Clinical characteristics and genetic analysis of A20 haploinsufficiency.

PURPOSE: To evaluate the clinical and genetic characteristics of 3 children with Haploinsufficiency of A20 (HA20). METHODS: The clinical and genetic testing data of 3 children with HA20 treated at Capital Institute of Pediatrics (CIP) between August 2016 and October 2019 were retrospectively analysed. RESULT: Patient 1 presented with arthritis and inflammatory bowel disease, patient 2 presented with axial spinal arthritis and lupus-like syndrome, and patient 3 presented with recurrent oral ulcers, gastrointestinal ulcers, and perianal abscesses. Regarding laboratory tests, patients were found to have elevated white blood cell (WBC) count, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The CRP and ESR was reported to be high in all the patients. The WBC was reported to be high in patient 1 and 3. Patient 2 was positive for antinuclear antibodies, anti-Sjögren's syndrome antigen A, dsDNA, rheumatoid factor and Coombs test. Genetic testing showed that all three patients had heterozygous mutation in TNFAIP3 gene. As for the treatment, patient 1 was treated with TNFα antagonist, patient 2 was treated with TNF α antagonist and sulfasalazine, and patient 3 was treated with corticosteroids and thalidomide. Patients 1 and 2 were followed for four and 3 months, respectively. There was an improvement in joint and gastrointestinal symptoms; inflammatory indices and rheumatoid factor (RF) were normal, and dsDNA and Coombs test became negative. Patient 3 was treated at another hospital and showed gradual improvement in oral ulcers and perianal abscesses. CONCLUSION: HA20 is a single-gene auto-inflammatory disease caused by mutation in tumour necrosis factor (TNF)-α-induced protein 3 (TNFAIP3) gene. It may present as Behçet-like syndrome and resemble various other autoimmune diseases as well. Corticosteroids and immunosuppressive agents are effective treatments, and cytokine antagonists can be used in refractory cases. Whole-exome genetic testing should be proactively performed for children with early-age onset or Behçet-like syndrome to achieve early diagnosis and accurate treatment.

Oligoclonal IgG antibodies in multiple sclerosis target patient-specific peptides.

IgG oligoclonal bands (OCBs) are present in the cerebrospinal fluid (CSF) of more than 95% of patients with multiple sclerosis (MS), and are considered to be the immunological hallmark of disease. However, the target specificities of the IgG in MS OCBs have remained undiscovered. Nevertheless, evidence that OCBs are associated with increased levels of disease activity and disability support their probable pathological role in MS. We investigated the antigen specificity of individual MS CSF IgG from 20 OCB-positive patients and identified 40 unique peptides by panning phage-displayed random peptide libraries. Utilizing our unique techniques of phage-mediated real-time Immuno-PCR and phage-probed isoelectric focusing immunoblots, we demonstrated that these peptides were targeted by intrathecal oligoclonal IgG antibodies of IgG1 and IgG3 subclasses. In addition, we showed that these peptides represent epitopes sharing sequence homologies with proteins of viral origin, and proteins involved in cell stress, apoptosis, and inflammatory processes. Although homologous peptides were found within individual patients, no shared peptide sequences were found among any of the 42 MS and 13 inflammatory CSF control specimens. The distinct sets of oligoclonal IgG-reactive peptides identified by individual MS CSF suggest that the elevated intrathecal antibodies may target patient-specific antigens.

Autologous Hematological Stem Cell Transplantation for Systemic Sclerosis in Israel.

