Ab1484 the Significance of Anti-Dfs70 Antibodies in Healthy Population as a Marker of Exclusion of Systemic Autoimmune Rheumatic Diseases

Abstract

BackgroundThe prevalence of anti-DFS70 antibodies in healthy volunteers (HV) by various methods ranges from 0 to 22% [1]. This pattern, which is rare in patients with systemic autoimmune rheumatic diseases (SARDs), has been described as the second most common in serum HV [2].ObjectivesTo study the frequency of detection of anti-DFS70 in HV, patients (pts) with undifferentiated SARDs and systemic lupus erythematosus (SLE).MethodsA total of 45 HV, 17 undifferentiated SARDs pts and 81 SLE pts were included in the study. Groups were comparable in gender and age among themselves. The diagnosis of SLE was performed according to the ACR/EULAR 2019 classification criteria. Serum samples were tested for anti-DFS70 (ANA HEp-2 ELITE/DFS70 knock-out IFA, “Trinity Biotech”, Ireland). Fluorescence titers ≥1:160 were considered as positive for ANA HEp-2 cell patterns.ResultsPositive results of the ANA study were found in 81 (100.0%) pts with SLE, in 16 (94.0%) pts with undifferentiated SARDs and 7 (15.6%) HV (Table 1). Abs to DFS70 were isolated, detected in 4 (57.1%) HV, in 9 (56.2%) undifferentiated SARDs, but were not detected in SLE pts. Classical HEp-2 cell patterns (homogeneous AC-1, speckled AC-4.5, homogeneous+speckled AC-1,4,5, cytoplasmic AC-19,20,21) without anti-DFS70 were deficient in 3 (42.9%) HV, in 7 (43.8%) patients with undifferentiated SARDs and in 81 (100%) patients with SLE (Table 2). Therefore, monospecific anti-DFS70 were detected in the HV and undifferentiated SARDs groups, but were not detected in patients with a reliable diagnosis of SLE.ConclusionMonospecific anti-DFS70 can potentially be considered as a possible marker for the exclusion of SARDs and a sign of benign autoimmunity.References[1]Conrad K, Röber N, Andrade LEC, Mahler M. The Clinical Relevance of Anti-DFS70 Autoantibodies. Clinic Rev Allerg Immunol (2017) 52:202–216.[2]Mariz HA, Sato EI, Barbosa SH, Rodrigues SH, Dellavance A, Andrade LEC (2011) Pattern on the antinuclear antibody-HEp-2 test is a critical parameter for discriminating antinuclear antibody-positive healthy individuals and patients with autoimmune rheumatic diseases. Arthritis Rheum 63:191–200.Disclosure of InterestsNone declared