Detection of Autoantibodies Against the Acetylcholine Receptor, Evaluation of Commercially Available Methodologies: Fixed Cell-Based Assay, Radioimmunoprecipitation Assay and Enzyme-Linked Immunosorbent Assay1.

Background/objective: Myasthenia Gravis (MG) is an autoimmune disorder characterized by pathogenic autoantibodies (AAbs) targeting nicotinic acetylcholine receptors (AChR), disrupting neuromuscular communication. RadioImmunoPrecipitation Assay (RIPA) is recommended to detect AChR AAbs, but its complexity and radioactive requirements limit widespread use. We compare non-RIPA anti-AChR immunoassays, including Cell-Based Assay (CBA) and two ELISA kits, against the gold standard RIPA.

Anti-ribosomal P (anti-P) antibodies in patients with autoimmune hepatitis.

Objective: Anti-P-ribosomal antibody is a biomarker of systemic lupus erythematosus mainly associated with renal, nervous, and hepatic involvement. Systemic lupus erythematosus may present with features similar to autoimmune hepatitis. This study aimed to investigate the association of Anti-P-ribosomal antibodies in systemic lupus erythematosus compared to autoimmune hepatitis in the general Brazilian population.

Brazilian autoimmune encephalitis network (BrAIN): antibody profile and clinical characteristics from a multicenter study.

Background: The frequency of antibodies in autoimmune encephalitis (AIE) may vary in different populations, however, data from developing countries are lacking. To describe the clinical profile of AIE in Brazil, and to evaluate seasonality and predictors of AIE in adult and pediatric patients.

Methods: We evaluated patients with possible AIE from 17 centers of the Brazilian Autoimmune Encephalitis Network (BrAIN) between 2018 and 2022.

Periostin as an important biomarker of inflammatory phenotype T2 in Brazilian asthma patients.

Objective: The aim of this study was to assess the laboratory performance of periostin associated with a panel of biomarkers to identify the inflammatory phenotype of Brazilian asthma patients.

Methods: We evaluated 103 Brazilian individuals, including 37 asthmatics and 66 nonasthmatic controls. Both groups underwent analyses for serum periostin, eosinophil levels in the peripheral blood, the fraction of exhaled nitric oxide (FeNO), total serum IgE, urinary leukotriene E4, and serum cytokines.

VI Brazilian consensus guidelines for detection of anti-cell autoantibodies on HEp-2 cells.

Background: The VI Brazilian Consensus on Autoantibodies against HEp-2 cells for determination of autoantibodies against cellular constituents on HEp-2 cells was held on September, 2019, in Fortaleza (CE, Brazil). The guidelines in this edition were formulated by the group of Brazilian experts discussing the classification of complex patterns, the classification of the nuclear discrete dots (few and multiple), the identification of the discrete fine speckled pattern (AC-4a) and improvements on the ANA report.

Mainbody: Sixteen Brazilian researchers and experts from universities and clinical laboratories representing the various geographical regions of Brazil participated in the meeting.

Transferrin saturation as a surrogate marker for assessment of labile nontransferrin bound iron in chronic liver disease.

Background: Increased transferrin saturation (TS) and ferritin are common in hereditary hemochromatosis (HH) but also in chronic liver diseases (CLD). Nontransferrin bound iron (NTBI) is believed to be associated with iron-induced cell damage. We aimed to evaluate NTBI in CLD and their relationship with liver damage.

Interkit Reproducibility of the Indirect Immunofluorescence Assay on HEp-2 Cells Depends on the Immunofluorescence Reactivity Intensity and Pattern.

Introduction: The indirect immunofluorescence assay on HEp-2 cells (HEp-2/IFA) is used worldwide for screening for autoantibodies to cellular antigens. Cell culture and fixation methods influence the cell distribution of autoantigens and the preservation of epitopes. Therefore, discrepancy of results obtained using different HEp-2/IFA kits (interkit nonreproducibility) is a common phenomenon in the clinical laboratory routine.

