Bronchoalveolar lavage fluid and blood natural killer and natural killer T-like cells in cryptogenic organizing pneumonia

Natural Killer T-like Cells: Immunobiology and Role in Disease

CD56+ T cells are generally recognized as a distinct population of T cells and are categorized as NKT-like cells. Although our understanding of NKT-like cells is far from satisfactory, it has been shown that aging and a number of disease situations have impacted these cells. To construct an overview of what is currently known, we reviewed the literature on human NKT-like cells. NKT-like cells are highly differentiated T cells with "CD1d-independent" antigen recognition and MHC-unrestricted cell killing. The genesis of NKT-like cells is unclear; however, it is proposed that the acquisition of innate characteristics by T cells could represent a remodeling process leading to successful aging. Additionally, it has been shown that NKT-like cells may play a significant role in several pathological conditions, making it necessary to comprehend whether these cells might function as prognostic markers. The quantification and characterization of these cells might serve as a cutting-edge indicator of individual immune health. Additionally, exploring the mechanisms that can control their killing activity in different contexts may therefore result in innovative therapeutic alternatives in a wide range of disease settings.

Diagnosing lung involvement in inflammatory rheumatic diseases-Where do we currently stand?

Lung involvement is the most common and serious organ manifestation in patients with inflammatory rheumatic disease (IRD). The type of pulmonary involvement can differ, but the most frequent is interstitial lung disease (ILD). The clinical manifestations of IRD-ILD and severity can vary from subclinical abnormality to dyspnea, respiratory failure, and death. Consequently, early detection is of significant importance. Pulmonary function test (PFT) including diffusing capacity of the lungs for carbon monoxide (DLCO), and forced vital capacity (FVC) as well as high-resolution computed tomography (HRCT) are the standard tools for screening and monitoring of ILD in IRD-patients. Especially, the diagnostic accuracy of HRCT is considered to be high. Magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) allow both morphological and functional assessment of the lungs. In addition, biomarkers (e.g., KL-6, CCL2, or MUC5B) are being currently evaluated for the detection and prognostic assessment of ILD. Despite the accuracy of HRCT, invasive diagnostic methods such as bronchoalveolar lavage (BAL) and lung biopsy are still important in clinical practice. However, their therapeutic and prognostic relevance remains unclear. The aim of this review is to give an overview of the individual methods and to present their respective advantages and disadvantages in detecting and monitoring ILD in IRD-patients in the clinical routine.

Diagnostic Value of Natural Killer Cells, CD56+ CD16+ Natural Killer Cells, NLRP3, and Lactate Dehydrogenase in Severe/Critical COVID-19: A Prospective Longitudinal Study According to the Severe/Critical COVID-19 Definitions

Innate immunity, as the first line of defense of our immune system, plays a crucial role in defending against SARS-CoV-2 infection and also its immunopathogenesis. We aim to investigate the immune status of natural killer (NK) cells, natural killer T (NKT) cells, and NLRP3 gene expression in COVID-19 patient blood samples. The immunophenotype of NK cell subsets and NKT cells was detected by flow cytometry and the expression of NLRP3 gene assessed by reverse transcriptase real-time polymerase chain reaction in 44 COVID-19 patients and 20 healthy individuals. The percentage of most of NK cell subpopulation and NKT cells was significantly decreased in COVID-19 patients. The percentage of CD56dim CD16- NK cell subsets, and NLRP3 gene expression increased. The percentage of total NK cells, CD56+ CD16+ NK cells, and NLRP3 gene expression had acceptable sensitivity and specificity for assisting diagnosis of severe/critical COVID-19. O₂ saturation% and lactate dehydrogenase levels showed valuable diagnostic value to identify critical cases. The declined NK and NKT cells in COVID-19 patients and enhanced NLRP3 gene expression were associated with disease severity. Total NK cells, CD56+ CD16+ NK cells, and NLRP3 gene expression might be used as meaningful indicators for assisting diagnosis of severe/critical COVID-19.

Phenotypic characterization of NKT-like cells and evaluation of specifically related cytokines for the prediction of unexplained recurrent miscarriage

Problem

Immune system dysregulation is a major cause of unexplained recurrent miscarriage (URM). Women with URM need screening for their pregnancy microenvironment and immune regulators, to prevent spontaneous abortion.

