[Advice in autoimmunity biological diagnosis: guidelines for drafting comments on biological results]. / Prestation de conseil en auto-immunité : aide à la rédaction de commentaires pour les comptes rendus de résultats.

The ISO 15189 accreditation of biological analysis requires the presence of interpretation in the analysis report. The interpretation in the field of autoimmunity which includes many analyses and methods can be complex for biologists who may not have clinical data and for clinicians who may not be aware of technical difficulties. The French group of the european group EASI (European autoimmunity standardisation initiative) proposes a list of comments and advice in order to help biologists when interpreting auto-immune analyses results in several situations. These comments should be adapted to the clinical and biological situation (other biological results, clinical data…) and should alert the clinician. A dialogue between the biologist and the clinician is essential to adjust the interpretation on clinical data in order to provide a better health care for the patient.

Prognosis and long-term outcomes in type I cryoglobulinemia: A multicenter study of 168 patients.

Type I cryoglobulinemia (CG) accounts for 10%-15% of all cryoglobulinemias and are exclusively seen in clonal proliferative hematologic conditions. In this multicenter nationwide cohort study, we analyzed the prognosis and long-term outcomes of 168 patients with type I CG (93 (55.4%) IgM and 75 [44.6%] IgG). Five- and 10-year event-free survivals (EFS) were 26.5% (95% CI 18.2%-38.4%) and 20.8% (95% CI 13.1%-33.1%), respectively. In multivariable analysis, factors associated with poorer EFS were renal involvement (HR: 2.42, 95% CI 1.41-4.17, p = .001) and IgG type I CG (HR: 1.96, 95% CI 1.13-3.33, p = 0.016), regardless of underlying hematological disorders. IgG type I CG patients had higher cumulative incidence of relapse (94.6% [95% CI 57.8%-99.4%] vs. 56.6% [95% CI 36.6%-72.4%], p = .0002) and death at 10 years (35.8% [19.8%-64.6%] vs. 71.3% [54.0%-94.2%], p = .01) as compared to IgM CG, respectively. Overall, complete response of type I CG at 6 months was 38.7%, with no significant difference between Igs isotypes. In conclusion, renal involvement and IgG CG were identified as independent poor prognostic factors of type I CG.

Detection of antinuclear antibodies: recommendations from EFLM, EASI and ICAP.

OBJECTIVES: Antinuclear antibodies (ANA) are important for the diagnosis of various autoimmune diseases. ANA are usually detected by indirect immunofluorescence assay (IFA) using HEp-2 cells (HEp-2 IFA). There are many variables influencing HEp-2 IFA results, such as subjective visual reading, serum screening dilution, substrate manufacturing, microscope components and conjugate. Newer developments on ANA testing that offer novel features adopted by some clinical laboratories include automated computer-assisted diagnosis (CAD) systems and solid phase assays (SPA). METHODS: A group of experts reviewed current literature and established recommendations on methodological aspects of ANA testing. This process was supported by a two round Delphi exercise. International expert groups that participated in this initiative included (i) the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group "Autoimmunity Testing"; (ii) the European Autoimmune Standardization Initiative (EASI); and (iii) the International Consensus on ANA Patterns (ICAP). RESULTS: In total, 35 recommendations/statements related to (i) ANA testing and reporting by HEp-2 IFA; (ii) HEp-2 IFA methodological aspects including substrate/conjugate selection and the application of CAD systems; (iii) quality assurance; (iv) HEp-2 IFA validation/verification approaches and (v) SPA were formulated. Globally, 95% of all submitted scores in the final Delphi round were above 6 (moderately agree, agree or strongly agree) and 85% above 7 (agree and strongly agree), indicating strong international support for the proposed recommendations. CONCLUSIONS: These recommendations are an important step to achieve high quality ANA testing.

Repository of intra- and inter-run variations of quantitative autoantibody assays: a European multicenter study.

