VII Brazilian Consensus guidelines for the detection and interpretation of anti-cell autoantibodies on HEp-2 cells

Abstract

Background: The VII Brazilian Consensus on Autoantibodies against HEp-2 Cells (BCA/HEp-2), dedicated to the identification of autoantibodies targeting cellular constituents in HEp-2 cells, was held on October 5–6, 2023, in Goiânia (GO, Brazil), as part of the 40th Brazilian Congress of Rheumatology. Main body: Nineteen researchers and experts from universities and clinical laboratories participated in this meeting, which resulted in important advancements. Among the key updates, two new nuclear patterns were incorporated into the Brazilian classification tree: the nuclear fine speckled with mitotic plate (AC-30) and the myriad discrete speckled pattern strongly associated with antibodies to SS-A/Ro60, previously categorized as AC-4a and now recognized as AC-31. Additionally, the mitotic pattern AC-28 (mitotic chromosomal), characterized by punctate staining of chromosomes in pro- and metaphase stages without interphase cell staining, was included. Adjustments to the classification tree were made to redistribute patterns based on morphological characteristics, harmonize composite pattern designations with ICAP nomenclature, and incorporate the AC-XX group into the classification structure. Guidance was also provided to laboratory analysts on the limitations of identifying patterns with weak reactivity, recommending that reports in such cases be issued according to the appropriate level of analytical competency. Conclusion: The recommendations aimed to establish clear guidelines for laboratories and clinicians, building upon those from the V and VI Consensuses while further aligning with ICAP recommendations. This consensus marks a significant step forward in adapting ICAP guidelines to the Brazilian context, refining the classification tree and addressing practical challenges faced by the scientific and clinical community.