Method of study

In this study we evaluated NKT-like cell subsets in peripheral venous blood of women with URM using flow cytometry. The expression levels of specifically related Th1 cytokines (IFN-γ and IL-2), Th2 cytokine (IL-4), and Th17 cytokines (IL-17), were measured using enzyme-linked immunosorbent assay.

Results

The percentage of CD16+CD56+NKT-like (Double Positive NKT-like; DPNKT-like) cell subset, and the levels of IL-2 and IFN-γ were significantly elevated in blood of non-pregnant and pregnant patients with URM compared with the healthy control groups, and these parameters were significantly increased after pregnancy in the same patients with URM. Based on the prevalence of the candidate immunological factors in patients with URM, the prognostic significance of the NKT-like cell subsets, IFN-γ and IL-2 profiles were evaluated as potential predictors of URM. A cut-off point of 2.55% for DPNKT-like cell subset in the blood and cut-off values of 39.5 and 20.5 pg/ml for the levels of IFN-γ and IL-2, respectively could be used for the prediction of the risk of spontaneous abortion. To the best of our knowledge, this is the first study that described the prognostic significance of the aforementioned immunological parameters before and after pregnancy, and highlighted the correlation of NKT-like cells and the candidate Th1 cytokines with pregnancy loss in women with URM.

Conclusions

DPNKT-like cells, IFN-γ and IL-2 patient profiles could be used as markers to predict the risk of miscarriage in patients with URM.

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Disturbance in the immune system's regulators is an essential factor for recurrent miscarriage.

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There is an urgent need for women who have suffered pregnancy loss to identify specific immune regulators that underline recurrent miscarriage, to prevent and control miscarriage.

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CD16+CD56+NKT-like cells, Interferon-γ and Interleukin-2 patient profile could be utilized as biomarkers to predict risk of miscarriage in women who have suffered spontaneous miscarriage.

Prognostic role of NK cell percentages in bronchoalveolar lavage from patients with different fibrotic interstitial lung diseases

BAL cellularity and lymphocyte immunophenotyping offer insights into lung inflammatory status. Natural killer (NK) cells are efficient effector cells, producing pro-inflammatory cytokines. A better understanding of the biology of NK cells in BAL in the lungs is necessary to improve the pathogenesis of fibrotic ILD and develop prospective targeted treatments. Our aim was to analyse NK and NKT-like cell percentages in BAL from 159 patients with different ILD: f-HP, f-NSIP, IPF and CTD-ILD, to evaluate their potential diagnostic/prognostic role. BAL NK cell percentages showed significantly higher values in IPF than in f-HP and f-NSIP, while BAL NKT-like cells showed significantly lower values in the f-NSIP than the f-HP and IPF. A cut-off of 4%NK cells in BAL of IPF showed a significant difference in survival rate. It suggests a possible new marker of survival and raises the possibility of new targeted approach in treatment and management of IPF.

Bronchoalveolar Lavage Lymphocytes in the Diagnosis of Hypersensitivity Pneumonitis among Patients with Interstitial Lung Disease

Rationale: Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) characterized by inflammation and/or fibrosis in response to an inhalational exposure.Objectives: To determine the value of bronchoalveolar lavage (BAL) fluid lymphocyte cellular analysis in the detection of HP among patients with newly detected ILD.Methods: This systematic review was undertaken in the context of development of an American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax clinical practice guideline. The clinical question was, "should patients with newly detected ILD undergo BAL fluid lymphocyte analysis to diagnose HP?" MEDLINE, EMBASE, and the gray literature were searched through October 2019. Studies that reported the percentage of BAL fluid lymphocytes for various ILDs were selected for inclusion. Meta-analyses compared the mean percentage of BAL fluid lymphocytes among patients with HP with that among patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis. The sensitivity and specificity by which various percentages of BAL fluid lymphocytes distinguish HP from IPF and sarcoidosis were also evaluated.Results: Eighty-four articles were selected. No randomized trials or observational studies were identified that compared BAL fluid lymphocyte analysis with no BAL fluid lymphocyte analysis in patients with ILD. Included studies were case series describing BAL fluid cell differentials in patients with various ILDs. The percentage of BAL fluid lymphocytes was significantly higher in both fibrotic and nonfibrotic HP compared with IPF. Similarly, the percentage of BAL fluid lymphocytes was significantly higher in both fibrotic and nonfibrotic HP compared with sarcoidosis. A threshold of 20% BAL fluid lymphocytes distinguished fibrotic HP from IPF with a sensitivity and specificity of 69% and 61%, respectively, and nonfibrotic HP from IPF with a sensitivity and specificity of 95% and 61%, respectively. It distinguished fibrotic HP from sarcoidosis with a sensitivity and specificity of 69% and 26%, respectively, and nonfibrotic HP from sarcoidosis with a sensitivity and specificity of 95% and 26%, respectively.Conclusions: The percentage of BAL fluid lymphocytes is higher in HP than IPF or sarcoidosis. However, a threshold that distinguishes HP from IPF or sarcoidosis with both high sensitivity and high specificity was not identified.

