ABSTRACT
Autoantibody detection is the cornerstone of autoimmune liver diseases (AILD) diagnosis. Standardisation of working algorithms among autoimmunity laboratories, as well as being aware of the sensitivity and specificity of various commercial techniques in daily practice, are still necessary. The aim of this nationwide study is to report the results of the 2020 Autoimmunity Workshop organised by the Autoimmunity Group of the Spanish Society of Immunology and to provide useful information to clinicians and laboratory specialists to improve the management of autoantibody detection in AILD diagnoses. Serum samples from 17 patients with liver diseases were provided by the organisers of the 2020 Autoimmunity Workshop and were subsequently analysed by the 40 participating laboratories. Each laboratory used different techniques for the detection of autoantibodies in each patients' serum sample, according to their working algorithm. Thus, almost 680 total complete patient reports were obtained, and the number of results from different autoantibody detection techniques was >3000. Up to eight different working algorithms were employed, including indirect immunofluorescence assays (IFA) and antigen-specific techniques (AgST). The IFA of HEp-2 cells was more sensitive than IFA of rat triple tissue for the study of anti-nuclear autoantibodies (ANA) associated with AILD. The IFA of a human neutrophil study for the analysis of anti-neutrophil cytoplasmic autoantibodies was not carried out systemically in all patients, or by all laboratories. AgSTs were the most sensitive methods for the detection of anti-smooth muscle/F-actin, soluble liver antigen, liver cytosol-1, M2-mitochondrial autoantibodies, and ANA associated with primary biliary cholangitis. The main differences in AMA detection were due to patients with autoantibodies against the non-dominant epitope of pyruvate dehydrogenase complex. Given that they are complementary, IFA and AgST should be performed in parallel. If there is high suspicion of AILD, AgST should always be performed.
ABSTRACT
OBJETIVO: O III Consenso Brasileiro para Pesquisa de Autoanticorpos em Células HEp-2 (FAN) objetivou discutir estratégias para controlar a qualidade do ensaio, promover a atualização das associações clínicas dos diversos padrões e avaliar as dificuldades de implantação do II Consenso ocorrido no ano de 2002. MÉTODOS: Nos dias 13 e 14 de abril de 2007 participaram do encontro em Goiânia pesquisadores e especialistas de diversos centros universitários e laboratórios clínicos de diferentes regiões do Brasil, com o propósito de discutir e aprovar as recomendações que visam a melhores padronização, interpretação e utilização do ensaio pelos clínicos. Foram convidados como ouvintes representantes comerciais de diferentes empresas produtoras de insumos para realização do teste de FAN. RESULTADOS E CONCLUSÃO: Dada a heterogeneidade de microscópios e reagentes disponíveis no mercado, o III Consenso enfatizou a necessidade do controle de qualidade em ensaios de imunofluorescência indireta. Foram também feitas algumas adequações na terminologia utilizada para classificar os diferentes padrões. Finalmente, foi realizada uma atualização das associações clínicas com finalidade de facilitar cada vez mais o melhor uso do ensaio pelos clínicos.
OBJECTIVE: The Third Brazilian Consensus for Autoantibodies Screening in HEp-2 Cells (ANA) had as purpose the evaluation of difficulties in the accomplishment of the 2nd Consensus recommendations that took place in the year of 2002, the discussion of strategies for quality control of the assay and the discussion of an update of the clinical associations of the several immunofluorescent patterns. METHODS: Several ANA experts from university centers and private laboratories in different areas in Brazil joined the workshop in Goiânia on 2007 April 13 and 14 with the purpose of discussing and approving the recommendations for standardization, interpretation and use of the test by physicians. Commercial representatives of different ANA slide brands were also invited as listeners to the workshop. RESULTS AND CONCLUSION: The 3rd ANA Consensus emphasized the need for quality control in indirect immunofluorescent assays since there is a considerable heterogeneity of available microscopes and reagents. It also promoted adaptations in the previously approved terminology used to classify the different patterns and finally updated the clinical associations of the several patterns with the purpose of providing guidance for interpretation of the assay by clinical pathologists and assistant physicians.
