Fibrosing alveolitis in systemic sclerosis: the need for early screening and treatment

Rituximab treatment for systemic sclerosis-associated interstitial lung disease: a case series of 13 patients

BACKGROUND

Systemic sclerosis (SSc) associated interstitial lung disease (ILD) is a common complication of SSc, with a high mortality, despite current available treatments. Rituximab has shown some promising, although varied, results for the treatment of SSc-ILD.

AIMS

To determine whether rituximab stabilised or improved pulmonary function at 12 months, in patients with SSc-ILD.

METHODS

A retrospective analysis of patients with SSc-ILD who progressed despite conventional therapy and received rituximab between 2008 and 2019 was performed at two tertiary centres. Baseline percentage forced vital capacity (FVC) and percentage diffusing capacity of carbon monoxide (DLCO) were compared with 1-year post the first dose of rituximab. Mean and median change in FVC (%) and DLCO (%) were calculated. For those with available data, the FVC (%) and DLCO (%) 2 years and 1 year prior to rituximab were compared with the change 12-months post-rituximab.

RESULTS

Thirteen patients were included in the analysis. All patients demonstrated stability in their pulmonary function testing at 1-year post-rituximab. The mean FVC (%) was 57.18 (±16.93 standard deviation (SD)) prior to rituximab and 59.75 (±18.83 SD) 12-month post-rituximab, demonstrating an increase of 2.57 (±4.70 SD; P-value 0.07). The mean DLCO (%) increased from 37.10 (±18.41 SD) prior to rituximab to 38.03 (±19.83) post-rituximab. The mean change in DLCO (%) was 0.93 (±5.05 SD; P-value 0.53). In the 2 years preceding rituximab, the mean FVC (%) and DLCO (%) declined by 9.25 and 9.66 respectively.

CONCLUSION

This case series suggests that rituximab might stabilise pulmonary function tests, and delay deterioration in patients with progressive SSc-ILD. These findings add to the growing body of evidence suggesting a role for rituximab in the treatment of SSc-ILD.

Trends in Systemic Sclerosis Mortality Over Forty-Eight Years, 1968-2015: A US Population-Based Study

OBJECTIVE

To identify secular trends associated with systemic sclerosis (SSc) mortality over a 48-year period.

METHODS

Using national mortality data compiled by the Centers for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research, and population data from the US Census Bureau, we calculated an age-standardized mortality rate (ASMR) for SSc and non-SSc (all other causes), and we also calculated the ratio of the SSc ASMR to the non-SSc ASMR for each year from 1968 to 2015. We then used a joinpoint regression model to evaluate mortality trends overall and by sex and race.

RESULTS

From 1968 to 2015, there were 46,798 deaths with SSc recorded as the "underlying" cause of death and 106,058,839 non-SSc deaths. There were an additional 9,063 deaths with SSc recorded as a "contributing" cause of death from 1999 to 2015. Whereas the non-SSc ASMR decreased throughout the 48-year time period, the SSc ASMR increased from 1968 to 2000, followed by decreases each year from 2001 to 2015. The SSc ASMR also decreased for deaths where SSc was a contributing cause from 1999 to 2015. Women and Black persons had higher SSc ASMRs and SSc ASMR to non-SSc ASMR ratios than men and White persons, respectively. Additionally, SSc ASMRs and SSc ASMR to non-SSc ASMR ratios increased at higher rates in women and White persons than in men and Black persons, respectively, during the initial three decades.

CONCLUSION

Mortality attributable to SSc increased from 1968 to 2000, followed by a steady decline from 2001 to 2015. However, SSc mortality relative to non-SSc mortality remains high. SSc mortality has disproportionately changed by sex and race over the 48-year period assessed in the present study.

Interstitial Lung Disease in Systemic Sclerosis

Interstitial lung disease is an early and serious complication of systemic sclerosis (SSc). Because it may be asymptomatic for a long period, and only the early (logistic phase is at present susceptible to treatment, early diagnosis and identification of risk are critical to the outcome. However, identifying SSc patients at risk for developing interstitial lung disease is at present difficult; therefore, a strict monitoring of the disease, especially in the first years, is mandatory. Treatment strategy is aimed at suppressing inflammation. Unfortunately, optimal therapy has not yet been established. Combination of corticosteroids and cyclophosphamide is considered the best therapeutic approach available so far, but doses and duration of treatment need to be determined. Future research should focus on new anti-inflammatory or immunosuppressive agents.