BACKGROUND: Autologous hematological stem cell transplantation (HSCT) is a novel therapy for systemic sclerosis (SSc) that has been validated in three randomized controlled trials. OBJECTIVES: To report the first Israeli experience with HSCT for progressive SSc and review the current literature. METHODS: Five SSc patients who were evaluated in our department and were treated by HSCT were included. Medical records were evaluated retrospectively. Demographic, clinical, and laboratory data were recorded. Continuous data are presented as the mean ± standard deviation. Categorical variables are presented as frequencies and percentages. RESULTS: Five SSc patients were treated with HSCT. Four patients were adults (mean age 53 ± 12 years) and one was a 12-year-old pediatric patient. All patients were female. HSCT was initiated 1.4 ± 0.8 years after diagnosis. Two patients were RNA POLIII positive, two were anti-topoisomerase 1 positive, and one only antinuclear antibodies positive. All patients had skin and lung involvement. The mean modified Rodnan Skin Score was 29 ± 4.7 before HSCT, which improved to 10.4 ± 9.6 after HSCT. The forced vital capacity improved from 68 ± 13% to 90 ± 28%. Diffusing capacity of the lungs for carbon monoxide increased by 6%. Among severe adverse events were cyclophosphamide-related congestive heart failure, antithymocyte globulin-related capillary leak syndrome, and scleroderma renal crisis. All symptoms completely resolved with treatment without sequela. No treatment related mortality was recorded. CONCLUSIONS: HSCT is an important step in the treatment of progressive SSc in Israel. Careful patient selection reduces treatment related morbidity and mortality.

Autoimmune Hepatitis A Case Report and Literature Review.

INTRODUCTION: Autoimmune hepatitis (AIH) is a cause of chronic liver disease. It is usually suspected based on clinical presentation and laboratory findings, but the diagnosis relies on the presence of specific autoantibodies and characteristic histology. Other unexplained findings should always prompt investigation for coexisting syndromes. CASE PRESENTATION: The patient is a 60-year-old Hispanic female with a history of mild asthma presented with exertional and pleuritic chest pain with weight loss, arthralgia, subjective fever, and night sweats for the last 3 months. Given the nonspecific nature of the presentation, further workup was pursued. Laboratory results indicated pancytopenia, elevated INR, and positive autoimmune panel including ANA, anti-chromatin, anti-histone, and rheumatoid factor as well as abnormal C3 and C4. Subsequent liver biopsy with interface hepatitis lead to a diagnosis of AIH with concurrent systemic lupus erythematosus suspected. CONCLUSION: The diagnostic work up for AIH is multimodal and aims to differentiate other etiologies such as congestive hepatopathy, iron overload, viral hepatitis, and other autoimmune liver diseases. In this particular case, unusual clinical and laboratory findings led to diagnosis of the overlap syndrome. Treatment for both was necessary to prevent further progression of disease.

Laboratory tests in rheumatology: A rational approach.

Laboratory tests are useful in diagnosing rheumatic diseases, but clinicians should be aware of the limitations of these tests. This article uses case vignettes to provide practical and evidence-based guidance on requesting and interpreting selected tests, including rheumatoid factor, anticitrullinated peptide antibody, antinuclear antibody, antiphospholipid antibodies, antineutrophil cytoplasmic antibody, and human leukocyte antigen-B27.

Myositis autoantibody profiles and their clinical associations in Greek patients with inflammatory myopathies.

Myositis-specific (MSAs) or-associated autoantibodies (MAAs) have been linked to particular clinical phenotypes of idiopathic inflammatory myopathies (IIM) and appear to aid diagnosis. The objective of this study was to analyze the prevalence of MSAs and MAAs and their possible clinical associations in Greek IIM patients. This study comprised 95 IIM patients classified based on the 2017 EULAR/ACR classification criteria. All patients had MSAs and MAAs measured in their sera by line immunoblot assay. Dermatomyositis was the most prevalent IIM clinical subtype. MSAs were found in 44% of the patients, whereas MAAs in 23%. The most frequently detected MSA was anti-Jo-1 (22%), while the most frequently detected MAA was anti-Ro-52 (30%). The distributions of MSAs/MAAs did not differ between the five IIM subgroups, except for anti-Mi-2 which was only detected in dermatomyositis patients. Patients with at least one MSA and/or MAA positivity showed more frequently IIM characteristic skin rashes, while those presenting solely MAA positivity had more often puffy hands and Raynaud's phenomenon. Anti-Jo1-positive patients presented more frequently lung disease, while anti-Ro52 positivity related to mechanic's hands. Anti-Ro-52 and anti-Jo-1 strongly associated with one another. Prevalence of IIM subtypes and of MSAs/MAAs in our patients is in line with published reports in populations of similar geographic distribution. While MSA and/or MAA positivity did associate with particular clinical manifestations, it did not predict in our cohort specific IIM subgroup as defined by the latest EULAR/ACR classification criteria. Future studies are warranted to conclusively decide if these autoantibodies, measured with a standardized method, should or not be incorporated in every day clinical practice to aid IIM diagnosis.

