Protein Autoantigens Research Articles

6441 Hyperthyroidism in a patient with Lyme disease

Abstract Disclosure: J. Epstein: None. C. Berman: None. Background: Lyme disease is known to cause inflammation in many organs. There are few case reports in the literature that discuss the association between Lyme disease and thyroiditis. This case underscores the need to further research the association between Lyme disease and thyroid physiology. Clinical Case: A 15-year-old female with a history of polycystic kidney disease is referred to a pediatric endocrinologist for primary amenorrhea and hyperthyroidism. Initial thyroid function tests demonstrated suppressed TSH of 0.03 mIU/L with an elevated free T4 level of 4.0 ng/dL and total T3 of 437 ng/dL. The patient was asymptomatic with normal vital signs, and physical exam was normal without goiter, tremor, tongue fasciculations, or exophthalmos. Thyroid ultrasound demonstrated a mildly heterogenous appearance without nodules. Incidentally, Lyme disease was concurrently diagnosed based on a positive screen confirmed with immunoblot. There was no known tick exposure or rash, but the patient had recently spent time outdoors in upstate New York. Doxycycline was started for the treatment of Lyme disease and repeat thyroid tests one week later showed a decrease in free T4 and total T3 levels, although still elevated. Thyroid antibodies including thyroid peroxidase (TPO), thyroglobulin and thyroid-stimulating immunoglobulin (TSI) were negative. After finishing doxycycline treatment, she developed a hypothyroid state with a TSH of 6.39 mIU/L, free T4 of 0.6 ng/dL, and a normal total T3 of 148 ng/dL. Free T4 has since normalized however TSH remains elevated. The patient continues to be monitored closely without pharmacologic treatment. The evolution of this patient’s thyroid function is consistent with thyroiditis and appears similar to the course of Hashitoxicosis, however antibodies remain negative. There is literature that suggests molecular mimicry between Borrelia proteins and thyroid autoantigens due to amino acid sequence homology. Some Borrelial proteins are found to share antigenic properties with multiple thyroid related proteins, specifically the TSH receptor, TPO, thyroglobulin and sodium iodine symporter, potentially leading to thyroiditis. Three case reports describe adults with hyperthyroidism in the setting of Lyme disease, however in these cases thyroid antibodies (TPO +/- thyroglobulin) were positive. Two of these patients were asymptomatic, similar to our patient. This phenomenon has never been described in a pediatric patient and illustrates the need to consider Lyme disease as a potential cause of destructive, transient, thyroiditis. Presentation: 6/1/2024

Identification of a mimotope of a complex gp41 Human Immunodeficiency VIrus epitope related to a non-structural protein of Hepacivirus previously implicated in Kawasaki disease.

We have previously isolated a highly mutated VH1-02 antibody termed group C 76-Q13-6F5 (6F5) that targets a conformational epitope on gp41. 6F5 has the capacity to mediate Ab dependent cell cytotoxicity (ADCC). When the VH1-02 group C 76 antibodies variable chain sequence was reverted to germline (76Canc), this still retained ADCC activity. Due to this ability for the 76Canc germline antibody to functionally target this epitope, we sought to identify a protein target for vaccine development. Initially, we interrogated peptide targeting by screening a microarray containing 29,127 linear peptides. Western blot and ELISAs were used to confirm binding and explore human serum targeting. Autoimmune targeting was further interrogated on a yeast-displayed human protein microarray. 76Canc specifically recognized a number of acidic peptides. Meme analysis identified a peptide sequence similar to a non-structural protein of Hepacivirus previously implicated in Kawasaki disease (KD). Binding was confirmed to top peptides, including the Hepacivirus-related and KD-related peptide. On serum competitions studies using samples from children with KD compared to controls, targeting of this epitope showed no specific correlation to having KD. Human protein autoantigen screening was also reassuring. This study identifies a peptide that can mimic the gp41 epitope targeted by 76C group antibodies (i.e. a mimotope). We show little risk of autoimmune targeting including any inflammation similar to KD, implying non-specific targeting of this peptide during KD. Development of such peptides as the basis for vaccination should proceed cautiously.

Decoding the relationship between cow's milk proteins and development of type 1 diabetes mellitus.

