Impaired heart rate variability one and six months post acute COVID-19

Background

Long COVID-19 syndrome is an increasingly recognized problem. Post-infectious cardiac autonomic dysfunction is commonly reported. This study aims to evaluate autonomic dysfunction by means of Heart rate variability (HRV) on post-COVID-19 patients.

Methods

Hospitalized patients for COVID-19 (either at the medical ward or Intensive Care Unit (ICU)) were followed up at 1 and 6 months after hospital discharge. Medical history and clinical information were collected. HRV was assessed by 24-hour ambulatory electrocardiography Holter, with the measure of the standard deviation of normal RR intervals in 24 h, ms (SDNN). The comparison was conducted with age and sex-matched non-COVID-19 controls.

Results

Thirty-four patients hospitalized with COVID-19 (20.6% admitted in ICU) were examined 1-month and 6-months post-hospital discharge. SDNN was significantly (p<0.001) reduced in the COVID-19 group (111±23 ms) compared to the control subjects (152±24 ms) 1-month after discharge. Subgroup analysis between COVID-19 group revealed that ICU subjects presented significantly (p<0.001) reduced SDNN compared to the medical ward, respectively (83±20 ms vs. 118±17 ms). At 6-months, an improvement was noted at SDNN 24h (6-month: 133±24 vs. control: 151±24 ms, p=0.004; 1-month: 111±23 ms vs. 6-month: 133±24 ms, p<0.001). Also at 6-months, ICU subjects noted significantly (p=0.003) reduced SDNN 24h compared to medical ward subjects (107±17 ms vs. 140±20 ms). On the 6-months follow-up, 32% of the subjects had “long-COVID-19” symptoms. Subjects with long COVID-19 symptoms had low SDNN values (“long-COVID-19”: 112±17 ms vs. non-“long-COVID-19”: 142±20 ms, p=0.001)

Conclusion

Patients hospitalized for COVID-19 have reduced SDNN, at one month post-hospital discharge which is improved at the six months follow-up. These findings emphasize the increased sympathetic drive activity in the post-acute COVID-19 phase and imply a link between autonomic dysfunction and long COVID-19.

Funding Acknowledgement

Type of funding sources: None.

The role of cardiometabolic risk factors and endothelial dysfunction in serum albumin levels and capillary leak syndrome of patients with COVID-19

Background

Growing evidence focuses on the role of hypoalbuminemia in the COVID-19 course and the role of vascular inflammation in the progression to Capillary Leak Syndrome (CLS). CLS may be mediated by a derangement of endothelial barrier following vascular endothelial dysfunction. We investigated the role of cardiometabolic risk factors in the association of hypoalbuminemia with endothelial dysfunction of hospitalized COVID-19 patients.

Methods

In this cross-sectional study, patients hospitalized for COVID-19 at the medical ward or Intensive Care Unit (ICU) were enrolled. Medical history and laboratory examinations were collected while the endothelial function was assessed by brachial artery flow-mediated dilation (FMD) between the first 24–72 hours of their admission to the hospital. According to the body mass index, history of hypertension, dyslipidemia, and diabetes mellitus, COVID-19 patients were categorized in those with Cardiometabolic Risk Factors (CRFact) or without CRFact (no-CRFact). From the study population, we excluded subjects with established cardiovascular disease.

Results

Sixty-six patients with COVID-19 (37% admitted in ICU) were recruited. From the study population, 41 were in the group of CRFact and 25 in the no-CRFact. Patients with CFRact were older (65±9 years vs. 53±14 years, p<0.001), had more impaired FMD (1.16±2.13% vs. 2.60±2.44%, p=0.01), and lower serum albumin levels (3.10±0.68 g/dL vs. 3.52±0.26 g/dL, p=0.006) compared to the no-CRFact group. Between CRFact and no-CRFact, there was no difference in CRP and IL-6 levels. Interestingly, serum albumin in patients with CRFact was significantly lower than the lower reference limit (LRL) (=3.5 g/dl) of albumin (p=0.001), while no such finding was noted in subjects with no CRFact (p=0.64). Furthermore, regression analysis revealed that, even after adjustment for age, the presence of CRFact was associated with decreased serum albumin levels by 0.31mg/dl (95% CI 0.08 to 0.63, p=0.04). In the CRFact population, there was a correlation of albumin with FMD (R=0.29, p=0.05) and an inverse correlation with CRP (rho=−0.48, p=0.02) and IL-6 (rho=−0.66, p<0.001), while in the no-CRFact group no such correlation were observed (p=NS for all).

