenting symptom. Systemic lupus erythematosus, Sjorgren's syndrome, Wegener's granulomatosis, sarcoidsosis, celiac disease, Crohn's disease, Behcet's, and Hashimoto's encephalopathy are reviewed. Mechanisms underlying CNS pathology in systemic autoimmune disorders-and specifically factors predisposing these patients-are discussed, including vascular disease (e.g., prothrombotic state, anticardiolipin antibody, emboli, vasculitis), antineuronal antibodies, immune complexes, cytokines, metabolic disorders, infection, and therapy. Diagnostic and therapeutic strategies must be individualized for both the disorder and the patient. Systemic autoimmune disorders affect multiple organ systems and frequently involve the central and peripheral nervous systems. Seizures are among the most common neurological manifestation and occasionally can be the presenting symptom. There are many causes of seizures in systemic autoimmune disorders (Table 1), and the first clinical challenge is to determine not only the cause but also the significance of seizures. In some cases, they are clues to metabolic or infectious disorders or medication toxicity; in other cases, seizures herald a life-threatening progression of the underlying illness.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF- κ B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.

Steroid-responsive thalamic lesions accompanying microbleeds in a case of Hashimoto's encephalopathy with autoantibodies against α-enolase

A 67-year-old man receiving antithrombotic therapy developed rapidly progressive amnesia. T2-weighted images of brain MRI revealed hyperintense lesions in the bilateral thalami accompanied by microbleeds. Antithyroglobulin antibodies and autoantibodies against the N-terminal of α-enolase (NAE) were identified in the patient's serum; therefore, Hashimoto's encephalopathy (HE) was suspected. Although the patient's radiological findings improved following steroid therapy, his symptoms did not improve, possibly due to increased thalamic microbleeds. Because anti-NAE antibodies are possibly associated with vasculitis, HE accompanied by anti-NAE antibodies may be exacerbated by microbleeds in patients receiving antithrombotic therapy.

Elevated Serum Levels of IL-21 in Kawasaki Disease

Purpose

The serum level of immunoglobulin (Ig)E has been reported to be elevated in patients with Kawasaki disease (KD). We investigated whether interleukin (IL)-21, rather than IL-4, could be related to elevated serum levels of IgE in KD.

Methods

Sera from 48 patients with KD and 12 controls with high fever were collected to determine the level of IgE using an immunoassay system and the levels of IL-4 and IL-21 were determined using enzyme-linked immunosorbent assay kits.

Results

The median IL-21 level of KD patients was significantly elevated, at 499.5 pg/mL (range: <62.5-1,544 pg/mL), whereas that of controls was <62.5 pg/mL (<62.5-825 pg/mL; P<0.001). The median IL-4 level of KD patients was not elevated (4.0 pg/mL; 2.1-7.6 pg/mL). The median level of total IgE in KD patients was 58.0 IU/mL (5-1,109 IU/mL). No statistically significant correlation was found between IL-21 and total IgE levels (Spearman's R=0.2; P=0.19).

Conclusions

Patients with KD have elevated levels of IL-21 in the serum. IL-21 may play a role in the pathogenesis of KD.

CD40 Gene polymorphisms associated with susceptibility and coronary artery lesions of Kawasaki disease in the Taiwanese population

BACKGROUND

Kawasaki disease (KD) is characterized by systemic vasculitis of unknown etiology. Our previous studies showed expression of CD40 ligand on CD4+ T cells correlated to the coronary artery lesion (CAL) and disease progress in KD. Other studies from Japan suggested the role of CD40L in the pathogenesis of CAL, and this might help explain the excessive number of males affected with KD but cannot be reproduced by Taiwanese population. This study was conducted to investigate the CD40 polymorphism in KD and CAL formation.

METHODS

A total of 950 subjects (381 KD patients and 569 controls) were investigated to identify 2 tagging single-nucleotide polymorphisms (tSNPs) of CD40 (rs4810485 and rs1535045) by using the TaqMan allelic discrimination assay.

RESULTS

A significant association was noted with regards to CD40 tSNPs (rs1535045) between controls and KD patients (P = 0.0405, dominant model). In KD patients, polymorphisms of CD40 (rs4810485) showed significant association with CAL formation (P = 0.0436, recessive model). Haplotype analysis did not yield more significant results between polymorphisms of CD40 and susceptibility/disease activity of KD.