To analyze in silico the evidence of molecular mimicry between human beta-cell autoantigens and cow's milk proteins as a potential type 1 diabetes mellitus (T1DM) trigger. The in silico analysis was performed using bioinformatics tools to compare the amino acid sequences of cow's milk proteins (bovine serum albumin [BSA] and beta-lactoglobulin [BLG]) and human beta-cell autoantigens (glutamic acid decarboxylase-65 [GAD-65], insulin, and zinc transporter 8 [ZnT8]). The structural and functional characteristics of the proteins were analyzed to identify potential molecular mimicry mechanisms. The results of the in silico analysis showed significant sequence similarity between BSA/BLG and GAD-65/human insulin/ZnT8, ranging from 19.64% to 27.27%. The cow's milk proteins evaluated shared structural features with the beta-cell antigens selected for comparison, indicating a potential for molecular mimicry between these proteins. The findings of this study provide further evidence for a potential role of cow's milk proteins in triggering T1DM. The in silico analysis suggests that molecular mimicry mechanisms between cow's milk proteins and human beta-cell antigens may contribute to the autoimmune response leading to T1DM.

Human leukocyte antigen-DQ risk heterodimeric haplotypes of left ventricular dysfunction in cardiac sarcoidosis: an autoimmune view of its role

Cardiac sarcoidosis (CS) is the scarring of heart muscles by autoimmunity, leading to heart abnormalities and patients with sarcoidosis with cardiac involvements have poor prognoses. Due to the small number of patients, it is difficult to stratify all patients of CS by human leukocyte antigen (HLA) analysis. We focused on the structure of antigen-recognizing pockets in heterodimeric HLA-class II, in addition to DNA sequences, and extracted high-affinity combinations of antigenic epitopes from candidate autoantigen proteins and HLA. Four HLA heterodimer-haplotypes (DQA1*05:03/05:05/05:06/05:08-DQB1*03:01) were identified in 10 of 68 cases. Nine of the 10 patients had low left ventricular ejection fraction (< 50%). Fourteen amino-acid sequences constituting four HLA anchor pockets encoded by the HLA haplotypes were all common, suggesting DQA1*05:0X-DQB1*03:01 exhibit one group of heterodimeric haplotypes. The heterodimeric haplotypes recognized eight epitopes from different proteins. Assuming that autoimmune mechanisms might be activated by molecular mimicry, we searched for bacterial species having peptide sequences homologous to the eight epitopes. Within the peptide epitopes form the SLC25A4 and DSG2, high-homology sequences were found in Cutibacterium acnes and Mycobacterium tuberculosis, respectively. In this study, we detected the risk heterodimeric haplotypes of ventricular dysfunction in CS by searching for high-affinity HLA-class II and antigenic epitopes from candidate cardiac proteins.

Engineering chimeric autoantibody receptor T cells for targeted B cell depletion in multiple sclerosis model: An in-vitro study

BackgroundRecent evidence suggests that B cells and autoantibodies have a substantial role in the pathogenesis of Multiple sclerosis. T cells could be engineered to express chimeric autoantibody receptors (CAARs), which have an epitope of autoantigens in their extracellular domain acting as bait for trapping autoreactive B cells. This study aims to assess the function of designed CAAR T cells against B cell clones reactive to the myelin basic protein (MBP) autoantigen. MethodsT cells were transduced to express a CAAR consisting of MBP as the extracellular domain. experimental autoimmune encephalomyelitis (EAE) was induced by injecting MBP into mice. The cytotoxicity, proliferation, and cytokine production of the MBP-CAAR T cells were investigated in co-culture with B cells. ResultsMBP-CAAR T cells showed higher cytotoxic activity against autoreactive B cells in all effector-to-target ratios compared to Mock T cell (empty vector-transduced T cell) and Un-T cells (un-transduced T cell). In co-cultures containing CAAR T cells, there was more proliferation and inflammatory cytokine release as compared to Un-T and Mock T cell groups. ConclusionBased on these findings, CAAR T cells are promising for curing or modulating autoimmunity and can be served as a new approach for clone-specific B cell depletion therapy in multiple sclerosis.

