Diagnostic and prognostic role of synovial tissue analysis in juvenile idiopathic arthritis: a monocentric study

OBJECTIVES

This study investigates the diagnostic role of synovial tissue analysis in children presenting with arthritis and assesses its prognostic significance to predict clinical outcome in juvenile idiopathic arthritis (JIA).

METHODS

Synovial samples of paediatric patients undergoing synovial biopsy between 1995 and 2020 were analysed histologically and immunohistochemically. Relationships between histological/immunohistochemical parameters and clinical variables were assessed.

RESULTS

Synovial biopsy was performed for diagnosis in 65 cases allowing to correctly classify 79% of patients.At histological analysis on 42 JIA samples, any difference in the number of synovial lining layers, subsynovial elementary lesions, fibrin deposit, Krenn Synovitis Score, inflammatory infiltrate score and pattern emerged between JIA subsets or on treatment exposure. Synovial tissue analysis predicted outcome: higher number of synovial layers predicted worse disease course (>4 flares during follow-up; 4.5 vs 3.0, p=0.035), even after adjusting for age at diagnosis and observation time (OR 2.2, p=0.007); subjects who had switched>2 biological disease-modifying antirheumatic drugs had higher prevalence of subsynovial elementary lesions (55.6% vs 10.3%, p=0.005) and fibrin deposits in synovial lining (60.0% vs 22.6%, p=0.049), even after adjustment for observation time and age at diagnosis (OR 8.1, p=0.047). At immunohistochemistry on 31 JIA samples, higher CD3 expression was described in polyarticular compared with oligoarticular subset (p=0.040). Patients with severe disease course had higher CD20+ rate (OR 7, p=0.023), regardless of JIA subset and treatment exposure.

CONCLUSIONS

Synovial tissue analysis might support the clinicians in the diagnostic approach of paediatric patients presenting with arthritis and guide the clinical management in JIA.

Fluctuation of Anti-Domain 1 and Anti-Β2 Glycoprotein I Antibody Titers Over Time in Patients with Persistently Positive Antiphospholipid Antibodies

OBJECTIVE

This work aims at evaluating longitudinally titers of antibodies against β2-glycoprotein I (β2GPI) and domain 1 (anti-D1), identifying predictors of the variation of anti-D1 and anti-β2GPI antibody titers and clarifying whether antibody titer fluctuations predict thrombosis in a large international cohort of patients persistently positive for antiphospholipid antibodies (aPL), the "APS ACTION Registry".

METHODS

Patients with available blood samples from at least 4 time points were included. Anti-β2GPI and anti-D1 IgG were tested by chemiluminescence (BioFlash, INOVA Diagnostics).

RESULTS

In a cohort of 230 patients, anti-D1 and anti-β2GPI titers decreased significantly over time (p<0.0001 and p=0.010, respectively). After adjustment for age, gender, and number of positive aPL tests, the fluctuation of anti-D1 and anti-β2GPI titers was associated with treatment with hydroxychloroquine (HCQ) at each time-point. Treatment with HCQ, but not immunosuppressors, was associated with 1.3-fold and 1.4-fold decrease in anti-D1 and anti-β2GPI titers, respectively. Incident vascular events were associated with 1.9-fold and 2.1-fold increase of anti-D1 and anti-β2GPI titers, respectively. Anti-D1 and anti-β2GPI titers at the time of thrombosis were lower compared to the other time-points: 1.6-fold decrease in anti-D1 titers and 2-fold decrease in anti-β2GPI titers conferred an OR for incident thrombosis of 6.0 (95%CI 0.62-59.3) and 9.4 (95%CI 1.1-80.2), respectively.

CONCLUSIONS

Treatment with HCQ and incident vascular events significant predicted anti-D1 and anti-β2GPI titer fluctuation over time. Both anti-D1 and anti-β2GPI titers drop around the time of thrombosis, with potential clinical relevance. This article is protected by copyright. All rights reserved.

Complement activation predicts negative outcomes in COVID-19: The experience from Northen Italian patients

Coronavirus disease 19 (COVID-19) may present as a multi-organ disease with a hyperinflammatory and prothrombotic response (immunothrombosis) in addition to upper and lower airway involvement. Previous data showed that complement activation plays a role in immunothrombosis mainly in severe forms. The study aimed to investigate whether complement involvement is present in the early phases of the disease and can be predictive of a negative outcome. We enrolled 97 symptomatic patients with a positive RT-PCR for SARS-CoV-2 presenting to the emergency room. The patients with mild symptoms/lung involvement at CT-scan were discharged and the remaining were hospitalized. All the patients were evaluated after a 4-week follow-up and classified as mild (n. 54), moderate (n. 17) or severe COVID-19 (n. 26). Blood samples collected before starting any anti-inflammatory/immunosuppressive therapy were assessed for soluble C5b-9 (sC5b-9) and C5a plasma levels by ELISA, and for the following serum mediators by ELLA: IL-1β, IL-6, IL-8, TNFα, IL-4, IL-10, IL-12p70, IFNγ, IFNα, VEGF-A, VEGF-B, GM-CSF, IL-2, IL-17A, VEGFR2, BLyS. Additional routine laboratory parameters were measured (fibrin fragment D-dimer, C-reactive protein, ferritin, white blood cells, neutrophils, lymphocytes, monocytes, platelets, prothrombin time, activated partial thromboplastin time, and fibrinogen). Fifty age and sex-matched healthy controls were also evaluated. SC5b-9 and C5a plasma levels were significantly increased in the hospitalized patients (moderate and severe) in comparison with the non-hospitalized mild group. SC5b9 and C5a plasma levels were predictive of the disease severity evaluated one month later. IL-6, IL-8, TNFα, IL-10 and complement split products were higher in moderate/severe versus non-hospitalized mild COVID-19 patients and healthy controls but with a huge heterogeneity. SC5b-9 and C5a plasma levels correlated positively with CRP, ferritin values and the neutrophil/lymphocyte ratio. Complement can be activated in the very early phases of the disease, even in mild non-hospitalized patients. Complement activation can be observed even when pro-inflammatory cytokines are not increased, and predicts a negative outcome.

Anti-Phospholipid Antibodies and Coronavirus Disease 2019: Vaccination Does Not Trigger Early Autoantibody Production in Healthcare Workers

A molecular mimicry between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human proteins supports the possibility that autoimmunity takes place during coronavirus disease 2019 (COVID-19) contributing to tissue damage. For example, anti-phospholipid antibodies (aPL) have been reported in COVID-19 as a result of such mimicry and thought to contribute to the immunothrombosis characteristic of the disease. Consistently, active immunization with the virus spike protein may elicit the production of cross-reactive autoantibodies, including aPL. We prospectively looked at the aPL production in healthcare workers vaccinated with RNA- (BNT162b2, n. 100) or adenovirus-based vaccines (ChAdOx1, n. 50). Anti-cardiolipin, anti-beta2 glycoprotein I, anti-phosphatidylserine/prothrombin immunoglobulin G (IgG), IgA, and IgM before and after vaccination were investigated. Anti-platelet factor 4 immunoglobulins were also investigated as autoantibodies associated with COVID-19 vaccination. Additional organ (anti-thyroid) and non-organ (anti-nuclear) autoantibodies and IgG against human proteome were tested as further post-vaccination autoimmunity markers. The antibodies were tested one or three months after the first injection of ChAdOx1 and BNT162b2, respectively; a 12-month clinical follow-up was also performed. Vaccination occasionally induced low titers of aPL and other autoantibodies but did not affect the titer of pre-existing autoantibodies. No significant reactivities against a microarray of approximately 20,000 human proteins were found in a subgroup of ChAdOx1-vaccinees. Consistently, we did not record any clinical manifestation theoretically associated with an underlying autoimmune disorder. The data obtained after the vaccination (two doses for the RNA-based and one dose for the adenovirus-based vaccines), and the clinical follow-up are not supporting the occurrence of an early autoimmune response in this cohort of healthcare workers.

POS0462 HYDROXYCHLOROQUINE REDUCES THE TITERS OF ANTI-DOMAIN 1 ANTIBODIES OVER TIME IN PATIENTS WITH PERSISTENTLY POSITIVE ANTIPHOSPHOLIPID ANTIBODIES: RESULTS FROM THE APS ACTION CLINICAL DATABASE AND REPOSITORY (“REGISTRY”)

Background

Data on fluctuation of antibodies directed against domain 1 (anti-D1) of β2-glycoprotein I (β2GPI) are scarce. Patients with antiphospholipid syndrome (APS) and all three criteria tests for antiphospholipid antibodies (aPL) display higher titers of anti-D1, which correlate with anti-β2GPI levels.

Objectives

This project aims at evaluating predictors of the variation of anti-D1 titers over time in a large international cohort of persistently aPL positive patients.

Methods

AntiPhospholipid Syndrome Alliance For Clinical Trials and InternatiOnal Networking (APS ACTION) Registry was created to study the course of persistently aPL-positive patients with or without autoimmune disorders over at least 10 years. Inclusion criteria are positive aPL by Updated Sapporo Criteria tested within one year prior to enrolment. Patients are followed every 12±3 months with clinical data and blood collection. Patients with available blood samples from at least three time points were included in this analysis. Anti-β2GPI and anti-D1 IgG were tested by chemiluminescence (BioFlash, Werfen) at APS ACTION core laboratories. Positive results were defined as >20 CU, according to the manufacturer. Clinical data were retrieved from APS ACTION online database. Anti-D1 titers within the same subject were compared by Friedman’s test. A mixed linear model was built to identify predictors of the fluctuation of anti-D1 antibody titers over time.