Myositis-specific autoantibodies in Japanese patients with juvenile idiopathic inflammatory myopathies.

OBJECTIVES: The aim of our study is to clarify the association of myositis-specific autoantibodies (MSAs) with clinical and laboratory features in Japanese patients with juvenile idiopathic inflammatory myopathies (JIIMs). METHODS: We retrospectively analyzed the frequency of MSAs and their association with clinical or laboratory findings in 25 Japanese patients with JIIMs in Hokkaido district. RESULTS: Eighteen of the 25 patients (72%) were positive for MSAs; seven with anti-melanoma differentiation associated gene (MDA) 5 (28%), five with anti-transcriptional intermediary factor (TIF)-1γ (20%), four with anti-MJ/nuclear matrix protein (NXP)-2 (16%), two with anti-Jo-1 (8%), one with anti- HMG-CoA reductase, one with anti-signal recognition peptide (SRP) antibodies (4% each), including co-existence and transition of MSAs in one patient each. Anti-MDA5 antibodies were related to interstitial lung disease (ILD) and arthritis but not to amyopathic juvenile dermatomyositis. Drug-free remission was achieved, once ILD was overcome in this group. Anti-TIF-1γ antibodies were associated with typical rashes and mild myositis. Anti-MJ/NXP2 and anti-SRP antibodies were associated with severe muscle weakness. No patient was complicated with malignancy. CONCLUSION: Anti-MDA5 antibodies are prevalent and closely associated with ILD in our series compared with other countries. There was no apparent difference in clinical features associated with other MSAs among races.

Associations between maternal clinical features and fetal outcomes in pregnancies of mothers with connective tissue diseases.

OBJECTIVES: The purpose of this study is to clarify associations between maternal clinical features and adverse pregnancy outcomes (APOs) in mothers with connective tissue diseases (CTDs). METHODS: We retrospectively examined maternal clinical features including backgrounds, autoantibodies, CTD flare-ups, and therapies during pregnancies as well as fetal outcomes in 90 pregnancies (66 mothers) at our hospital from January 2006 to September 2016. RESULTS: Underlying CTDs were SLE (N = 41), MCTD (N = 10), RA (N = 15), SS (N = 10), and others (N = 14). Anti-SS-A antibody was detected in 60.3%, lupus anticoagulant (LAC) was in 11.4%, and anti-cardiolipin-ß2glycoprotein1 antibody was in 18.5%. Flare-ups of CTDs occurred in 20 pregnancies (22.2%). Corticosteroids (CS) was administered in 73 pregnancies, immunosuppressants in four, and biologics in one. Among the 85 pregnancies other than five early abortions within 12 weeks of gestational age, 33 cases had APOs while the remaining 52 cases were normal. Although disease duration, MCTD, high dose of CS, flare-ups of CTDs, and positive LAC significantly correlated with APOs by univariate analysis, only MCTD was a significant independent predictor for APOs by multivariate analysis. CONCLUSION: Disease duration, MCTD, high dose of CS, flare-ups of CTDs, and LAC might be possible predictive risk factors for APOs in pregnancies with CTDs. Of these, MCTD was a significant independent risk factor.

Ni los anticuerpos antinucleares ni los anticuerpos dirigidos contra antígenos extraíbles del núcleo son lo que solían ser. Un futuro cambio de nomenclatura y recomendaciones para su determinación en práctica clínica habitual / Neither the anti-nuclear antibodies nor the anti-extractable nuclear antigens Are What They Used to Be. A Future Change of Nomenclature

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The clinical usage and definition of autoantibodies in immune-mediated liver disease: A comprehensive overview.