Interaction of the antiphospholipid syndrome autoantigen beta-2 glycoprotein I with DNA and neutrophil extracellular traps

Beta-2 glycoprotein I (β2GPI) is a phospholipid-binding plasma protein and prominent autoantigen in antiphospholipid syndrome (APS). Here, we tested the hypothesis that β2GPI might bind to not only phospholipids, but also cell-free DNA and neutrophil extracellular traps (NETs). We report that β2GPI interacts with cell-free DNA from different species, as well as NETs, in a dose-dependent manner, retarding their migration in an agarose-gel electrophoretic mobility shift assay. We confirm the direct binding interaction of β2GPI with DNA and NETs by ELISA. We also demonstrate that β2GPI colocalizes with NET strands by immunofluorescence microscopy. Finally, we provide evidence that β2GPI-DNA complexes can be detected in the plasma of APS patients, where they positively correlate with an established biomarker of NET remnants. Taken together, our findings indicate that β2GPI interacts with DNA and NETs, and suggest that this interaction may play a role as a perpetuator and/or instigator of autoimmunity in APS.

Dual inhibition of phosphoinositide 3-kinases delta and gamma reduces chronic B cell activation and autoantibody production in a mouse model of lupus.

Phosphoinositide 3-kinase delta (PI3Kδ) plays key roles in normal B cell activation and is chronically activated in malignant B cells. Targeting of PI3Kδ using FDA-approved drugs Idelalisib or Umbralisib has shown efficacy in treatment of multiple B cell malignancies. Duvelisib, an inhibitor targeting both PI3Kδ and PI3Kγ (PI3Kδγi) has also been used for treatment of several leukemias and lymphomas and was suggested to offer potential additional benefits in supressing T cell and inflammatory responses. Transcriptomics analyses indicated that while most B cell subsets predominantly express PI3Kδ, plasma cells upregulate PI3Kγ. We thus assessed whether PI3Kδγi treatment can impact chronic B cell activation in the context of an autoantibody-mediated disease. Using the TAPP1R218LxTAPP2R211L (TAPP KI) mouse model of lupus-like disease driven by dysregulated PI3K pathway activity, we performed 4 week PI3Kδγi treatments and found significant reduction in CD86+ B cells, germinal center B cells, follicular helper T cells and plasma cells in multiple tissues. This treatment also significantly attenuated the abnormally elevated serum levels of IgG isotypes observed in this model. The profile of autoantibodies generated was markedly altered by PI3Kδγi treatment, with significant reductions in IgM and IgG targeting nuclear antigens, matrix proteins and other autoantigens. Kidney pathology was also impacted, with reduced IgG deposition and glomerulonephritis. These results indicate that dual inhibition of PI3Kδ and PI3Kγ can target autoreactive B cells and may have therapeutic benefits in autoantibody-mediated disease.

Enrichment of Complement, Immunoglobulins, and Autoantibody Targets in the Proteome of Platelets from Patients with Systemic Lupus Erythematosus.

Background Systemic lupus erythematosus (SLE) is a complex disease characterized by autoimmunity toward apoptotic cells, excessive amounts of circulating immune complexes, and complement activation. A decreased platelet size has been observed in SLE and their nonhemostatic functions may play an active role in the disease. The main objective of this study was to find clues that could explain their decreased size and functional role, analyzing the entire platelet proteome. Methods Platelets were isolated from 23 patients with SLE. The five individuals with the highest and lowest average platelet forward scatter were selected for further analysis. Platelet protein content was analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and compared with platelets from five healthy controls. Data are available via ProteomeXchange with identifier PXD031202. Results Out of 2,572 proteins identified, 396 had significantly different levels (ANOVA q -value ≤ 0.01). Forty proteins, including immunoglobulin-, complement- and phosphatidylserine-binding proteins had higher abundance in platelets from SLE patients, largely independent of size (fold difference of ≥1.5 and a t -test p -value of ≤0.05 as cut-off). Functional characterization revealed increased degranulation and skewed hemostatic balance in platelets from SLE patients. In the SLE proteome, immunoglobulin proteins were negatively correlated to serum complement C3 and C4 and the highest relative levels were detected in platelets of normal size. Conclusion Platelets from SLE patients shared a specific protein profile, including immunoglobulins, complement proteins, and autoantigens, largely independent of the platelet size and in agreement with an integrated role for platelets in SLE.