OBJECTIVES: No reference data are available on repositories to measure precision of autoantibody assays. The scope of this study was to document inter- and intra-run variations of quantitative autoantibody assays based on a real-world large international data set. METHODS: Members of the European Autoimmunity Standardisation Initiative (EASI) group collected the data of intra- and inter-run variability obtained with assays quantifying 15 different autoantibodies in voluntary participating laboratories from their country. We analyzed the impact on the assay performances of the type of immunoassay, the number of measurements used to calculate the coefficient of variation (CVs), the nature and the autoantibody level of the internal quality control (IQC). RESULTS: Data were obtained from 64 laboratories from 15 European countries between February and October 2021. We analyzed 686 and 1,331 values of intra- and inter-run CVs, respectively. Both CVs were significantly dependent on: the method of immunoassay, the level of IQC with higher imprecision observed when the antibody levels were lower than 2-fold the threshold for positivity, and the nature of the IQC with commercial IQCs having lower CVs than patients-derived IQCs. Our analyses also show that the type of autoantibody has low impact on the assay' performances and that 15 measurements are sufficient to establish reliable intra- and inter-run variations. CONCLUSIONS: This study provides for the first time an international repository yielding values of intra- and inter-run variation for quantitative autoantibody assays. These data could be useful for ISO 15189 accreditation requirements and will allow clinical diagnostic laboratories to assure quality of patient results.

Immunochemotherapy versus rituximab in anti-myelin-associated glycoprotein neuropathy: A report of 64 patients.

Monoclonal immunoglobulin M (IgM) anti-myelin-associated glycoprotein (MAG) neuropathy is a rare disabling condition, most commonly treated with rituximab monotherapy (R), which leads to neurological improvement in only 30%-50% of patients. The combination of rituximab plus chemotherapy has been proven to improve the level of responses. We studied the outcomes of anti-MAG neuropathy patients treated either by R, or by immunochemotherapy (ICT) in our centre, focusing on the incidence of the first neurological response evaluated by the modified Rankin scale (mRS). From 2011 to 2018, 64 patients were studied: 34 were treated with R and 30 with ICT. According to our treatment decision-making process, the median mRS was higher in the ICT group (mRS 2) than in the R group (mRS 1). At one year, improvements of the mRS rates were 46% and 18% in the ICT and R groups of patients respectively, with median times to response of eight and 13 months (p = 0.023). Adverse effects were higher in the ICT group: 62% vs 15% (p Ë‚ 0.01), all grades included. One secondary acute leukaemia occurred five years after treatment with ICT. In conclusion, ICT may be used as a valid option for patients with rapidly progressive and/or severe anti-MAG neuropathy symptoms.

The International Consensus on ANA Patterns (ICAP) in 2021-The 6th Workshop and Current Perspectives.

The establishment of the International Consensus on ANA Patterns (ICAP) in 2014-2015 was welcomed by members of the medical community as a significant improvement in guiding harmonization of ANA test interpretation and reporting. In the subsequent years, several itinerant meetings and continuous interaction with the community contributed to disseminate the ICAP harmonization on the immunofluorescence patterns observed in the indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and to promote progressive improvement in the classification of HEp-2 IFA patterns. The 6th ICAP Workshop was held in person on September 6, 2021 as a satellite meeting of the 15th Dresden Symposium on Autoantibodies. This article summarizes the major discussions at the meeting as well as outlining the current plans for the ICAP committee.

How to report the antinuclear antibodies (anti-cell antibodies) test on HEp-2 cells: guidelines from the ICAP initiative.

Results of the anti-nuclear antibodies-indirect immunofluorescence assay (anti-cell antibodies test) on HEp-2 cell substrates should be communicated to clinicians in a standardized way, adding value to laboratory findings and helping with critical clinical decisions. This paper proposes a test report based on the practices informed by 118 laboratories in 68 countries, with recommendations from the International Consensus on ANA Patterns (ICAP) group. Major focus is placed on the report format containing endpoint titers, immunofluorescence patterns together with anti-cell (AC) nomenclature, remarks on follow-up or reflex testing, and possible other autoantibody associations. ISO 15,189 directives were integrated into the test report. Special situations addressed include serum screening dilutions and endpoint titers, relevance of immunofluorescence patterns with special attention to cytoplasmic patterns, mixed and compound patterns, and how to report different titers corresponding to multiple patterns or autoantibodies in the same sample. This paper suggests a subtitle for the HEp-2-IIFA, namely anti-cell antibodies test, which could gradually substitute the original outdated ANA nomenclature. This ICAP pro forma report represents a further step in harmonizing the way relevant clinical information could be provided by laboratories.

