Anti-dense fine speckled (DFS) antibody: its staining pattern in indirect immunofluorescence and its clinical relevance.

Background: Dense fine speckled (DFS) pattern is defined by very intense, heterogeneous speckled staining of nucleoplasms of interphase HEp-2 cells and chromosomal areas of metaphase cells. The association of Anti-DFS70 and rheumatologic signs, symptoms, and diagnosis were evaluated.Methods: One-hundred-eight anti-DFS70 positives who got consecutively admitted to the Rheumatology clinic between January and June 2020 were analyzed. The clinical and laboratory findings of positives for anti-DFS70 antibody were compared with those with DFS pattern ANA IFA staining rates. Also, anti-DFS70 positivity rates and their correlation with the DFS staining pattern were analyzed retrospectively in 1016 CTD patients.Results: The most common complaint was joint pain seen in 77 (71.3%) and the most common laboratory abnormality was RF-positivity observed in 10/108 (9.3%) who had anti-DFS70 positivity. The most common ANA staining pattern was DFS (72/108; 66.7%); one-third had other than DFS. No statistical significance was found for the association of any of the rheumatological complaints and laboratory findings with the DFS staining pattern. ANA analysis was performed in a total of 964/1016 (94.88%) CTD patients and 44 (4.56%) of these positive for anti-DFS70. The correlation coefficient showed good correlations between the DFS pattern staining and anti-DFS70 antibody positivity (r=+0.773, p<0.001).Conclusions: Anti-DFS70-positives have a low rate of CTD. A low anti-DFS70 positivity rate was observed in patients with CTD. As such, it can be considered that anti-DFS70 does not predict CTD or even excludes it.