Serological biomarkers as risk factors of SLE-associated pulmonary arterial hypertension: a systematic review and meta-analysis

Risk factors of systemic lupus erythematosus patients with pulmonary arterial hypertension: A systematic review and meta-analysis

BACKGROUND

To investigate the risk factors for the development of pulmonary arterial hypertension (PAH) in patients with systemic lupus erythematosus (SLE).

METHODS

The literature related to risk factors for the development of PAH in SLE patients was searched by the computer on China national knowledge infrastructure (CNKI), PubMed, and Embase, and the literature search was limited to the period of library construction to October 2022. Two researchers independently performed literature screening and literature information extracting, including first author, publication time, case collection time, sample size, and study factors, and used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of the literature. The relationship between each clinical manifestation and laboratory index and the occurrence of PAH in SLE patients was evaluated based on the ratio (OR value) and its 95% CI.

RESULTS

A total of 24 publications were included, including 23 case-control studies and 1 cohort study with NOS ≥ 6, and the overall quality of the literature was high. The risk of PAH was higher in SLE patients who developed Raynaud phenomenon than in those who did not [OR = 2.39, 95% CI (1.91, 2.99), P < .05]; the risk of PAH was higher in SLE patients who were positive for anti-RNP antibodies than in those who were negative for anti-RNP antibodies [OR = 1.77, 95% CI (1.17, 3.2.65), P < .05]; the risk of PAH was higher in SLE patients with interstitial lung lesions than in those without combined interstitial lung lesions [OR = 3.28, 95% CI (2.37, 4.53), P < .05]; the risk of PAH was higher in SLE patients with combined serositis than in those without serositis [OR = 2.28, 95% CI (1.83, 2.84), P < .05]. The risk of PAH was higher in SLE patients with combined pericardial effusion than in those without pericardial effusion [OR = 2.97, 95% CI (2.37, 3.72), P < .05]; the risk of PAH was higher in SLE patients with combined vasculitis than in those without vasculitis [OR = 1.50, 95% CI (1.08, 2.07), P < .05]; rheumatoid factor-positive SLE patients had a higher risk of PAH than those with rheumatoid factor-negative [OR = 1.66, 95% CI (1.24, 2.24), P < .05].

CONCLUSION

Raynaud phenomenon, vasculitis, anti-RNP antibodies, serositis, interstitial lung lesions, rheumatoid factor, and pericardial effusion are risk factors for the development of PAH in patients with SLE.

Risk Factors for Pulmonary Arterial Hypertension in Patients With Systemic Lupus Erythematosus: A Systematic Review and Expert Consensus

OBJECTIVE

This study aimed to identify risk factors associated with the development of pulmonary arterial hypertension (PAH) in patients with systemic lupus erythematosus (SLE).

METHODS

We conducted a systematic literature review of studies focusing on adult patients classified as having SLE-related PAH by searching the electronic databases Embase, Medline, Medline in-progress, Wanfang, China National Knowledge Infrastructure, Ichushi Web, Kmbase, and KoreaMed. Based on the findings, we conducted a Delphi survey to build expert consensus on issues related to screening for PAH in patients with SLE and on the importance and feasibility of measuring the identified factors in clinical practice.

RESULTS

We included 21 eligible studies for data synthesis. Sixteen factors were associated with an increased risk of SLE-PAH: pericardial effusion, serositis, longer duration of SLE, arthritis, acute and subacute cutaneous lupus, scleroderma pattern on nailfold capillaroscopy, diffusion capacity of carbon monoxide in the lungs (DLCO) <70% predicted, interstitial lung disease, thrombocytopenia, and seven serological factors. Six factors were associated with a decreased risk of SLE-PAH: malar/acute rash, hematologic disorder, renal disorder, higher Systemic Lupus Erythematosus Disease Activity Index score, and two serological factors. Among these, there were six risk factors on which the panelists reached strong or general consensus (peak tricuspid regurgitation velocity on echocardiography >2.8 m/s, pericardial effusion, DLCO <70% predicted, scleroderma pattern on nailfold capillaroscopy, brain natriuretic peptide >50 ng/l, and N-terminal pro-brain natriuretic peptide >300 ng/l). The Delphi panel confirmed the need for a screening tool to identify patients with SLE at high risk of developing PAH and provided consensus on the importance and/or practicality of measuring the identified factors.