[Autoimmunity accreditation: training, accreditation and maintenance of skills in indirect immunofluorescence]. / Accréditation en auto-immunité : formation, habilitation et maintien des compétences en immunofluorescence indirecte.

The ISO 15189 accreditation of biological analysis needs the validation of the analytical methods allowing the evaluation of their performance including all the factors that could influence the quality of their results. The field of autoimmunity includes many analyses and methods such as the indirect immunofluorescence technique (IIF) and the performance of this technique largely depends on the competency of staff members. For each staff member, the required levels of competency have to be precisely defined and evaluated after a period of formation before the final habilitation for the IIF technique. The French group of the international group called EASI (European autoimmunity standardisation initiative) proposes two habilitation forms to be filled with criteria, evidence and maintenance of target skills for the IIF preparation of slides and reading. These forms could be used as a model for the IIF formation and habilitation and have to be adapted to the routine practice of the laboratories.

Quality and best practice in medical laboratories: specific requests for autoimmunity testing.

Special conditions associated with laboratory autoimmune testing are not well compatible with recent developments in regulatory frameworks such as EN/ISO 15189 accreditation or in vitro diagnostic medical device regulation (IVD-R). In addition, international recommendations, guidelines and disease criteria are poorly defined with respect to requirements on autoantibody testing. Laboratory specialists from Austria, Belgium, Croatia, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, and The Netherlands collected information, reported national experience, and identified quality issues in relation to autoantibody testing that require consensus on interpretation of the regulatory frameworks and guidelines. This process has been organized by the European Autoimmunity Standardisation Initiative (EASI). By identifying the critical items and looking for a consensus, our objective was to define a framework for, in particular, EN/ISO accreditation purposes. Here, we present a review of current publications and guidelines in this field to unify national guidelines and deliver in this way a European handout on quality control and accreditation for laboratories involved in autoantibody testing. We focus on quality items that can be checked during accreditation visits. Despite various local varieties, we encountered an overwhelming dedication to quality assurance in all contributing countries.

Cryoglobulinemia after the era of chronic hepatitis C infection.

OBJECTIVES: Historically chronic hepatitis C virus (HCV) infection accounted for the majority of mixed cryoglobulinemia (MC). The advent of direct-acting antivirals (DAA) against HCV has dramatically changed the management and the prevalence of chronic HCV infection. We aimed to describe the spectrum of MC in the era of DAA agents. METHODS: We performed a longitudinal cohort study between 2011 and 2018 from a single-center French university hospital's database of 15 970 patients screened for MC. Epidemiological, clinical and immunological data of MC were recorded. We evaluated the incidence and evolution of MC before and after the era of DAA agents and compared HCV and non-HCV related MC. RESULTS: Among 742 patients who tested positive for cryoglobulin, 679 [mean age 55.5 years, 54.5% female and 381 (56.1%) with chronic HCV infection] patients with persistent MC were included in the study. 373 (54.9%) had type II and 306 (45.1%) type III cryoglobulin, and 139 (21.5%) had cryoglobulinemia vasculitis (CryoVas). The incidence of MC decreased steadily with 395 and 284 incident cases during 2011-2014 and 2015-2018, respectively. In 2011, the leading cause was chronic HCV infection (62.5% of all MC). Currently, autoimmune diseases [systemic lupus erythematosus (28.9%) and Sjögren's syndrome (10.7%)] are the main cause of MC. The incidence of CryoVas was similar between HCV-and non HCV-related MC. CONCLUSION: Direct-acting antivirals have dramatically changed the landscape and the incidence of MC.

Precision of autoantibody assays in clinical diagnostic laboratories: What is the reality?

