VI Brazilian consensus guidelines for detection of anti-cell autoantibodies on HEp-2 cells.

BACKGROUND: The VI Brazilian Consensus on Autoantibodies against HEp-2 cells for determination of autoantibodies against cellular constituents on HEp-2 cells was held on September, 2019, in Fortaleza (CE, Brazil). The guidelines in this edition were formulated by the group of Brazilian experts discussing the classification of complex patterns, the classification of the nuclear discrete dots (few and multiple), the identification of the discrete fine speckled pattern (AC-4a) and improvements on the ANA report. MAINBODY: Sixteen Brazilian researchers and experts from universities and clinical laboratories representing the various geographical regions of Brazil participated in the meeting. Four main topics were discussed: (1) How to classify patterns with fluorescence in more than one cell compartment considering three relevant categoris: composite patterns, mixed patterns and multiple patterns; (2) The splitting of the discrete nuclear dots pattern into the multiple discrete nuclear dots (AC-6) and few discrete nuclear dots (AC-7) patterns, respectively; (3) Inclusion of a novel nuclear pattern characterized by discrete fine speckled pattern highly associated with antibodies to SS-A/Ro60, classified as AC-4a. In addition, adjustments on the Brazilian Consensus nomenclature were implemented aiming to harmonize the designation of some patterns with the International Consensus on ANA Patterns (ICAP). Furthermore, the designations of the PCNA-like pattern (AC-13), CENP-F-like pattern (AC-14) and Topo I-like pattern (AC-29) were adjusted in accordance to ICAP. Finally, there was a recommendation for adjustment in the test report in order to address the status of nuclear envelope staining. For all topics, the aim was to establish specific guidelines for laboratories and clinicians. All recommendations were based on consensus among participants. All recommendations from the V Consensus were maintained and there was relevant progress in the BCA/HEp-2 guidelines and further harmonization with ICAP. CONCLUSION: The VI BCA/HEp-2 edition was successful in establishing important recommendations regarding the classification of complex patterns, in supporting the identification of a novel pattern within the AC-4 group and in the harmonization process with the ICAP terminology.

IV Brazilian guidelines for autoantibodies on HEp-2 cells.

OBJECTIVE: The Fourth Brazilian Consensus for Autoantibodies Screening in HEp-2 Cells (ANA) was held in Vitória, Espírito Santo, and aimed to discuss strategies and recommendations about the technique, standardization, interpretation and quality control of the indirect immunofluorescence reaction on HEp-2 cells. METHODS: Twenty three ANA experts from university centers and private laboratories in different areas from Brazil discussed and agreed upon recommendations for the fourth edition of the Brazilian Consensus for Autoantibodies Screening in HEp-2 Cells. RESULTS AND CONCLUSION: The 4th ANA Consensus included three novel patterns into the existing algorithm (cytoplasmic Rods and Rings, nuclear Quasi-homogeneous, and CENP-F). Emphasis was given to the need of attention in describing the peculiar mixed pattern elicited by anti-DNA topoisomerase I (Scl-70) autoantibodies, comprising nuclear fine specked, nucleolar homogeneous pattern, NOR staining in metaphase plates, and cytoplasmic fine speckled patterns. The group also emphasized the need for continuous quality control in indirect immunofluorescence assays, the establishment of screening dilutions, as well as conjugate titration. An alert was made regarding the heterogeneity of commercial kits in defining patterns and the use of solid phase methodologies to determine the presence of autoantibodies.

A comparative study of IgG second- and third-generation anti-cyclic citrullinated peptide (CCP) ELISAs and their combination with IgA third-generation CCP ELISA for the diagnosis of rheumatoid arthritis.

To compare IgG anti-cyclic citrullinated peptide (CCP) enzyme-linked immunosorbent assays (ELISAs) of second (anti-CCP2) and third generations (anti-CCP3) for the diagnosis of rheumatoid arthritis (RA), an IgA CCP3 ELISA was also evaluated. Combinations of the use of the three tests were evaluated. Anti-CCP2 IgG, anti-CCP3 IgG, and anti-CCP3 IgA antibody levels were determined by ELISAs in the serum of 70 patients with rheumatoid arthritis, 34 patients with systemic lupus erythematosus (SLE), and 54 normal subjects. We evaluated the serum levels, diagnostic performance, and the use of a combination of tests for RA diagnosis. Statistical analyses include receiver operating curves (ROCs) and others. The serum levels were higher in RA patients. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio (LR), and negative LR were, respectively, 78.6%, 94.3%, 91.7%, 84.7%, 13.8, and 0.23 for anti- CCP2 IgG and 82.9%, 93.2%, 90.6%, 87.2%, 12.2, and 0.18 for anti-CCP3 IgG. These values were better than the same statistical tests for anti-CCP3 IgA. ROC analysis showed that anti-CCP2 IgG and anti-CCP3 IgG had good performance and similar areas. Measuring both IgG and IgA anti-CCP tests increases the specificity if both tests were positive and increases the sensitivity if either test were positive. In our population, anti-CCP2 IgG and anti-CCP3 IgG had good diagnostic performance. Anti-CCP3 IgG had 4.3% more sensitivity than the anti-CCP2 IgG test while sustaining high specificity. This and other studies suggest the development of a dual test--CCP3 IgG and IgA that may be a potential diagnostic tool.