Israel Medical Association Journal

Background: Patients with autoimmune disease (AID) and coronavirus disease 2019 (COVID-19) could have higher mortality due to the co-morbidity and the use of immunosuppressive therapy.

Objectives: To analyze the risk factors and outcomes of patients with AID and COVID-19 versus a control group.

Methods: A prospective cohort study included patients with and without AID and COVID-19. Patients were paired by age and sex. Clinical, biochemical, immunological treatments, and outcomes (days of hospital stay, invasive mechanical ventilation [IMV], oxygen at discharge, and death) were collected.

Results: We included 226 COVID-19 patients: 113 with AID (51.15 ± 14.3 years) and 113 controls (53.45 ± 13.3 years). The most frequent AIDs were Rheumatoid arthritis (26.5%), systemic lupus erythematosus (21%), and systemic sclerosis (14%). AID patients had lower lactate dehydrogenas, C-reactive protein, fibrinogen, IMV (P = 0.027), and oxygen levels at discharge (P ≤ 0.0001) and lower death rates (P ≤ 0.0001). Oxygen saturation (SaO₂) ≤ 88% at hospitalization provided risk for IMV (RR [relative risk] 3.83, 95% confidence interval [95%CI] 1.1–13.6, P = 0.038). Higher creatinine and LDH levels were associated with death in the AID group. SaO₂ ≤ 88% and CO-RADS ≥ 4 were risk factors for in-hospital mortality (RR 4.90, 95%CI 1.8–13.0, P = 0.001 and RR 7.60, 95%CI 1.4–39.7, P = 0.016, respectively). Anticoagulant therapy was protective (RR 0.36, 95%CI 0.1–0.9, P = 0.041)

Conclusions: Patients with AID had better outcomes with COVID-19 than controls. Anticoagulation was associated with a lower death in patients with AID.

Background: The activated NLRP3 inflammasome is associated with the etiology of fibrotic diseases. The role of inflammasomes in SSc is still poorly understood.

Objectives: To determine the expression of NLRP3 (nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3) in the skin of patients with systemic sclerosis (SSc) and its relationship with pro-inflammatory cytokines and vascular mediators expression.

Methods: Skin biopsies were taken from 42 patients with either limited or diffuse SSc (21 lcSSc and 21 dcSSc), and from 13 healthy individuals. Using real-time polymerase chain reaction (PCR), the relative expression of caspase-1, IL-1β, IL-18, IL-33, TGF-β, ET-1, iNOS and eNOS genes, were measured. The location of NLRP3 and IL-1β were also determined by immunohistochemistry. Clinical characteristics were evaluated.

Results: The mean age of the patients was 49.3 ± 12.9 (lcSSc), 44.6 ±1 3.8 (dcSSc), and 45 ± 14.1 (healthy individuals). Compared to healthy individuals, the skin of both subtypes of SSc showed a significant increase (P < 0.05) in NLRP3, caspase-1, IL-1β, IL-18 and ET-1. Samples of lcSSc also showed a significant increase of eNOS (P < 0.029), iNOS (P < 0.04) and TGF-β (P < 0.05). Dermal fibrosis evaluated by modified Rodnan skin score (MRSS) had significant correlation with NLRP3, IL-1β, IL-18, and ET-1. Immunohistochemical analysis showed stronger staining of NLRP3 and IL-1β cytoplasmic expression in the keratinizing squamous epithelium of skin from SSc patients compared to controls.

Conclusions: This study identified NLRP3 over-expression in skin of patients with SSc. Skin thickness correlates positively with the NLRP3 inflammasome gene expression and with the vascular mediator and pro-fibrotic ET-1, suggesting that NLRP3 inflammasome plays a role in the pathophysiology of skin fibrosis in human SSc.