[Use of pulmonary function tests and biomarkers studies to diagnose and follow-up interstitial lung disease in systemic sclerosis]

Interstitial lung disease (ILD) is becoming one of the main causes of death of patients with systemic sclerosis (SSc). The prevalence of ILD associated with SSc (SSc-ILD) varies from 33% to 100% according to diagnostic methods. Clinical features such as dyspnea on exertion, dry cough, and chest pains are not specific and usually late-appearing, implying more specific tests in the diagnostic, prognosis, and follow-up of ILD in patients with SSc. High resolution thoracic CT scanner (HRCT) is more sensitive than chest X-ray in the detection of SSc-ILD. Pulmonary function tests (PFT) are non-invasive and periodically used to assess the impacts of SSc on respiratory function. Diagnostic values of bronchoalveolar lavage and histological examination on lung biopsy are controversial. However, these techniques are essential for studying cellular and molecular mechanisms underlying the pathophysiology of SSc-ILD. Several biomarkers such as surfactant-A (SP-A), -D (SP-D), mucin-like high molecular weight glycoprotein (KL-6), and chemokine CCL-18 have been implicated in SSc-PID. Serum levels of these proteins are correlated with the severity of SSc-ILD, as assessed by HRCT and/or PFT. Finally, alveolar concentration of exhaled nitric oxide can be used to screen SSc patients with high risk of deterioration of respiratory function, in whom immunosuppressant treatment could be useful in preventing the evolution to irreversible lung fibrosis.

Scleroderma lung disease, variation in screening, diagnosis and treatment practices between rheumatologists and respiratory physicians

BACKGROUND

Interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) represent the leading causes of death in systemic sclerosis (SSc). Screening for these complications has assumed greater importance, but is not universal. The aim of this study is to determine the self-reported screening, diagnosis and treatment practices of rheumatologists and respiratory physicians for SSc-related lung disease.

METHODS

Email survey of 270 rheumatologists and 600 respiratory physicians.

RESULTS

Responses were received from 42 (16%) rheumatologists and 68 (11%) respiratory physicians. Of SSc patients seen by rheumatologists, 17% had ILD and 7.5% had a diagnosis of PAH compared with 31% and 21% for respiratory physicians. Forty per cent of all physicians screened asymptomatic SSc patients without a known diagnosis of ILD or PAH less than annually or not at all. The most commonly used screening investigations were pulmonary function tests (PFT) (95%) and transthoracic echocardiogram (TTE) (78%). In suspected ILD, both groups used high-resolution computed tomography scans and PFT in >90% of patients. In suspected PAH, both used TTE and PFT (>90%); right heart catheterisation was used by only 50% of physicians. In treatment of ILD, rheumatologists used intravenous (IV) cyclophosphamide more often (CYC) (59% vs 28%, P= 0.003) and more respiratory physicians used oral CYC (44% vs 28%, P= 0.012). In PAH, more respiratory physicians used warfarin (68% vs 40%, P= 0.006). Only approximately 65% of physicians had used specific PAH therapy, which may reflect lack of access to a designated PAH treatment centre.

CONCLUSION

The heterogeneity of responses revealed in this study raises the importance of screening, diagnosis and treatment algorithms in the management of this potentially life-threatening disease.

The pro-fibrotic factor IGFBP-5 induces lung fibroblast and mononuclear cell migration

We have previously shown that insulin-like growth factor-binding protein-5 (IGFBP-5) is overexpressed in fibrotic lung tissues and that it induces production of extracellular matrix components such as collagen and fibronectin both in vitro and in vivo. We recently observed mononuclear cell infiltration in lung tissues of mice expressing IGFBP-5. We therefore examined the role of IGFBP-5 on the migration of immune cells. Migration assays demonstrated that IGFBP-5 induced migration of peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. Preferential migration of monocytes/macrophages, natural killer cells, and T cells was observed. Moreover, the CD4/CD8 ratio of migrating cells was significantly higher in vitro and in vivo in response to IGFBP-5. IGFBP-5 resulted in preferential migration of activated CD4(+) T cells and monocytes. Interestingly, IGFBP-5 also induced migration of primary human lung fibroblasts. Exogenous administration of IGFBP-5 induced activation of mitogen-activated protein kinase (MAPK) signaling cascade but not PI3K in PBMCs. IGFBP-5-induced migration was blocked by the MEK1/2 inhibitor U0126, suggesting that IGFBP-5-induced migration occurs via MAPK activation. Furthermore, monocytes treated with recombinant IGFBP-5 expressed the mesenchymal markers alpha-smooth muscle actin and fibronectin in vitro and in vivo, suggesting that IGFBP-5 can induce the transformation of monocytes into mesenchymal cells. Collectively, our results suggest that IGFBP-5 induces cell migration via MAPK-dependent and IGF-I-independent mechanisms.