CONCLUSION

The risk factors we identified could be used in a screening algorithm to identify patients with SLE with a high risk of developing PAH to facilitate early diagnosis, which could improve prognosis and management of these patients.

In-depth characterization of pulmonary arterial hypertension in mixed connective tissue disease: a French national multicentre study

OBJECTIVE

Pulmonary arterial hypertension (PAH) is a leading cause of death in MCTD. We aimed to describe PAH in well-characterized MCTD patients.

METHODS

MCTD patients enrolled in the French Pulmonary Hypertension Registry with a PAH diagnosis confirmed by right heart catheterization were included in the study and compared with matched controls: MCTD patients without PAH, SLE patients with PAH and SSc patients with PAH. Survival rates were estimated by the Kaplan-Meier method and risk factors for PAH in MCTD patients and risk factors for mortality in MCTD-PAH were sought using multivariate analyses.

RESULTS

Thirty-six patients with MCTD-PAH were included in the study. Comparison with MCTD patients without PAH and multivariate analysis revealed that pericarditis, polyarthritis, thrombocytopenia, interstitial lung disease (ILD) and anti-Sm antibodies were independent predictive factors of PAH/PH in MCTD. Estimated survival rates at 1, 5 and 10 years following PAH diagnosis were 83%, 67% and 56%, respectively. MCTD-PAH presentation and survival did not differ from SLE-PAH and SSc-PAH. Multivariate analysis revealed that tobacco exposure was an independent factor predictive of mortality in MCTD-PAH.

CONCLUSION

PAH is a rare and severe complication of MCTD associated with a 56% 10-year survival. We identified ILD, pericarditis, thrombocytopenia and anti-Sm antibodies as risk factors for PAH in MCTD and tobacco exposure as a predictor of mortality in MCTD-PAH.

The Role of Anti-U1 RNP Antibody in Connective Tissue Disease-Associated Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis

Connective tissue disease (CTD) patients may suffer from pulmonary arterial hypertension (PAH), a serious complication, and anti-U1 ribonucleoprotein (RNP) antibodies can be used as a potential indicator for the development and prognosis of CTD-associated PAH (CTD-PAH). However, there are still some controversies; thus, a systematic review and meta-analysis were performed. We searched PubMed, Embase, Cochrane Library, and Scopus for eligible studies and assessed their quality using Newcastle−Ottawa scales or Agency for Healthcare Research and Quality indicators according to the type of research. Odds ratio (OR) was adopted as a measure of effect in risk factor analysis, and hazard ratio (HR) was adopted for prognostic factor analysis. Publication bias was evaluated using the Egger’s test. Thirteen studies were finally included. Anti-U1 RNP antibody was proved as a risk factor for PAH among CTD patients (OR = 5.30, 95%CI 2.96−9.48, p < 0.05) and a protective factor against mortality among CTD-PAH patients (HR = 0.55, 95%CI 0.36−0.83, p < 0.05). CTD patients with positive anti-U1 RNP antibodies are at high risk for PAH, so routine screening examinations, including echocardiography, are recommended. Additionally, anti-U1 RNP positivity has been linked to decreased mortality in patients with CTD-PAH.

Severe Pulmonary Artery Hypertension in Otherwise Silent Lupus: A Unique Hybrid Treatment Approach Using Hydroxychloroquine and Sildenafil

Pulmonary hypertension (PH) is a rare manifestation of systemic lupus erythematosus (SLE). Even more rare is pulmonary artery hypertension (PAH) presenting as the initial manifestation of SLE and may be a cause of diagnostic delay. As symptoms of PAH are very mild in the early stages, prompt diagnosis is crucial to prevent the progression of the disease. Echocardiographic evaluation involving the measurement of different right-sided heart variables in addition to estimated pulmonary artery pressure helps in reducing the false-positive rates of detection of PAH. The role of immunosuppression in addition to PAH-specific vasodilator therapy is one of the key aspects of management to minimize flares and improve hemodynamics. Equally important is the choice of a regimen best suited to minimize complications. We present a case of PAH in newly diagnosed SLE and the diagnostic and treatment challenges as a safety net hospital.