Autoimmune serology is key to the diagnosis and management of autoimmune liver diseases. Its correct use in clinical practice requires a basic knowledge of the laboratory techniques used for autoantibody detection. Indirect immunofluorescence (IIF) on triple rodent tissue is still the gold standard screening procedure for liver-relevant autoantibodies, while HEp2 cells and human ethanol-fixed neutrophils are used as substrates to characterize nuclear reactivities and to detect anti-neutrophil cytoplasm antibody, respectively. Assays based on purified or recombinant antigens are increasingly used, having the main advantage of being observer-independent and the disadvantage of detecting only autoantibodies whose antigenic target has been identified. The AIH-specific anti-soluble liver antigen antibody cannot be detected by IIF and a molecular-based assay should be used at the screening level. Since autoantibodies may be present in the context of viral hepatitides and other inflammatory liver diseases it is important to exclude these conditions before diagnosing autoimmune liver disease. Anti-nuclear antibody (ANA), most often with a homogeneous IIF pattern on HEp2 cells, characterizes type 1 autoimmune hepatitis (AIH), and is found in association with anti-smooth muscle antibody in about half of the cases. Two IIF ANA patterns are specific for primary biliary cholangitis, namely the rim-like/membranous pattern, and the multiple nuclear dots pattern. Anti-liver kidney microsomal antibody type 1 is the serological hallmark of type 2 AIH, often in association with anti-liver cytosol type 1 antibody. Atypical perinuclear anti-neutrophil antibody, referred to as perinuclear anti-neutrophil nuclear antibody, is frequently detected in primary sclerosing cholangitis, in AIH type 1 and in inflammatory bowel diseases. The anti-asiaglycoprotein receptor antibody is liver-specific but not disease-specific, and reliable commercial assays for its detection are lacking. Anti-mitochondrial antibody is the hallmark of primary biliary cholangitis (PBC), being disease-specific and present in about 95% of the PBC patients. Its incidental detection presages the future development of PBC.

Novel enzyme immunoassay system for simultaneous detection of six subclasses of antiphospholipid antibodies for differential diagnosis of antiphospholipid syndrome.

: Antiphospholipid syndrome, which often complicates systemic lupus erythematosus (SLE), features high occurrence of arterial and/or venous thrombosis and recurrent fetal loss. However, which antibody subclass contributes to which clinical event remains uncertain. We newly developed an up-to-date enzyme immunoassay system using the AcuStar automated analyzer (Instrumentation Laboratory, Bedford, Massachusetts, USA) for parallel detection of six subclasses of antiphospholipid antibodies (aPLs): anticardiolipin antibodies (aCL) of IgG, IgM, and IgA and anti-ß2-glycoprotein I antibodies (aß2GPI) of IgG, IgM, and IgA. They were measured in 276 healthy volunteers and 138 patients with SLE: 45 with thromboembolic complications (29 arterial; 16 venous) and 93 without. Lupus anticoagulant activity in their plasma was measured according to the guidelines recommended by the Subcommittee on Lupus Anticoagulant/Phospholipid-Dependent Antibodies. aCL/ß2GPI was measured with a standard ELISA kit commonly used in Japan. The positive results of IgG aCL, IgA aCL, and IgG aß2GPI were closely associated with thromboembolic complications, whereas IgM aCL and IgM aß2GPI were not. receiver operating characteristic analysis revealed that the accuracy of predicting thromboembolic complications based on the composite test results of the former three antibodies were obviously higher than by each alone. Regarding agreement with the test results of lupus anticoagulant activity, IgG aß2GPI showed the closest match. Patients with SLE frequently possess various combinations of the six aPL subclasses, and this antibody spectrum is closely associated with thromboembolic events in these patients. This new automated enzyme immunoassay system allows simultaneous analysis of the profile of aPL subclasses for the differential diagnosis of antiphospholipid antibody syndrome in its early stage.

Inositol 1,4,5-trisphosphate receptor type 1 autoantibodies in paraneoplastic and non-paraneoplastic peripheral neuropathy.

