AUTHOR=Wu Ziyan , Xu Honglin , Zhang Shulan TITLE=AC-X: Characteristic Antinuclear Antibody Patterns of Two Anti-Mi-2 Autoantibody-Positive Dermatomyositis Patients—A Case Report JOURNAL=Frontiers in Immunology VOLUME=Volume 13 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.857030 DOI=10.3389/fimmu.2022.857030 ISSN=1664-3224 ABSTRACT=Here we reported two anti-Mi-2 autoantibody positive dermatomyositis (DM) patients with characteristic antinuclear antibody(ANA)immunofluorescence pattern. Autoantibodeswerescreenedby indirect immunofluorescence (IIF)onHEp-2 cells(Euroimmune, Germany)andconfirmed by line immunoblot (ANA Profile 3 - Euroimmune, Germany). These two patients were positive for ANA(speckled, titer 1:320),followed by confirmation of positiveanti-Mi-2α and anti-Mi-2β positive and negative for all other antibodies. We found characteristic ANA pattern of anti-Mi-2 antibody that differed from the AC-4 pattern ,especially in the morphology of mitotic cells (metaphase, anaphase, and telophase). Thus, we would like to suggest reporting this characteristic antinuclear antibody patterns as a new AC type, as AC-X.