Patients with incomplete systemic lupus erythematosus (iSLE) have lupus features, but do not meet classification criteria for SLE. Type I interferons (IFN) are important early mediators in SLE, and IFN upregulation in incomplete SLE may be associated with progression to SLE. Since many patients present with skin symptoms, the aim of this study is to investigate IFN type I expression and IFN-related mediators in the blood and skin of iSLE patients. Twenty-nine iSLE patients (ANA titer ≥ 1:80, symptoms < 5 years, ≥ 1 objectified clinical criterion), 39 SLE patients with quiescent disease (fulfilling ACR or SLICC criteria, SLEDAI ≤4), and 22 healthy controls were included. IFN signature was measured in whole blood, based on 12 IFN-related genes, using RT-PCR, and IFN-score was calculated. IFN-related mediators myxovirus-resistance protein A (MxA), IFN-γ-induced protein 10 (IP-10), and monocyte chemoattractant protein (MCP-1) were measured using ELISA. IFN type I expression in the unaffected skin was analyzed by immunostaining with MxA. IFN-score was increased in 50% of iSLE patients and 46% of SLE patients and correlated positively with the number of autoantibodies, anti-SSA titer, ESR, and IgG and negatively with C4 in iSLE. Levels of MxA correlated strongly with IFN-score (r = 0.78, p < 0.0001). Furthermore, MxA expression was found in 29% of unaffected skin biopsies of iSLE and 31% of SLE patients and also correlated with IFN-score (r = 0.54, p < 0.0001). IFN-score was increased in half of the iSLE patients, and given the correlation with complement and autoantibody diversity, this suggests a higher risk for disease progression. MxA in the blood and unaffected skin correlated strongly with the IFN-score and is possibly an easily applicable marker for IFN upregulation.

中文翻译：

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干扰素评分在不完整的系统性红斑狼疮中增加，并且与血液和皮肤中的抗粘病毒病毒蛋白A相关。

系统性红斑狼疮（iSLE）不完全的患者具有狼疮特征，但不符合SLE的分类标准。I型干扰素（IFN）是SLE的重要早期介质，不完全SLE中的IFN上调可能与SLE的进展有关。由于许多患者都出现皮肤症状，因此本研究的目的是研究iSLE患者血液和皮肤中I型IFN的表达以及与IFN相关的介质。包括29名iSLE患者（ANA滴度≥1:80，症状<5年，≥1个客观临床标准），39例具有静止性疾病的SLE患者（满足ACR或SLICC标准，SLEDAI≤4）和22个健康对照。使用RT-PCR，基于12个与IFN相关的基因，在全血中测量IFN标记，并计算IFN评分。IFN相关介质黏液抗病毒蛋白A（MxA），使用ELISA测量IFN-γ诱导的蛋白10（IP-10）和单核细胞趋化蛋白（MCP-1）。通过用MxA免疫染色分析未受影响皮肤中的IFN型I表达。iSLE患者中50％和SLE患者中IFN得分升高，分别为50％和46％，与iSLE中自身抗体，抗SSA滴度，ESR和IgG的数量呈正相关，与C4呈负相关。MxA水平与IFN评分高度相关（r = 0.78，p <0.0001）。此外，在29％的iSLE皮肤活检和31％的SLE患者的皮肤活检中发现MxA表达，并且与IFN评分相关（r = 0.54，p <0.0001）。一半的iSLE患者的IFN评分增加，并且考虑到与补体和自身抗体多样性的相关性，这表明疾病进展的风险更高。