Autoantibodies against DFS70 (dense fine speckles 70) antigen (also known as lens epithelium-derived growth factor) have been recently identified among the antinuclear antibodies (ANAs) in patients with atopic disorders. We undertook this study to examine the frequency of anti-DFS70 antibodies in a large number of healthy people.
Sera of 597 healthy individuals working in a hospital (142 men, 455 women) were analyzed for ANAs and for anti-DFS70 antibodies by indirect immunofluorescence (IIF) with HEp-2 cells as a substrate and by immunoblotting using DFS70 recombinant protein and whole HeLa cell extract.
ANAs were present in 20% of all individuals by IIF. Nine percent of subjects were ANA positive at a serum dilution of 1:40, 4.0% at 1:80, 5.5% at 1:160, 1.0% at 1:320, and 0.3% at 1:640. There were 64 anti-DFS70 antibody-positive individuals. Surprisingly, this was 11% of the whole population and 54% of the ANA-positive population. The percentage of female anti-DFS70 antibody-positive subjects (86%; 55 of 64 subjects) was higher than the percentage of female anti-DFS70 antibody-negative subjects (75%; 398 of 533 subjects) (P < 0.05). The prevalence of anti-DFS70 antibody-positive sera decreased with increasing age (P = 0.0017).
Considering that anti-DFS70 antibody positivity is rare in patients with systemic autoimmune diseases, introducing the anti-DFS70 antibody examination as a screening test for ANA-positive persons could be used to rule out systemic autoimmune diseases, resulting in considerable cost-saving potential. In addition, this test defines a subpopulation of healthy people in whom long-term followup might reveal health-related implications of this finding, since anti-DFS70 antibodies have been shown to be associated with some illnesses.