Anti-Nuclear Antibodies in Daily Clinical Practice: Prevalence in Primary, Secondary, and Tertiary Care

Abstract

For the diagnosis of systemic autoimmune rheumatic diseases (SARD), patients are screened for anti-nuclear antibodies (ANA). ANA, as assessed by indirect immunofluorescence (IIF), have a poor specificity. This hampers interpretation of positive results in clinical settings with low pretest probability of SARD. We hypothesized that the utility of positive ANA IIF results increases from primary to tertiary care. We retrospectively determined ANA, anti-ENA, and anti-dsDNA antibody prevalence in patient cohorts from primary (n = 1453), secondary (n = 1621), and tertiary (n = 1168) care settings. Results reveal that from primary care to tertiary care, ANA prevalence increases (6.2, 10.8, and 16.0%, resp.). Moreover, in primary care low titres (70% versus 51% and 52% in secondary and tertiary care, resp.) are more frequent and anti-ENA/dsDNA reactivities are less prevalent (21% versus 39% in secondary care). Typically, in tertiary care the prevalence of anti-ENA/dsDNA reactivities (21%) is lower than expected. From this descriptive study we conclude that positive ANA IIF results are more prone to false interpretation in clinical settings with low pretest probabilities for SARD, as in primary care. Whether alternative approaches, that is, immunoadsorption of anti-DFS70 antibodies or implementation of anti-ENA screen assays, perform better, needs to be determined.

Autoimmune markers and autoimmune disorders in patients with postural tachycardia syndrome (POTS)

“…6,7 We also found a higher prevalence of any co-morbid autoimmune disorders in POTS patients compared to the general population (20% vs. estimated up to 9.4%, OR 2.4, CI 1.5-3.9, p < 0.001) in patients with POTS (Table 2, Figure 1). 8 Compared to the general population, POTS patients had a higher prevalence of Hashimoto's thyroiditis (11% vs. up to 2%, OR 6.1, CI 3.2-11.3, p < 0.001), 9 followed by RA (4% vs. up to 1%, OR 4.1, CI 1.5-11.2, p < 0.01) 10 and SLE (2% vs. up to 0.12%, OR 17, CI 4.1-69.7, p < 0.001).…”

Response to: ‘Antinuclear antibodies: mitotic patterns and their clinical associations’ by Betancur and Gómez-Puerta

“…First, as the authors noted themselves, the study cohort is characterised by a very high positivity rate: 53% of all the tests were positive. There may be different explanations for this finding, which is in sharp contrast with our own study revealing only 16% positive results,8 but by including consecutive samples, it is to be expected that follow-up samples of the same patients were included. Second, in the positive cohort, 0.46%, that is, 278 sera, revealed a NuMA-like MSA pattern.…”

Vitamin D deficiency as a risk factor for the development of autoantibodies in patients with ASIA and silicone breast implants: a cohort study and review of the literature

“…If a positive ANA was found, serum was tested for anti-double-stranded DNA antibodies (anti-dsDNA) [26], and if the ANCA test was positive, samples were additionally tested for PR3-ANCA and MPO-ANCA [25]. …”