CONCLUSIONS

This study showed for the first time that polymorphisms of CD40 are associated with susceptibility to KD and CAL formation, in the Taiwanese population.

Hashimoto's encephalopathy: neuropsychological findings

Hashimoto encephalopathy (HE) is a rare and often reversible neurological syndrome associated with autoimmune thyroiditis and steroid-responsiveness. This syndrome includes behavioral symptoms like delusions and delirium, mood disturbances, epilepsy, progressive cognitive impairment and alteration of vigilance and consciousness with confused state until coma. Two subtypes of clinical presentation are described: ictal onset with seizures and stroke like episode and insidious onset with progressive dementia. The pathogenesis is uncertain; several theories have been proposed: autoimmune, vasculitic and demyelinating. Here, we report the case of a patient with HE who was submitted to exhaustive neuropsychological exams in the premorbid and the acute phase, and following resolution of the acute phase. After the initial confusional state resolved, results of the neuropsychological exams revealed a diffuse pattern of cognitive impairment that eventually evolved toward a selective deficit in executive functions. This pattern of cognitive impairment suggests that, after an initial phase characterized by diffuse brain involvement, our patient was primarily affected by frontal lobe sufferance.

Multidimensional degradomics identifies systemic autoantigens and intracellular matrix proteins as novel gelatinase B/MMP-9 substrates

The action radius of matrix metalloproteinases or MMPs is not restricted to massive extracellular matrix (ECM) degradation, it extends to the proteolysis of numerous secreted and membrane-bound proteins. Although many instances exist in which cells disintegrate, often in conjunction with induction of MMPs, the intracellular MMP substrate repertoire or degradome remains relatively unexplored. We started an unbiased exploration of the proteolytic modification of intracellular proteins by MMPs, using gelatinase B/MMP-9 as a model enzyme. To this end, multidimensional degradomics technology was developed by the integration of broadly available biotechniques. In this way, 100-200 MMP-9 candidate substrates were isolated, of which 69 were identified. Integration of these results with the known biological functions of the substrates revealed many novel MMP-9 substrates from the intracellular matrix (ICM), such as actin, tubulin, gelsolin, moesin, ezrin, Arp2/3 complex subunits, filamin B and stathmin. About 2/3 of the identified candidates were autoantigens described in multiple autoimmune conditions and in cancer (e.g. annexin I, nucleolin, citrate synthase, HMGB1, alpha-enolase, histidyl-tRNA synthetase, HSP27, HSC70, HSP90, snRNP D3). These findings led to the insight that MMPs and other proteases may have novel (immuno)regulatory properties by the clearance of toxic and immunogenic burdens of abundant ICM proteins released after extensive necrosis. In line with the extracellular processing of organ-specific autoantigens, proteolysis might also assist in the generation of immunodominant 'neo-epitopes' from systemic autoantigens. The study of proteolysis of ICM molecules, autoantigens, alarmins and other crucial intracellular molecules may result in the discovery of novel roles for proteolytic modification.

Hashimoto's encephalopathy

Hashimoto's encephalopathy (HE) is a controversial neurological disorder that comprises a heterogenous group of neurological symptoms that manifest in patients with high titers of antithyroid antibodies. Clinical manifestations of HE may include encephalopathic features such as seizures, behavioral and psychiatric manifestations, movement disorders, and coma. Although it has been linked to cases of Hashimoto's thyroiditis or thyroid dysfunction, the most common immunological feature of HE is the presence of high titers of antithyroglobulin or anti-TPO (antimicrosomal) antibodies. At present, it is unclear whether antithyroid antibodies represent an immune epiphenomenon in a subset of patients with encephalopathic processes or they are really associated with pathogenic mechanisms of the disorder. The significance of classifying encephalopathies under the term HE will be determined in the future once the relevance of the role of antithyroid antibodies is demonstrated or dismissed by more detailed experimental and immunopathological studies. The responsiveness of HE to steroids or other therapies such as plasmapheresis supports the hypothesis that this is a disorder that involves immune pathogenic mechanisms. Further controlled studies of the use of steroids, plasmapheresis, or immunosuppressant medications are needed in the future to prove the concept of the pathogenic role of antithyroid antibodies in HE.