[Therapy of systemic sclerosis]

The therapy of systemic sclerosis (SSc) remains a challenge for dermatology, rheumatology, internal medicine, and other disciplines. Organ involvement, above all kidney and lungs, is a key therapeutic issue. The current developments in organ-specific therapy are the main topic of the article. Finally, possibilities of disease-modifying drugs and value of HSCT are discussed.

Use of mycophenolate mofetil to treat scleroderma-associated interstitial lung disease

Up to 80% of patients with scleroderma have lung disease, with interstitial lung disease (ILD) being the most common manifestation. Currently, there is no definitive therapy for this condition. The objective of the study is to investigate the use of mycophenolate mofetil (MMF) to treat scleroderma interstitial ILD. We report a retrospective chart review of 17 patients with scleroderma ILD treated with MMF (2g/day) for at least 12 months. Demographics, bronchoalveolar lavage (BAL) findings, pulmonary physiology and high-resolution computed tomography were recorded at baseline and after 12 and 24 months of therapy. Baseline BAL (n=12) showed alveolitis (median of 18% neutrophils). Ninety-four percent of subjects had either improved or stable lung function after 12 months of treatment: four improved, 12 were stable and only one worsened. All patients had radiographic abnormalities consistent with ILD. After 12 months of therapy, radiological findings (n=15) were stable in 11 patients, worse in three, and improved in one. There were no side effects attributable to MMF therapy recorded. Treatment of patients with scleroderma ILD for up to 24 months with MMF was generally associated with stable pulmonary function. These data argue for a prospective trial using MMF to treat scleroderma ILD.

Pulmonary arterial hypertension in systemic sclerosis: the need for early detection and treatment

Pulmonary arterial hypertension (PAH) is an important cause of mortality in systemic sclerosis (SSc). The symptoms are non-specific and can be ascribed to other features of the disease, so it is often underrecognized until the late stages. Earlier treatment with new agents is associated with better treatment outcomes. The aim of this article is to develop evidence-based guidelines for screening for PAH and interstitial lung disease (ILD) in SSc. PAH occurs in up to 27% of patients with SSc. Abnormal pulmonary function, particularly a disproportionate fall in carbon monoxide diffusing capacity (DLCO), can identify patients in the early stages of PAH, prompting further investigation in high-risk patients (limited SSc of >10 years' duration, symptoms and/or signs of PAH, DLCO <50% predicted, a rapid or large fall in DLCO without evidence of ILD and/or estimated systolic pulmonary artery pressure >45 mmHg on echocardiography). Right heart catheter remains the diagnostic gold standard. An algorithm for screening with regular pulmonary function tests for the early detection of PAH and ILD in SSc is proposed.

Insulin-like growth factor-binding protein-5 induces pulmonary fibrosis and triggers mononuclear cellular infiltration

We have recently shown that insulin-like growth factor-binding protein (IGFBP)-5 is overexpressed in idiopathic pulmonary fibrosis lung tissues and increases collagen and fibronectin deposition. Here, we further examined the effect of IGFBP-5 in vivo by intratracheal administration of replication-deficient adenovirus expressing human IGFBP-5 (Ad5), IGFBP-3 (Ad3), or no cDNA (cAd) to wild-type mice. Increased cellular infiltration and extracellular matrix deposition were observed in mice after Ad5 administration compared with Ad3 and cAd. Mononuclear cell infiltration consisted predominantly of T lymphocytes at day 8. By day 14, the number of infiltrating T cells decreased, whereas that of B cells and monocytes/macrophages increased. IGFBP-5 also induced migration of peripheral blood mononuclear cells in vitro, suggesting that in vivo mononuclear cell infiltration may be the direct result of IGFBP-5 expression. alpha-Smooth muscle actin and Mucin-1 co-localized in cells of mice treated with Ad5, suggesting that IGFBP-5 induced epithelial-mesenchymal transition. In addition, exogenous IGFBP-5 induced alpha-smooth muscle actin expression in primary fibroblasts and epithelial-mesenchymal transition of pulmonary epithelial cells in vitro. In conclusion, our results suggest that overexpression of IGFBP-5 in mouse lung results in fibroblast activation, increased extracellular matrix deposition, and myofibroblastic changes. Thus, the IGFBP-5-induced fibrotic phenotype in vivo may represent a novel model to better understand the pathogenesis of fibrosis.

Scleroderma: it has been a long hard journey

Progress in the understanding of the aetiopathogenesis of scleroderma (systemic sclerosis) has been painfully slow and this has greatly impeded the application of specific disease modifying treatments. This article provides a brief historical overview of scleroderma (including the important Australian contribution of Dr Alfred Barnett and colleagues--see accompanying article in this issue on pages 513-18), highlights some recent pathogenic developments and summarises some exciting new therapies. Cautious optimism can now be offered to scleroderma sufferers.