The significance of cytoplasmic antinuclear antibody patterns in autoimmune liver disease

Clinical relevance and frequency of cytoplasmic patterns observed in ANA-Hep-2: experience of Cairo University Hospitals

Antinuclear antibodies (ANA) are the most common biomarkers observed in autoimmune diseases. Cytoplasmic staining patterns on ANA-Hep-2 are gaining recognition but with scanty information about their clinical and diagnostic role. The aim is to assess the frequency of cytoplasmic ANA patterns in autoimmune diseases, and to evaluate their possible associations with clinical diagnoses and autoantibodies. This observational cross-sectional study was conducted by examining and/or reviewing ANA by indirect immunofluorescence assay during a 13-month period. This was followed by testing the group of patients with a positive cytoplasmic staining pattern (n = 92) using the Microblot-Array ANA plus for the presence of 44 specific autoantibodies. Out of 2741 samples, 1791 (65.3%) tested negative, 845 (30.9%) tested positive nuclear staining patterns, 56 (2.0%) positive solitary cytoplasmic staining patterns, and 49 (1.8%) positive mixed nuclear and cytoplasmic patterns. Ninety-two cases (3.4% of the total cases) were analyzed using Microblot-Array ANA plus, with reticular as the most frequent cytoplasmic pattern, followed by dense fine speckled. The most frequently associated disease with reticular pattern was primary biliary cholangitis (28.9%), and the most frequently detected autoantibodies were against M2 (66.7%). The most frequently associated disease with dense fine speckled pattern was systemic lupus erythematosus (69.4%), and the most frequently detected autoantibodies were against nucleosome (57.7%) and ribosomal P0 (53.8%). This study highlights the significance of reporting cytoplasmic staining patterns and their importance in assessment of autoimmune diseases. Larger cohort studies on treatment naïve patients are recommended.

Clinical Significance of Uncommon, Non-Clinical, and Novel Autoantibodies

Autoantibodies are a common mark of autoimmune reaction and their identification in the patients' serum, cerebrospinal fluid, or tissues is generally believed to represent diagnostic or prognostic biomarkers of autoimmune diseases or autoinflammatory conditions. Traditionally, autoantibody testing is an important part of the clinical examination of suspected patients, and in the absence of reliable T cell tests, characterization of autoantibody responses might be suitable in finding causes of specific autoimmune responses, their strength, and sometimes commencement of autoimmune disease. Autoantibodies are also useful for prognostic stratification in clinically diverse groups of patients if checked repeatedly. Antibody discoveries are continuing, with important consequences for verifying autoimmune mechanisms, diagnostic feasibility, and clinical management. Adding newly identified autoantibody-autoantigen pairs to common clinical laboratory panels should help upgrade and harmonize the identification of systemic autoimmune rheumatic disorders and other autoimmune conditions. Herein, we aim to summarize our current knowledge of uncommon and novel autoantibodies in the context of discussing their validation, diagnostic practicability, and clinical relevance. The regular updates within the field are important and well justified.

Complex patterns on HEp-2 indirect immunofluorescence assay in a large sample referred for anti-cell autoantibodies detection

Introduction

The combination of patterns is a frequent and challenging situation in the daily laboratory routine of autoantibodies testing using HEp-2 cells indirect immunofluorescence assay (HEp-2-IFA). Recently, the Brazilian Consensus on Autoantibodies (BCA) named these combinations as complex patterns (CPs) and organized them into 3 subtypes: multiple, mixed, and composite. This study aimed to describe the most frequent combinations of HEp-2-IIF patterns according to this new nomenclature.

Methods

Routine HEp-2-IFA results reported in January and June 2017 were reviewed using the new BCA classification. Visual pattern recognition was performed by experts on HEp-2-IFA readings, using the International Consensus on Antinuclear Antibodies (ANA) Patterns (ICAP) and BCA recommendations.