BACKGROUND: ISO 15189 accreditation remains a challenge for specialized laboratories. In the field of autoimmunity, beside the crucial problem of absence of standardization, laboratories have to manage the analytical performances of the large panel of assays in terms of sensitivity and specificity, but also on their measurement precision for which no reference values are available on biorepositories. METHODS: As an initiative of the French EASI (European Autoimmunity Standardization Initiative) group, French clinical diagnostic laboratories were requested to participate in a survey aiming to analyze the coefficients of variation (CVs) of intra-run and inter-run variability obtained with assays quantifying 14 different autoantibodies. Two performance goals corresponding to the 90th percentile and the 50th percentile (lowest CV values reached by 90% and 50% of laboratories respectively) defined for three levels of concentration were calculated. The impact on the assay performances of the number of measurements, of the nature of the internal quality control (IQC) and the type of immunoassay, was also analyzed. RESULTS: 414 and 616 values of intra-run and inter-run CVs were collected, respectively. The 50th percentile performance goals were comprised between 1.0% and 8.9% for the intra-run CVs, and between 1.8% and 14.6% for the inter-run CVs. At 90th percentile, the performance goals were comprised between 3.2% and 13.5% for the intra-run CVs, and between 7.3% and 30.8% for the inter-run CVs. CVs calculated from 10 values were similar to those obtained from more values. Higher imprecision was observed when the antibody levels of the IQC was lower than 2 fold the positive threshold. Commercial IQCs gave lower CVs than IQCs derived from patient samples. CONCLUSION: Our results allow proposing some acceptability limits for the precision performances of the autoantibody assays, compatible with the reality of life in diagnostic laboratories and clinical care.

Severe Acute Flaccid Myelitis Associated With Enterovirus in Children: Two Phenotypes for Two Evolution Profiles?

Acute flaccid myelitis (AFM) is an acute paralysis syndrome defined by a specific inflammation of the anterior horn cells of the spinal cord. From 2014, worrying waves of life-threatening AFM consecutive to enterovirus infection (EV-D68 and EV-A71) have been reported. We describe 10 children displaying an AFM with an EV infection, the treatments performed and the 1 to 3-years follow-up. Two groups of patients were distinguished: 6 children ("polio-like group") had severe motor disability whereas 4 other children ("brainstem group") displayed severe brainstem weakness requiring ventilation support. Electrodiagnostic studies (n = 8) support the presence of a motor neuronopathy associated to myelitis. The best prognosis factor seems to be the motor recovery after the first 4 weeks of the disease.

Rituximab-associated Vasculitis Flare: Incidence, Predictors, and Outcome.

OBJECTIVE: To report the incidence, predictors, and outcome of rituximab (RTX)-associated autoimmune disease flare. METHODS: We conducted a retrospective study in a tertiary referral center from 2005 to 2015. Disease flare was defined as the onset of a new organ involvement or worsening of autoimmune disease within 4 weeks following RTX. RESULTS: Among the 185 patients, we identified 7 disease flares (3.4%). All were due to type II mixed cryoglobulinemia vasculitis. Vasculitis flare occurred after a median time of 8 days (range 2-16) following RTX infusion and included acute kidney insufficiency (n = 7), purpura with cutaneous (n = 7), gastrointestinal (GI) tract involvement (n = 4), and myocarditis (n = 1). Patients with RTX-associated cryoglobulinemia vasculitis flare had these conditions more frequently: renal involvement (p = 0.0008), B cell lymphoproliferation (p = 0.015), higher level of cryoglobulin (2.1 vs 0.4 g/l, p = 0.0004), and lower level of C4 (0.02 vs 0.05, p = 0.023) compared to patients without flare after RTX (n = 43). Four patients (57%) died after a median time of 3.3 months. The 1-year survival rate was poorer in patients with vasculitis flare after RTX compared to their negative counterpart [43% (95% CI 18-100) vs 97% (95% CI 92-100), p < 0.001]. Immunofluorescence analysis of kidney biopsy in patients with worsening RTX-associated vasculitis highlighted the presence of RTX-, IgM-, and IgG1-positive staining of endomembranous deposits and thrombi within kidney lesions. CONCLUSION: RTX-associated cryoglobulinemia vasculitis flare is associated with high mortality rate. We provided evidence that kidney lesions are due to immune complex deposition and to glomerular obstruction by cryoglobulinemia and RTX.

Anti-MDA5 juvenile idiopathic inflammatory myopathy: a specific subgroup defined by differentially enhanced interferon-α signalling.

