Background: Anti-dense fine speckled 70 (DFS70) autoantibodies have more often been described in apparently healthy individuals than in patients with systemic autoimmune rheumatic diseases (SARD). The aim of this study was to explore the link between anti-DFS70 autoantibodies and vitamin D (25(OH)D) levels in an Italian adult cohort.

Methods: Serum samples from 34 (five males and 29 females) anti-DFS70 positive patients (index cases), 34 ANA-negative healthy controls, 34 ANA-positive anti-DFS70 negative SLE patients, both groups age- and gender-matched with the index cases, 23 ANA-positive anti-DFS70 negative healthy blood donors and six female SARD patients showing mixed DFS positive pattern were collected and tested for 25(OH)D levels. Relevant demographics and lifestyle practices, body mass index (BMI), comorbidities, and use of medication were recorded for patients and healthy controls.

Results: Mean serum levels of 25(OH)D were significantly higher in anti-DFS70 positive subjects (mean ± SD: 22.1 ± 9.8 ng/ml) than in ANA-negative healthy controls (mean ± SD: 17.3 ± 6.7 ng/ml; p = .03), ANA-positive healthy controls (mean ± SD: 15.2 ± 6.8 ng/ml; p = .01), SLE patients (16.6 ± 11.0 ng/ml; p = .01) and in patients with SARD (15.0 ± 5.6 ng/ml; p = .01). No statistically relevant differences in BMI, clinical, or demographic parameters were found.

Conclusions: Our findings showed higher levels of vitamin D in anti-DFS70 positive subjects than in the controls, which is compatible with the hypothesis of the “benign” nature of anti-DFS70 antibodies.

背景：与系统性自身免疫性风湿性疾病（SARD）患者相比，在看起来健康的个体中更经常描述抗密集斑点70（DFS70）自身抗体。这项研究的目的是探讨意大利成人队列中抗DFS70自身抗体与维生素D（25（OH）D）水平之间的关系。

方法：从34例年龄和性别相匹配的患者中抽取34例抗DFS70阳性患者（索引病例），34例ANA阴性健康对照，34例ANA阳性抗DFS70阴性SLE患者的血清样本在索引病例中，收集了23名ANA阳性抗DFS70阴性健康献血者和6名表现出混合DFS阳性模式的女性SARD患者，并测试了25（OH）D水平。记录患者和健康对照者的相关人口统计学和生活方式，体重指数（BMI），合并症和用药情况。

结果：抗DFS70阳性受试者的平均血清25（OH）D水平显着高于ANA阴性健康对照者（平均值±SD：22.1±9.8 ng / ml）（平均值±SD：17.3±6.7 ng / ml） ; p  = .03），ANA阳性健康对照组（平均值±SD：15.2±6.8 ng / ml; p  = .01），SLE患者（16.6±11.0 ng / ml; p =  .01）和SARD患者（15.0±5.6ng / ml；p ＝  0.01）。没有发现BMI，临床或人口统计学参数的统计学相关差异。

结论：我们的研究结果表明，抗DFS70阳性受试者的维生素D水平高于对照组，这与抗DFS70抗体的“良性”假设相符。