Results

54,990 serum samples from different patients were tested for ANA-HEp-2, and 11,478 (20.9%) were positive at a titer ≥ 1/80. Among these positive samples, 1,111 (9.7%) displayed CPs, divided into 95 different combinations. A higher proportion of CPs was observed in the pediatric age group. Multiple, mixed, and composite patterns were present in 85.3, 5.4, and 9.5% of the samples, respectively. In the multiple/mixed pattern group (n=1,005), double, triple, and quadruple combinations (ICAP/BCA codes) were observed in 97.7%, 2.2%, and 0.1%, respectively. The double nuclear pattern was the most prevalent combination observed (67.6%). The most common CPs registered were AC-4 (nuclear fine speckled) + AC-6,7 (nuclear discrete dots) (n=264); AC-2 (nuclear dense fine speckled) + AC-6,7 (n=201); AC-4+AC-8,9,10 (nucleolar) (n=129); and AC-3 (centromere)+AC-4 (n=124). All of these combinations were in the multiple subgroup.

Conclusion

Almost 10% of positive results in the HEp-2 procedure displayed CPs. Among the 3 subtypes of CPs proposed, the multiple pattern was the most prevalent, especially in the pediatric population. The AC-4, AC-2, and AC-6,7 were the most prevalent single patterns observed in the combinations described in this study. There was a significant association between age and the prevalence of most combined patterns. The AC-4+AC-6,7 combination was the most prevalent complex pattern detected regardless of the age group. The AC-2+AC-6,7 was more prevalent in younger individuals. The concepts involved in the CPs definition should add value to the reading and interpretation of the HEp-2-IIF assay.

Clinical value of chemiluminescence method for detection of antinuclear antibody profiles

BACKGROUND

Antinuclear antibodies (ANAs) are crucial in diagnosing autoimmune diseases, mainly systemic lupus erythematosus (SLE). This study aimed to compare the performance of chemiluminescence assay (CLIA) and line immunoassay (LIA) in detecting ANAs in patients with autoimmune diseases, evaluate their diagnostic accuracy for SLE, and develop a novel diagnostic model using CLIA-detected antibodies for SLE. Specimens from patients with autoimmune diseases and physical examination specimens were collected to parallel detect specific antibodies. Individual antibodies' diagnostic performance and a model combining multiple antibodies were assessed. The findings provide valuable insights into improving the diagnosis of SLE through innovative approaches.

AIM

To compare the performance of CLIA and LIA in detecting ANAs in patients with autoimmune diseases, assess their accuracy for SLE, and develop a novel diagnostic model using CLIA-detected antibodies for SLE.

METHODS

Specimens have been obtained from 270 patients with clinically diagnosed autoimmune disorders, as well as 130 physical examination specimens. After that, parallel detection of anti-double-stranded DNA (dsDNA) antibody, anti-histone (Histone) antibody, anti-nucleosome (Nuc) antibody, anti-Smith (Sm) antibody, anti-ribosomal P protein (Rib-P) antibody, anti-sicca syndrome A (Ro60) antibody, anti-sicca syndrome A (Ro52) antibody, anti-sicca syndrome (SSB) antibody, anti-centromere protein B (Cenp-B) antibody, anti-DNA topoisomerase 1 (Scl-70) antibody, anti-histidyl tRNA synthetase (Jo-1) antibody, and anti-mitochondrial M2 (AMA-M2) antibody was performed using CLIA and LIA. The detection rates, compliance rates, and diagnostic performance for SLE were compared between the two methodologies, followed by developing a novel diagnostic model for SLE.