Patient‐specific Autoantigen Sample Preparation and Analysis Using the Reversible Protein Tag ProMTag

Autoimmune diseases affect &gt;20 million people in the US today. Currently, disease‐specific autoantibodies are thought to be the best biomarkers for diagnosis. Conventional immunoprecipitation methods have been used to identify autoantigens from the most common autoimmune diseases. However, these diseases account for only 6.5 million of the 20 million patients suffering from autoimmune diseases, leaving many without diagnoses until irreversible damage occurs. The remaining 13.5 million patients have &gt;70 autoimmune disorders without well characterized autoantibodies. The state‐of‐the‐art diagnostic test of these remaining diseases relies on gel electrophoresis of immunoprecipitated radiolabeled proteins, which cannot be identified by MS due to safety issues and the overwhelming presence of immunoglobulins.We have created an immunoprecipitation method that uses serum from patients with any autoimmune disorder to identify patient‐specific autoantigen proteins. This method uses a reversible click chemistry tag, called ProMTag. One end of the ProMTag forms a reversible, covalent bond with protein by coupling to lysines and amino termini. The other end of the ProMTag can form an irreversible, covalent bond with a solid bead support via a click chemistry, methyltetrazine‐TCO, pairing. In this study, the proteins of cell lysates that contain potential autoantigens were labeled with ProMTag. The ProMTagged‐proteins were exposed to patient antibodies bound to Protein A beads, thus capturing the ProMTagged autoantigens. All proteins were released from the Protein A beads, including ProMTagged‐autoantigens and untagged‐antibodies. The ProMTagged‐autoantigens were subsequently coupled to TCO beads, and the untagged‐antibodies were washed away. The linkage between the ProMTag and autoantigens was then reversed, yielding autoantigen proteins with greatly reduced antibody contamination ready for MS analysis. MS analysis successfully identified autoantigens from patient serums with rheumatoid arthri. This autoimmune biomarker discovery method can accelerate sample testing for known autoantigens and facilitating rapid discovery of novel autoantigens for both diagnostic and predictive biomarkers.

Is primary membranous nephropathy a complement mediated disease?

Membranous nephropathy (MN) is an immune complex mediated disease. Although limited to the kidney, in up to 20% of patients MN is associated with other autoimmune, infectious or malignant diseases. The initial pathogenetic event in what is still considered “primary” MN is the binding of circulating autoantibodies to proteins (autoantigens) expressed in glomerular podocytes. This antibody binding leads to the formation of immune complexes in the glomerular basement membrane. There is clinical and experimental evidence that these immune deposits lead to the activation of the complement system. Experimental studies in the MN model of Heymann’s nephritis show that the terminal membrane attack complex (MAC) of the complement system induces a disturbance of the glomerular filtration barrier and leads to proteinuria, the clinical hallmark of MN. After the discovery of the phospholipase A2 receptor 1 and thrombospondin type 1 domain containing protein 7A as endogenous antigens, it is assumed that IgG4 antibodies directed against these proteins induce MN in over 85% of patients with primary MN. As a result, the role of complement in the pathogenesis of MN needs to be defined in light of these developments. In this review we describe the current knowledge on the function of the complement system in primary MN and discuss the open questions, which have to be solved for a better understanding of the potential role of complement in the pathophysiology of primary MN.

Generation of Distinct Patterns of Rheumatoid Arthritis Autoantigens by Peptidylarginine Deiminase Types 2 and 4 During Perforin-Induced Cell Damage.

To address the independent roles of peptidylarginine deiminase type 2 (PAD2) and PAD4 in generating rheumatoid arthritis (RA) autoantigens by using a system that mimics intracellular citrullination in the RA joint. PAD2- or PAD4-expressing 293T cells and mock-transfected cells were used as targets in cytotoxic assays using lymphokine-activated killer cells, cytotoxic YT cell granule contents, or purified human perforin. Protein citrullination and autoantigen production were determined by immunoblotting using the anti-modified citrulline-Senshu method and RA sera (n = 30), respectively. RA sera recognized at least 3 categories of autoantigens in PAD-expressing target cells killed by the cytotoxic lymphocyte granule-induced death pathway. These included: 1) autoantigens targeted in their native form, 2) citrullinated antigens, and 3) antigens cleaved by cytotoxic proteases (e.g., granzymes). Interestingly, although target cells expressing PAD2 or PAD4 showed prominent hypercitrullination of a broad range of proteins during cytotoxic granule-induced cell damage, autoantibodies in RA sera targeted only a very limited number of antigens in hypercitrullinated cells. Furthermore, RA sera showed distinct reactivities to autoantigens generated by PAD2 or PAD4. The cytotoxic granule-induced death pathway has the capacity to modify antigens by inducing hypercitrullination and antigen cleavage in target cells. Interestingly, among a large number of citrullinated proteins generated by PAD2 and PAD4 in cells, only a few are likely involved in the production of autoantibodies in RA.