Prognostic value of lymphocyte counts in bronchoalveolar lavage fluid in patients with acute respiratory failure: a retrospective cohort study

Background

Cellular patterns in bronchoalveolar lavage fluid (BALF) are used to distinguish or rule out particular diseases in patients with acute respiratory failure (ARF). However, whether BALF cellular patterns can predict mortality or not is unknown. We test the hypothesis that BALF cellular patterns have predictive value for mortality in patients with ARF.

Methods

This was a retrospective single-center observational study conducted in a Japanese University Hospital. Consecutive patients (n = 78) with both pulmonary infiltrates and ARF who were examined by bronchoalveolar lavage (BAL) between April 2015 and May 2018 with at least 1 year of follow-up were analyzed. Primary analysis was receiver operating characteristic curve—area under the curve (ROC-AUC) analysis for 1-year mortality.

Results

Among the final sample size of 78 patients, survivors (n = 56) had significantly increased lymphocyte and eosinophil counts and decreased neutrophil counts in BALF compared with non-survivors (n = 22). Among the fractions, lymphocyte count was the most significantly different (30 [12-50] vs. 7.0 [2.9-13]%, P <0.0001). In the ROC curve analysis of the association of BALF lymphocytes with 1-year mortality, the AUC was 0.787 (P <0.0001, cut-off value [Youden index] 19.0%). Furthermore, ≥20% BALF lymphocytes were significantly associated with increased survival with adjustment for baseline imbalances (1-year adjusted hazard ratio, 0.0929; 95% confidence interval, 0.0147–0.323, P <0.0001; 90-day P =0.0012). Increased survival was significantly associated with ≥20% BALF lymphocytes in both interstitial lung disease (ILD) and non-ILD subgroups (P =0.0052 and P =0.0033, respectively). In secondary outcome analysis, patients with ≥20% BALF lymphocytes had significantly increased ventilator-free days, which represents less respiratory dysfunction than those with <20% BALF lymphocytes.

Conclusions

In the patients with ARF, ≥20% lymphocytes in BALF was associated with significantly less ventilatory support, lower mortality at both 90-day and 1-year follow-ups.

Baseline effector cells predict response and NKT cells predict pulmonary toxicity in advanced breast cancer patients treated with everolimus and exemestane

BACKGROUND

The mTOR inhibitor everolimus used in cancer has immune-modulating effects, potentially contributing to an antitumor response but also leading to pulmonary toxicity. We studied the association of immunological cell subsets with antitumor response and pulmonary toxicity in breast cancer patients treated with everolimus plus exemestane.

METHODS

In this exploratory analysis, peripheral blood mononuclear cells (PBMCs) were collected at baseline and 14, 35, 60, and 90 days after start of treatment, and at the moment of pulmonary toxicity. The percentage and absolute number of T-cells, B-cells, NK-cells, monocytes and numerous subtypes were measured in peripheral blood using flow cytometric analysis and were compared using a (paired) t-test.

RESULTS

From 20 patients, a total of 89 samples were collected. At baseline, responders versus non-responders had 0.86% versus 0.32% CD4+ effector cells (CD45RA+CD27-) (p = 0.1266) and non-response could be predicted with 0.71 sensitivity and 0.82 specificity. Patients who developed pulmonary toxicity compared to patients without pulmonary toxicity had relatively more NKT-cells at baseline (6.0% versus 1.3%, p = 0.0068, 59 k versus 12 k * 10⁹/l, p = 0.0081) and at the moment of toxicity (5.2% versus 1.2%, p = 0.0106 and 47 k versus 16 k * 10⁹/l, p = 0.0466). Baseline percentage NKT cells predicted pulmonary toxicity with 0.78 sensitivity and 1.0 specificity.

