Predictive role of natural killer cells in bronchoalveolar lavage fluid of patients with sarcoidosis

Sarcoidosis is a rare granulomatous disease of unknown aetiology belonging to the wide group of interstitial lung diseases.). Although the limitlessness of BAL fluid is debated, it remains one of the best matrices for studying the pathogenesis of sarcoidosis. Natural killer (NK) cells have been described in BAL fluid from sarcoidosis patients. Elevated NK cells in BAL fluid from sarcoidosis patients have been found to be associated with poor outcomes. In this study, NK cells were evaluated in BAL samples from sarcoidosis patients at the time of diagnosis and associated with clinical characteristics in order to evaluate their prognostic role. Of the 276 patients suspected to have sarcoidosis on the basis of clinical and radiological findings, 248 had a final diagnosis of sarcoidosis. Clinical parameters, Scadding stage, and extrapulmonary localization were collected in a database. It resulted in fibrotic sarcoidosis patients being associated with an increase in lymphocyte percentages in BAL samples, particularly NK cells when compared with other groups. From ROC analysis, NK cell percentages in BAL samples resulted as being the best predictive markers in discriminating stage 4 of sarcoidosis from other RX stages (AUC=0.85, p<0.0001). Furthermore, after the stratification of patients on the basis of the number of extrapulmonary localizations, patients with an higher number of extrapulmonary localizations also showed higher percentages of NK cells in BAL fluid. In conclusion, NK cell percentages in BAL fluid can be considered a good prognostic marker of fibrotic phenotypes of sarcoidosis and involvement of other organs, although their diagnostic utility was poor.

Collagen Type IV Alpha 5 Chain in Bronchiolitis Obliterans Syndrome After Lung Transplant: The First Evidence

INTRODUCTION

Bronchiolitis obliterans syndrome (BOS) is the most common form of CLAD and is characterized by airflow limitation and an obstructive spirometry pattern without parenchymal opacities. The protein signature of BOS lesions concerns extracellular matrix organization and aberrant basement membrane composition. In this pilot study, we investigated the presence of COL4A5 in the serum of patients with BOS.

METHODS

41 patients who had undergone LTX were enrolled. Of these, 27 developed BOS and 14 (control group) were considered stable at the time of serum sampling. Of BOS patients, serum samples were analysed at the time of BOS diagnosis and before the clinical diagnosis (pre-BOS). COL4A5 levels were detected through the ELISA kit.

RESULTS

Serum concentrations of COL4A5 were higher in pre-BOS than in stable patients (40.5 ± 13.9 and 24.8 ± 11.4, respectively, p = 0.048). This protein is not influenced by comorbidities, such as acute rejection or infections, or by therapies. Survival analysis also reveals that a higher level of COL4A5 was also associated with less probability of survival. Our data showed a correlation between concentrations of COL4A5 and FEV1 at the time of diagnosis of BOS.

CONCLUSION

Serum concentrations of COL4A5 can be considered a good prognostic marker due to their association with survival and correlation with functional parameters.

POS0823 KL-6 IN ANCA-ASSOCIATED VASCULITIS PATIENTS WITH AND WITHOUT ILD: A MACHINE LEARNING APPROACH

Background

ANCA-associated vasculitis (AAV) are small vessel vasculitis which may variously affect upper and lower respiratory tract. Patients with microscopic polyangiitis (MPA) and, less commonly, granulomatosis with polyangiitis (GPA), especially those who are ANCA-MPO-positive, may suffer from interstitial lung disease (ILD), which is associated with high morbidity and mortality as it is often underdiagnosed and responds poorly to conventional treatments

Objectives

In this study, we aimed to assess whether Krebs von den Lungen-6 (KL-6), a marker of fibrotic ILD, may be useful for distinguishing AAV patients with ILD from those without ILD, and whether its changes over time are correlated with disease activity.

Methods

We enrolled all consecutive patients evaluated in the period December 2020 - November 2021. Inclusion criteria were a diagnosis of GPA or MPA, active disease, and eligibility for Rituximab treatment according to EULAR recommendations. All patients underwent concomitant rheumatological and pneumological evaluation, lung function tests, routine blood tests, autoimmunity evaluation and KL-6 assay. Current and previous treatments, Birmingham vasculitis score (BVAS) and vasculitis damage index were also recorded.