OBJECTIVES: JDM and juvenile overlap myositis represent heterogeneous subtypes of juvenile idiopathic inflammatory myopathy (JIIM). Chronic evolution can occur in up to 60% of cases, and morbidity/mortality is substantial. We aimed to describe the clinical, biological, histological and type I IFN status in JIIM associated with anti-melanoma differentiation-associated protein 5 (anti-MDA5) autoantibodies at presentation (group 1) in comparison with other JIIM (group 2). METHODS: This was a retrospective and prospective study of patients with JIIM ascertained from three French paediatric rheumatology reference centres between 2013 and 2019. Muscle biopsies were reviewed. Type I interferon pathway activity was assessed by dosage of IFNα serum protein and the expression of IFN-stimulated genes. RESULTS: Sixty-four patients were included, 13 in group 1 (54% JDM and 46% juvenile overlap myositis) and 51 in group 2 (76% JDM and 24% juvenile overlap myositis). Group 1 patients demonstrated more arthritis, skin ulcerations, lupus features and interstitial lung disease, and a milder muscular involvement. Serum IFNα levels were higher in group 1 than 2, and decreased after treatment or improvement in both groups. Outcome was similar in both groups. Unconventional treatment (more than two lines) was required in order to achieve remission, especially when skin ulceration was reported. CONCLUSION: This study indicates a higher frequency of arthritis, skin ulcerations and interstitial lung disease, but milder muscular involvement, in JIIM with positive anti-MDA5 autoantibodies compared with other JIIM. Our data support an important role of systemic IFNα in disease pathology, particularly in the anti-MDA5 auto-antibody-positive subgroup. In severe and refractory forms of JIIM, IFNα may represent a therapeutic target.

Development of a New Classification System for Idiopathic Inflammatory Myopathies Based on Clinical Manifestations and Myositis-Specific Autoantibodies.

Importance: Idiopathic inflammatory myopathies are heterogeneous in their pathophysiologic features and prognosis. The emergence of myositis-specific autoantibodies suggests that subgroups of patients exist. Objective: To develop a new classification scheme for idiopathic inflammatory myopathies based on phenotypic, biological, and immunologic criteria. Design, Setting, and Participants: An observational, retrospective cohort study was performed using a database of the French myositis network. Patients identified from referral centers for neuromuscular diseases were included from January 1, 2003, to February 1, 2016. Of 445 initial patients, 185 patients were excluded and 260 adult patients with myositis who had complete data and defined historical classifications for polymyositis, dermatomyositis, and inclusion body myositis were enrolled. All patients were tested for anti-histidyl-ARN-t- synthetase (Jo1), anti-threonine-ARN-t-synthetase (PL7), anti-alanine-ARN-t-synthetase (PL12), anti-complex nucleosome remodeling histone deacetylase (Mi2), anti-Ku, anti-polymyositis/systemic scleroderma (PMScl), anti-topoisomerase 1 (Scl70), and anti-signal recognition particle (SRP) antibodies. A total of 708 variables were collected per patient (eg, cancer, lung involvement, and myositis-specific antibodies). Main Outcomes and Measures: Unsupervised multiple correspondence analysis and hierarchical clustering analysis to aggregate patients in subgroups. Results: Among 260 participants (163 [62.7%] women; mean age, 59.7 years; median age [range], 61.5 years [48-71 years]), 4 clusters of patients emerged. Cluster 1 (n = 77) included patients who were male, white, and older than 60 years and had finger flexor and quadriceps weakness and findings of vacuolated fibers and mitochondrial abnormalities. Cluster 1 regrouped patients who had inclusion body myositis (72 of 77 patients [93.5%]; 95% CI, 85.5%-97.8%; P < .001). Cluster 2 (n = 91) regrouped patients who were women and had high creatine phosphokinase levels, necrosis without inflammation, and anti-SRP or anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies corresponding to immune-mediated necrotizing myopathy (53 of 91 [58.2%]; 95% CI, 47.4%-68.5%; P < .001). Cluster 3 (n = 52) regrouped patients who had dermatomyositis rash and anti-Mi2, anti-melanoma differentiation-associated protein 5 (MDA5), or anti-transcription intermediary factor-1γ (TIF1γ) antibodies, mainly corresponding with patients who had dermatomyositis (43 of 52 [82.7%]; 95% CI, 69.7%-91.8%; P < .001). Cluster 4 (n = 40) was defined by the presence of anti-Jo1 or anti-PL7 antibodies corresponding to antisynthetase syndrome (36 of 40 [90.0%]; 95% CI, 76.3%-97.2%; P < .001). The classification of an independent cohort (n = 50) confirmed the 4 clusters (Cohen κ light, 0.8; 95% CI, 0.6-0.9). Conclusions and Relevance: These findings suggest a classification of idiopathic inflammatory myopathies with 4 subgroups: dermatomyositis, inclusion body myositis, immune-mediated necrotizing myopathy, and antisynthetase syndrome. This classification system suggests that a targeted clinical-serologic approach for identifying idiopathic inflammatory myopathies may be warranted.