CONCLUSIONS

Our results suggest that baseline CD4+ effector cells may be predictive of antitumor responses and baseline NKT cells may be predictive of pulmonary toxicity. These results warrant further validation.

Major reduction of NKT cells in patients with severe COVID-19 pneumonia

Background

NK cells seem to be mainly involved in COVID-19 pneumonia. Little is known about NKT cells which represent a bridge between innate and adaptive immunity.

Methods

We characterized peripheral blood T, NK and NKT cells in 45 patients with COVID-19 pneumonia (COVID-19 subjects) and 19 healthy donors (HDs). According to the severity of the disease, we stratified COVID-19 subjects into severe and non-severe groups.

Results

Compared to HDs, COVID-19 subjects showed higher percentages of NK CD57+ and CD56dim NK cells and lower percentages of NKT and CD56bright cells. In the severe group we found a significantly lower percentage of NKT cells. In a multiple logistic regression analysis, NKT cell was independently associated with the severity of the disease.

Conclusions

The low percentage of NKT cells in peripheral blood of COVID-19 subjects and the independent association with the severity of the disease suggests a potential role of this subset.

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High percentages of NK CD57+ cells and CD56dimNK cells in COVID-19 subjects

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Low percentages of CD56bright and NKT cells in COVID-19 subjects

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Severe COVID-19 pneumonia and NKT cell reduction were independently associated

Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline

Background: This guideline addresses the diagnosis of hypersensitivity pneumonitis (HP). It represents a collaborative effort among the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax.Methods: Systematic reviews were performed for six questions. The evidence was discussed, and then recommendations were formulated by a multidisciplinary committee of experts in the field of interstitial lung disease and HP using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.Results: The guideline committee defined HP, and clinical, radiographic, and pathological features were described. HP was classified into nonfibrotic and fibrotic phenotypes. There was limited evidence that was directly applicable to all questions. The need for a thorough history and a validated questionnaire to identify potential exposures was agreed on. Serum IgG testing against potential antigens associated with HP was suggested to identify potential exposures. For patients with nonfibrotic HP, a recommendation was made in favor of obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis, and suggestions for transbronchial lung biopsy and surgical lung biopsy were also made. For patients with fibrotic HP, suggestions were made in favor of obtaining BAL for lymphocyte cellular analysis, transbronchial lung cryobiopsy, and surgical lung biopsy. Diagnostic criteria were established, and a diagnostic algorithm was created by expert consensus. Knowledge gaps were identified as future research directions.Conclusions: The guideline committee developed a systematic approach to the diagnosis of HP. The approach should be reevaluated as new evidence accumulates.

NK and NKT cells in the diagnosis of diffuse lung diseases presenting with a lymphocytic alveolitis

Background

Diffuse lung diseases (DLD) are characterized by different immunophenotypes in the bronchoalveolar lavage fluid (BALF). We aimed to evaluate the diagnostic value of BALF NK and NKT cell counts of patients with DLD and lymphocytic alveolitis.

Methods

We assessed 202 patients with DLD, who underwent BALF immunophenotyping. Samples were routinely processed by flow cytometry and lymphocyte subsets were compared between patients with sarcoidosis (n = 106), hypersensitivity pneumonitis (HP; n = 53), and other DLDs (n = 43). We compared absolute counts and percentages of NK and NKT cells between patients with HP versus the remaining DLD patients. To assess the accuracy of BALF lymphocyte subsets in the diagnosis of HP, we calculated the respective areas under the receiver operating characteristic curves (AUC-ROC).

Results

Patients with HP had significantly higher numbers of BALF NK cells, and its percentage was significantly associated with a higher odds of HP, even after adjustment for the NKT and CD8⁺ cells. For the absolute number of BALF NK cells, we found an AUC-ROC of 0.76 (95%CI = 0.68–0.84) when comparing patients with HP versus the remaining DLD. The cut-offs of 2000 NK cells/mL and of 2.4% NK cells in the BALF had a specificity and a negative predictive value over 80% for the diagnosis of HP. BALF NK cells absolute counts were significantly higher in HP patients with a restrictive pattern. No such differences were observed for NKT cells.

