Clinical utility of anti-DFS70 for identifying antinuclear antibody-positive patients without systemic autoimmune rheumatic disease

Abstract

INTRODUCTION The antinuclear antibody (ANA) test is a screening test for systemic autoimmune rheumatic disease (SARD). We hypothesised that the presence of anti-DFS70 in ANA-positive samples was associated with a false-positive ANA test and negatively associated with SARD. METHODS A retrospective analysis of patient samples received for ANA testing from 1 January 2016 to 30 June 2016 was performed. Patient samples underwent ANA testing via indirect immunofluorescence method and anti-DFS70 testing using enzyme-linked immunosorbent assay. RESULTS Among a total of 645 ANA-positive samples, the majority (41.7%) were positive at a titre of 1:80. The commonest nuclear staining pattern (65.5%) was speckled. Only 9.5% of ANA-positive patients were diagnosed with SARD. Anti-DFS70 was found to be present in 10.0% of ANA-positive patients. The majority (51/59, 86.4%) of patients did not have SARD. Seven patients had positive ANA titre > 1:640, the presence of anti-double stranded DNA and/or anti-Ro60. The presence of anti-DFS70 in ANA-positive patients was not associated with the absence of SARD (Fisher’s exact test, p = 0.245). CONCLUSION The presence of anti-DFS70 was associated with a false-positive ANA test in 8.6% of our patients. Anti-DFS70 was not associated with the absence of SARD.

Anti-DFS70 antibodies in systemic lupus erythematosus: Prevalence in a large Chinese cohort and an unexpected association with anti-dsDNA antibodies by a long-term follow-up

“…It was consistent with our recent study, which suggested that anti-DFS70 antibodies were associated with anti-dsDNA antibodies in lupus nephritis (LN) patients ( 15 ). In addition, our findings also agree with one recent study on anti-DFS70 antibodies that showed that all eight anti-DFS70-positive patients with SARD were Chinese and 75% (6/8) of them had anti-dsDNA antibodies as well ( 25 ). It indicated a potential relationship of anti-DFS70 antibodies with anti-dsDNA in Chinese SLE patients.…”

Anti-DFS70 Antibodies for Differentiating Systemic Autoimmune Rheumatic Disease in Patients with Positive ANA Tests: A Systematic Review and Meta-Analysis

“…In this study, we also found that different definitions of SARD may influence the diagnostic performance of anti-DFS70 antibodies. In the literature, the term SARD describes autoimmune disorders affecting multiple organs, such as SLE, systemic sclerosis, rheumatoid arthritis and systemic vasculitis [ 31 , 36 , 39 ]. However, a positive ANA test is only essential in the diagnosis of some disorders included in SARD [ 40 ].…”

“…For the reference standard, only one of the studies applied the classification criteria of SARD [2]. Due to possible heterogeneity in the clinical diagnosis and practice, the studies using reference standards other than classification criteria were assessed as having an unclear risk of bias and applicability in the reference standard [30][31][32][33][34][35][36]. For flow and timing, because none of the enrolled studies specified the time interval between the index test and the diagnosis of SARD, the appropriateness of the interval between the index test (anti-DFS70 antibodies) and the reference standard (the diagnosis of SARD) could not be assessed.…”

The significance of dense fine speckled pattern in antinuclear antibody‐associated rheumatic disease and coexisting autoantibodies: A propensity score‐matched cohort study

“…11,[13][14][15][16][17] Recent studies have cast doubt on the performance of anti-DFS70 antibodies for excluding AARD. 16,[18][19][20][21][22] The prevalence of anti-DFS70 antibodies in AARD varies in different studies. 16 , 23-25 A meta-analysis found that in patients with positive ANA test results, the pooled specificity of using anti-DFS70 antibodies to exclude AARD was 98%, but the pooled sensitivity was only 18%.…”