V Brazilian consensus guidelines for detection of anti-cell autoantibodies on hep-2 cells

Abstract

Background: The V Brazilian Consensus for determination of autoantibodies against cellular constituents on HEp-2 cells, held in Brasilia (DF, Brazil) on August 27, 2016, discussed the harmonization between the Brazilian Consensus on ANA (BCA) guidelines and the International Consensus on ANA Patterns (ICAP) recommendations (www.anapatterns.org). Initial guidelines were formulated by the group of Brazilian experts with the purpose of guiding and enabling Brazilian clinical laboratories to adopt recommendations and to provide a common standard for national and international consensuses.Mainbody: Twenty Brazilian researchers and experts from universities and clinical laboratories representing the various geographical regions of the country participated in the meeting. Three main topics were discussed, namely the harmonization between the BCA guidelines and latest recommendations of the ICAP initiative, the adjustment of the terminology and report on HEp-2 patterns, and a reassessment of quality assurance parameters. For the three topics, our aim was to establish specific guidelines. All recommendations were based on consensus among participants. There was concrete progress in the adjustment of the BCA guidelines to match the ICAP guidelines. To a certain extent, this derives from the fact that ICAP recommendations were largely based on the algorithm and recommendations of the IV Brazilian ANA Consensus, as consistently recognized in the ICAP publications and presentations. However, although there is great overlap between the two Consensuses, there are some point divergences. These specific items were individually and extensively discussed, and it was acknowledged that in several points ICAP improved recommendations previously issued by the Brazilian ANA Consensus and these changes were readily implemented. Regarding some specific topics, the BCA panel of experts felt that the previously issued recommendations remained relevant and possibly will require further discussion with ICAP. The term anti-cell antibodies was adopted as the recommended designation, recognizing that the assay addresses antibodies against antigens in the nucleus and in other cell compartments. However, the acronym ANA HEp-2 was maintained due to historical and regulatory reasons. It was also signalized that the latest trend in ICAP is to adopt the term Indirect Immunofluorescent Assay on HEp-2 cell substrate (HEp-2 IIFA). In addition, the quality assurance strategies previously presented were ratified and emphasized.(Continued on next page)

Standardization and Quality Assessment Under the Perspective of Automated Computer-Assisted HEp-2 Immunofluorescence Assay Systems

“…Accumulated evidence has made clear that the best compromise between sensitivity and specificity of the ANA test be at least 1:80. Furthermore, the choice of 1:80 as the best screening dilution is consistent with the results obtained by Tan et al (18) on more than 22,000 healthy individuals, showing that this titer corresponds to the 95%ile of healthy controls, as recommended by the EASI group (4) and various national guidelines (19)(20)(21). The new classification criteria for systemic lupus erythematosus also recommend a screening dilution of 1:80 (22).…”

“…A further contribution to the harmonization of the process concerns the choice of the cutoff titer, which is fundamental for a correct classification of the samples as positive or negative. While it would be recommended for each laboratory to determine its own screening dilution for the local population to distinguish healthy and diseased states, in practice, this procedure is not followed by the vast majority of laboratories because there is a high consensus in the literature that the titer of 1:80 can be considered the best compromise between diagnostic sensitivity and specificity (21,36,(50)(51)(52). Furthermore, since the titer 1:80 is the screening dilution adopted by all manufacturers of CAD systems for automated reading and interpretation of ANA (24), this methodological approach represents a first and concrete step to achieve the harmonization of ANA HEp-2 IIF results.…”

Assessment of antinuclear antibodies by indirect immunofluorescence assay: report from a survey by the American Association of Medical Laboratory Immunologists

“…This report follows the administration of a survey on the performance and utilization of the HEp-2 IFA test and reflects the essence of the discussions that followed when the results were presented at the most recent Association of Medical Laboratory Immunologists 2019 meeting in Cleveland, OH. Similar surveys were led by professionals in Brazil [11,12] and more recently by the European Autoimmunity Standardization Initiative (EASI) [13], ICAP (personal communication) and the Korean Society of Laboratory Medicine (presented at the 60th Annual Meeting in Busan, Korea, September 26-28, 2019). Despite its shortcomings, the HEp-2 IFA test is regarded by some as the 'gold standard' method for detecting ANA in the evaluation of systemic autoimmune rheumatic diseases [14][15][16][17].…”

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

“…Fourteen countries (14/68, 21%) informed that there are National Consensuses or Guidelines in place. Argentina [18], Belgium [19], Brazil [9][10][11][12]20], Chile [21],…”