Pulmonary arterial hypertension (PAH) from autopsy study: T-cells, B-cells and mastocytes detection as morphological evidence of immunologically mediated pathogenesis

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by severe vascular remodelling, resulting in increased pulmonary vascular resistance with cardiac hypertrophy and heart failure. However, the diagnosis of PAH is often inaccurate. Many cases of PAH are incorrectly diagnosed or missed, and they are often associated with death. The aim of this study was to verify the morphological and histological criteria of fatal cases of PAH and evaluate the lymphocytic populations associated to lesions with reactive neo-angiogenesis.

METHODS

Pulmonary lung sections from 10 cases of sudden unexpected death (SUD) in the absence of previously diagnosed diseases and in an apparent state of well-being, with final histological post autopsy diagnosis of PAH were collected. The pathological findings were compared using ten controls from non-pathological lung from deaths from other causes. The autopsies included 4 males (40%) and 6 females (60%) with an average age of 52.1 ± 10.1 years. Sections stained with hematoxylin and eosin (H&E) were revised for a morphological diagnosis. Subsequently, serial sections were performed and stained with immunohistochemistry for anti-CD20 (B-lymphocytes), anti-CD3 (T-lymphocytes), anti-CD4 (T-helper lumphocytes), anti-CD8 (T-cytotoxic lymphocytes) and anti-CD117/C-Kit (mast cells/MCs) to detect inflammatory infiltrate and different ratios of cell-type. Statistical analysis was conducted using a paired t-test looking at 100 cells in 3 different tissue samples representative of vascular lesion and 3 different random normal lung parenchyma fields without lesion (from 10 normal control lungs), to identify specific lymphocyte subpopulations in inflammatory infiltrates.

RESULTS

There was a significant percentage increase of CD20 (p < 0.001), CD8 (p = 0.002), CD4 (p < 0.001), and CD117/C-Kit positive (C-Kit+; p < 0.001) cells mainly detected around wall vessels; while increased MCs positivity and C-Kit+ were observed especially in alveolar septa. In addition, reactive angiomatosis was observed.

CONCLUSIONS

The inflammatory infiltrate should be included for a correct diagnosis of PAH besides the vascular remodelling. The inflammatory infiltrate seems to be implicated as a main factor in the pathogenesis. This finding is important to rule out secondary pulmonary hypertension, to identify SUDs of unknown causes and to add new elements to the literature that can explain the immunologically related pathogenesis of PAH.

Exploration of the Shared Gene Signatures and Molecular Mechanisms Between Systemic Lupus Erythematosus and Pulmonary Arterial Hypertension: Evidence From Transcriptome Data

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect multiple systems. Pulmonary arterial hypertension (PAH) has a close linkage with SLE. However, the inter-relational mechanisms between them are still unclear. This article aimed to explore the shared gene signatures and potential molecular mechanisms in SLE and PAH.

Methods

The microarray data of SLE and PAH in the Gene Expression Omnibus (GEO) database were downloaded. The Weighted Gene Co-Expression Network Analysis (WGCNA) was used to identify the co-expression modules related to SLE and PAH. The shared genes existing in the SLE and PAH were performed an enrichment analysis by ClueGO software, and their unique genes were also performed with biological processes analyses using the DAVID website. The results were validated in another cohort by differential gene analysis. Moreover, the common microRNAs (miRNAs) in SLE and PAH were obtained from the Human microRNA Disease Database (HMDD) and the target genes of whom were predicted through the miRTarbase. Finally, we constructed the common miRNAs–mRNAs network with the overlapped genes in target and shared genes.

Results

Using WGCNA, four modules and one module were identified as the significant modules with SLE and PAH, respectively. A ClueGO enrichment analysis of shared genes reported that highly activated type I IFN response was a common feature in the pathophysiology of SLE and PAH. The results of differential analysis in another cohort were extremely similar to them. We also proposed a disease road model for the possible mechanism of PAH secondary to SLE according to the shared and unique gene signatures in SLE and PAH. The miRNA–mRNA network showed that hsa-miR-146a might regulate the shared IFN-induced genes, which might play an important role in PAH secondary to SLE.