BACKGROUND: Recently, we described a novel autoantibody, anti-Sj/ITPR1-IgG, that targets the inositol 1,4,5-trisphosphate receptor type 1 (ITPR1) in patients with cerebellar ataxia. However, ITPR1 is expressed not only by Purkinje cells but also in the anterior horn of the spinal cord, in the substantia gelatinosa and in the motor, sensory (including the dorsal root ganglia) and autonomic peripheral nervous system, suggesting that the clinical spectrum associated with autoimmunity to ITPR1 may be broader than initially thought. Here we report on serum autoantibodies to ITPR1 (up to 1:15,000) in three patients with (radiculo)polyneuropathy, which in two cases was associated with cancer (ITPR1-expressing adenocarcinoma of the lung, multiple myeloma), suggesting a paraneoplastic aetiology. METHODS: Serological and other immunological studies, and retrospective analysis of patient records. RESULTS: The clinical findings comprised motor, sensory (including severe pain) and autonomic symptoms. While one patient presented with subacute symptoms mimicking Guillain-Barré syndrome (GBS), the symptoms progressed slowly in two other patients. Electrophysiology revealed delayed F waves; a decrease in motor and sensory action potentials and conduction velocities; delayed motor latencies; signs of denervation, indicating sensorimotor radiculopolyneuropathy of the mixed type; and no conduction blocks. ITPR1-IgG belonged to the complement-activating IgG1 subclass in the severely affected patient but exclusively to the IgG2 subclass in the two more mildly affected patients. Cerebrospinal fluid ITPR1-IgG was found to be of predominantly extrathecal origin. A 3H-thymidine-based proliferation assay confirmed the presence of ITPR1-reactive lymphocytes among peripheral blood mononuclear cells (PBMCs). Immunophenotypic profiling of PBMCs protein demonstrated predominant proliferation of B cells, CD4 T cells and CD8 memory T cells following stimulation with purified ITPR1 protein. Patient ITPR1-IgG bound both to peripheral nervous tissue and to lung tumour tissue. A nerve biopsy showed lymphocyte infiltration (including cytotoxic CD8 cells), oedema, marked axonal loss and myelin-positive macrophages, indicating florid inflammation. ITPR1-IgG serum titres declined following tumour removal, paralleled by clinical stabilization. CONCLUSIONS: Our findings expand the spectrum of clinical syndromes associated with ITPR1-IgG and suggest that autoimmunity to ITPR1 may underlie peripheral nervous system diseases (including GBS) in some patients and may be of paraneoplastic origin in a subset of cases.

Survival and organ involvement in patients with limited cutaneous systemic sclerosis and anti-topoisomerase-I antibodies: determined by skin subtype or auto-antibody subtype? A long-term follow-up study.

OBJECTIVE: LcSSc is associated with ACAs and a mild course, whereas dcSSc is associated with anti-topoisomerase antibodies (ATAs) and a more severe course. However, ATAs are also present in lcSSc. Little is known about survival and organ involvement in this subgroup. The aim of this study is to determine whether survival and organ involvement of lcSSc ATA-positive patients differs from lcSSc ATA-negative or dcSSc ATA-positive patients. Furthermore, transition from lcSSc to dcSSc was evaluated. METHODS: Data from The Nijmegen Systemic Sclerosis cohort were used, with up to 15 years of follow-up. Kaplan-Meier analysis was performed for survival and organ involvement, including interstitial lung disease, pulmonary arterial hypertension, cardiac involvement and Scleroderma Renal Crises. Cox proportional hazard modelling was performed to adjust for confounders. RESULTS: A total of 460 patients were included: 58 (13%) lcSSc ATA-positive patients, 237 (52%) lcSSc ATA-negative patients and 78 (17%) dcSSc ATA-positive patients. Cumulative survival in lcSSc ATA-positive patients was 75%, in lcSSc ATA-negative patients 58% and in dcSSc ATA-positive patients 53%. Interstitial lung disease was more prevalent in lcSSc ATA-positive patients (49%) than in lcSSc ATA-negative patients (25%), but less than in dcSSc ATA-positive patients (60%). Forty-eight patients developed dcSSc: 24 ATA-negative and 24 ATA-positive (P < 0.001). CONCLUSION: LcSSc ATA-positive patients differ from lcSSc ATA-negative patients and dcSSc ATA-positive patients concerning survival and organ involvement. LcSSc patients who are ATA-positive are more likely to develop dcSSc than lcSSc patients who are ATA negative.

Detection methods for neural autoantibodies.