Strong Association of the Myriad Discrete Speckled Nuclear Pattern With Anti-SS-A/Ro60 Antibodies: Consensus Experience of Four International Expert Centers.

Introduction: The morphological patterns in indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) reflect the autoantibodies in the sample. The International Consensus on ANA Patterns (ICAP) classifies 30 relevant patterns (AC-0 to AC-29). AC-4 (fine speckled nuclear pattern) is associated to anti-SS-A/Ro, anti-SS-B/La, and several autoantibodies.

Antineutrophil cytoplasmic antibody profiles differ according to type of primary sclerosing cholangitis and autoimmune hepatitis.

Objectives: To determine the frequency of the antineutrophil cytoplasmic antibodies (ANCA), antiproteinase-3 and antimyeloperoxidase, in primary sclerosing cholangitis (PSC) with or without inflammatory bowel disease (IBD+ or IBD-) and in different types of autoimmune hepatitis (AIH). Additionally, to verify the agreement between ANCA patterns by indirect immunofluorescence and their antigenic specificities by ELISA.

Methods: For this study, 249 patients were enrolled (42 PSC/IBD+; 33 PSC/IBD-; 31 AIH type-1; 30 AIH type-2; 31 AIH type-3; 52 primary biliary cirrhosis; 30 healthy controls) whose serum samples were tested for ANCA autoantibodies.

Changes in the result of antinuclear antibody immunofluorescence assay on HEp-2 cells reflect disease activity status in systemic lupus erythematosus.

Background The objective of the study was to determine whether the staining pattern and titer of indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) are associated with systemic lupus erythematosus (SLE) disease activity. Methods A total of 269 consecutive patients meeting the ACR and SLICC criteria for SLE were classified into three groups according to the SLE Disease Activity Index 2000 (SLEDAI2K): Remission (SLEDAI2K = 0; n = 47); Intermediate (SLEDAI2K = 1-5; n = 111); Active (SLEDAI2K ≥ 6; n = 111). All subjects were assessed for HEp-2 IFA titer and staining pattern and nine traditional parameters of SLE disease activity.

NMDAR Encephalitis Associated With Acute Chikungunya Virus Infection: A New Trigger?

Anti-NMDAR encephalitis is the most frequent cause of autoimmune encephalitis. Chikungunya (CHIK) is an arbovirus responsible for outbreaks of fever, cutaneous rash and arthritis in underdeveloped countries, and a trigger for autoimmunity. We report a five-year-old male patient with fever, myalgia, headache and conjunctivitis for 5 days.

Evolving liver inflammation in biochemically normal individuals with anti-mitochondria antibodies.

Background: Anti-mitochondria autoantibodies (AMA) occur in > 95% primary biliary cholangitis (PBC) patients. Biochemically normal AMA-positive (BN/AMA+) individuals, occasionally noticed by indirect immunofluorescence (IIF) on HEp-2 cells and confirmed in AMA-specific assays, may represent early stages of PBC. The Enhanced Liver Fibrosis (ELF) score is a surrogate marker for liver fibrosis.

Correction to: V Brazilian consensus guidelines for detection of anti-cell autoantibodies on hep-2 cells.

After publication of the original article [1], we were notified that there is a mistake in Fig. 2.

V Brazilian consensus guidelines for detection of anti-cell autoantibodies on hep-2 cells.

Background: The V Brazilian Consensus for determination of autoantibodies against cellular constituents on HEp-2 cells, held in Brasilia (DF, Brazil) on August 27, 2016, discussed the harmonization between the Brazilian Consensus on ANA (BCA) guidelines and the International Consensus on ANA Patterns (ICAP) recommendations ( www.anapatterns.org ).

Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies: proof-of-concept study for a novel Megapool strategy by pooling individual specific sera.

Background International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies.

Detection of Autoantibodies by Indirect Immunofluorescence Cytochemistry on Hep-2 Cells.