Conclusion

Our work firstly revealed the high IFN response in SLE patients might be a crucial susceptible factor for PAH and identified novel gene candidates that could be used as biomarkers or potential therapeutic targets.

Predicting the Risk of Pulmonary Arterial Hypertension in Systemic Lupus Erythematosus: A Chinese Systemic Lupus Erythematosus Treatment and Research Group Cohort Study

OBJECTIVE

Pulmonary arterial hypertension (PAH) is a life-threatening complication of systemic lupus erythematosus (SLE). However, there is no algorithm to identify those at high risk. This study was undertaken to develop a prediction model for PAH in patients with lupus that provides individualized risk estimates.

METHODS

A multicenter, longitudinal cohort study was undertaken from January 2003 to January 2020. The study collected data on 3,624 consecutively evaluated patients diagnosed as having SLE. The diagnosis of PAH was confirmed by right-sided heart catheterization. Cox proportional hazards regression and least absolute shrinkage and selection operator were used to fit the model. Model discrimination, calibration, and decision curve analysis were performed for validation.

RESULTS

Ninety-two lupus patients (2.54%) developed PAH during a median follow-up of 4.84 years (interquartile range 2.42-8.84). The final prediction model included 5 clinical variables (acute/subacute cutaneous lupus, arthritis, renal disorder, thrombocytopenia, and interstitial lung disease) and 3 autoantibodies (anti-RNP, anti-Ro/SSA and anti-La/SSB). A 10-year PAH probability-predictive nomogram was established. The model was internally validated by Harrell's concordance index (0.78), the Brier score (0.03), and a satisfactory calibration curve. According to the net benefit and predicted probability thresholds, we recommend annual screening in high-risk (>4.62%) lupus patients.

CONCLUSION

We developed a risk stratification model using routine clinical assessments. This new tool may effectively predict the future risk of PAH in patients with SLE.

The Third Man: DNA sensing as espionage in pulmonary vascular health and disease

For as long as nucleic acids have been utilized to vertically and horizontally transfer genetic material, living organisms have had to develop methods of recognizing cytosolic DNA as either pathogenic (microbial invasion) or physiologic (mitosis and cellular proliferation). Derangement in key signaling molecules involved in these pathways of DNA sensing result in a family of diseases labeled interferonopathies. An interferonopathy, characterized by constitutive expression of type I interferons, ultimately manifests as severe autoimmune disease at a young age. Afflicted patients present with a constellation of immune-mediated conditions, including primary lung manifestations such as pulmonary fibrosis and pulmonary hypertension. The latter condition is especially interesting in light of the known role that DNA damage plays in a variety of types of inherited and induced pulmonary hypertension, with free DNA detection elevated in the circulation of affected individuals. While little is known regarding the role of cytosolic DNA sensing in development of pulmonary vascular disease, exciting new research in the related fields of immunology and oncology potentially sheds light on future areas of fruitful exploration. As such, the goal of this review is to summarize the state of the field of nucleic acid sensing, extrapolating common shared pathways that parallel our knowledge of pulmonary hypertension, in a molecular and cell-specific manner. Principles of DNA sensing related to known pulmonary injury inducing stimuli are also evaluated, in addition to potential therapeutic targets. Finally, future directions in pulmonary hypertension research and treatments will be briefly discussed.

Pulmonary arterial hypertension associated with primary Sjögren's syndrome: a multicentre cohort study from China

OBJECTIVES

Primary Sjögren's syndrome (pSS) is an important cause of pulmonary arterial hypertension (PAH), which remains insufficiently studied and needs attention. This study aimed to investigate the clinical characteristics, risk factors, prognosis and risk assessment of pSS-PAH.

METHODS

We established a multicentre cohort of pSS-PAH diagnosed by right heart catheterisation. The case-control study was conducted with pSS-non-PAH patients as a control group to identify the risk factors for PAH. In the cohort study, survival was calculated, and risk assessment was performed at both baseline and follow-up visits.

