To test the postulate that there is a higher prevalence of antinuclear antibodies (ANAs) in serum samples from blood relatives and from spouses of patients with scleroderma than in control samples, and that this provides evidence for both genetic and environmental factors influencing autoimmunity in scleroderma.
Testing for ANAs was performed on 58 patients with scleroderma, 30 of their spouses, 74 first degree relatives, and 66 control subjects broadly age matched to the patients, their spouses, and about half of the relatives (siblings and parents).
On the basis of an ANA titre of > 40 as positive, 12 (18%) of the controls, 55 (95%) of the patients, one (3%) of the spouses and five (7%) of the relatives would be classified as positive. Thirty seven (64%) of the patients had defined specificities (ACA, Scl 70, U1 (RNP)) but none of the controls, spouses, or relatives had antibodies of these specificities.
These findings give no support to the postulate that environmental or genetic factors contribute to the ANAs in scleroderma.