Indirect immunofluorescence assay (IFA) has been used for detection of autoantibodies against cellular antigens for more than 50 years. Originally using rodent tissue as substrate, the method was optimized by using the human immortal HEp-2 cell line derived from a larynx epidermal carcinoma. The HEp-2/IFA platform allows for optimal visualization of several cellular domains recognized by autoantibodies in the samples being tested.

Latent Class Analysis of Noninvasive Methods and Liver Biopsy in Chronic Hepatitis C: An Approach without a Gold Standard.

Aims: To evaluate the applicability of the Latent Class Analysis (LCA) and accuracy of transient elastography (TE), aspartate-to-platelet-ratio-index (APRI), enhanced liver fibrosis (ELF), and liver biopsy (LB) for liver fibrosis assessment in a model without a gold standard.

Methods: Significant fibrosis was defined as TE ≥ 7.1 kPa, APRI ≥ 1.

Enhanced liver fibrosis (ELF) score: Analytical performance and distribution range in a large cohort of blood donors.

Background: The Enhanced Liver Fibrosis (ELF) is a serological score that includes hyaluronic acid (HA), tissue inhibitor of matrix metalloproteinases-1(TIMP-1), and aminoterminal propeptide of type III procollagen (PIIINP) and shows good performance for detecting liver fibrosis. There are few studies evaluating ELF's intra and inter-assay variation and stability of the samples. The influence of host variables, such as age, gender and body mass index (BMI) is also not well known.

Strategies for building reference standards for autoantibodies.

Producing robust, certified, traceable reference material for autoantibody testing is a vital element in maintaining the validity of results that are generated in the daily clinical laboratory routine. This is a huge challenge because of the high number of variables involved in the detection and measurement of the autoantibodies. The production of such materials is time consuming and needs rigorous attention to detail; this is best achieved by an overarching independent body who will oversee the process in a "not for profit" manner.

The challenge of identification of autoantibodies specific to systemic autoimmune rheumatic diseases in high throughput operation: proposal of reliable and feasible strategies.

Background: Autoantibodies to extractable nuclear antigens (ENA) are good biomarkers for systemic autoimmune rheumatic diseases (SARD), but no one assay for the detection of these antibodies provides satisfactory sensitivity and positive predictive value (PPV). Here we evaluate current assays and propose novel strategies to detect anti-ENA antibodies.

Methods: Diagnostic performance of double immunodiffusion (DID) and several enzyme immunoassays (EIA) for the detection of anti-ENA autoantibodies was determined using samples from 144 patients with a previous clinical diagnosis of SARD and 121 non-autoimmune individuals.

IV Brazilian guidelines for autoantibodies on HEp-2 cells.

Objective: The Fourth Brazilian Consensus for Autoantibodies Screening in HEp-2 Cells (ANA) was held in Vitória, Espírito Santo, and aimed to discuss strategies and recommendations about the technique, standardization, interpretation and quality control of the indirect immunofluorescence reaction on HEp-2 cells.

Methods: Twenty three ANA experts from university centers and private laboratories in different areas from Brazil discussed and agreed upon recommendations for the fourth edition of the Brazilian Consensus for Autoantibodies Screening in HEp-2 Cells.

Results And Conclusion: The 4th ANA Consensus included three novel patterns into the existing algorithm (cytoplasmic Rods and Rings, nuclear Quasi-homogeneous, and CENP-F).

Enhanced liver fibrosis panel as a predictor of liver fibrosis in chronic hepatitis C patients.

Background: Evaluation of fibrosis is crucial in the assessment of chronic hepatitis C (CHC). The enhanced liver fibrosis (ELF) is a serological panel including hyaluronic acid (HA), tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), and amino-terminal propeptide of type III procollagen (PIIINP) that has shown good results in predicting liver fibrosis in distinct scenarios of chronic liver diseases.

Aims: We aimed to assess the performance of ELF on the detection of fibrosis and cirrhosis in a CHC patient cohort and to compare the results of ELF and transient elastography (TE-Fibroscan) using liver biopsy as reference.