RESULTS

In total, 103 patients with pSS-PAH were enrolled, with 526 pSS-non-PAH patients as controls. The presence of anti-SSB (p<0.001, OR 4.095) and anti-U1RNP antibodies (p<0.001, OR 29.518), the age of pSS onset (p<0.001, OR 0.651) and the positivity of corneal staining (p=0.003, OR 0.409) were identified as independent risk factors for PAH. The 1-, 3- and 5-year survival rates were 94.0%, 88.8% and 79.0%, respectively. Cardiac index (p=0.010, hazard ratio (HR) 0.161), pulmonary vascular resistance (p=0.016, HR 1.105) and Sjögren's syndrome disease damage index (p=0.006, HR 1.570) were identified as potential predictors of death in pSS-PAH. Long-term outcomes were improved in patients in the low-risk category at baseline (p=0.002) and follow-up (p<0.0001).

CONCLUSION

The routine screening of PAH is suggested in pSS patients with early onset and positivity for anti-SSB or anti-U1RNP antibodies. Patient prognosis might be improved by improving reserved cardiopulmonary function, by achieving a damage-free state and especially by achieving low-risk category, which supports the treat-to-target strategy for pSS-PAH.

Perivascular Inflammation in Pulmonary Arterial Hypertension

Perivascular inflammation is a prominent pathologic feature in most animal models of pulmonary hypertension (PH) as well as in pulmonary arterial hypertension (PAH) patients. Accumulating evidence suggests a functional role of perivascular inflammation in the initiation and/or progression of PAH and pulmonary vascular remodeling. High levels of cytokines, chemokines, and inflammatory mediators can be detected in PAH patients and correlate with clinical outcome. Similarly, multiple immune cells, including neutrophils, macrophages, dendritic cells, mast cells, T lymphocytes, and B lymphocytes characteristically accumulate around pulmonary vessels in PAH. Concomitantly, vascular and parenchymal cells including endothelial cells, smooth muscle cells, and fibroblasts change their phenotype, resulting in altered sensitivity to inflammatory triggers and their enhanced capacity to stage inflammatory responses themselves, as well as the active secretion of cytokines and chemokines. The growing recognition of the interaction between inflammatory cells, vascular cells, and inflammatory mediators may provide important clues for the development of novel, safe, and effective immunotargeted therapies in PAH.

Severe Pulmonary Hypertension as Initial Presentation of SLE: A Case Report and Literature Review

Severe pulmonary artery hypertension (PAH) is a rare initial presentation of systemic lupus erythematosus (SLE). SLE associated with PAH carries worse prognosis that isolated SLE. However, there has been improvement in mortality of the patients in the recent years owing to newer treatment options available. Early recognition remains of prime importance. We present here a case of young female who presented with severe pulmonary hypertension with right heart failure leading to cardiogenic shock and was found to have SLE. She was started on appropriate treatment; however, given the severity of her illness, the patient did not survive. This case highlights the importance of early recognition and prompt treatment of SLE-associated PAH, which might improve the survival rate in the patients.

Pulmonary Involvement in Children With Systemic Lupus Erythematosus

Background: Symptomatic pulmonary involvement in systemic lupus erythematosus (SLE) seems not uncommon in children. However, there are few data on the characteristics and laboratory parameters of SLE patients with pulmonary involvement. Methods: This was a hospital-based study involving 111 SLE patients from 1 January 2012 to 31 December 2016. The demographic, clinical, and laboratory data of the patients were prospectively collected. They were followed as outpatients until December 2019. Clinical characteristics and laboratory parameters of patients with and without pulmonary involvement were compared. Results: Of the 111 patients with SLE, we identified 18 patients (16.2%) with pulmonary involvement. The most common HRCT findings were ground glass opacity, interlobular septal thickening, bilateral diffuse infiltrates, and pleurisy/pleural effusion (55.6, 50, 50, and 44.4%, respectively). SLE patients with pulmonary involvement tended to have a longer disease duration (14 [12-24.5] vs. 5 [2-9] months, P < 0.01). We also observed a significant association between the presence of anti-Sm antibody, ANCA, Anti-RNP and the presence of pulmonary involvement of SLE (all P < 0.001). Conclusions: Lung involvement was frequent in SLE patients from Southeast China. Patients with a longer duration of symptoms before SLE diagnosis tended to have pulmonary involvement. When children with SLE are found to have anti-RNP antibody and positive ANCA, it should be alert to the occurrence of pulmonary involvement.

