Diagnostic profile on the IFA 40: HEp-20-10 – an immunofluorescence test for reliable antinuclear antibody screening

Abstract

Indirect immunofluorescence assay is the recommended gold standard to test for antinuclear antibodies (ANA), which are important biomarkers for systemic rheumatic autoimmune diseases. It is internationally accepted that indirect immunofluorescence assay ANA screening is most sensitive on human epithelial (HEp-2) cells. The cells present a multitude of antigens that display distinguishable localization patterns in interphase and mitotic cells in indirect immunofluorescence analysis. Here, we present the IFA 40: HEp-20-10 test kit (Euroimmun AG, Lübeck, Germany), which is cleared for sale on the US market by the FDA. The test has been designed for qualitative and semiquantitative screening of ANA in human sera. It uses the commonly applied 1:40 cutoff dilution and the enhanced HEp-20-10 cell line for more efficient pattern recognition and has been validated in various studies and by method comparison. The IFA 40: HEp-20-10 test fulfills the essential criteria for reliable application in autoimmune diagnostics.

Keywords:

• antinuclear antibodies
• HEp-20-10
• human epithelial cell line (HEp-2)
• indirect immunofluorescence assay (IIFA)
• systemic rheumatic diseases

Acknowledgements

The authors thank the Department of Clinical Pathology and Laboratory Medicine within the Perelman School of Medicine at the University of Pennsylvania for providing confirmatory testings. The authors thank Jacqueline Gosink for careful and critical reading of the manuscript.

Financial & competing interests disclosure

E Rohwäder, J Fraune and K Fechner are employees of Euroimmun AG (Lübeck, Germany). M Locke is employees of Euroimmun US, Inc. (New Jersey, USA). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical statement

The studies were performed in accordance with 1997 Declaration of Helsinki developed by the World Medical Association for medical research involving human subjects.

Key issues

• IFA 40: HEp-20-10 was designed for qualitative and semiquantitative screening of ANA by indirect immunofluorescence microscopy.

• The HEp-20-10 cell line is a variant of the HEp-2 cell line, which exhibits an elevated amount of mitotic cells.

• A screening (cutoff) titer of 1:40 was assessed to yield high specificity and sensitivity of the IFA 40: HEp-20-10.

• IFA 40: HEp-20-10 revealed broad consensus on qualitative and semiquantitative results in a comparison with the predicate device.

• IFA 40: HEp-20-10 is compatible with the automated IIFA interpretation system of the EUROPattern-Suite 1.5.

Notes