Anti-brain protein autoantibodies are detectable in extraparenchymal but not parenchymal neurocysticercosis

Neurocysticercosis (NC) presents a spectrum of clinical manifestations, with two broad clinical entities based on the central nervous system location of the parasite: extraparenchymal (EP-NC) and parenchymal (P-NC). In this work, using quantitative immunoblot methodology, we demonstrate the presence of autoantibodies to brain proteins in CSF from EP-NC, but not P-NC, patients. There was striking correlation between the level of autoantibodies and the levels of the secreted metacestode glycoprotein HP-10, suggesting that the level of stimulation of the autoantibody response may be a function of the number of viable parasites. Nine corresponding proteins autoantigens were provisionally identified by mass spectroscopy.

Tocopherol Emulsions as Functional Autoantigen Delivery Vehicles Evoke Therapeutic Efficacy in Experimental Autoimmune Encephalomyelitis.

Contemporary approaches to treating autoimmune diseases like multiple sclerosis broadly modulate the immune system and leave patients susceptible to severe adverse effects. Antigen-specific immunotherapies (ASIT) offer a unique opportunity to selectively suppress autoreactive cell populations but have suffered from marginal efficacy even when employing traditional adjuvants to improve delivery. The development of immunologically active antigen delivery vehicles could potentially increase the clinical success of antigen-specific immunotherapies. An emulsion of the antioxidant tocopherol delivering an epitope of proteolipid protein autoantigen (PLP139-151) yielded significant efficacy in mice with experimental autoimmune encephalomyelitis (EAE). In vitro studies indicated tocopherol emulsions reduced oxidative stress in antigen-presenting cells. Ex vivo analysis revealed that tocopherol emulsions shifted cytokine responses in EAE splenocytes. In addition, IgG responses against PLP139-151 were increased in mice treated with tocopherol emulsions delivering the antigen, suggesting a possible skew in immunity. Overall, tocopherol emulsions provide a functional delivery vehicle for ASIT capable of ameliorating autoimmunity in a murine model.

Thermophoretic diagnosis of autoimmune diseases based on Escherichia coli with autodisplayed autoantigens

The autoimmune diseases systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS) are diagnosed by detection of autoantibodies against Ro and La protein autoantigens, respectively. In this work, the diagnosis of autoimmune diseases SLE and SS was demonstrated using thermophoresis of Escherichia coli with the autodisplayed autoantigens. Ro and La protein autoantigens were autodisplayed by constitutive expression together with a fluorescent protein called tdTomato in the cytosol. The binding affinity of the autodisplayed autoantigens was tested against positive and control sera by using FACS as a reference method. The factors influencing interactions between E. coli with autodisplayed autoantigens and autoantibodies in sera during thermophoresis were analyzed by measurement of cell surface charge and size before and after interaction. Finally, the thermophoretic diagnosis of autoimmune diseases SLE and SS was demonstrated using sera from patients afflicted with the respective diseases by estimating sensitivity and selectivity from ROC plots.

Simultaneous Distinction of Monospecific and Mixed DFS70 Patterns During ANA Screening with a Novel HEp-2 ELITE/DFS70 Knockout Substrate

Systemic autoimmune connective tissue disorders are characterized by circulating antinuclear antibodies (ANA). Although there are several technologies available for ANA screening, indirect immunofluorescence (IIF) using Human epithelial cells-2 (HEp-2) substrate remains the primary and recommended method because of its superior sensitivity. HEp-2 substrates can detect a multitude of patterns resulting from autoantibody binding to various protein and nucleic acid autoantigens distributed throughout the nucleus and cytoplasm of the cells. The great diversity of monospecific and mixed patterns resulting from positive reactions on HEp-2 substrate also complicate the interpretation and accuracy of reporting. One specific example which received utmost attention recently is the dense fine speckled 70 (DFS70) pattern resulting from autoantibodies that specifically bind to a protein called lens epithelium derived growth factor (LEDGF). Lack of clear association with a specific systemic autoimmune disease and high prevalence in healthy populations have made accurate interpretation of DFS70 pattern important. Accurate distinction of DFS70 pattern from disease-associated patterns using conventional HEp-2 substrate is challenging. Moreover, frequent co-occurrence of DFS70 pattern along with disease-associated patterns such as homogeneous, speckled, and mixed homogeneous-speckled patterns complicate the IIF interpretation. The goal of this paper is to demonstrate the utility of a novel engineered HEp-2 IIF substrate that retains all advantages of conventional HEp-2 substrate while simultaneously providing the ability to distinguish DFS70 pattern with high confidence in both monospecific and mixed ANA positive examples. The new substrate is further able to unmask disease-associated ANA patterns previously concealed by DFS70 pattern.

