Smoking associates with distinct clinical phenotypes in patients with systemic lupus erythematosus: a nationwide Danish cross-sectional study

Microplastics exposure induced and exacerbated the development of systemic lupus erythematosus in mice

Environmental exposure may function as a contributing risk factor in the development of systemic lupus erythematosus (SLE). Recently, the global issue of microplastics (MPs) pollution has garnered increasing concern, yet its potential impact on SLE remains unexplored. This study seeks to elucidate the ramifications of MPs exposure on lupus manifestations in spontaneous lupus MRL/lpr mice and normal C57L/6 mice. MPs exposure demonstrated the capacity to induce lupus-like symptoms in C57BL/6 mice and exacerbate lupus symptoms in MRL/lpr mice. This was manifested by MPs triggering abnormal elevation of spleen DN T, plasma cells, serum anti-dsDNA, ANA, IL-6, and TNF-α, coupled with a reduction in spleen CD4+/CD8+ cell ratio, and impairment in renal pathology. Moreover, a 4D-DIA quantitative proteomic analysis was employed to unveil substantial alterations in renal proteins attributed to MPs exposure. The findings indicated that the KEGG pathways significantly enriched by MPs-associated different proteins in C57BL/6 mice were closely aligned with the enriched KEGG pathways associated with lupus. Unlike C57BL/6 mice, there were no significantly enriched KEGG pathways identified among the MPs-associated different proteins in MRL/lpr mice. In addition, proteins related to the SLE pathway illuminated that MPs exposure induced renal damage through activation of MHCII and histone H3, culminating in the production of MAC in both C57BL/6 and MRL/lpr mice. However, a specific elevation in cathepsin and elastase caused by MPs was observed in C57BL/6 mice but not in MRL/lpr mice. This study represents a significant stride in bridging the existing knowledge gap pertaining to the intricate relationship between MPs exposure and the development of SLE.

Risk of End-Stage Renal Disease in Patients With Systemic Lupus Erythematosus and Diabetes Mellitus: A Danish Nationwide Cohort Study

OBJECTIVE

The risk of end-stage renal disease (ESRD) is increased in patients with systemic lupus erythematosus (SLE). This study was undertaken to determine whether diabetes mellitus (DM) increases ESRD risk in a large inception cohort of SLE patients.

METHODS

By means of the Danish National Patient Registry, we identified 3,178 adult patients diagnosed as having SLE between January 1, 1996, and July 31, 2018. DM was defined as the date of first hospital contact for DM or date of a first prescription of an antidiabetic drug. ESRD was defined as first registration of dialysis, renal transplant, or terminal renal insufficiency in the Danish National Patient Registry. ESRD incidence was compared between SLE patients with DM (SLE-DM) and those without DM (SLE-non-DM). Hazard ratios (HRs), adjusted for sex, age, educational level, and occupational status at baseline were calculated for sex, age, educational level, and hypertension (at baseline or during follow-up) strata. The overall hazard ratio (HR) was also adjusted for hypertension.

RESULTS

The SLE-DM group included 290 patients, of whom 77% were female, compared with 85% of the 2,859 patients in the SLE-non-DM group. SLE-DM patients had a 3 times higher risk of ESRD compared with SLE-non-DM patients (multivariable-adjusted HR 3.3 [95% confidence interval 1.8-6.1]). In stratified multivariable-adjusted analyses, DM increased the rate of ESRD in women and men, patients ≥50 years old at baseline, those with low educational level at baseline, and those with concomitant hypertension.

CONCLUSION

Our findings indicate that SLE patients with DM have a markedly higher risk of developing ESRD compared with SLE patients without DM.

Systemic Lupus Erythematosus Risk: The Role of Environmental Factors

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease. The etiology of SLE is multifactorial and includes potential environmental triggers, which may occur sequentially (the "multi-hit" hypothesis). This review focuses on SLE risk potentially associated with environmental factors including infections, the microbiome, diet, respirable exposures (eg, crystalline silica, smoking, air pollution), organic pollutants, heavy metals, and ultraviolet radiation.

The role of environmental exposures and gene-environment interactions in the etiology of systemic lupus erythematous

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease, whose etiology includes both genetic and environmental factors. Individual genetic risk factors likely only account for about one-third of observed heritability among individuals with a family history of SLE. A large portion of the remaining risk may be attributable to environmental exposures and gene-environment interactions. This review focuses on SLE risk associated with environmental factors, ranging from chemical and physical environmental exposures to lifestyle behaviors, with the weight of evidence supporting positive associations between SLE and occupational exposure to crystalline silica, current smoking, and exogenous estrogens (e.g., oral contraceptives and postmenopausal hormones). Other risk factors may include lifestyle behaviors (e.g., dietary intake and sleep) and other exposures (e.g., ultraviolet [UV] radiation, air pollution, solvents, pesticides, vaccines and medications, and infections). Alcohol use may be associated with decreased SLE risk. We also describe the more limited body of knowledge on gene-environment interactions and SLE risk, including IL-10, ESR1, IL-33, ITGAM, and NAT2 and observed interactions with smoking, UV exposure, and alcohol. Understanding genetic and environmental risk factors for SLE, and how they may interact, can help to elucidate SLE pathogenesis and its clinical heterogeneity. Ultimately, this knowledge may facilitate the development of preventive interventions that address modifiable risk factors in susceptible individuals and vulnerable populations.