Results

A total of 13 patients (Table 1) were enrolled. One was excluded due to a concomitant diagnosis of lung cancer. Higher serum KL-6 were in AAV-ILD compared with those without ILD (972.8±398.5 vs 305.4±93.9, p=0.0040). Area under the Receiver Operating Characteristics curve showed 100% of the diagnostic performance of KL-6 for identifying the ILD involvement (accuracy 91.7%) and the best cutoff value of 368 U/mL (Sensitivity 100% and specificity 87.5%). The decision-tree model showed a 33% improvement in class purity using a cut-off value of 513 U/mL to distinguish AAV patients with and without ILD (Figure 1). Stratifying AAV patients as MPA and GPA with and without ILD considering T0 and T1 KL-6, the model obtained an improvement of 40% for classifying GPA non-ILD with a T0 serum KL-6 cut-off value of 513 U/mL and a T1 KL-6 cut-off of 301 U/mL. A direct correlation was found between serum T0 KL-6 and T0 BVAS (r=0.578, p=0.044).

Table 1.

Patients’ features

Sex/ageDiagnosisLength of disease * (months)Organs involvedType of lung involvementT0 KL6 levelsT0 BVAST0 VDIT1 KL6 levelsT1 BVAST1 VDIF/83MPA28Lung, kidney, PNSILD, alveolar hemorrhage6258732507M/48GPA1Lung, kidney, nose, eyeNodules35218027920F/55GPA252Lung, skinNodules40115360233F/38MPA1Skin-34760---F/74MPA180Kidney, PNS-36811541405M/77MPA8Lung, kidney, PNS, skinILD, alveolar hemorrhage982241---F/49GPA60Nose, eye-1226211602M/60MPA40Skin, PNS-20591---F/39GPA4Nose-31063---M/71GPA24Lung, eye, jointsNodules, ILD152893---F/64MPA24LungILD7564-10030-F/59GPA72LungNodules3384--0-Figure 1.

ROC curve and decision tree model

Conclusion

Our multicentre study demonstrated KL-6 as a reliable, non-invasive and easy-to-perform marker of ILD in AAV patients and its helpfulness for disease activity assessment. Changes in serum concentrations of KL-6 over time could be useful for monitoring AAV patients. Further study of KL-6 as a marker of response to therapy during long-term follow-up would also be worthwhile.

Disclosure of Interests

None declared

AB0611 Neutrophil extracellular traps and interstitial lung disease in ANCA-associated vasculitis: a scoping review

Background

Deregulated neutrophil extracellular traps (NET) formation is implicated in various diseases, including ANCA-associated vasculitis and pulmonary fibrosis (PF). Lung involvement is frequent in AAV, and interstitial lung diseases (ILD) are strongly related to MPO-ANCA positivity and mainly reported in microscopic polyangiitis. The association between AAV and ILD is a strong indicator of poor prognosis and limited survival. Neutrophils, ANCA and NET interplay in PF development in AAV.

Objectives

This study aimed to review the literature concerning the implications of NET in lung fibrogenesis focused specifically on AAV associated with ILD, and the potential of NET as a theranostic marker.

Methods

Through scoping review methodology, we used a descriptive thematic analysis to understand the pathogenic role of NETs in patients with AAV and pulmonary fibrosis and their further role as a theranostic marker of this disease.

Results

Quality assessment of articles was evaluated through SANRA methodology (Table 1). The implications of NET in the pathogenesis of AAV and ILD (Figure 1), as well as an association between these two diseases, have been identified, but the underlying pathophysiological mechanisms are still unknown. Pharmacological or genetic inhibition of NET release reduces disease severity in multiple inflammatory disease models, indicating that NETs are potential therapeutic targets. In this regard, despite the lack of clinical data, we may hypothesize that an optimal management of AAV-ILD patients would require not only B-cells targeted therapy, but also NETs inhibition.

Table 1.

SANRA Score for quality assessment

N°.AuthorsJustification of the article’s importance for the readershipStatement of concrete aims or formulation of questionsDescription of the literature searchReferencingScientific ReasoningAppropriate presentation of dataTotal score1Pandolfi L et al. 202122012292Radermecker C et al. 202012022183Zhang S et al. 201921022184Skopelja-Gardner S et al. 201911012275Khawaja AA et al. 202022012186Chrysanthopoulou A et al. 201421022187Kraaij T et al. 201821021288Tang S et al. 201521012179Yoshida M et al. 2016120121710Nakazawa D et al. 2014210222911Hattanda F et al. 2019220121812Schreiber A et al. 2017220112813van Dam LS et al. 2019220111714Roitsch S et al. 2018120122815Takeuchi H et al. 20172202221016Su B et al. 2021210122817Söderberg D et al. 2015210121718Surmiak M et al. 20161201228Figure 1.

The role of NET in interstitial lung disease associated with ANCA-associated vasculitis

Conclusion

Preliminary findings seem to display a lack of efficacy of traditional immunosuppressants, such as Rituximab, in this subset of patients, while to date no patients suffering from a definite ILD was enrolled in clinical trials. Further insights would be provided by their employment, as a combination treatment, in the common clinical practice. Although we can imagine that inhibition of NETs in patients with AAV-ILD could reduce severity and mortality, we still lack a scientific basis that could improve our understanding of the disease from a molecular point of view.