Results

In this longitudinal study, 230 patients with anti-D1 tested at 4 time points were included (Table 1). Patients with thrombotic APS had anti-D1 titers significantly higher than those without thrombosis (p=0.022). Among 135 patients with at least one anti-D1 positive result, anti-D1 titers varied significantly over time (Friedman statistics: 508.5, p<0.0001; anti-D1 geometric mean at baseline 189.0; T1 132.3 [-15%]; T2 113.8 [-17%]; T3 109.2 [-6% versus T2, -38% versus T1]). Anti-D1 titers were significantly higher at baseline compared to T3 (p=0.029). In the 4 years of follow-up, 18 new thrombotic events occurred. Patients with double/triple aPL positivity displayed 12.5 fold increase [95%CI 7.4-20.0] in baseline anti-D1 titers. After adjustment for age, gender and number of positive aPL tests, the fluctuation of anti-D1 titers was associated with treatment with hydroxychloroquine (HCQ) at each time-point. In particular, treatment with HCQ, but not those with conventional immunosuppressors, was associated with a 1.3-fold decrease in anti-D1 titers [95%CI 1.1-1.5]. In the same multivariable model, incident vascular events were associated with a 1.5 fold increase of anti-D1 titers. A concomitant diagnosis of systemic lupus erythematosus did not affect the fluctuation of anti-D1 titers.

Table 1.

Demographic and Clinical Characteristics of 230 APS ACTION Registry Patients with anti-D1 tested ≥3 time points during the follow-up

Anti-D1 pos samplesAnti-D1 neg samplesp-valueOverall sample(n=135)(n=95)(n=230)Age [years] mean (SD)42.3 (11.8)48.8 (13.0)0.000145.0 (12.7)%Female (n)71.9 (97)65.3 (62)0.35869.1 (159)Associated systemic autoimmune disease39.3 (53)44.2 (42)0.53941.3 (95)aPL without APS19.3 (26)34.7 (33)0.01025.7 (59)Thrombotic APS54.1 (73)53.7 (51)53.9 (124)Obstetric APS11.9 (16)5.3 (5)9.1 (21)Thrombotic/+obstetric APS14.8 (20)6.3 (6)11.3 (26)aCL IgG89.5 (119/133)25.5 (24/94)<0.000163.0 (143/227)aCL, IgM36.1 (48/133)27.7 (26/94)0.23432.6 (74/227)Anti-2GPI, IgG93.2 (124/133)39.4 (37/94)<0.000170.9 (161/227)Anti-2GPI, IgM34.6 (46/133)21.3 (20/94)0.04329.1 (66/227)LA82.8 (82/99)59.5 (44/74)0.00172.8 (126/173)

Conclusion

Treatment with HCQ and vascular events during follow-up were identified as significant predictors of the fluctuation of anti-D1 antibody titers over time.

Disclosure of Interests

None declared.

Tumor Necrosis Factor-α Inhibition Before and After Rituximab Treatment in Juvenile Idiopathic Arthritis: What Shall We Expect? A Pilot Study

Rituximab (RTX), a chimeric monoclonal antibody against B cell antigen CD20, has been used in patients with recalcitrant juvenile idiopathic arthritis ( JIA) with some efficacy.1,2 The resetting of peripheral B cells promoted by RTX represents quite an interesting option in autoimmune diseases such as JIA, not only for the immediate effect but also for the possible use of other therapies that might be necessary to achieve disease control.

Pregnancy in juvenile idiopathic arthritis: maternal and foetal outcome, and impact on disease activity

Objective:

This retrospective cohort study describes the modulation of disease activity during gestation and in the year following delivery as well as maternal and neonatal outcomes in a monocentric cohort of women with juvenile idiopathic arthritis (JIA).

Methods:

Disease activity was assessed using DAS28-CRP before conception and every 3 months during pregnancy and in the first year postpartum. The risk of complicated pregnancies was measured applying a generalized estimating equation model. Changes in disease activity during gestation and in the first year postpartum were assessed in a linear mixed model for repeated measures.

Results:

Thirty-one women (49 pregnancies) with persisting JIA and at least one conception were enrolled. Adjusted DAS28-CRP levels remained stable from preconception through the first trimester, but increased significantly in the second and decreased not significantly in the third. In the postpartum, adjusted disease activity peaked at 3 months after delivery, stabilized at 6 months to decrease at 1 year, although not significantly. Preconceptional DAS28-CRP and number of biological drugs predicted disease activity fluctuation during gestation. The number of biological drugs and the length of gestational exposure to biologics significantly predicted pregnancy morbidity. In particular, JIA women had a higher probability of preterm delivery compared with healthy and disease controls. Adjusted for breastfeeding and DAS28-CRP score in the third trimester, postconceptional exposure to biologics was inversely related with disease activity in the postpartum: the longer the patient continued treatment, the lower the probability of experiencing an adverse pregnancy outcome.

Conclusion:

These data offer novel insights on how treatment affects disease activity during pregnancy and postpartum as well as obstetric outcomes in women with JIA.

Hyaluronic Acid Therapy in Hip OA Does Not Perform Equally in Osteoarthritis Secondary to Juvenile Idiopathic Arthritis When Compared to Primary Osteoarthritis: A 2-Year Preliminary Evaluation

OBJECTIVE

Hip involvement in juvenile idiopathic arthritis (JIA) is one of most important causes of pain and disability. Total hip arthroplasty (THA) is considered the standard when medical approaches fail to relieve pain. However, THA is problematic for many reasons. As current literature lacks studies valuating medical management of osteoarthritis (OA) secondary to JIA, we assessed the long-term pain relief effect of US-guided intra-articular viscosupplementation in hip osteoarthritis secondary to JIA versus primary OA under different etiological conditions.

METHODS

Patients in both groups received intra-articular Hylan G-F 20 2 ml once a month for 3 consecutive months and every 6 months for 2 years as maintenance. Effectiveness (VAS and WOMAC), NSAID/analgesic consumption, tolerability, withdrawals and reason for discontinuation were collected at each time point. An inverse probability weighting was used to balance the two groups.

RESULTS

We retrospectively retrieved data of 14 JIA patients and 26 primary OA. Weighting successfully accounted for differences between the disease groups supporting the results. Viscosupplementation led to an early and significant improvement of pain and function and concomitant decrease in NSAIDs consumption, while the response diverged over 1 year with loss of benefits in JIA. The worst outcome was observed in active JIA.

CONCLUSIONS

Duration of symptom relief after intra-articular injection of hyaluronic acid depends on the nature of arthritis. Multiple courses of viscosupplementation are required to maintain low-dose NSAIDs consumption in patients responsive to treatment while shortening the time between consecutive injections might provide persistent positive results in patients suffering from JIA.

Neuropsychiatric involvement in juvenile-onset systemic lupus erythematosus: Data from the UK Juvenile-onset systemic lupus erythematosus cohort study

INTRODUCTION

Juvenile-onset systemic lupus erythematosus (JSLE) is a rare autoimmune/inflammatory disease with significant morbidity and mortality. Neuropsychiatric (NP) involvement is a severe complication, encompassing a heterogeneous range of neurological and psychiatric manifestations.

METHODS

Demographic, clinical, and laboratory features of NP-SLE were assessed in participants of the UK JSLE Cohort Study, and compared to patients in the same cohort without NP manifestations.

RESULTS

A total of 428 JSLE patients were included in this study, 25% of which exhibited NP features, half of them at first visit. Most common neurological symptoms among NP-JSLE patients included headaches (78.5%), mood disorders (48.6%), cognitive impairment (42%), anxiety (23.3%), seizures (19.6%), movement disorders (17.7%), and cerebrovascular disease (14.9%). Peripheral nervous system involvement was recorded in 7% of NP-SLE patients. NP-JSLE patients more frequently exhibited thrombocytopenia (<100 × 109/L) (p = 0.04), higher C-reactive protein levels (p = 0.01), higher global pBILAG score at first visit (p < 0.001), and higher SLICC damage index score at first (p = 0.02) and last (p < 0.001) visit when compared to JSLE patients without NP involvement.

CONCLUSIONS

A significant proportion of JSLE patients experience NP involvement (25%). Juvenile-onset NP-SLE most commonly affects the CNS and is associated with increased overall disease activity and damage.

Psychosocial burden in young patients with primary anti-phospholipid syndrome: an Italian nationwide survey (The AQUEOUS study)

OBJECTIVES

The AQUEOUS (Anti-phospholipid syndrome: a QUEstionnaire for yOUng patientS) study aimed to assess how the diagnosis of primary anti-phospholipid syndrome (PAPS) affects the psychosocial status of young patients.

METHODS

Subjects with PAPS aged 18-45 years were invited to compile an ad hoc designed questionnaire and the Short Form-12 to assess quality of life (QoL).

RESULTS

Ninety-two patients (83.7% females) were recruited in 10 Italian centres. Vascular and obstetric manifestations were equally represented. Nearly half of the patients perceived the need for psychological support, 89.2% when considering women after pregnancy complications. Social activities and working efficiency were reduced in APS patients, also intimacy was threatened. In all cases, fatigue appeared to be the main determinant. PAPS affected family planning, due to fears of treatment side-effects, disease hereditariness, inability to care for the newborn child. Fertility appeared to be conserved: the median time to pregnancy was 2 months; assisted reproduction techniques were pursued by 5 women. Our survey documented significantly lower rates of hospitalisation and learning disabilities in 51 children born after APS diagnosis as compared to 48 children born before. PAPS patients displayed lower QoL in physical and, to a greater extent, mental scores compared to the general Italian population. Both components were significantly lower in women and in patients with fatigue.

