The clinical utility of anti-double-stranded DNA antibodies and the challenges of their determination.

Autoantibodies against double-stranded DNA (dsDNA) were first described >60 years ago and although they are still one of the most clinically relevant autoantibodies, test results may be more challenging to interpret compared to other autoantibody tests. They are a serological hallmark of systemic lupus erythematosus (SLE) and are included in both the American College of Rheumatology (ACR) and the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE. Furthermore, anti-dsDNA antibodies (a-dsDNA) have been shown to associate with SLE disease activity and coincide with renal involvement. Given their importance and long history, one might assume that immunological tests for a-dsDNA are standardized and give comparable results. However, even though there has been an international reference standard serum (the WHO Wo/80), different methods for the detection of a-dsDNA and tests from different manufacturers give different results for the same samples. This disparity is due to the diversity of possible antibodies generated to this biochemically complex antigen, which may have different clinical associations. The goal of this review is to summarize the current knowledge regarding the clinical associations with a-dsDNA, highlight challenges in a-dsDNA testing, and elucidate the reasons for discrepant results between methods or manufacturers.

Recognition of the dense fine speckled (DFS) pattern remains challenging: results from an international internet-based survey.

PURPOSE: The dense fine speckled (DFS) pattern as detected by indirect immunofluorescence (IIF) on HEp-2 cells has been associated with several inflammatory diseases but is most commonly observed in individuals that do not have an antinuclear antibody (ANA)-associated rheumatic disease and even in apparently healthy individuals. Consequently, the accurate identification and correct reporting of this IIF pattern is of utmost importance and accordingly has been recognized by several international study groups for the detection of ANA. Furthermore, the DFS IIF pattern has recently been recommended as a competency level recognition pattern by the International Consensus on Antinuclear Antibody (ANA) Pattern (ICAP, http://www.anapatterns.org/ ) Committee. The objective of this study was to use an internet-based survey to assess how accurately the DFS IIF pattern was recognized by experienced technologists. METHODS: High-resolution digital IIF images were captured using the automated IIF NOVA View instrument (Inova Diagnostics, San Diego, CA). Ten images were posted in an anonymous, international, internet-based interpretive survey. Two hundred and thirty IIF technologists were invited to participate. Four of the images in the survey were from previously characterized serum samples with classical ANA IIF patterns (nucleolar, centromere, homogeneous, and speckled) and two of the images were from samples with a DFS IIF ANA pattern and isolated anti-DFS70 antibodies as determined by a chemiluminescence immunoassay. The remaining four images were from sera with the classic IIF ANA patterns referred to above and mixed with a monospecific anti-DFS70-positive sample. The survey included multiple choice selections: homogeneous, DFS, centromere, nucleolar, speckled, other, or unrecognizable. RESULTS: 125 of the 230 participants who completed the survey had diverse levels of experience in IIF pattern recognition on HEp-2 cells ranging from <1 year to >10 years of experience (average >10 years). Participants had a high concordance in correctly classifying the classical ANA IIF patterns: ranging from 95.2 % for centromere to 74.4 % for nucleolar patterns. The unmixed DFS pattern was recognized with significantly lower accuracy (~50 %; p < 0.05). However, less than 10 % correctly identified mixed patterns derived from the sera containing both clinically relevant ANA and anti-DFS70 antibodies. CONCLUSIONS: Recognizing the DFS ANA IIF pattern and mixed IIF patterns composed of DFS + clinically relevant ANA patterns poses a significant challenge. Consequently, it seems imperative that DFS-specific immunoassays should be used to confirm the presence of anti-DFS70 antibodies before definitive results are reported to physicians.

Randomized feeding intervention in infants at high risk for celiac disease.

BACKGROUND: A window of opportunity has been suggested for reducing the risk of celiac disease by introducing gluten to infants at 4 to 6 months of age. METHODS: We performed a multicenter, randomized, double-blind, placebo-controlled dietary-intervention study involving 944 children who were positive for HLA-DQ2 or HLA-DQ8 and had at least one first-degree relative with celiac disease. From 16 to 24 weeks of age, 475 participants received 100 mg of immunologically active gluten daily, and 469 received placebo. Anti-transglutaminase type 2 and antigliadin antibodies were periodically measured. The primary outcome was the frequency of biopsy-confirmed celiac disease at 3 years of age. RESULTS: Celiac disease was confirmed by means of biopsies in 77 children. To avoid underestimation of the frequency of celiac disease, 3 additional children who received a diagnosis of celiac disease according to the 2012 European Society for Pediatric Gastroenterology, Hepatology, and Nutrition diagnostic criteria (without having undergone biopsies) were included in the analyses (80 children; median age, 2.8 years; 59% were girls). The cumulative incidence of celiac disease among patients 3 years of age was 5.2% (95% confidence interval [CI], 3.6 to 6.8), with similar rates in the gluten group and the placebo group (5.9% [95% CI, 3.7 to 8.1] and 4.5% [95% CI, 2.5 to 6.5], respectively; hazard ratio in the gluten group, 1.23; 95% CI, 0.79 to 1.91). Rates of elevated levels of anti-transglutaminase type 2 and antigliadin antibodies were also similar in the two study groups (7.0% [95% CI, 4.7 to 9.4] in the gluten group and 5.7% [95% CI, 3.5 to 7.9] in the placebo group; hazard ratio, 1.14; 95% CI, 0.76 to 1.73). Breast-feeding, regardless of whether it was exclusive or whether it was ongoing during gluten introduction, did not significantly influence the development of celiac disease or the effect of the intervention. CONCLUSIONS: As compared with placebo, the introduction of small quantities of gluten at 16 to 24 weeks of age did not reduce the risk of celiac disease by 3 years of age in this group of high-risk children. (Funded by the European Commission and others; PreventCD Current Controlled Trials number, ISRCTN74582487.).