Disclosure of Interests

None declared

Speckle tracking echocardiography as a promising tool for the prognostic assessment of patients with sarcoidosis

Background

Sarcoidosis is a chronic granulomatous disease characterized by multiorgan inflammatory involvement and recurrent relapses with significant impact on morbidity and mortality. The prognostic assessment of these patients is still challenging. Although the international guidelines didn't recommend basic transthoracic echocardiography (TTE) for diagnostic and prognostic assessment of sarcoidosis, speckle tracking echocardiography (STE) has emerged as more sensitive for the early detection of cardiac sarcoidosis and outcome.

Purpose

This prospective study aimed to assess the potential value of STE parameters for the prediction of major adverse cardiac events (MACE) and sarcoidosis relapse.

Methods

Consecutive patients with confirmed diagnosis of sarcoidosis who underwent transthoracic echocardiography (TTE) and subsequent pulmonary function tests (PFTs) were enrolled. Patients with acute events or treatment escalation between TTE and PFTs and previous cardiac surgery were excluded. All patients were followed for sarcoidosis relapse requiring increase in step-up therapy and MACE (cardiovascular death, cardiovascular hospitalizations, arrhythmias).

Results

172 patients were included (111 females, 57.4±12.6 years); 56 patients showed extrapulmonary localizations of sarcoidosis; at baseline, 99 patients were on steroid and/or immunosuppressive therapy. During a median follow up of 2217 days, 8 deaths (3 cardiovascular deaths), 23 MACE and 36 sarcoidosis relapses were reported. Patients with MACE were older (p=0.0022), but didn't show significant differences in PFTs and sarcoidosis phenotype. LV global longitudinal strain (GLS) was the only echocardiographic index to show significant differences (lower values) in patients with MACE (p=0.025). LV GLS ≤17.13% (absolute value) was identified as a fair predictor of MACE both with ROC curves (AUC=0.64) and Kaplan Meier analysis (Fig. 1).

No significant differences of demographic, clinical, functional, and therapeutic data were observed between patients with/without sarcoidosis relapse. TTE revealed a significant reduction of LV ejection fraction (p=0.0432), tricuspid annular plane systolic excursion (TAPSE, p=0.0272) and global peak atrial longitudinal strain (PALS, p=0.0012) in patients with relapse. Among these 3 parameters, PALS ≤28.5% showed to be the best predictor of sarcoidosis relapse with ROC (AUC=0.7155) and Kaplan Meier curves (Fig. 2).

Conclusions

Our results highlight a potential role of LV GLS and PALS as prognostic markers in sarcoidosis, suggesting the use of STE in the clinical management of these patients, regardless the evidence or the suspect of cardiac localizations of the disease.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Differential redox proteomic profiles of serum from severe asthma patients after one month of benralizumab and mepolizumab treatment

Mepolizumab and Benralizumab are biological drugs for severe asthma patients able to reduce moderate-to-severe exacerbation rate (peripheral eosinophilial % mepolizumab 1.6 ± 1.2; benralizumab 0; p < 0.0001), improving the quality of life and lung function parameters (FEV1%: mepolizumab 87.1 ± 21.5; benralizumab 89.7 ± 15, p < 0.04). Here we report a preliminary redox proteomic study highlighting the level of oxidative burst present in serum from patients before and after one month of both treatments. Our results highlighted apolipoprotein A1 oxidation after Mepolizumab treatment, that could be related to HDL functionality and could represent a potential biomarker for the treatment. On the other hand, after one month of Benralizumab we detected higher oxidation levels of ceruloplasmin and transthyretin, considered an important oxidative stress biomarker which action help to maintain redox homeostasis.

Regulatory T Cells in Severe Persistent Asthma in the Era of Monoclonal Antibodies Target Therapies

Asthma is an immunoinflammatory disease characterized by bronchial hyper-reactivity to different external stimuli. New monoclonal target treatments have been developed, but few studies have investigated the role of regulatory T cells in severe asthma and the modulatory effect of biological therapy on regulatory T cell functions. Their dysfunction may contribute to the development and exacerbation of asthma. Here we review the recent literature on the potential immunological role of regulatory T cells in the pathogenesis of severe asthma. The analysis of the role of regulatory T cells was performed in terms of functions and their possible interactions with mechanisms of action of the novel treatment for severe asthma. In an era of biological therapies for severe asthma, little data is available on the potential effects of what could be a new therapy: monoclonal antibody targeting of regulatory T cell numbers and functions.