Conclusions

BALF NK immunophenotyping may be a helpful adjunct to the diagnostic work-up of DLD, particularly in the differential diagnosis of HP.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0802-1) contains supplementary material, which is available to authorized users.

Human NK cells adapt their immune response towards increasing multiplicities of infection of Aspergillus fumigatus

BACKGROUND

The saprophytic fungus Aspergillus fumigatus reproduces by generation of conidia, which are spread by airflow throughout nature. Since humans are inhaling certain amounts of spores every day, the (innate) immune system is constantly challenged. Even though macrophages and neutrophils carry the main burden, also NK cells are regarded to contribute to the antifungal immune response. While NK cells reveal a low frequency, expression and release of immunomodulatory molecules seem to be a natural way of their involvement.

RESULTS

In this study we show, that NK cells secrete chemokines such as CCL3/MIP-1α, CCL4/MIP-1β and CCL5/RANTES early on after stimulation with Aspergillus fumigatus and, in addition, adjust the concentration of chemokines released to the multiplicity of infection of Aspergillus fumigatus.

CONCLUSIONS

These results further corroborate the relevance of NK cells within the antifungal immune response, which is regarded to be more and more important in the development and outcome of invasive aspergillosis in immunocompromised patients after hematopoietic stem cell transplantation. Additionally, the correlation between the multiplicity of infection and the expression and release of chemokines shown here may be useful in further studies for the quantification and/or surveillance of the NK cell involvement in antifungal immune responses.

A 12-week combination of clarithromycin and prednisone compared to a 24-week prednisone alone treatment in cryptogenic and radiation-induced organizing pneumonia

Background: Some data suggest that anti-inflammatory macrolides may be effective to treat organizing pneumonia (OP) and prevent relapses, but no formal comparison with prednisone alone is available. To explore this issue, we retrospectively compared the efficacy of a 12-week combined regimen of clarithromycin and prednisone with a 24-week prednisone alone regimen in OP. Methods: A standard 12-week regimen of combined clarithromycin and prednisone was designed for the treatment of cryptogenic or radiation-induced OP, aiming at reducing the cumulated prednisone dose and the relapse rate. Its use was left to the discretion of the treating physicians, members of the Groupe d'Etudes et de Recherche sur les Maladies Orphelines Pulmonaires. Data were compared to a historical control group treated with a standard 24-week prednisone alone regimen. Results: 16 patients were treated with combined therapy and 21 with prednisone alone. Complete radiological remission was achieved in 63% of the combined therapy group and 81% of the prednisone alone group (p=0.38). Symptomatic relapses occurred in 81% of the combined therapy group, and 52% of the prednisone alone group (p=0.14). No side effect of clarithromycin was reported. Conclusions: In patients with cryptogenic or radiation-induced OP, a 12-week regimen of clarithromycin and prednisone showed no benefit on remission rate and relapse rate as compared to a 24-week prednisone only regimen. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 230-238).

[Cryptogenic organizing pneumonia]

INTRODUCTION

Organizing pneumonia is a particular type of inflammatory reaction of the lung which gives rise to a clinico-pathological syndrome. It is called "secondary" when a cause such as an infection, a drug toxicity, or a connective tissue disease can be identified, or "cryptogenic" when no cause is identified. The clinical picture is usually characterized by the subacute onset of fever, fatigue, cough and dyspnea, with multiple subpleural areas of consolidation on thoracic imaging.

STATE OF THE ART

Organizing pneumonia is characterised by the presence of buds of endoalveolar connective tissue. These result from an injury to the alveolar epithelium, followed by the deposition of fibrin in the alveolar spaces, and the migration of fibroblasts which produce a myxoid endoalveolar matrix. A remarkable feature of organizing pneumonia is the complete disappearance of these endoalveolar buds with corticosteroid treatment, in sharp contrast with what is seen in pulmonary fibrosis. The clinical response to corticosteroids is usually prompt and excellent. Relapses are frequent but usually benign.

PERSPECTIVES AND CONCLUSION

As the clinical, imaging and pathological characteristics of organizing pneumonia are now well established, many questions remain unanswered, such as the mechanisms involved in the complete reversibility of the pulmonary lesions, and the role of steroid-sparing treatments such as immunomodulatory macrolides.