CONCLUSIONS

The AQUEOUS study assessed for the first time the unmet needs of young PAPS patients, enabling the development of a future "youth-focused" strategy to reduce disease burden.

Exosome microRNAs in Amyotrophic Lateral Sclerosis: A Pilot Study

The pathogenesis of amyotrophic lateral sclerosis (ALS), a lethal neurodegenerative disease, remains undisclosed. Mutations in ALS related genes have been identified, albeit the majority of cases are unmutated. Clinical pathology of ALS suggests a prion-like cell-to-cell diffusion of the disease possibly mediated by exosomes, small endocytic vesicles involved in the propagation of RNA molecules and proteins. In this pilot study, we focused on exosomal microRNAs (miRNAs), key regulators of many signaling pathways. We analyzed serum-derived exosomes from ALS patients in comparison with healthy donors. Exosomes were obtained by a commercial kit. Purification of miRNAs was performed using spin column chromatography and RNA was reverse transcribed into cDNA. All samples were run on the miRCURY LNA^TM Universal RT miRNA PCR Serum/Plasma Focus panel. An average of 29 miRNAs were detectable per sample. The supervised analysis did not identify any statistically significant difference among the groups indicating that none of the miRNA of our panel has a strong pathological role in ALS. However, selecting samples with the highest miRNA content, six biological processes shared across miRNAs through the intersection of the GO categories were identified. Our results, combined to those reported in the literature, indicated that further investigation is needed to elucidate the role of exosome-derived miRNA in ALS.

Clinical and peculiar immunological manifestations of SARS-CoV-2 infection in systemic lupus erythematosus patients

Objectives

The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with systemic lupus erythematosus (SLE) remains unclear and data on clinical manifestations after infection are lacking. The aim of this multicentre study is to describe the effect of SARS-CoV-2 in SLE patients.

Methods

SLE patients referring to 4 Italian centres were monitored between February 2020 and March 2021. All patients with SARS-CoV-2 infection were included. Disease characteristics, treatment, disease activity, and SARS-CoV-2 related symptoms were recorded before and after the infection.

Results

Fifty-one (6.14%) SLE patients were included among 830 regularly followed-up. Nine (17.6%) had an asymptomatic infection. Five (9.8%), out of 42 (82.6%) symptomatic, developed interstitial pneumonia (no identified risk factor). The presence of SLE major organ involvement (particularly renal involvement) was associated with asymptomatic SARS-CoV-2 infection (p-value = 0.02). Chronic corticosteroid therapy was found to be associated with asymptomatic infection (p-value = 0.018). Three SLE flares (5.9%) were developed after SARS-CoV-2 infection: one of them was characterized by MPO-ANCA positive pauci-immune crescentic necrotizing glomerulonephritis and granulomatous pneumonia.

Conclusions

SARS-CoV-2 infection determined autoimmune flares in a small number of our patients. Our data seem to confirm that there was not an increased risk of SARS-CoV-2 in SLE. Patients with asymptomatic SARS-CoV-2 infections were those having major SLE organ involvement. This may be explained by the high doses of corticosteroids and immunosuppressive agents used for SLE treatment.

EUREKA algorithm predicts obstetric risk and response to treatment in women with different subsets of anti-phospholipid antibodies

OBJECTIVES

aPL, the serum biomarkers of APS, are the most common acquired causes of pregnancy morbidity (PM). This study investigates the impact of aPL positivity fulfilling classification criteria ('criteria aPL') and at titres lower than thresholds considered by classification criteria ('low-titre aPL') on PM and assesses the effectiveness of low-dose aspirin (LDASA), low molecular weight heparin (LMWH) and HCQ in reducing the probability of PM (PPM).

METHODS

Longitudinal data on 847 pregnancies in 155 women with persistent aPL at any titre and 226 women with autoimmune diseases and negative aPL were retrospectively collected. A generalized estimating equations model for repeated measures was applied to quantify PPM under different clinical situations.

RESULTS

EUREKA is a novel algorithm that accurately predicts the risk of aPL-associated PM by considering aPL titres and profiles. aPL significantly impact PPM when at low titres and when fulfilling classification criteria. PPM was further stratified upon the aPL tests: aCL IgG/IgM and anti-β2-glycoprotein I (β2GPI) IgM, alone or combined, do not affect the basal risks of PPM, an increase occurs in case of positive LA or anti-β2GPI IgG. LDASA significantly affects PPM exclusively in women with low-titre aPL without anti-β2GPI IgG. The LDASA + LMWH combination significantly reduces PPM in all women with low-titre aPL and women with criteria aPL, except those carrying LA and anti-β2GPI IgG. In this group, the addition of HCQ further reduces PPM, although not significantly.

CONCLUSION

EUREKA allows a tailored therapeutic approach, impacting everyday clinical management of aPL-positive pregnant women.

POS1315 USEFULNESS OF SYNOVIAL BIOPSY IN THE DIFFERENTIAL DIAGNOSIS AND AS POSSIBLE PREDICTOR OF RESPONSE TO TREATMENT IN JUVENILE IDIOPATHIC ARTHRITIS

Background:

While synovial biopsy is an invasive procedure and is not required for the diagnosis of juvenile idiopathic arthritis (JIA), it may be useful in doubtful cases.

Objectives:

Aims of the study were i.to verify the role of synovial biopsy in the differential diagnosis of JIA and ii. to review the pathology slides in order to evaluate possible associations of a histologic pattern with response to treatment.

Methods:

We reviewed data from medical records of patients under the age of 18 years who underwent a synovial biopsy requested by our Pediatric Rheumatology Unit over the last 10 years. We collected information on demographic, clinical, laboratory, radiological, histopathological characteristics, as well as treatment response (in particular, remission at the last visit and number of examination, number of biologic drugs used). Among variables in the histologic score, number of layers in the synovial lining and inflammatory infiltrate (0-5) were compared to clinical status at last visit. Potential differences in variables between responders and non responders were assessed by unpaired t-test or non-parametric Mann-Whitney test, as appropriate.

Results:

We identified 64 patients (40F, 24M) with a median age at disease onset of 9 years (range 1-15) and a median follow-up time of 161 months (range 8-1160). We recognized two groups of interest: patients with a known JIA diagnosis (28/64) and patients with unknown diagnosis (36/64) at the moment of synovial biopsy. In the group with known JIA, most underwent the procedure during orthopedic surgery, and in all cases the histology was consistent with JIA. Among the unknown diagnosis group, in 19 cases results were consistent with a chronic synovitis, while among the other 17 histology could lead to a diagnosis of other conditions in 6 cases (foreign body and villonodular synovitis n=2 each, sarcoidosis and osteochondromatosis n=1 each). In the remaining 11 the final diagnoses were varied (mostly genetic forms eg skeletal dysplasia, CACP, Thiemann disease).

Between the two groups we identified 46 patients with a definite JIA diagnosis. At the last follow-up visit 29 of them were in clinical remission, albeit on medication. The remaining 17 had a severe course of disease, with persistent activity and use of at least two biologic drugs. In 26 cases we could evaluate the correlation between status at last visit and number of layers/inflammatory infiltrate, but no statistical significant correlation was found.

Conclusion:

Despite its limited use nowadays, synovial biopsy may still be a useful tool in patients whose diagnosis is unclear. In our study, while it confirmed the suspicion in most cases, in other instances it allowed the diagnosis of rare conditions that would have been otherwise missed. No association between disease course and histological features in a small JIA cohort was found. We are currently expanding the study with a larger series.

Disclosure of Interests:

None declared

Efficacy of R-COMP in comparison to R-CHOP in patients with DLBCL: A systematic review and single-arm metanalysis

Doxorubicin represents the mainstay in the upfront treatment of diffuse large B-cell lymphoma (DLBCL) patients. However, its administration is sometimes hampered by the coexistence of former comorbidities/cardiac issues, especially in the elderly population. Liposome encapsulated drug delivery systems have been adopted to reduce the exposure of normal tissues to the drug, both in solid cancers and lymphomas. Despite claims for lower toxicity, the efficacy of non-pegylated liposome doxorubicin (NPLD) in DLBCL, as compared to standard doxorubicin, has never been established. We systematically reviewed relevant literature of NPLD in lymphoma treatment. Adjusting for age/comorbidities, our metanalysis revealed that the use of combinations including NPLD (R-COMP) were non-inferior in terms of response, overall and progression-free survival to the standard of care (R-CHOP) in overlapping series of DLBCL patients. R-COMP may represent a safe and active option for elderly patients with DLBCL, or for those with some extent of cardiac impairment at baseline.

Anti-Phospholipid Antibodies in COVID-19 Are Different From Those Detectable in the Anti-Phospholipid Syndrome

Background

Critically ill patients with coronavirus disease 2019 (COVID-19) have a profound hypercoagulable state and often develop coagulopathy which leads to organ failure and death. Because of a prolonged activated partial-thromboplastin time (aPTT), a relationship with anti-phospholipid antibodies (aPLs) has been proposed, but results are controversial. Functional assays for aPL (i.e., lupus anticoagulant) can be influenced by concomitant anticoagulation and/or high levels of C reactive protein. The presence of anti-cardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI), and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies was not investigated systematically. Epitope specificity of anti-β2GPI antibodies was not reported.

Objective

To evaluate the prevalence and the clinical association of aPL in a large cohort of COVID-19 patients, and to characterize the epitope specificity of anti-β2GPI antibodies.

Methods

ELISA and chemiluminescence assays were used to test 122 sera of patients suffering from severe COVID-19. Of them, 16 displayed major thrombotic events.