Antibodies are part of the adaptive immune response that provides protection against microorganisms. In rare instances individuals can develop antibodies that bind to normal central nervous system structures. These antibodies have been classified into two groups depending on the subcellular location of their target antigens. Biomarker antibodies bind to cytosolic or nuclear targets. They do not impact on the normal function of the cell, but are most often paraneoplastic biomarkers that may suggest screening for different cancers. The second, more recently discovered group of antibodies recognize the three-dimensional structure of native proteins that are accessible on the cell surface. Understanding of this important difference is reflected in the nature of assays used to detect antibodies in these two groups. Western blots and, more recently, line blots, both of which use linear, denatured targets, are used to detect antibodies to intracellular targets. Newer assays have been developed that maintain the native structure of protein targets to permit detection of antibodies that recognize extracellular targets. In this chapter we describe the methods used to detect both antibody types, and discuss assay cut-offs, sample handling, and which biologic fluid to test.

[Non-identified antinuclear antibodies in systemic sclerosis]. / Facteurs anti-nucléaires " non-identifiés " dans la sclérodermie systémique.

INTRODUCTION: Systemic sclerosis is a rare auto immune disease characterized by a local or diffuse skin condition and a variable visceral impairment. Anti nuclear antibodies (ANA) can be found in 95 % of patients. The most frequent are the anti topoisomerase 1 or anti Scl 70 and the anti-centromeres. Other antibodies have been reported but they are not conventionally sought in clinical practice. They are referred to as " non identified " ANA. OBJECTIVE: To seek the " non identified " antibodies in patients with scleroderma at Erasme Hospital, to assess their prevalence in this cohort and to correlate their presence with the clinical characteristics. METHODS: 89 patients out of the cohort of Erasme hospital patients with scleroderma have been looked at. Their clinical and biological data have been identified and a detection of antibodies have been performed by first an immonudot technique and second an EliA technique. RESULTS: 17 out of the 89 patients of our cohort had " non identified " ANA. Among them, antibodies in 11 patients have been identified by the immunodot, among which 7 anti-PmScl 75 and/or 100,3 RNA polymerase III and 1 antifibrillarin. The EliA technique identif ied antibodies in 10 patients among which 5 anti- PmScl, 2 anti RNA polymerase, 2 anti-fibrillarin and 1 anti-centromere. CONCLUSION: Auto antibodies other than the antitopoisomerase and anti-centromere have been found in patients with scleroderma in our cohort. Certain links exist between the presence of a given antibody and clinical features. We still have to define whether there exist other auto antibodies of which we still are unaware since in some patient no antibodies were detected.

INTRODUCTION: La sclérodermie systémique est une maladie auto-immune rare caractérisée par une atteinte cutanée locale ou diffuse ainsi qu'une atteinte viscérale variable. On retrouve des facteurs anti-nucléaires (FAN) chez environ 95 % des malades, dont les plus fréquents sont les anti-topoisomérase I (ou anti-Scl 70) et les anticentromères. D'autres auto-anticorps ont été décrits mais ceux-ci ne sont pas classiquement recherchés en pratique clinique, on les dénomme alors " FAN non identifiés ". OBJECTIF: Rechercher les anticorps " non identifiés " chez les patients sclérodermiques de l'hôpital Erasme, établir leur prévalence dans cette cohorte et corréler leur présence avec les caractéristiques cliniques. METHODES: Quatre-vingt-neuf patients issus de la cohorte des patients sclérodermiques de l'hôpital Erasme ont été étudiés. Leurs données cliniques et biologiques ont été relevées, puis une détection d'anticorps a été effectuée d'une part par une technique d'immunodot (topoisomérase I, centromères, ARN polymérase III, fibrillarine, Pm/Scl 75 et 100, PDGFR, NOR 90, Ku et Ro 52) et d'autre part par une technique EliA (topoisomérase I, centromères, ARN polymérase III, fibrillarine et PmScl). RESULTATS: Dix-sept des 89 patients de notre cohorte avaient des FAN " non identifiés ". Parmi ceux-ci, l'immunodot a identifié des anticorps chez 11 patients dont 7 anti-PmScl 75 et/ou 100, 3 anti-ARN pol III et 1 anti-fibrillarine. La technique EliA a permis d'identifier des anticorps chez 10 patients dont 5 anti-PmScl, 2 anti-ARN pol III, 2 anti-fibrillarine et 1 anti-centromère. CONCLUSION: Des auto-anticorps autres que les anti-topoisomérase I et anti-centromères ont été retrouvés chez les patients sclérodermiques de notre cohorte. Il existe certains liens entre la présence d'un anticorps donné et la clinique associée. Il reste à définir s'il existe d'autres auto-anticorps qui ne sont pas encore connus puisque chez certains patients, aucun anticorps n'a été mis en évidence.

