A recent 12-year follow-up study performed on first-degree relatives (FDRs) of patients with systemic lupus erythematosus (SLE) showed an increased frequency of autoantibodies such as anti-nuclear antibodies (ANA) when compared to healthy controls.
The study, “Autoantibodies persist in relatives to systemic lupus erythematosus patients during 12 years follow-up,” was published in the journal Lupus.
SLE is an autoimmune disease that affects several organs and is characterized by the presence of autoantibodies. The processes that lead to SLE are not fully understood, but the increase in autoantibody production is a central factor. Autoantibodies like ANA can be detected several years before the appearance of symptoms and SLE diagnosis.
In the study, 226 FDRs of a population-based cohort of SLE patients were examined for the occurrence of autoantibodies, including ANA and anti-double stranded DNA (dsDNA), and completed self-reported health questionnaires. After 12 years, only 143 (74%) FDRs were re-examined.
Questionnaires and blood samples were collected, and 200 healthy individuals (blood donors) were used as a control group for autoantibodies at baseline and 12 years after. The medical records of deceased SLE patients during the study period were also examined.
“FDRs reported more rheumatic diseases compared to the background population,” the researchers wrote.
But although the study is in agreement with previous studies reporting an increased risk for autoimmune diseases among FDRs compared to the background population, the prognostic value of ANA positivity was unsatisfactory.
Six of 51 (12%) of the baseline ANA-positive FDRs developed a self-reported autoimmune disease, such as SLE, rheumatoid arthritis (RA), and other connective tissue diseases, compared to eight of 92 (9%) of the baseline ANA negative FDRs after 12 years of follow-up.
The authors acknowledged some limitations of the study, like the short follow-up period used to study rare health conditions such as SLE and RA, and the lack of evaluation of self-reported diseases.
Still, based on the results, the authors concluded that “FDRs of SLE patients have an increased prevalence of ANA compared to healthy controls. The prevalence increased during follow-up, and ANA positive FDRs at baseline were prone to be ANA positive at follow-up. ANA positive FDRs had more self-reported autoimmune diseases, including SLE and rheumatoid arthritis, than reported from other population-based investigations.”