Results

Anti-β2GPI IgG/IgA/IgM was the most frequent in 15.6/6.6/9.0% of patients, while aCL IgG/IgM was detected in 5.7/6.6% by ELISA. Comparable values were found by chemiluminescence. aPS/PT IgG/IgM were detectable in 2.5 and 9.8% by ELISA. No association between thrombosis and aPL was found. Reactivity against domain 1 and 4-5 of β2GPI was limited to 3/58 (5.2%) tested sera for each domain and did not correlate with aCL/anti-β2GPI nor with thrombosis.

Conclusions

aPL show a low prevalence in COVID-19 patients and are not associated with major thrombotic events. aPL in COVID-19 patients are mainly directed against β2GPI but display an epitope specificity different from antibodies in antiphospholipid syndrome.

Anti-phospholipid antibodies in COVID-19 are different from those detectable in the anti-phospholipid syndrome

BACKGROUND

Critically ill patients with coronavirus disease 2019 (COVID-19) have a profound hypercoagulable state and often develop coagulopathy which leads to organ failure and death. Because of a prolonged activated partial-thromboplastin time (aPTT), a relationship with anti-phospholipid antibodies (aPL) has been proposed, but results are controversial. Functional assays for aPL (i.e., lupus anticoagulant) can be influenced by concomitant anticoagulation and/or high levels of C reactive protein. The presence of anti-cardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies was not investigated systematically. Epitope specificity of anti-β2GPI antibodies was not reported.

OBJECTIVE

To evaluate the prevalence and the clinical association of aPL in a large cohort of COVID-19 patients, and to characterize the epitope specificity of anti-β2GPI antibodies.

METHODS

ELISA and chemiluminescence assays were used to test 122 sera of patients suffering from severe COVID-19. Of them, 16 displayed major thrombotic events.

RESULTS

Anti-β2GPI IgG/IgA/IgM were the most frequent in 15.6/6.6/9.0% of patients, while aCL IgG/IgM were detected in 5.7/6.6% by ELISA. Comparable values were found by chemiluminescence. aPS/PT IgG/IgM were detectable in 2.5 and 9.8% by ELISA. No association between thrombosis and aPL was found. Reactivity against domain 1 and 4-5 of β2GPI was limited to 3/58 (5.2%) tested sera for each domain and did not correlate with aCL/anti-β2GPI nor with thrombosis.

CONCLUSIONS

aPL show a low prevalence in COVID-19 patients and are not associated with major thrombotic events. aPL in COVID-19 patients are mainly directed against β2GPI but display an epitope specificity different from antibodies in antiphospholipid syndrome.

Nonpeghylated liposomal doxorubicin combination regimen (R-COMP) for the treatment of lymphoma patients with advanced age or cardiac comorbidity

Doxorubicin is the most effective single agent in the treatment of non‐Hodgkin's lymphoma (NHL). Its use is limited because of the cardiac toxicity primarily in elderly patients (pts) and in pts with history of cardiac disease. Liposomal doxorubicin has been proven to reduce cardiotoxicity. The aim of this retrospective study was the use of nonpeghylated liposomal doxorubicin (NPLD) in term of efficacy, response rate and incidence of cardiac events. We retrospectively collected the experience of 33 Hematological Italian Centers in using NPLD. Nine hundred and forty‐six consecutive pts treated with R‐COMP (doxorubicin was substituted with NPLD, Myocet) were collected. Median age was 74 years, the reasons for use of NPLD were: age (466 pts), cardiac disease (298 pts), uncontrolled hypertension (126 pts), other reasons (56 pts). According to clinicians' evaluation, 49.9% of pts would not have used standard doxorubicin for different situations (age, cardiomyopathy, previous use of doxorubicin, and uncontrolled hypertension). Overall 687 pts (72.6%) obtained a complete remission (CR). About 5% (n = 51) of subjects developed major cardiotoxic events including heart failure (N = 31), ischemic heart disease (N = 16), acute heart attack (N = 3), and acute pulmonary oedema (N = 1). After a median follow‐up of 32 months, 651 pts were alive and the overall survival (OS) was 72%. After a median observation period of 23 months disease free survival (DFS) was 58%. Either in univariate or in multivariate analysis OS and DFS were not significantly affected by age or cardiac disease. Our findings strongly support that including R‐COMP is effective and safe when the population is at high risk of cardiac events and negatively selected. Moreover, the use of this NPLD permitted that about half of our population had the opportunity to receive the best available treatment.

FRI0154 SHOULD BE OLDER PATIENTS TESTED FOR ANTIPHOSPHOLIPID ANTIBODIES? 695 CASES FROM THE RETROSPECTIVE SERIES HIBISCUS

Background:

Although guidelines do not recommend antiphospholipid antibodies testing after 60 yo, recent data reported late onset antiphospholipid syndrome (APS).

Objectives:

To comparatively analyse the clinical, laboratory features and outcomes in 695 cases with primary APS between patients older and younger than 70 yo.

Methods:

we have performed an international study within the framework of the International Registry of primary APS patients treated with Hydroxychloroquine, HIBISCUS (an ongoing retrospective and prospective register launched in 2016). 28 centres from 17 countries participate. Data about late onset APS were analysed in 695 patients and were obtained from a standardized form registered in the database containing 66 items with respect to demographics, clinical and biological features.

Results:

Arterial events and especially stroke represented the main initial and recurrent clinical manifestation in 40 primary APS patients older than 70 yo. There were not statistically significant differences with respect to cardiovascular risk factors between the two groups of patients. A significant male predominance, a familial APS history, a higher prevalence of triple positivity, lower complement levels, and anticardiolipin antibodies (aCL) IgA isotype were found in older patients. Low anticoagulation regimens were safe and efficient, with a low relapse rate in older patients.

Conclusion:

we suggest that the detection of aPL antibodies should be included into the initial screening panel tests in elderly with thrombotic events, especially arterial, in particular those with recurrent stroke and familial APS.

Our study further suggests that lower intensity anticoagulation regimens could be a therapeutic option in older APS patients, as no differences in outcomes and relapse rate were found between patients with high and low intensity anticoagulation regimens.

References:

[1]Grimaud F et al. Rheumatology. 2019;58:1006-10.

[2]Goldman-Mazur S et al. Thromb Res. 2019;176:67-73.

[3]Hirmerova J et al. 2017;36:167-73.

Disclosure of Interests:

Cristina Belizna: None declared, Omar Latino: None declared, Ljudmila Stojanovich: None declared, Patrick Saulnier: None declared, Katrien Devreese: None declared, Sebastien Udry: None declared, Natasa Stanisavljevic: None declared, Aleksandra Djokovic Speakers bureau: KRKA, Astra Zeneca, Actavis, Jaume Alijotas-Reig: None declared, Enrique Esteve-Valverde: None declared, Raquel Ferrer-Oliveras: None declared, Angela Tincani: None declared, Laura Andreoli: None declared, Francesca Regola: None declared, Maarten Limper: None declared, Alexander Makatsariya: None declared, Jamilya Khizroeva: None declared, Viktoria Bitsadze: None declared, Cecilia Chighizola: None declared, Francesca Pregnolato: None declared, Maria Orietta Borghi: None declared, Pier Luigi Meroni: None declared

FRI0169 ANTINUCLEAR ANTIBODY SEROCONVERSION DURING FOLLOW-UP IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the presence of autoantibodies and a variable spectrum of clinical manifestations and disease severity. The 2019 criteria for SLE classification by the American College of Rheumatology and European League against Rheumatism define ANA positivity by immunofluorescence or by an equivalent solid-phase assay as the entry criterion (1). However, the prevalence of ANA positivity and the reliability of solid-phase assays in SLE are still a matter of controversy (2). Furthermore, the significance of ANA negativisation during follow-up is uncertain (3).

Objectives:

Our aim was to retrospectively analyse data on the frequency of ANA seroconversion during the follow-up in a cohort of SLE patients with renal involvement.

Methods:

Adult patients independent of age at SLE onset with a follow-up duration of at least 36 months starting from January 2009 (for standardization of ANA measurement) and with at least one ANA measurement per year were included in this retrospective longitudinal study. Data on demographic, clinical and laboratory characteristics of the study population are reported in table 1. ANA have been measured with Hep2 cell immunofluorescence assay.

Table 1.

Demographic, clinical and laboratory baseline characteristics of the 121 patients suffering from systemic lupus erythematosus (SLE).

DemographicsGender,%F (n)93 (112)Age in years,mean±SD41.6±12.6Clinical featuresAge at SLE onset in years,mean±SD28.0±11.9SLE duration in years,mean±SD13.8±9.5SLEDAI,median (min-max)4 (0 – 27)Laboratory profileSerum creatinine mg/dL,median (min-max)0.8 (0.4 – 2)24h urine protein g/24h,median (min-max)0.5 (0 – 13.8)ANA,%pos (n)93 (112)Anti-ENA,%pos (n)49 (59)Anti-dsDNA,%pos (n)43 (51)

Results:

A total of 121 SLE subjects with renal involvement were enrolled. Mean follow-up ± standard deviation (SD) was 8 ± 2 years. Ten subjects (8.3%) with positive ANA at the beginning resulted ANA negative at the end of the follow-up. These subjects had different initial ANA titres: 1:1280 (n=1), 1:640 (n=2), 1:320 (n=2), 1:160 (n=3) and 1:80 (n=2); 48 subjects (39.7%) showed a decrease in ANA titre. Of the 9 patients (7.4%) that were negative at the beginning of follow-up, 6 remained negative, whereas 3 showed ANA positivity at the end of the follow-up with ANA titres 1:160 (n=2) and 1:320 (n=1). No differences between subjects with and without ANA titre variations in terms of age (p=0.551), disease duration (p=0.786), SLEDAI at the beginning (p=0.453) and at the end of follow-up (p=0.169) were observed. ANA negativisation and titre variations at the end of follow-up did not correlate with any of the treatments taken during follow-up, including a history of cyclophosphamide (p=0.788).