Serum levels of immunoglobulins G1 and G4 targeting the non-collagenous 16A domain of BP180 reflect bullous pemphigoid activity and predict bad prognosis.

Bullous pemphigoid (BP) is an autoimmune subepidermal bullous disease, and different immunoglobulin (Ig)G autoantibody subclasses may play different roles in the pathogenesis of BP. This study aims to evaluate the relationship between specific IgG subclasses and BP. Enzyme-linked immunoassays (ELISA) were developed to test the IgG subclasses targeting the non-collagenous 16A (NC16A) domain of BP180. A statistical analysis was carried out to assess the relationship of BP and IgG subclasses as well as other factors. The correlation coefficients between the ELISA scores for four IgG subclasses and disease severity scores were 0.586 for IgG, 0.441 for IgG1, 0.594 for IgG2, 0.345 for IgG3, and 0.448 for IgG4 before treatment. After treatment, the correlation coefficient was 0.376 for IgG, 0.522 for IgG1, 0.314 for IgG2, 0.582 for IgG3 and 0.503 for IgG4. Spearman's rank correlation coefficient was 0.801 for IgG1, 0.66 for IgG2, 0.575 for IgG3 and 0.463 for IgG4 between the ELISA scores of IgG subclasses and the disease severity score variation. The ELISA scores of IgG subclasses in patients with mucosal involvement were higher than those without. Survival analysis showed that sex, IgG1 and IgG4 were the independent predictors for BP. In conclusion, the serum levels of IgG1 and IgG4 targeting BP180NC16A were paralleled with disease severity in BP patients. IgG1 and IgG4 and sex were the independent prognostic factors for an early prognosis of BP.

ADAMTS13 and anti-ADAMTS13 autoantibodies in thrombotic thrombocytopenic purpura - current perspectives and new treatment strategies.

A deficiency in ADAMTS13 (A Disintegrin And Metalloprotease with ThromboSpondin type-1 repeats, member 13) is associated with thrombotic thrombocytopenic purpura (TTP). Congenital TTP is caused by a defect in the ADAMTS13 gene resulting in decreased or absent enzyme activity; acquired TTP results from autoantibodies that either inhibit the activity or increase the clearance of ADAMTS13. Despite major progress in recent years in our understanding of the disease, many aspects around the pathophysiology of TTP are still unclear. Newer studies expanded the TTP field from ADAMTS13 and inhibitory antibodies to immune complexes, cloned autoantibodies, and a possible involvement of other proteases. Additionally, several new treatment strategies supplementing plasma-exchange and infusion are under investigation for a better and more specific treatment of TTP patients. In this review, we discuss the recent insights in TTP pathophysiology and describe upcoming therapeutic opportunities.

Case of pemphigus with immunoglobulin G and A antibodies, binding to both the intercellular spaces and basement membrane zone.

We report a case involving a 62-year-old woman with in vivo-bound immunoglobulin (Ig)G and IgA antibodies in both the intercellular space (ICS) and basement membrane zone (BMZ). Her clinical and histopathological features were identical with those of pemphigus vulgaris, while the immunopathological findings suggested IgG/IgA pemphigus. Direct immunofluorescence (IF) showed in vivo-bound IgG and IgA antibodies in the ICS and BMZ, whereas indirect IF showed circulating IgG but not IgA antibodies in the ICS and BMZ. The anti-ICS IgG bound to desmoglein-3, while the anti-BMZ antibodies bound to the epidermal side of 1 mol/L NaCl-split skin. To the best of our knowledge, only two similar cases have been reported so far. Furthermore, we also examined IgG subclass distribution of the in vivo-bound and circulating anti-ICS and BMZ antibodies, and found that IgG1, IgG2 and IgG4 bound to ICS of the lesional skins, while IgG1 and IgG3 bound to the BMZ. The circulating anti-ICS antibodies belonged to IgG1 and IgG4, while the circulating anti-BMZ antibodies to IgG1, IgG2 and IgG4. We report a case involving a 62-year-old woman with in vivo-bound immunoglobulin (Ig)G and IgA antibodies in both the intercellular space (ICS) and basement membrane zone (BMZ). Her clinical and histopathological features were identical with those of pemphigus vulgaris, while the immunopathological findings suggested IgG/IgA pemphigus. Direct immunofluorescence (IF) showed in vivo-bound IgG and IgA antibodies in the ICS and BMZ, whereas indirect IF showed circulating IgG but not IgA antibodies in the ICS and BMZ. The anti-ICS IgG bound to desmoglein-3, while the anti-BMZ antibodies bound to the epidermal side of 1 mol/L NaCl-split skin. To the best of our knowledge, only two similar cases have been reported so far. Furthermore, we also examined IgG subclass distribution of the in vivo-bound and circulating anti-ICS and BMZ antibodies, and found that IgG1, IgG2 and IgG4 bound to ICS of the lesional skins, while IgG1 and IgG3 bound to the BMZ. The circulating anti-ICS antibodies belonged to IgG1 and IgG4, while the circulating anti-BMZ antibodies to IgG1, IgG2 and IgG4.