Pulmonary arterial hypertension in systemic lupus erythematosus based on a CSTAR-PAH study: Baseline characteristics and risk factors

AIM

Pulmonary arterial hypertension (PAH) is a complex and devastating complication of systemic lupus erythematosus (SLE). We sought to describe the baseline characteristics of right heart catheterization (RHC)-confirmed SLE-associated PAH and identify risk factors for PAH in SLE patients.

METHODS

A multicenter, cross-sectional study was conducted using the Chinese SLE Treatment and Research group (CSTAR) registry. Baseline data for patients with SLE-associated PAH and SLE patients without PAH were collected and compared. Risk factors for PAH among patients with SLE were identified.

RESULTS

A total of 292 patients with SLE-associated PAH were enrolled. RHC was used to reveal hemodynamic features, including mean pulmonary arterial pressure (46.2 ± 12.0 mm Hg), pulmonary arterial wedge pressure (7.84 ± 3.92 mm Hg), pulmonary vascular resistance (10.86 ± 5.57 Wood units), and cardiac index (2.77 ± 0.91 L/min × m² ). A multivariate logistic regression analysis showed that serositis (odds ratio [OR] = 5.524, 95% CI 3.605-8.465, P < 0.001), anti-ribonucleoprotein (RNP) antibody positivity (OR = 13.332, 95% CI 9.500-18.710, P < 0.001), and diffusion capacity of carbon monoxide in the lung (DLCO)/%Pred <70% (OR = 10.018, 95% CI 6.619-15.162, P < 0.001) were independent predictors of PAH. We recommend using transthoracic echocardiography (TTE) to perform early screening of SLE patients who have serositis, anti-RNP antibody positivity, or DLCO/%Pred <70%. RHC is suggested for patients suspected of having PAH. Once a diagnosis of SLE-PAH is confirmed, evaluation and treatment should immediately begin.

CONCLUSION

Overall, we recommend performing early screening using TTE in SLE patients with serositis, anti-RNP antibodies, or a DLCO/%Pred <70%, even for patients in a relatively stable condition according to SLE disease activity index.

Primary respiratory disease in patients with systemic lupus erythematosus: data from the Spanish rheumatology society lupus registry (RELESSER) cohort

Background

The purpose of this study was to assess the prevalence, associated factors, and impact on mortality of primary respiratory disease in a large systemic lupus erythematosus (SLE) retrospective cohort.

Methods

All adult patients in the RELESSER-TRANS (Registry of Systemic Lupus Erythematosus Patients of the Spanish Society of Rheumatology [SER], cross-sectional phase) registry were retrospectively investigated for the presence of primary pleuropulmonary manifestations.

Results

In total 3215 patients were included. At least one pleuropulmonary manifestation was present in 31% of patients. The most common manifestation was pleural disease (21%), followed by lupus pneumonitis (3.6%), pulmonary thromboembolism (2.9%), primary pulmonary hypertension (2.4%), diffuse interstitial lung disease (2%), alveolar hemorrhage (0.8%), and shrinking lung syndrome (0.8%).

In the multivariable analysis, the variables associated with the development of pleuropulmonary manifestation were older age at disease onset (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.02–1.04), higher SLEDAI (Systemic Lupus Erythematosus Disease Activity Index) scores (OR 1.03, 95% CI 1.00–1.07), the presence of Raynaud’s phenomenon (OR 1.41, 95% CI 1.09–1.84), secondary antiphospholipid syndrome (OR 2.20, 95% CI 1.63–2.97), and the previous or concomitant occurrence of severe lupus nephritis, (OR 1.48, 95% CI 1.12–1.95) neuropsychiatric manifestations (OR 1.49, 95% CI 1.11–2.02), non-ischemic cardiac disease (OR 2.91, 95% CI 1.90–4.15), vasculitis (OR 1.81, 95% CI 1.25–2.62), hematological manifestations (OR 1.31, 95% CI 1.00–1.71), and gastrointestinal manifestations, excluding hepatitis (OR 2.05, 95% CI 1.14–3.66). Anti-RNP positivity had a clear tendency to significance (OR 1.32, 95% CI 1.00–1.75; P = 0.054).