Smoking associates with increased BAFF and decreased interferon-γ levels in patients with systemic lupus erythematosus

Objective

In SLE, smoking increases the burden of cutaneous disease and organ damage, and leads to premature mortality. However, the effect of smoking on disease manifestations and cytokine levels of patients with SLE is unclear. This study compared characteristics of patients with SLE across smoking status, and determined the association of smoking with serum cytokine levels.

Method

A cross-sectional study of patients with SLE (n=99) during a research visit in which smoking status was ascertained. Smoking status was compared across classification criteria (American College of Rheumatology Classification Criteria for SLE (ACR97)), disease activity (SLE Disease Activity Index), autoantibody levels, accrued damage (Systemic Lupus International Collaborating Clinics/ACR Damage Index), and circulating concentrations of serum interferon-gamma (IFN-γ), interleukin (IL)-1β, IL-4, IL-6, IL-10, IL-12, IL-17, B cell-activating factor (BAFF), tumour necrosis factor-alpha, transforming growth factor beta 1 (TGF-β1), macrophage inflammatory protein 1 alpha (MIP-1α), MIP-1β and monocyte chemoattractant protein 1. Linear regression models determined the association between smoking and cytokine levels, adjusting for age and sex, clinical characteristics (model 1), and anti-inflammatory (IL-4, IL-10 and TGF- β1) and regulatory (IL-1β) cytokines (model 2).

Results

Among patients with SLE (97.9% ANA+; mean 48.48 years old; 86.9% female; mean 10 years of disease duration), 35.4% (n=35 of 99) were smoking (an average of 7 cigarettes/day for 24 years). Smokers had increased odds of prevalent ACR97 malar rash (OR 3.40, 95% CI 1.23 to 9.34) and mucosal ulcers (OR 3.31, 95% CI 1.36 to 8.05). Smokers had more arthritis (OR 3.19, 95% CI 1.19 to 8.60), migraine (OR 2.82, 95% CI 1.07 to 7.44), Raynaud’s phenomenon (OR 5.15, 95% CI 1.95 to 13.56) and increased non-steroidal anti-inflammatory drug use (OR 6.88, 95% CI 1.99 to 23.72). Smoking associated with 27% increased BAFF levels (95% CI 6% to 48%) and 42% decreased IFN-γ levels (95% CI −79% to −5%) in model 2.

Conclusion

In patients with SLE, smoking independently associated with increased BAFF and decreased IFN-γ levels, and an increased frequency of arthritis, migraine and Raynaud’s phenomenon. Smoking cessation is advisable to reduce systemic inflammation, reduce disease activity and improve host defence.

Patient-reported outcome measures in systemic lupus erythematosus by a web-based application: A randomized, crossover, agreement study

OBJECTIVES

Patient-reported outcome measures (PROMs) are evaluated in randomized controlled trials (RCTs) in patients with systemic lupus erythematosus (SLE), but not widely used in clinical practice. However, interest in incorporating PROMs into the management of SLE is increasing as PROMs provide a unique insight into the patient's perception of lupus disease activity. The objective was to assess agreement in PROMs answered using a web app versus an outpatient touchscreen among patients with SLE.

METHODS

In a crossover RCT, SLE patients answered the following PROMs in a random order using the web app and the outpatient touchscreen: Systemic Lupus Erythematosus Activity Questionnaire (SLAQ) Global Health, SLAQ Symptom, SLAQ Total, SLAQ Worsening, Pain Visual Analog Scale (VAS), Fatigue VAS, Patient Global Health VAS, Health Assessment Questionnaire Disability Index (HAQ-DI), Patient Acceptable Symptom State (PASS), and an Anchoring Question. Equivalence between the two device types was demonstrated if the 95% confidence interval (95% CI) of the difference in PROM scores was within the prespecified equivalence margin. Agreement between the two device types was assessed using mixed linear models.

RESULTS

Thirty-four patients with SLE were included. Equivalence was demonstrated between the two device types for SLAQ Global Health with a difference of -0.21 (95% CI: -0.65 to 0.23). Moreover, equivalence was also found for HAQ-DI, Pain VAS, and Fatigue VAS whereas only comparability within the limits of the Minimal Clinically Important Difference (MCID) was demonstrated for VAS Patient Global Health. Statistical comparability was demonstrated for SLAQ Total, SLAQ Worsening, PASS, and Anchoring Question (no predefined MCID/equivalence margins available). However, a statistically significant difference between device types was observed for the SLAQ Symptom of -0.56 (95% CI: -1.10 to -0.01). The difference was, however, very small when considering the scale range of 0-24; thus, it was not judged to be of clinical relevance. Preference for the web app was very high (91.2%).

CONCLUSION

For the first time ever, equivalence and comparability between two electronic device types for various PROMs were demonstrated among patients with SLE. Implementation of the device is expected to improve the management of SLE.