Lupus anti-ribosomal P autoantibody proteomes express convergent biclonal signatures.

Lupus-specific anti-ribosomal P (anti-Rib-P) autoantibodies have been implicated in the pathogenesis of neurological complications in systemic lupus erythematosus (SLE). The aim of the present study was to determine variable (V)-region signatures of secreted autoantibody proteomes specific for the Rib-P heterocomplex and investigate the molecular basis of the reported cross-reactivity with Sm autoantigen. Anti-Rib-P immunoglobulins (IgGs) were purified from six anti-Rib-P-positive sera by elution from enzyme-linked immunosorbent assay (ELISA) plates coated with either native Rib-P proteins or an 11-amino acid peptide (11-C peptide) representing the conserved COOH-terminal P epitope. Rib-P- and 11-C peptide-specific IgGs were analysed for heavy (H) and light (L) chain clonality and V-region expression using an electrophoretic and de-novo and database-driven mass spectrometric sequencing workflow. Purified anti-Rib-P and anti-SmD IgGs were tested for cross-reactivity on ELISA and their proteome data sets analysed for shared clonotypes. Anti-Rib-P autoantibody proteomes were IgG1 kappa-restricted and comprised two public clonotypes defined by unique H/L chain pairings. The major clonotypic population was specific for the common COOH-terminal epitope, while the second shared the same pairing signature as a recently reported anti-SmD clonotype, accounting for two-way immunoassay cross-reactivity between these lupus autoantibodies. Sequence convergence of anti-Rib-P proteomes suggests common molecular pathways of autoantibody production and identifies stereotyped clonal populations that are thought to play a pathogenic role in neuropsychiatric lupus. Shared clonotypic structures for anti-Rib-P and anti-Sm responses suggest a common B cell clonal origin for subsets of these lupus-specific autoantibodies.

Autoantibodies and their Judicious Use in Pediatric Rheumatology Practice.

Autoantibody testing forms an important part of diagnostic workup of patients in Pediatric rheumatology practice. However it is important to understand that the mere presence of autoantibodies does not necessarily mean the presence of an underlying autoimmune disease. Autoantibodies may be present decades before the development of clinical manifestations of an autoimmune disease and may be viewed as harbingers of Autoimmune disease. On the other hand, low-affinity autoantibodies may be present in normal healthy individuals; these natural autoantibodies serve an important function in immune regulation and tolerance. Autoantibody testing in pediatric practice mainly includes testing for anti-nuclear antibodies, anti-dsDNA antibodies, anti-neutrophil cytoplasmic autoantibodies and antiphospholipid antibodies. Rheumatoid factor and anti-CCP do not have much significance in the diagnostic schema in pediatric rheumatology, except perhaps for classification of juvenile idiopathic arthritis (JIA) and prognostication in late-onset polyarticular JIA. The positive predictive value (PPV) of any laboratory test depends on the prevalence of the disease in the population being tested. Hence, test ordering practices greatly impact the performance characteristics and positive predictive value of any laboratory test. A restricted test ordering only in patients with clinical signs and symptoms suggestive of autoimmune disease would thus greatly increase the PPV of tests such as antinuclear antibody used for diagnosing autoimmunity.