The development of pleuropulmonary manifestations independently contributes to a diminished survival (hazard ratio of 3.13). However, not all complications will influence the prognosis in the same way. Whereas the occurrence of pleural disease or pulmonary thromboembolism has a minimal impact on the survival of these patients, the remaining manifestations have a major impact on mortality.

Conclusion

Except for pleural disease, the remaining respiratory manifestations are very uncommon in SLE (<4%). Pleuropulmonary manifestations independently contributed to a decreased survival in these patients.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1776-8) contains supplementary material, which is available to authorized users.

Anti-RNA binding protein positivity in idiopathic interstitial pneumonia

INTRODUCTION

Idiopathic interstitial pneumonias (IIP) are diffuse lung diseases whose cause is unknown and often present with features of autoimmunity despite not meeting criteria for a connective tissue disease (CTD). Recent studies suggest that anti-RNA binding protein (anti-RBP) antibodies, which include anti-SSA, anti-SSB, anti-Sm, and anti-RNP, play a role in the loss of immune tolerance and severity of pulmonary hypertension (PH) in CTDs. We hypothesized that anti-RBP positive (RBP+) subjects would have worse measures of lung function, radiographic findings, PH, and survival than anti-RBP negative (RBP-) subjects.

METHODS

Subjects with both IIP and serologies for review were identified retrospectively and stratified based on anti-RBP antibody seropositivity. Baseline cohort characteristics, pulmonary function tests (PFT), ambulatory oxygen requirement, radiographic characteristics, markers of PH, and transplant-free survival were compared between anti-RBP positive and negative groups.

RESULTS

Five hundred twenty patients with IIP were identified, of which ten percent (n = 53) were anti-RBP positive. RBP+ as compared to RBP- subjects had significantly worse PFTs as indicated by FEV1 (59.6 vs. 64.9, p = 0.046) and FVC (71.6 vs. 78.8, p = 0.018). There was a higher prevalence of radiographic honeycombing (49.1% vs. 38.3%, p = 0.006) and emphysema (22.6% vs. 5.1%, p < 0.001) in the RBP+ group despite no difference in smoking history. The Pulmonary Artery-Aorta ratio was also larger in the RBP+ group (0.93 vs. 0.88, p = 0.040). There was no difference in transplant-free survival between groups (log rank = 0.912).

CONCLUSION

Anti-RBP+ IIP patients may have worse lung function, increased chest radiographic abnormalities, and PH compared with those without these antibodies.

Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is a devastating pulmonary vascular disease in which autoimmune and inflammatory phenomena are implicated. B cells and autoantibodies have been associated with IPAH and identified as potential therapeutic targets. However, the specific populations of B cells involved and their roles in disease pathogenesis are not clearly defined. We aimed to assess the levels of activated B cells (plasmablasts) in IPAH, and to characterize recombinant antibodies derived from these plasmablasts. Blood plasmablasts are elevated in IPAH, remain elevated over time, and produce IgA autoantibodies. Single-cell sequencing of plasmablasts in IPAH revealed repertoires of affinity-matured antibodies with small clonal expansions, consistent with an ongoing autoimmune response. Recombinant antibodies representative of these clonal lineages bound known autoantigen targets and displayed an unexpectedly high degree of polyreactivity. Representative IPAH plasmablast recombinant antibodies stimulated human umbilical vein endothelial cells to produce cytokines and overexpress the adhesion molecule ICAM-1. Together, our results demonstrate an ongoing adaptive autoimmune response involving IgA plasmablasts that produce anti-endothelial cell autoantibodies in IPAH. These antibodies stimulate endothelial cell production of cytokines and adhesion molecules, which may contribute to disease pathogenesis. These findings suggest a role for mucosally-driven autoimmunity and autoimmune injury in the pathogenesis of IPAH.