Summary
Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that derives its name from the characteristic finding of abundant IgG4+ plasma cells in affected tissues, as well as the presence of elevated serum IgG4 concentrations in many patients. In contrast to fibrotic disorders, such as systemic sclerosis or idiopathic pulmonary fibrosis in which the tissues fibrosis has remained largely intractable to treatment, many IgG4-RD patients appear to have a condition in which the collagen deposition is reversible. The mechanisms underlying this peculiar feature remain unknown, but the remarkable efficacy of B cell depletion in these patients supports an important pathogenic role of B cell/T cell collaboration. In particular, aberrant T helper type 2 (Th2)/regulatory T cells sustained by putative autoreactive B cells have been proposed to drive collagen deposition through the production of profibrotic cytokines, but definitive demonstrations of this hypothesis are lacking. Indeed, a number of unsolved questions need to be addressed in order to fully understand the pathogenesis of IgG4-RD. These include the identification of an antigenic trigger(s), the implications (if any) of IgG4 antibodies for pathophysiology and the precise immunological mechanisms leading to fibrosis. Recent investigations have also raised the possibility that innate immunity might precede adaptive immunity, thus further complicating the pathological scenario. Here, we aim to review the most recent insights on the immunology of IgG4-RD, focusing on the relative contribution of innate and adaptive immune responses to the full pathological phenotype of this fibrotic condition. Clinical, histological and therapeutic features are also addressed.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/cei.12641

Immunology of IgG4‐related disease

Summary Background Systemic sclerosis-associated interstitial lung disease (ILD) carries a high mortality risk; expert guidance is required to aid early recognition and treatment. We aimed to develop the first expert consensus and define an algorithm for the identification and management of the condition through application of well established methods. Methods Evidence-based consensus statements for systemic sclerosis-associated ILD management were established for six domains (ie, risk factors, screening, diagnosis and severity assessment, treatment initiation and options, disease progression, and treatment escalation) using a modified Delphi process based on a systematic literature analysis. A panel of 27 Europe-based pulmonologists, rheumatologists, and internists with expertise in systemic sclerosis-associated ILD participated in three rounds of online surveys, a face-to-face discussion, and a WebEx meeting, followed by two supplemental Delphi rounds, to establish consensus and define a management algorithm. Consensus was considered achieved if at least 80% of panellists indicated agreement or disagreement. Findings Between July 1, 2018, and Aug 27, 2019, consensus agreement was reached for 52 primary statements and six supplemental statements across six domains of management, and an algorithm was defined for clinical practice use. The agreed statements most important for clinical use included: all patients with systemic sclerosis should be screened for systemic sclerosis-associated ILD using high-resolution CT; high-resolution CT is the primary tool for diagnosing ILD in systemic sclerosis; pulmonary function tests support screening and diagnosis; systemic sclerosis-associated ILD severity should be measured with more than one indicator; it is appropriate to treat all severe cases; no pharmacological treatment is an option for some patients; follow-up assessments enable identification of disease progression; progression pace, alongside disease severity, drives decisions to escalate treatment. Interpretation Through a robust modified Delphi process developed by a diverse panel of experts, the first evidence-based consensus statements were established on guidance for the identification and medical management of systemic sclerosis-associated ILD. Funding An unrestricted grant from Boehringer Ingelheim International.

https://www.thelancet.com/pdfs/journals/lanrhe/PIIS2665-9913(19)30144-4.pdf

The identification and management of interstitial lung disease in systemic sclerosis: evidence-based European consensus statements

A multicenter, open-label, comparative study of B-cell depletion therapy with Rituximab for systemic sclerosis-associated interstitial lung disease

Objectives SSc is characterized by fibrotic changes in the skin and lung, and the mainstay of treatment has been CYC. B cell involvement suggests that rituximab (RTX) may also be of therapeutic benefit. The aim of the study was to compare the efficacy and safety of RTX compared with CYC in retarding the progression of interstitial lung disease and skin manifestations of primary SSc. Methods We randomly assigned 60 patients of dcSSc, age 18-60 years with skin and lung involvement, to monthly pulses of CYC 500 mg/m2 or RTX 1000 mg × 2 doses at 0, 15 days. Primary outcomes were forced vital capacity (FVC) percent predicted at 6 months. Secondary outcomes were: absolute change in litres (FVC-l) at 6 months; modified Rodnan skin scores at 6 months, 6-min walk test, Medsgers score and new onset or worsening of existing pulmonary hypertension by echocardiographic criteria. Results The FVC [%mean (s.d.)] in the RTX group improved from 61.30 (11.28) to 67.52 (13.59), while in the CYC group it declined from 59.25 (12.96) to 58.06 (11.23) at 6 months (P = 0.003). The change of FVC was 1.51 (0.45) l to 1.65 (0.47) l in the RTX group, compared with 1.42 (0.49) to 1.42 (0.46) l in the CYC group. The mRSS changed from 21.77 (9.86) to 12.10 (10.14) in the RTX group and 23.83 (9.28) to 18.33 (7.69) in the CYC group after 6 months. Serious adverse events were more common in the CYC group. Conclusion RTX is a safe and effective alternative to CYC in the primary therapy of skin and lung manifestations of scleroderma. Trial registration Clinical Trials Registry - India, www.ctri.nic.in, CTRI/2017/07/009152.

/pdf/intravenous-cyclophosphamide-vs-rituximab-for-the-treatment-11bc0d2wh4.pdf

Intravenous cyclophosphamide vs rituximab for the treatment of early diffuse scleroderma lung disease: open label, randomized, controlled trial

Systemic sclerosis-associated interstitial lung disease.

OBJECTIVES To assess the effects of Rituximab (RTX) on skin and lung fibrosis in patients with systemic sclerosis (SSc) belonging to the European Scleroderma Trial and Research (EUSTAR) cohort and using a nested case-control design. METHODS Inclusion criteria were fulfilment of American College of Rheumatology classification criteria for SSc, treatment with RTX and availability of follow-up data. RTX-treated patients were matched with control patients from the EUSTAR database not treated with RTX. Matching parameters for skin/lung fibrosis were the modified Rodnan Skin Score (mRSS), forced vital capacity (FVC), follow-up duration, scleroderma subtype, disease duration and immunosuppressive co-treatment. The primary analysis was mRSS change from baseline to follow-up in the RTX group compared with the control group. Secondary analyses included change of FVC and safety measures. RESULTS 63 patients treated with RTX were included in the analysis. The case-control analysis in patients with severe diffuse SSc showed that mRSS changes were larger in the RTX group versus matched controls (N=25; -24.0±5.2% vs -7.7±4.3%; p=0.03). Moreover, in RTX-treated patients, the mean mRSS was significantly reduced at follow-up compared with baseline (26.6±1.4 vs 20.3±1.8; p=0.0001). In addition, in patients with interstitial lung disease, RTX prevented significantly the further decline of FVC compared with matched controls (N=9; 0.4±4.4% vs -7.7±3.6%; p=0.02). Safety measures showed a good profile consistent with previous studies in autoimmune rheumatic diseases. CONCLUSIONS The comparison of RTX treated versus untreated matched-control SSc patients from the EUSTAR cohort demonstrated improvement of skin fibrosis and prevention of worsening lung fibrosis, supporting the therapeutic concept of B cell inhibition in SSc.

/pdf/effects-and-safety-of-rituximab-in-systemic-sclerosis-an-4akdr917sw.pdf

Gabriela Szucs

Papers

Effects and safety of rituximab in systemic sclerosis: an analysis from the European Scleroderma Trial and Research (EUSTAR) group