Fatigue severity in anti-nuclear antibody-positive individuals does not correlate with pro-inflammatory cytokine levels or predict imminent progression to symptomatic disease.

BACKGROUND: Fatigue is a common symptom of systemic autoimmune rheumatic disease (SARD). Patients with SARD have a protracted pre-clinical phase during which progressive immunologic derangements occur culminating in disease. In this study, we sought to determine when fatigue develops and whether its presence correlates with inflammatory factors or predicts disease progression. METHODS: Anti-nuclear antibody (ANA)-negative healthy controls (HCs) and ANA-positive participants with no criteria, at least one clinical criteria (undifferentiated connective tissue disease, UCTD), or meeting SARD classification criteria were recruited. Fatigue was assessed using a modified version of the FACIT-F questionnaire and the presence of fibromyalgia determined using a questionnaire based on the modified 2010 ACR criteria. Peripheral blood expression of five IFN-induced genes was quantified by NanoString and the levels of IL-1ß, IL-6, or TNF-α by ELISA. RESULTS: Fatigue was as prevalent and severe in individuals lacking SARD criteria as it was in UCTD and SARD. Overall, ~ 1/3 of ANA+ subjects met fibromyalgia criteria, with no differences between sub-groups. Although fatigue was more severe in these individuals, those lacking fibromyalgia remained significantly more fatigued than ANA- HC. However, even in these subjects, fatigue correlated with the widespread pain index and symptom severity scores on the fibromyalgia questionnaire. Fatigue was not associated with elevated cytokine levels in any of the ANA+ sub-groups and did not predict imminent disease progression. CONCLUSIONS: Fatigue is common in ANA+ individuals lacking sufficient criteria for a SARD diagnosis, correlates with fibromyalgia-related symptoms, and is not associated with inflammation or predictive of disease progression.

Presence of an interferon signature in individuals who are anti-nuclear antibody positive lacking a systemic autoimmune rheumatic disease diagnosis.

BACKGROUND: Elevated levels of type I interferons (IFNs) are a characteristic feature of the systemic autoimmune rheumatic diseases (SARDs) and are thought to play an important pathogenic role. However, it is unknown whether these elevations are seen in anti-nuclear antibody-positive (ANA+) individuals who lack sufficient criteria for a SARD diagnosis. We examined IFN-induced gene expression in asymptomatic ANA+ individuals and patients with undifferentiated connective tissue disease (UCTD) to address this question. METHODS: Healthy ANA- control subjects and ANA+ titre (≥1:160 by immunofluorescence) participants meeting no criteria, meeting at least one criterion (UCTD) or meeting SARD classification criteria were recruited. Whole peripheral blood IFN-induced and BAFF gene expression were quantified using NanoString technology. The normalized levels of five IFN-induced genes were summed to produce an IFN5 score. RESULTS: The mean IFN5 scores were increased in all ANA+ participant subsets as compared with healthy control subjects. We found that 36.8% of asymptomatic ANA+ and 50% of UCTD participants had IFN5 scores >2 SD above the mean for healthy control subjects. In all ANA+ subsets, the IFN5 score correlated with the presence of anti-Ro/La antibodies. In the asymptomatic ANA+ subset, this score also correlated with the ANA titre, whereas in the other ANA+ subsets, it correlated with the number of different ANA specificities. Development of new SARD criteria was seen in individuals with normal and high IFN5 scores. CONCLUSIONS: An IFN signature is seen in a significant proportion of ANA+ individuals and appears to be associated with ANA titre and type of autoantibodies, rather than with the presence or development of clinical SARD symptoms.

Systemic lupus erythematosus.

Systemic lupus erythematosus is a remarkable and challenging disorder. Its diversity of clinical features is matched by the complexity of the factors (genetic, hormonal, and environmental) that cause it, and the array of autoantibodies with which it is associated. In this Seminar we reflect on changes in its classification criteria; consider aspects of its more serious clinical expression; and provide a brief review of its aetiopathogenesis, major complications, coping strategies, and conventional treatment. Increased understanding of the cells and molecules involved in the development of the diseases has encouraged the identification of new, better targeted biological approaches to its treatment. The precise role of these newer therapies remains to be established.