Conclusion:

In our cohort of patients with SLE and renal involvement, 10% of patients experienced negativisation and around 40% of patients showed a decrease in ANA titre during follow-up, independent of disease characteristics and previous treatment. Further studies are warranted to clarify the underlying mechanisms and clinical significance of ANA seroconversion and titre variation in SLE patients. However, based on our results, ANA positivity seems to be a relatively stable parameter further supporting its use as an entry classification criterion for SLE.

References:

[1]Aringer M et al. Arthritis Rheumatol. 2019; 71(9):1400-1412.

[2]Pisetsky DS et al. Autoimmun Rev. 2019; 18(12):102400.

[3]Frodlund M et al. Clin Exp Immunol. 2019. Epub ahead of print.

Disclosure of Interests:

None declared

Hyaluronic Acid Injections in the Treatment of Osteoarthritis Secondary to Primary Inflammatory Rheumatic Diseases: A Systematic Review and Qualitative Synthesis

The purpose of this study is to review the current literature on the use of hyaluronic acid (HA) specifically applied to the treatment of osteoarthritis (OA) secondary to primary inflammatory rheumatic diseases. Osteoarthritis should be carefully considered because it has potentially devastating effects on health-related quality of life. Locally injected HA seems to be an effective treatment for OA but it is not clear how to place this treatment in the context of inflammatory rheumatic disorders. To retrieve relevant articles, we conducted the search through MEDLINE, EMBASE and Cochrane Databases performing the PICO strategy. We finally selected four randomized clinical trials and six observational studies and grouped them in accordance with its main objective within three focuses: the clinical effect of HA therapy in joints without any signs of inflammation, the clinical effects of HA therapy in joints with active synovitis, and the involvement and changes of synovial fluid in the treatment of secondary OA. Our qualitative analysis clearly showed that the current literature is marked by high levels of heterogeneity and therefore difficult to interpret. Therefore, our hypothesis that viscosupplementation should be considered as a treatment for chronic moderate symptomatic OA secondary to inflammatory rheumatic diseases, and not for flares with joint swelling, cannot be definitely supported. Well-designed studies are necessary to definitively clarify the range of application of intra-articular HA injections in the treatment of inflammatory rheumatic disorders.

In utero exposure to Azathioprine in autoimmune disease. Where do we stand?

Azathioprine (AZA), an oral immunosuppressant, is safe during pregnancy. Some reports suggested different impairments in the offspring of mothers with autoimmune diseases (AI) exposed in utero to AZA. These observations are available from retrospective studies or case reports. However, data with respect to the long-term safety in the antenatally exposed child are still lacking. The aim of this study is to summarize the current knowledge in this field and to focus on the need for a prospective study on this population. We performed a PubMed search using several search terms. The actual data show that although the risk of congenital anomalies in offspring, as well as the infertility risk, are similar to those found in general population, there is a higher incidence of prematurity, of lower weight at birth and an intra-uterine delay of development. There is also an increased risk of materno- fetal infections, especially cytomegalovirus infection. Some authors raise the interrogations about neurocognitive impairment. Even though the adverse outcomes might well be a consequence of maternal illness and disease activity, interest has been raised about a contribution of this drug. However, the interferences between the external agent (in utero exposure to AZA), with the host (child genetic susceptibility, immune system anomalies, emotional status), environment (public health, social context, availability of health care), economic, social, and behavioral conditions, cultural patterns, are complex and represent confounding factors. In conclusion, it is necessary to perform studies on the medium and long-term outcome of children born by mothers with autoimmune diseases, treated with AZA, in order to show the safety of AZA exposure. Only large-scale population studies with long-term follow-up will allow to formally conclude in this field. TAKE HOME MESSAGES.

Effectiveness and Tolerability of Repeated Courses of Viscosupplementation in Symptomatic Hip Osteoarthritis: A Retrospective Observational Cohort Study of High Molecular Weight vs. Medium Molecular Weight Hyaluronic Acid vs. No Viscosupplementation

Background: Nonsurgical management of symptomatic hip osteoarthritis needs real-world evidence. We evaluated the effectiveness and tolerability of US-guided intra-articular treatment of two hyaluronic acids (HAs) commercially available in Italy and investigated predictors of response.

Methods: Outpatient records including three cohorts: 122 subjects treated with medium (1,500–3,200 kDa; Hyalubrix^®) molecular weight (MW) or high (hylan G-F20; Synvisc^®) MW HAs and 20 controls taking NSAIDs/analgesics on demand were retrospectively analyzed. Pain VAS score, WOMAC, NSAID/analgesic consumption, and causes of suspension were available at 1, 6, 12, and 24 months after first administration. As selection bias usually affects observational retrospective studies, a quasi-randomization process was attained by performing propensity score approach.

Results: Propensity score adjustment successfully allowed comparisons among balanced groups of treatments. VAS and WOMAC considerably decreased over time in treated groups independently of the radiological grade (p<0.001). On the other hand, the control group showed only a slight and rather uneven variation in VAS. Mean score changes were comparable in both HA cohorts from the earliest stages (ΔVAS(HA1,500–3,200kDa)_T1vsT0 = −20%; ΔVAS(hylan G-F20)_T1vsT0 = −23%/ΔWOMAC(HA1,500–3,200kDa)_T1vsT0 = −17%; ΔWOMAC(hylan G-F20)_T1vsT0 = −19%), reaching a further substantial reduction after 12 months (ΔVAS(HA1,500–3,200kDa)_T12vsT0 = −52%; ΔVAS(hylan G-F20)_T12vsT0 = −53%/ΔWOMAC(HA1,500–3,200kDa)_T12vsT0 = −45%; and ΔWOMAC(hylan G-F20)_T12vsT0 = −47%). Almost 11% (=13/122) of ineffectiveness and few moderate local side effects 3% (=4/122) were detected.

Conclusions: Viscosupplementation in a real-life setting seems to provide a sound alternative in pain management in comparison to oral NSAIDs/analgesics, guaranteeing a reduced intake of pain killer medications. Analgesic effectiveness, functional recovery, and reduced joint stiffness extend and improve over 12 and 24 months, suggesting that repeated administrations achieve an additive effect.

Only monospecific anti-DFS70 antibodies aid in the exclusion of antinuclear antibody associated rheumatic diseases: an Italian experience

Background

The dense fine speckled (DFS) is one of the most common patterns that can be observed as a result of the anti-nuclear antibodies (ANA) test on HEp-2 cells and is mostly caused by antibodies to DFS70 as the main antigenic target. As was recently demonstrated, isolated anti-DFS70 positivity can be used as an aid in the exclusion of ANA associated rheumatic diseases (AARD) due to the opportunity to better interpret unexplained positive IIF ANA results.

Methods

Our study included 333 subjects with AARD, 51 undifferentiated connective tissue disease (UCTD) patients, 235 disease controls and 149 healthy blood donors from an Italian cohort. All samples were tested for anti-DFS70 and anti-ENA antibodies using QUANTA Flash assays (Inova Diagnostics, San Diego, CA, USA).

Results

No differences in the prevalence of anti-DFS70 antibodies were seen among AARD, non-AARD and UCTD (2.1% [7/333] vs. 2.3% [9/384] vs. 5.9% [3/51], respectively; p-value = 0.188). AARD patients positive for anti-DFS70 antibodies showed in all cases an accompanying anti-ENA specificity. In contrast, monospecific anti-DFS70 antibodies showed a significantly different distribution with a clear trend across the main groups (AARD vs. non-AARD vs. UCTD: 0% [0/7] vs. 22% [2/9] vs. 100% [3/3], p = 0.007). Anti-DFS70 antibody levels among AARD, non-AARD and UCTD patients were not significantly different (p = 0.094). Within the anti-DFS70 antibody positive cases, AARD cohort showed a higher variability (median [min–max]: 3.2 [3.2–450.8] CU) compared to non-AARD (median [min–max]: 3.2 [3.2–75.7] CU) and UCTD patients (median [min–max]: 3.2 [3.2–59.0] CU).

Conclusions

Our preliminary data showed a similar frequency of anti-DFS70 antibodies in AARD, UCTD and non-AARD cohorts. Monospecificity of anti-DFS70 antibodies but not their mere presence is the key element in the diagnostic algorithm. Mono-specific anti-DFS70 antibodies might be a helpful biomarker to discriminate individuals with AARD from non-AARD presenting with a positive ANA.