RESULTS

CLIA and LIA exhibited essentially comparable detection rates for anti-dsDNA antibody, anti-Histone antibody, anti-Nuc antibody, anti-Sm antibody, anti-Rib-P antibody, anti-Ro60 antibody, anti-Ro52 antibody, anti-SSB antibody, anti-Cenp-B antibody, anti-DNAScl-70 antibody, anti-Jo-1 antibody and anti-AMA-M2 antibody (P > 0.05). The two methods displayed identical results for the detection of anti-dsDNA antibody, anti-Histone antibody, anti-Nuc antibody, anti-Sm antibody, anti-Ro60 antibody, anti-Ro52 antibody, anti-SSB antibody, anti-Cenp-B antibody, anti-Scl-70 antibody, and anti-AMA-M2 antibody (Kappa > 0.7, P < 0.05), but showed a moderate agreement for the detection of anti-Rib-P antibody and anti-Jo-1 antibody (Kappa = 0.671 and 0.665; P < 0.05). In addition, the diagnostic performance of these antibodies detected by both methods was similar for SLE. The diagnostic model's area under the curve values, sensitivity, and specificity, including an anti-dsDNA antibody and an anti-Ro60 antibody detected by CLIA, were 0.997, 0.962, and 0.978, respectively. These values were higher than the diagnostic performance of individual antibodies.

CONCLUSION

CLIA and LIA demonstrated excellent overall consistency in detecting ANA profiles. A diagnostic model based on CLIA-detected antibodies can successfully contribute to developing a novel technique for detecting SLE.

Uncommon types of autoantibodies - Detection and clinical associations

Immunofluorescence is a basic method for detection of autoantibodies in serum. It is used as screening for people with symptoms suggesting autoimmune process and disease. Antinuclear antibodies (ANA) assay detecting antibodies against nuclear proteins used commonly for diagnosis of systemic autoimmune disease, although antibodies against cytoplasmic components and mitotic structures are usable in clinic. The majority of ANA nuclear patterns have been comprehensively studied with increasing data. However, the cytoplasmic and mitotic patterns are underestimated and still require further assessment. In this review the clinical associations and significance of uncommon types of autoantibodies are presented and discussed.

The Ultrastructure of Hepatic Stellate Cell-Macrophage Intercellular Crosstalk as a New Morphological Insight into Phenomenon of Fibrogenesis in Pediatric Autoimmune Hepatitis

The aim of the study was the pioneering retrospective ultrastructural evaluation of respective forms of hepatic stellate cells (HSCs) and analysis of their crosstalk with other adjacent nonparenchymal cells (NPCs), especially Kupffer cells/macrophages (KCs/MPs), in pediatric autoimmune hepatitis (AIH).

METHODS

Ultrastructural assessment of the HSC population and NPCs was performed in transmission electron microscopy (TEM) using pretreatment liver biopsies from 25 children (8 boys and 17 girls) aged 4-17 with clinic-pathologically diagnosed untreated AIH.

RESULTS

Submicroscopic evaluation allowed easy identification of numerous HSCs in the form of transitory cells, i.e., T-HSCs, accompanied by signs of fibrosis. T-HSCs included cells with features of activation initiation (iHSCs) and activation perpetuation (pHSCs), indicating high HSC activation plasticity. The pHSCs were markedly elongated and mainly showed a distinct loss of lipid cytoplasmic material, expanded and dilated channels of granular endoplasmic reticulum, and linear bundles of microfilaments beneath the cell membrane. They were surrounded by usually mature collagen fibers. Frequently activated KCs/MPs adhered directly to T-HSCs. Between them, tight intercellular junctions were formed by means of point desmosomes.

CONCLUSIONS

Our qualitative TEM observations indicate a key role of T-HSCs in liver fibrogenesis in pediatric AIH, with the essential involvement of activated KCs/MPs that directly adhere to them. Tight intercellular junctions, being the ultrastructural exponent of the specific cellular mechanisms of the crosstalk between NPCs, can play a vital role in hepatic collagen fibroplasia. A better understanding of HSC population morphology at the ultrastructural level in AIH seems important not only to improve the disease morphological diagnostics but to also provide new insights into therapeutic interventions for the phenomenon of liver fibrogenesis.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.