Abstract
Background: Anti-DFS70 antibodies, corresponding to the dense fine speckled ANA indirect immunofluorescence pattern in HEp-2 substrates, have been observed in chronic inflammatory conditions, cancers and even in healthy individuals but only in a small percentage of patients with systemic autoimmune rheumatic diseases (SARD).
Aim of this study: To investigate the frequency of serum anti-DFS70 in patients with ILD and a possible correlation with ANA status and the presence of CTD.
Methods: 113 patients with ILD (70 IPF and 43 NSIP), 50 healthy controls and 36 scleroderma patients as negative control were studied. 14 patients had or developed CTD during 24 months of follow up (1 IPF and 13 NSIP). Serum anti-DFS70 at baseline was measured by ELISA (Medical and Biological Laboratories Co., Ltd., Japan), and the cut-off for positivity was set at 400 U/ml.
Results: ANA were positive in 20/43 (47%) NSIP patients and 22/70 (31%) IPF patients. All healthy controls were ANA negative and 36% anti-DFS70 positive. All scleroderma ILD patients were ANA positive and only 6% anti-DFS70 positive.
Anti-DFS70 were positive in 7/43 (16%) NSIP patients and 15/70 (21%) IPF patients. Among ANA(+) ILD patients (42), only 6 (14%) were anti-DFS70 positive and among ANA(-) ILD patients (71), 16 (23%) were anti-DFS70 positive. 8/36 (22%) of ILD patients with ANA(+) and anti-DFS70(-) and 1/6 (16%) of ILD patients with ANA(+) and anti-DFS70(+) had or developed CTD over time, all of them had NSIP.
Conclusions: Anti-DFS70 positivity is more frequent in ANA negative healthy subjects. ANA positivity combined with anti-DFS70 negativity seems to be associated with CTD in NSIP patients.
- Copyright ©the authors 2016