Blood Cell-Bound C4d as a Marker of Complement Activation in Patients With the Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a chronic and disabling condition characterized by recurrent thrombosis and miscarriages mediated by antibodies against phospholipid-binding proteins (aPL), such as beta₂glycoprotein I (β₂GPI). Complement is involved in APS animal models and complement deposits have been documented in placenta and thrombotic vessels despite normal serum levels. Analysis of circulating blood cells coated with C4d displays higher sensitivity than the conventional assays that measure soluble native complement components and their unstable activation products in systemic lupus erythematosus (SLE). As C4d-coated blood cell count has been reported to be more sensitive than serum levels of complement components and their activation products in systemic lupus erythematosus (SLE) patients, we decided to evaluate the percentage of C4d positive B lymphocytes (BC4d), erythrocytes (EC4d), and platelets (PC4d) in primary APS patients and asymptomatic aPL positive carriers as marker of complement activation in APS. We assessed by flow cytometry the percentages of BC4d, EC4d, and PC4d in primary APS (PAPS; n. 23), 8 asymptomatic aPL positive carriers, 11 APS-associated SLE (SAPS), 17 aPL positive SLE, 16 aPL negative SLE, 8 aPL negative patients with previous thrombosis, 11 immune thrombocytopenia (ITP) patients, and 26 healthy subjects. In addition, we used an in vitro model to evaluate the ability of a monoclonal anti-β₂GPI antibody (MBB2) to bind to normal resting or activated platelets and fix complement. EC4d and PC4d percentages were significantly higher in PAPS and aPL carriers as well as aPL positive SLE and SAPS than in aPL negative controls. The highest values were found in PAPS and in SAPS. The EC4d and PC4d percentages were significantly correlated with serum C3/C4 and anti-β₂GPI/anti-cardiolipin IgG. In vitro studies showed that MBB2 bound to activated platelets only and induced C4d deposition. The detection of the activation product C4d on circulating erythrocytes and platelets supports the role of complement activation in APS. Complement may represent a new therapeutic target for better treatment and prevention of disability of APS patients.

New insight into antiphospholipid syndrome: antibodies to β2glycoprotein I-domain 5 fail to induce thrombi in rats

Clinical studies have reported different diagnostic/predictive values of antibodies to domain 1 or 4/5 of β₂glycoproteinI in terms of risk of thrombosis and pregnancy complications in patients with antiphospholipid syndrome. To obtain direct evidence for the pathogenic role of anti-domain 1 or anti-domain 4/5 antibodies, we analyzed the in vivo pro-coagulant effect of two groups of 5 sera IgG each reacting selectively with domain 1 or domain 5 in lipopolysaccharide (LPS)-treated rats. Antibody-induced thrombus formation in mesenteric vessels was followed by intravital microscopy, and vascular deposition of β₂glycoproteinI, human IgG and C3 was analyzed by immunofluorescence. Five serum IgG with undetectable anti-β₂glycoproteinI antibodies served as controls. All the anti-domain 1-positive IgG exhibited potent pro-coagulant activity while the anti-domain 5-positive and the negative control IgG failed to promote blood clot and vessel occlusion. A stronger granular deposit of IgG/C3 was found on the mesenteric endothelium of rats treated with anti-domain 1 antibodies, as opposed to a mild linear IgG staining and absence of C3 observed in rats receiving anti-domain 5 antibodies. Purified anti-domain 5 IgG, unlike anti-domain 1 IgG, did not recognize cardiolipin-bound β₂glycoproteinI while being able to interact with fluid-phase β₂glycoproteinI. These findings may explain the failure of anti-domain 5 antibodies to exhibit a thrombogenic effect in vivo, and the interaction of these antibodies with circulating β₂glycoproteinI suggests their potential competitive role with the pro-coagulant activity of anti-domain 1 antibodies. These data aim at better defining “really at risk” patients for more appropriate treatments to avoid recurrences and disability.

HIBISCUS: Hydroxychloroquine for the secondary prevention of thrombotic and obstetrical events in primary antiphospholipid syndrome

The relapse rate in antiphospholipid syndrome (APS) remains high, i.e. around 20%-21% at 5 years in thrombotic APS and 20-28% in obstetrical APS [2, 3]. Hydroxychloroquine (HCQ) appears as an additional therapy, as it possesses immunomodulatory and anti-thrombotic various effects [4-16]. Our group recently obtained the orphan designation of HCQ in antiphospholipid syndrome by the European Medicine Agency. Furthermore, the leaders of the project made the proposal of an international project, HIBISCUS, about the use of Hydroxychloroquine in secondary prevention of obstetrical and thrombotic events in primary APS. This study has been launched in several countries and at now, 53 centers from 16 countries participate to this international trial. This trial consists in two parts: a retrospective and a prospective study. The French part of the trial in thrombosis has been granted by the French Minister of Health in December 2015 (the academic trial independent of the pharmaceutical industry PHRC N PAPIRUS) and is coordinated by one of the members of the leading consortium of HIBISCUS.

Gene expression profiling identifies distinct molecular signatures in thrombotic and obstetric antiphospholipid syndrome

Antiphospholipid antibodies (aPL) cause vascular thrombosis (VT) and/or pregnancy morbidity (PM). Differential mechanisms however, underlying the pathogenesis of these different manifestations of antiphospholipid syndrome (APS) are not fully understood. Therefore, we compared the effects of aPL from patients with thrombotic or obstetric APS on monocytes to identify different molecular pathways involved in the pathogenesis of APS subtypes. VT or PM IgG induced similar numbers of differentially expressed (DE) genes in monocytes. However, gene ontology (GO) analysis of DE genes revealed disease-specific genome signatures. Compared to PM, VT-IgG showed specific up regulation of genes associated with cell response to stress, regulation of MAPK signalling pathway and cell communication. In contrast, PM-IgG regulated genes involved in cell adhesion, extracellular matrix and embryonic and skeletal development. A novel gene expression analysis based on differential variability (DV) was also applied. This analysis identified similar GO categories compared to DE analysis but also uncovered novel pathways modulated solely by PM or VT-IgG. Gene expression analysis distinguished a differential effect of VT or PM-IgG upon monocytes supporting the hypothesis that they trigger distinctive physiological mechanisms. This finding contributes to our understanding of the pathology of APS and may lead to the development of different targeted therapies for VT or PM APS.

Taurine Administration Recovers Motor and Learning Deficits in an Angelman Syndrome Mouse Model

Angelman syndrome (AS, MIM 105830) is a rare neurodevelopmental disorder affecting 1:10–20,000 children. Patients show moderate to severe intellectual disability, ataxia and absence of speech. Studies on both post-mortem AS human brains and mouse models revealed dysfunctions in the extra synaptic gamma-aminobutyric acid (GABA) receptors implicated in the pathogenesis. Taurine is a free intracellular sulfur-containing amino acid, abundant in brain, considered an inhibiting neurotransmitter with neuroprotective properties. As taurine acts as an agonist of GABA-A receptors, we aimed at investigating whether it might ameliorate AS symptoms. Since mice weaning, we orally administered 1 g/kg/day taurine in water to Ube3a-deficient mice. To test the improvement of motor and cognitive skills, Rotarod, Novel Object Recognition and Open Field tests were assayed at 7, 14, 21 and 30 weeks, while biochemical tests and amino acid dosages were carried out, respectively, by Western-blot and high-performance liquid chromatography (HPLC) on frozen whole brains. Treatment of Ube3a^m−/p+ mice with taurine significantly improved motor and learning skills and restored the levels of the post-synaptic PSD-95 and pERK1/2-ERK1/2 ratio to wild type values. No side effects of taurine were observed. Our study indicates taurine administration as a potential therapy to ameliorate motor deficits and learning difficulties in AS.

Beyond thrombosis: Anti-β2GPI domain 1 antibodies identify late pregnancy morbidity in anti-phospholipid syndrome

Antibodies against β2 glycoprotein I (anti-β2GPI) have been identified as the main pathogenic autoantibody subset in anti-phospholipid syndrome (APS); the most relevant epitope is a cryptic and conformation-dependent structure on β2GPI domain (D) 1. Anti-β2GPI domain profiling has been investigated in thrombotic APS, leading to the identification of antibodies targeting D1 as the main subpopulation. In contrast, scarce attention has been paid to obstetric APS, hence this study aimed at characterizing the domain reactivity with regards to pregnancy morbidity (PM). To this end, 135 women with persistently positive, medium/high titre anti-β2GPI IgG, without any associated systemic autoimmune diseases and at least one previous pregnancy were included: 27 asymptomatic carriers; 53 women with obstetric APS; 20 women with thrombotic APS; and 35 women with both thrombotic and obstetric complications. Anti-D1 and anti-D4/5 antibodies were tested using a chemiluminescent immunoassay and a research ELISA assay, respectively (QUANTA Flash^® β2GPI Domain 1 IgG and QUANTA Lite^® β2GPI D4/5 IgG, Inova Diagnostics). Positivity for anti-D1 antibodies, but not anti-D4/5 antibodies, was differently distributed across the 4 subgroups of patients (p < 0.0001) and significantly correlated with thrombosis (χ2 = 17.28, p < 0.0001) and PM (χ2 = 4.28, p = 0.039). Patients with triple positivity for anti-phospholipid antibodies displayed higher anti-D1 titres and lower anti-D4/5 titres compared to women with one or two positive tests (p < 0.0001 and p = 0.005, respectively). Reactivity against D1 was identified as a predictor for PM (OR 2.4, 95% confidence interval [CI] 1.2-5.0, p = 0.017); in particular, anti-D1 antibodies were predictive of late PM, conveying an odds ratio of 7.3 (95% CI 2.1-25.5, p = 0.022). Positivity for anti-D1 antibodies was not associated with early pregnancy loss. Anti-D4/5 antibodies were not associated with clinical APS manifestations. As a whole, our data suggest that anti-D1 antibodies are significantly associated not only with thrombosis, but also with late PM, while positive anti-D4/5 antibodies are not predictive of thrombosis or PM.

Baseline ultrasound examination as possible predictor of relapse in patients affected by juvenile idiopathic arthritis (JIA)

Objectives

To define the correlation between joint ultrasonography and clinical examination in patients with juvenile idiopathic arthritis (JIA) and to assess whether synovitis detected by ultrasonography in clinically inactive patients predicts arthritis flares.

Methods

88 consecutive patients with JIA—46 (52%) with persistent oligoarthritis, 15 (17%) with extended oligoarthritis, 15 (17%) with rheumatoid factor-negative polyarthritis and 12 (14%) with other forms of JIA, all clinically inactive for a minimum of 3 months—underwent ultrasound (US) assessment of 44 joints. Joints were scanned at study entry for synovial hyperplasia, joint effusion and power Doppler (PD) signal. Patients were followed clinically for 4 years.

