Israel Medical Association Journal

Abstract

Background: Scleroderma lung disease (ILD-SSc) is treated mainly with cyclophosphamide (CYC). The effectiveness of CYC was judged after 12–24 months in most reports.

Objectives: To analyze the effect of monthly intravenous CYC on pulmonary function tests including forced vital capacity (FVC) and diffusing lung capacity (DLCO), as well as Rodnan skin score (mRSS), during long-term follow-up.

Methods: We retrospectively collected the data on 26 ILD-SSc patients who began CYC treatments before 2007. Changes in FVC, DLCO and mRSS before treatment, and at 1, 4 and 7 years after completion of at least six monthly intravenous CYC treatments for ILD-SSc were analyzed.

Results: Mean cumulative CYC dose was 8.91 ± 3.25 G. More than 30% reduction in FVC (0%, 8%, and 31% of patients), DLCO (15%, 23%, 31%), and mRSS (31%, 54%, 62%) at years 1, 4 and 7 was registered. During the years 0–4 and 4–7, annual changes in FVC, DLCO and mRSS were 3.2 vs. 0.42% (P < 0.040), 4.6 vs. 0.89% (P < 0.001), and 1.8 vs. 0.2 (P = 0.002). The greatest annual FVC and DLCO reduction over the first 4 years correlated with mortality (P = 0.022). There were no differences in the main variables regarding doses of CYC (< 6 G and > 6 G).

Conclusions: In patients with ILD-SSc, CYC stabilized the reduction of FVC during treatment, but this effect was not persistent. The vascular characteristic of ILD-SSc (DLCO) was not affected by CYC treatment. CYC rapidly improved the mRSS. This effect could be achieved with at least 6 G of CYC. Higher rates of annual reduction in FVC and DLCO in the first 4 years indicate the narrow window of opportunity and raise the question regarding ongoing immunosuppression following CYC infusions.

 

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.