Simultaneous Distinction of Monospecific and Mixed DFS70 Patterns During ANA Screening with a Novel HEp-2 ELITE/DFS70 Knockout Substrate.

Systemic autoimmune connective tissue disorders are characterized by circulating antinuclear antibodies (ANA). Although there are several technologies available for ANA screening, indirect immunofluorescence (IIF) using Human epithelial cells-2 (HEp-2) substrate remains the primary and recommended method because of its superior sensitivity. HEp-2 substrates can detect a multitude of patterns resulting from autoantibody binding to various protein and nucleic acid autoantigens distributed throughout the nucleus and cytoplasm of the cells. The great diversity of monospecific and mixed patterns resulting from positive reactions on HEp-2 substrate also complicate the interpretation and accuracy of reporting. One specific example which received utmost attention recently is the dense fine speckled 70 (DFS70) pattern resulting from autoantibodies that specifically bind to a protein called lens epithelium derived growth factor (LEDGF). Lack of clear association with a specific systemic autoimmune disease and high prevalence in healthy populations have made accurate interpretation of DFS70 pattern important. Accurate distinction of DFS70 pattern from disease-associated patterns using conventional HEp-2 substrate is challenging. Moreover, frequent co-occurrence of DFS70 pattern along with disease-associated patterns such as homogeneous, speckled, and mixed homogeneous-speckled patterns complicate the IIF interpretation. The goal of this paper is to demonstrate the utility of a novel engineered HEp-2 IIF substrate that retains all advantages of conventional HEp-2 substrate while simultaneously providing the ability to distinguish DFS70 pattern with high confidence in both monospecific and mixed ANA positive examples. The new substrate is further able to unmask disease-associated ANA patterns previously concealed by DFS70 pattern.

Exploring pathogenesis of primary biliary cholangitis by proteomics: A pilot study.

AIMTo explore the pathogenesis of primary biliary cholangitis (PBC) by identifying candidate autoantibodies in serum samples by proteomics and bioinformatics.METHODSNine antimitochondrial antibody (AMA)-positive PBC patients and nine age- and sex-matched AMA-negative PBC patients were recruited. Antigen enrichment technology was applied to capture autoantigens of human intrahepatic biliary epithelial cells (HiBECs) that are recognized by autoantibodies from the sera of PBC patients. Candidate autoantigens were identified by label-free mass spectrometry. Bioinformatics analysis with MaxQuant software (version 1.5.2.8), DAVID platform, and Cytoscape v.3.0 allowed illustration of pathways potentially involved in the pathogenesis of PBC.RESULTSIn total, 1081 candidate autoantigen proteins were identified from the PBC patient pool. Among them, 371 were determined to be significantly differentially expressed between AMA-positive and -negative PBC patients (P < 0.05). Fisher’s exact test was performed for enrichment analysis of Gene Ontology protein annotations (biological processes, cellular components, and molecular functions) and the Kyoto Encyclopedia of Genes and Genomes pathways. Significantly different protein categories were revealed between AMA-positive and -negative PBC patients. As expected, autoantigens related to mitochondria were highly enriched in AMA-positive PBC patients. However, lower levels of AMA were also detected in AMA-negative PBC patients. In addition, autoantigens of AMA-negative PBC patients were mainly involved in B-cell activation, recognition of phagocytosis, and complement activation.CONCLUSIONAMA-negative PBC individuals may not exist, but rather, those patients exhibit pathogenesis pathways different from those of AMA-positive PBC. Comprehensive research is needed to confirm these observations.

HPV and systemic lupus erythematosus: a mosaic of potential crossreactions.