Results

US was abnormal in 20/88 (22.7%) patients and in 38/3872 (0.98%) joints. Extended oligoarthritis and rheumatoid factor-negative polyarthritis were more frequent in US-positive than in US-negative patients (35.0% vs 11.8% and 30.0% vs 13.2%, respectively; P=0.005). During 4 years of follow-up, 41/88 (46.6%) patients displayed a flare; 26/68 (38.2%) were US-negative and 15/20 (75%) were US-positive at baseline. Abnormality on US examination, after correction for therapy modification, significantly increased the risk of flare (OR=3.8, 95% CI 1.2 to 11.5). The combination of grey scale and PD abnormalities displayed a much higher predictive value of relapse (65%, 13/20) than grey scale alone (33%, 6/18).

Conclusions

US abnormalities are a strong predictor of relapse at individual patient level. Irrespective of treatment, the risk of flare in US-positive versus US-negative patients was almost four times higher. In case of US abnormalities, patients should be carefully followed regardless of both the International League of Associations for Rheumatology and Wallace categories.

N-terminal pro Brain Natriuretic Peptide as predictor of outcome in scleroderma renal crisis

OBJECTIVES

Although in scleroderma renal crisis (SRC) outcome has improved to a great extent with the introduction of ACE inhibitors, there remains significant mortality and morbidity with frequent requirement for renal replacement therapy. Therefore, novel biomarkers to identify patients at high risk of poor outcome would be valuable. The aim of this study was to assess the role of the N terminal fragment of pro Brain Natriuretic Peptide (N-TproBNP) as predictor of outcome in SRC.

METHODS

20 subjects with confirmed SRC were retrospectively enrolled. Clinical data, full blood count, creatinine, eGFR and N-TproBNP at presentation were collected.

RESULTS

Patients requiring renal replacement therapy presented significantly higher levels of N-TproBNP and creatinine (p>0.01), lower eGFR (p<0.01) and haemoglobin levels (p=0.01) and shorter disease duration (p<0.01) compared to those who did not require dialysis. Whereas all the candidate variables significantly predicted renal outcome in univariate models, N-TproBNP was the only variable to hold significance in predicting renal outcome in a Firth's multivariate logistic regression model (p=0.05, OR 7.6). ROC curve of N-TproBNP to identify patients requiring renal replacement therapy provided a sensitivity of 88.9%, with a specificity of 81.8% at a cut-off value of 360 pmol/L (95% CI 0.84-1.00, area under the curve 0.94). In our cohort, this provided a positive predictive value of 80% and a negative predictive value of 90%.

CONCLUSIONS

N-TproBNP peptide may be a useful biomarker in risk-stratification of renal outcome in SRC, selectively identifying patients likely to require renal replacement therapy.

Twelve-Year Retention Rate of First-Line Tumor Necrosis Factor Inhibitors in Rheumatoid Arthritis: Real-Life Data From a Local Registry

OBJECTIVE

To evaluate the 12-year survival of the first tumor necrosis factor inhibitor (TNFi) treatment in a cohort of rheumatoid arthritis (RA) patients, comparing the between-groups discontinuation rates for infliximab, etanercept, and adalimumab.

METHODS

RA patients treated with their first TNFi were investigated from a local registry. Before and after adjusting for propensity scores, overall and by individual TNFi 12-year drug retention was evaluated. Drug survival rates were calculated using the Kaplan-Meier method and compared by the Cox extended model. Subanalyses were performed according to concomitant methotrexate (MTX) and discontinuation reasons.

RESULTS

Of 583 patients, 222 were treated with infliximab, 179 with etanercept, and 182 with adalimumab; 33.7% and 26% discontinued the first TNFi because of inefficacy or adverse events, respectively. The overall 12-year drug survival rate for the unmatched population was 23.4%. In the propensity score-adjusted population, the hazard ratio (HR) for treatment discontinuation was significantly greater for adalimumab and infliximab versus etanercept (HR 2.89 [95% confidence interval (95% CI) 2.2-3.78] and HR 2.56 [95% CI 1.92-3.4], respectively), and no difference was found between and for adalimumab versus infliximab (HR 1.16 [95% CI 0.91-1.47]). The incidence of withdrawal due to secondary inefficacy was stable from 3 to 12 years for etanercept, but progressively increased for the monoclonal antibodies. Concomitant MTX significantly increased the survival of both adalimumab and etanercept (HR 1.48 [95% CI 1.18-1.86]).

CONCLUSION

The overall 12-year drug survival rate was 23.4%, being significantly higher for etanercept than adalimumab and infliximab. Etanercept discontinuations for inefficacy did not increase from 3 to 12 years. Concomitant MTX increased adalimumab and etanercept drug survival.

Measuring IgA Anti-β2-Glycoprotein I and IgG/IgA Anti-Domain I Antibodies Adds Value to Current Serological Assays for the Antiphospholipid Syndrome

Introduction

Currently available clinical assays to detect antiphospholipid antibodies (aPL) test for IgG and IgM antibodies to cardiolipin (aCL) and β₂-glycoprotein I (aβ₂GPI). It has been suggested that testing for IgA aPL and for antibodies to Domain I (DI), which carries the key antigenic epitopes of β₂GPI, could add value to these current tests. We performed an observational, multicenter cohort study to evaluate the utility of IgG, IgM and IgA assays to each of CL, β₂GPI and DI in APS.

Methods

Serum from 230 patients with APS (n = 111), SLE but not APS (n = 119), and 200 healthy controls were tested for IgG, IgM and IgA aCL, aβ₂GPI and aDI activity. Patients with APS were further classified into thrombotic or obstetric APS. Logistic regression and receiver operator characteristic analyses were employed to compare results from the nine different assays.

Results

All assays displayed good specificity for APS; IgG aCL and IgG aβ₂GPI assays however, had the highest sensitivity. Testing positive for IgA aβ₂GPI resulted in a higher hazard ratio for APS compared to IgM aβ₂GPI. Positive IgG, IgM or IgA aDI were all associated with APS, and in subjects positive for aCL and/or aβ₂GPI, the presence of aDI raised the hazard ratio for APS by 3–5 fold. IgG aCL, aβ₂GPI, aDI and IgA aDI were associated with thrombotic but not obstetric complications in patients with APS.

Conclusion

Measuring IgG aDI and IgA aβ₂GPI and aDI may be useful in the management of patients with APS, particularly thrombotic APS.

Antiphospholipid Antibodies and Infertility: A Gene Expression Study in Decidual Stromal Cells

BACKGROUND

Antiphospholipid antibodies (aPL) have been advocated as potential mediators of unexplained female infertility, but no evidence has yet been raised to support such an association.

OBJECTIVES

To test the hypothesis that aPL might interfere with uterine decidualization, a gene expression study was performed on decidual stromal cells treated with different aPL preparations.

METHODS

Decidual stromal cells were isolated from first-trimester deciduas obtained from two women undergoing elective abortion, and treated with: (i) a β2GPI-dependent aPL monoclonal antibody (IS3); (ii) IS3 plus TIFI, a synthetic peptide mimicking PL-binding region of β2GPI; and (iii) IgG from healthy subjects (NHS). Gene expression data were acquired using human HT-12 v3 beadchip arrays (Illumina). Differential expression analysis was performed by fitting a gene-wise linear model using the treatment group and decidual source as covariates.

RESULTS

In the comparison of IS3 versus IgG NHS-treated decidual cells, gene ontology (GO) enrichment was expressed in terms relating to well-characterized aPL-mediated cellular effects: "inflammatory response," "immune response," "response to stress," "oxydoreductase activity," "metalloendopeptidase activity," and "cytokine/chemokine activity." As expected, almost all genes were up-regulated by IS3 treatment. The same GO categories appeared to be differentially expressed when IS3 treatment was compared to IS3 + TIFI, but with most genes being down-regulated.

CONCLUSIONS

Given the inflammatory response evinced on gene expression analysis of decidual stromal cells treated with a β2GPI -dependent aPL monoclonal antibody, it is feasible that aPL might interfere with uterine decidualization, affecting the early stages of implantation and ultimately resulting in female infertility.

Antiglutamate Receptor Antibodies and Cognitive Impairment in Primary Antiphospholipid Syndrome and Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome have an increased risk to develop cognitive impairment. A possible role for antiphospholipid antibodies (aPL) and antiglutamate receptor (anti-NMDA) antibodies in the pathogenesis of neurological manifestations of these two conditions, have been suggested. In particular, the role of anti-NMDA antibodies in the pathogenesis of neuropsychiatric SLE is supported by several experimental studies in animal models and by the finding of a correlation between anti-NMDA positivity in cerebrospinal fluid and neurological manifestations of SLE. However, data from the literature are controversial, as several studies have reported a correlation of these antibodies with mild cognitive impairment in SLE, but more recent studies have not confirmed this finding. The synergism between anti-NMDA and other concomitant autoantibodies, such as aPL, can be hypothesized to play a role in inducing the tissue damage and eventually the functional abnormalities. In line with this hypothesis, we have found a high incidence of at least one impaired cognitive domain in a small cohort of patients with primary APS (PAPS) and SLE. Interestingly, aPL were associated with low scoring for language ability and attention while anti-NMDA titers and mini-mental state examination scoring were inversely correlated. However, when patients were stratified according to the presence/absence of aPL, the correlation was confirmed in aPL positive patients only. Should those findings be confirmed, the etiology of the prevalent defects found in PAPS patients as well as the synergism between aPL and anti-NMDA antibodies would need to be explored.