Detection in whole blood of autoantibodies for the diagnosis of connective tissue diseases in near patient testing condition.

A novel technology, photonic ring immunoassay (PRI), for detecting 12 autoantibodies simultaneously in whole blood in less than 15 minutes was evaluated by comparing results from 235 clinically diagnosed patients with standard laboratory tests. The overall agreement was greater than 91% for 10 of the 12 assays, with positive percent agreement greater than 89% for 9 of the assays and negative percent agreement greater than 91% for 10 of them. Thus, the clinical sensitivities and specificities were similar for the 2 methods. In addition, 199 normal blood donors were tested on the ANA 12 PRI, yielding specificities greater than 97.5% for all assays. This proof of concept study shows that this new system is suitable for point of care testing for clinically useful autoantibodies, allowing the doctor to have test results in minutes rather than days.

[Research and identification of antinuclear antibodies: analysis of a questionnaire from the European EASI group and confrontation of French practices to international recommendations]. / Recherche et identification des anticorps antinucléaires : analyse du questionnaire européen de l'EASI groupe et confrontation des pratiques françaises aux recommandations internationales.

Antinuclear antibodies (ANA) are prescribed as first-line autoantibodies in suspicion of mainly systemic autoimmune diseases. They include antibodies recognizing antigenic structures localized in the nucleus of cells, but also in the cytoplasm, at the membranes or transitional structures related to the cell cycle. Their research is based on screening and identification tests. For these tests, there is little or no standardization and harmonization of professional practices is necessary. From a questionnaire sent to healthcare professionals involved in the realization and interpretation of tests of autoimmunity, an overwiew of routine practices for the research of the ANA and their identification, was directed by the EASI Group International. Here, we present the results of the survey carried out in France. The analysis of these results faced with that of other countries as well as international recommendations allowed us to propose a synthesis of the main recommendations adapted to the regulatory texts of the NABM in France. These recommendations are addressed to those who prescribe, to those who perform biological analysis and to clinicians and biologists who interpret the results. They allow better understanding and admitting the methodological differences and their evolutions, to encourage the choice of the best technique based on the clinical context, to inform the clinician of the characteristics of the tests used.

Testing anti-neutrophil cytoplasmic antibodies (ANCA): analysis of the European EASI survey on the daily practice of the French laboratories.

Anti-neutrophil cytoplasmic antibodies (ANCA) are mainly searched for the diagnosis of autoimmune vasculitis. They may be found also in other conditions with chronic inflammation. Testing ANCA is based on two main technics: indirect immunofluorescence (IFI) and immunochemical technics to identify the antigenic specificity of the autoantibodies. There is heterogeneity among the laboratories' daily practice. An international group called EASI (European autoimmunity standardisation initiative), composed of 15 countries, comprising France, works to harmonize the practices of the biological diagnosis of the autoimmune diseases. It elaborated a survey consisting of 54 questions related to the analytic parameters of the technics, the algorithms for their use and their biological interpretation; and submitted it to European laboratories. We propose an analysis of the answers obtained from 36 French laboratories specialized in autoimmunity. We compare them to the ones obtained from the other countries and discussed them according to the international recommendations. The analysis reveals a predominant use of IFI as a first step with variable strategies for the identification of the antigenic specificity of the autoantibodies. Overall, the practices are chiefly conformed to the recommendations for the diagnosis of vasculitis, but they are less consensual when the ANCA are performed in other clinical situations.