Etiology, pathogenesis, and immunology of systemic lupus erythematosus (SLE) form a complex, still undeciphered picture that recently has been further made complicated by a new factor of morbidity: human papillomaviruses (HPVs). Indeed, a prevalence of HPV infections has been reported among SLE patients. Searching for molecular mechanisms that might underlie and explain the relationship between HPV infection and SLE, we explored the hypothesis that immune responses following HPV infection may crossreact with proteins that, when altered, associate with SLE. Analyzing HPV L1 proteins and using Epstein-Barr virus (EBV) and human retrovirus (HERV) as controls, we found a vast peptide overlap with human proteins comprehending lupus Ku autoantigen proteins p86 and p70, lupus brain antigen 1 homolog, lupus antigen expressed in neurons and muscles, natural killer cell IgG-like receptors, complement proteins C4-A and C4-B, complement receptor CD19, and others. The multitude and heterogeneity of peptide overlaps not only further support the hypothesis that crossreactivity can represent a primum movens in SLE onset, but also provide a molecular framework to the concept of SLE as "an autoimmune mosaic syndrome." Finally, once more, it emerges the need of using the principle of peptide uniqueness as a new paradigm for safe and efficacious vaccinology.

Gene Polymorphisms for Both Auto-antigen and Immune-Modulating Proteins Are Associated with the Susceptibility of Autoimmune Myasthenia Gravis.

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease against antigens at the neuromuscular junction. Both genetic and environmental factors contribute to the susceptibility of MG. We undertook a case-control study to explore the contribution of genes of the auto-antigen and immune-modulating proteins in the pathogenesis of MG. We enrolled 389 adult MG patients and 487 healthy controls. Eighteen SNPs were selected from genes of cholinergic receptor nicotinic alpha 1 (CHRNA1), autoimmune regulator (AIRE), cytotoxic T lymphocyte-associated protein 4 (CTLA-4), protein tyrosine phosphatase nonreceptor type 22 (PTPN22), and interleukin-10 (IL-10). Rs16862847 and rs2229957 in CHRNA1, rs3761389 in AIRE, and rs733618 in CTLA-4 were significantly associated with MG, with the highest association in SNPs of CHRNA1. Carrier of rs16862847 G allele was found to be an independent risk factor in predicting high-level acetylcholine receptor (AChR) antibodies (P = 0.003, OR = 10.296). Genetic interaction analysis revealed a synergistic effect of CHRNA1 (rs16862847), AIRE (rs3761389), and CTLA-4 (rs733618) in the susceptibility of MG (P < 0.0001, OR = 1.95). These findings highlight the role of auto-antigen gene (CHRNA1) in the autoimmune reactions against AChR and reveal synergistic contribution of genes of both auto-antigen and immune-regulating proteins (AIRE and CTLA-4) in the pathogenesis of MG.

Serological and Genetic Evidence for Altered Complement System Functionality in Systemic Lupus Erythematosus: Findings of the GAPAID Consortium

Systemic lupus erythematosus is a chronic autoimmune disease with multifactorial ethiopathogenesis. The complement system is involved in both the early and late stages of disease development and organ damage. To better understand autoantibody mediated complement consumption we examined ex vivo immune complex formation on autoantigen arrays. We recruited patients with SLE (n = 211), with other systemic autoimmune diseases (n = 65) and non-autoimmune control subjects (n = 149). Standard clinical and laboratory data were collected and serum complement levels were determined. The genotype of SNP rs1143679 in the ITGAM gene was also determined. Ex vivo formation of immune complexes, with respect to IgM, IgG, complement C4 and C3 binding, was examined using a functional immunoassay on autoantigen microarray comprising nucleic acids, proteins and lipids. Complement consumption of nucleic acids increased upon binding of IgM and IgG even when serum complement levels were decreased due to consumption in SLE patients. A negative correlation between serum complement levels and ex vivo complement deposition on nucleic acid autoantigens is demonstrated. On the contrary, complement deposition on tested protein and lipid autoantigens showed positive correlation with C4 levels. Genetic analysis revealed that the non-synonymous variant rs1143679 in complement receptor type 3 is associated with an increased production of anti-dsDNA IgG antibodies. Notwithstanding, homozygous carriers of the previously reported susceptible allele (AA) had lower levels of dsDNA specific IgM among SLE patients. Both the non-synonymous variant rs1143679 and the high ratio of nucleic acid specific IgG/IgM were associated with multiple organ involvement. In summary, secondary complement deficiency in SLE does not impair opsonization of nucleic-acid-containing autoantigens but does affect other antigens and potentially other complement dependent processes. Dysfunction of the receptor recognizing complement opsonized immune complexes promotes the development of class-switched autoantibodies targeting nucleic acids.