Clinical usefulness of autoantibodies to M-type phospholipase A2 receptor (PLA2R) for monitoring disease activity in idiopathic membranous nephropathy (IMN)

Autoantibodies to M-type phospholipase A2 receptor (PLA2R) are specific markers of idiopathic membranous nephropathy (IMN). They can differentiate IMN from other glomerular diseases and primary from secondary forms of MN. Preliminary data suggest that anti-PLA2R antibody titer correlates with disease activity but more solid evidence is needed. To evaluate the performance of anti-PLA2R antibody for monitoring nephropathy activity, 149 anti-PLA2R antibody measurements were performed during the follow-up of 42 biopsy proven IMN consecutive patients. Patients were enrolled either at time of diagnosis (33 cases, inception cohort) or after diagnosis (9 patients, non-inception cohort). Anti-PLA2R detection was performed using the highly sensitive transfected cell-based indirect immunofluorescence (IIFT). Over the follow-up there was a linear time-trend of decreasing proteinuria (P<0.001), increasing serum albumin (P<0.001) and decreasing PLA2R antibody levels (P=0.002). There was a statistically significant association between changes in PLA2R antibody levels and the clinical course of PLA2R-positive IMN. The positive PLA2R serum antibody status was linearly associated with increasing proteinuria and decreasing serum albumin over time, compared with negative antibody status. Moreover, the strong correlation between the clinical conditions and PLA2R antibody levels allowed the prediction of prevalence distribution of patients with active disease, partial and complete remission. Over the course of the follow-up, the probability of halving proteinuria increased 6.5 times after disappearance of PLA2R antibodies. Our data suggest that the serial evaluation of anti-PLA2R antibodies could help in optimal timing and duration of the immunosuppressive therapy, reducing over(under)-treatment and associated side-effects.

Clinical characterization of antiphospholipid syndrome by detection of IgG antibodies against β2 -glycoprotein i domain 1 and domain 4/5: ratio of anti-domain 1 to anti-domain 4/5 as a useful new biomarker for antiphospholipid syndrome

OBJECTIVE

It has been suggested that only antibodies against domain 1 (D1) of β2 -glycoprotein I (β2 GPI) are pathogenic and diagnostic. The role of antibodies against other β2 GPI domains is still debated. This study was undertaken to evaluate the clinical relevance of domain specificity profiling of anti-β2 GPI IgG antibodies in antiphospholipid syndrome (APS) patients and in control groups of patients with systemic autoimmune rheumatic diseases and in asymptomatic antiphospholipid antibody (aPL) carriers.

METHODS

We evaluated 159 subjects with persistently positive, medium or high-titer anti-β2 GPI IgG, including 56 patients with thrombotic (obstetric or nonobstetric) primary APS, 31 women with obstetric primary APS, 42 aPL-positive patients with systemic autoimmune rheumatic diseases, and 30 asymptomatic aPL carriers. One hundred healthy donors were included. Anti-β2 GPI D1 and D4/5 IgG were tested on research enzyme-linked immunosorbent assays containing recombinant β2 GPI domains.

RESULTS

As compared to other groups, aPL carriers displayed higher frequency/titer of anti-D4/5 IgG. Unlike anti-D4/5, anti-D1 IgG antibodies were more frequent and at higher titer in triple than in single or double aPL-positive subjects. An anti-D1 to anti-D4/5 ratio of ≥1.5 was predictive of systemic autoimmunity (odds ratio 3.25 [95% confidence interval 1.45-7.49], P = 0.005). Neither anti-D1 nor anti-D4/5 antibodies were associated with APS clinical criteria.

CONCLUSION

Anti-D1 IgG is the preferential specificity not only in vascular and obstetric primary APS, but also in patients with systemic autoimmune rheumatic disease with no clinical features of APS. Conversely, aPL carriers do not have a polarized profile toward D1. Combined testing for anti-β2 GPI IgG with different domain specificity allows a more accurate aPL profiling, with polarization toward anti-D1 IgG as a possible fingerprint of systemic autoimmunity.

Anti-Ro/SSA-p200 antibodies in the prediction of congenital heart block. An Italian multicentre cross-sectional study on behalf of the 'Forum Interdisciplinare per la Ricerca nelle Malattie Autoimmuni (FIRMA) Group'

OBJECTIVES

To verify the association between the presence of specific anti-52 Ro/SSA-p200 antibodies and congenital heart block (CHB).

METHODS

207 pregnant Italian women carrying anti-Ro/SSA Ab were retrospectively evaluated. Anti-p200 Ab were investigated in the mothers' sera by ELISA (Euro-Diagnostica,Wieslab SS-A p200).

RESULTS

CHB occurred in 42 children (34 complete CHB), whereas 165 were not affected. All CHB cases were previously identified with an ELISA screening for anti-Ro/SSA 60 kD Ab. Anti-p200 Ab were more frequently positive (81.0% vs. 59.1%, p=0.013) and at a higher titer in CHB mothers (Absorbance ratio: 2.030 (0.208-4.052) vs. 0.925 (0.200-3.816); p=0.017). This association was maintained even when the 42 mothers of children with CHB were compared with a control group matched for age and diagnosis (80.9% vs. 50.0%; p=0.006). The presence of anti-p200 Ab provided an odds ratio (OR) for CHB of 2.98 (CI: 1.30-6.83), which was higher than that of other variables, such as maternal disease and other antibody specificities. CHB risk significantly decreased in the absence of this fine specificity (OR:0.34, CI: 0.15-0.77). However, while the negative predictive value related to anti-Ro/SSA 60 kD Ab ELISA was 100%, almost 20% of mothers negative for anti-p200 Ab delivered babies with CHB.

CONCLUSIONS

Anti-p200 antibodies seem to be associated with CHB with a higher probability than anti-Ro/SSA Ab, and therefore may be an additional test to identify mothers at higher risk to deliver affected children. An ELISA screening for anti-Ro/SSA 60 kD Ab is nevertheless mandatory given the probability of developing CHB also in the absence of anti-p200 Ab.

Anti-phosphatidylserine/prothrombin antibodies: an additional diagnostic marker for APS?

Among the diagnostic assays for anti-phospholipid syndrome (APS), lupus anticoagulant (LA) is the strongest predictor of thrombosis; however, it presents several limitations as interference with anticoagulant therapy and poor inter-laboratory agreement. Two-thirds of LA activity is apparently due to antibodies against prothrombin (PT), usually detectable by ELISA. Binding of PT to phosphatidylserine (PS) has been shown to enhance solid-phase anti-PT assay sensitivity. To determine the prevalence of antibodies against PS/PT (aPS/PT) in APS, we tested the semiquantitative QUANTA Lite(®) aPS/PT ELISA in a cohort of 80 APS patients. The prevalence of aPS/PT was 81.3%, rising to 87.6% when considering LA-positive subjects only. We observed a strong correlation between aPS/PT and LA (p = 0.006). To note, APS patients with thrombotic manifestations displayed significantly higher IgG aPS/PT titers compared to 20 aPL asymptomatic carriers (p = 0.012). To rule out a possible cross-reactivity of anti-β2 glycoprotein I antibodies (aβ2GPI) with PS/PT complex, we tested two monoclonal aβ2GPI antibodies and an affinity-purified (AP) polyclonal aβ2GPI IgG obtained from the serum of a patient reacting against both β2GPI and PS/PT. The two monoclonal antibodies did not show any reactivity against PS/PT complex, similarly the AP IgGs did not react toward PS/PT antigen while preserved their aβ2GPI activity. Our findings suggest that aPS/PT are a definite antibody population in APS. Moreover, the good correlation between aPS/PT ELISA and LA may support its use as a surrogate test for LA, particularly useful to overcome the technical limitations of the functional assay.

Automated interpretation of ANCA patterns - a new approach in the serology of ANCA-associated vasculitis

Introduction

Indirect immunofluorescence (IIF) employing ethanol-fixed neutrophils (ethN) is still the method of choice for assessing antineutrophil cytoplasmic antibodies (ANCA) in ANCA-associated vasculitides (AAV). However, conventional fluorescence microscopy is subjective and prone to high variability. The objective of this study was to evaluate novel pattern recognition algorithms for the standardized automated interpretation of ANCA patterns.

Methods

Seventy ANCA-positive samples (20 antimyeloperoxidase ANCA, 50 antiproteinase3 ANCA) and 100 controls from healthy individuals analyzed on ethN and formalin-fixed neutrophils (formN) by IIF were used as a 'training set' for the development of pattern recognition algorithms. Sera from 342 patients ('test set') with AAV and other systemic rheumatic and infectious diseases were tested for ANCA patterns using the novel pattern recognition algorithms and conventional fluorescence microscopy.

Results

Interpretation software employing pattern recognition algorithms was developed enabling positive/negative discrimination and classification of cytoplasmic ANCA (C-ANCA) and perinuclear ANCA (P-ANCA). Comparison of visual reading of the 'test set' samples with automated interpretation revealed Cohen's kappa (κ) values of 0.955 on ethN and 0.929 on formN for positive/negative discrimination. Analysis of the 'test set' with regard to the discrimination between C-ANCA and P-ANCA patterns showed a high agreement for ethN (κ = 0.746) and formN (κ = 0.847). There was no significant difference between visual and automated interpretation regarding positive/negative discrimination on ethN and formN, as well as ANCA pattern recognition (P > 0.05, respectively).

Conclusions

Pattern recognition algorithms can assist in the automated interpretation of ANCA IIF. Automated reading of ethN and formN IIF patterns demonstrated high consistency with visual ANCA assessment.