Conclusion

COVID-19 patients with cardiometabolic risk factors present with low serum albumin levels early at the course of the disease, which may be driven by endothelial dysfunction and vascular inflammation. This data gives insights into the potential association of a dysfunctional endothelial layer and the progression to capillary leak syndrome.

Funding Acknowledgement

Type of funding sources: None.

Inside the “brain” of an artificial neural network: an interpretable deep learning approach to paroxysmal atrial fibrillation diagnosis from electrocardiogram signals during sinus rhythm

Background

With the ongoing, rapid advances in Deep Learning (DL), such solutions can now detect medical conditions even invisible to the human eye. In this direction, efforts have been made to develop DL algorithms that diagnose paroxysmal atrial fibrillation (PAF) from electrocardiogram (ECG) signals in sinus rhythm (SR). However, many of the available approaches function as “black boxes”, with physicians unable to understand and trust their predictions.

Purpose

To train a DL model to detect PAF patients while in SR and apply an algorithm that interprets and visualises its decisions.

Methods

We obtained ECG samples from PAF and non-PAF patients during SR, from the PAF Prediction Challenge Database. After discarding unannotated samples and augmenting the sample size (by dividing each signal into 30-second segments), we split the whole dataset into a train (68%), a validation (16%) and a test (16%) set. No pair of samples belonging to different sets originated from the same patient. We trained the InceptionTime neural network on the train/validation sets and tested on the “unseen” test set after “hiding” the correct answers. Its performance was evaluated with the following metrics: Accuracy, f1-score, precision and recall (sensitivity). After repeating this process 20 times, we obtained a distribution for each score. Finally, we adjusted the Grad-CAM interpretation algorithm to our data and used it to visualise the areas perceived as important by the model.

Results

After pre-processing, 4,080, 30-second, two-lead ECG signals were allocated to the train set, 960 to the validation and 960 to the test set. Each subset contained an equal number of PAF and non-PAF samples. After repeated training and testing, we obtained a median accuracy of 0.84 (interquartile range, IQR: 0.66–0.88), an f1-score of 0.82 (IQR: 0.68–0.88) and a median precision and recall equal to 0.93 (IQR: 0.67–0.99) and 0.77 (IQR: 0.68–0.93), respectively. The Grad-CAM technique highlighted the ECG areas of interest that led to each decision. We selected and present both PAF-positive and -negative samples, perceived either correctly or falsely. Interestingly, correct model decisions tend to focus on the P-wave, while false ones fixate on other regions.

Conclusions

Although a pilot study with considerable limitations (small sample size, disregard of possible confounding due to comorbidities or other factors), this work shows how DL can be employed to distinguish between PAF and non-PAF patients from SR ECG samples, and confirms the potential of DL-enabled approaches to offer novel diagnostic capabilities. Most importantly, our effort provides a comprehensible, visual interpretation of the model's decisions. Demystifying DL behaviour can, not only improve such efforts by explaining false decisions, but also cultivate trust among clinicians and, possibly, point out directions for future research, since we can now see through the magnifying lens of a neural network.

Funding Acknowledgement

Type of funding sources: None.

Optimising and validating deep learning approaches for diagnosing atrial fibrillation from few-lead ambulatory electrocardiogram signals

Funding Acknowledgements

Type of funding sources: None.

Background

Deep learning (DL) has received much attention as a solution for automatically diagnosing atrial fibrillation (AF) from raw ECG signals. However, few studies exist to investigate how DL approaches can be optimally configured and whether their diagnostic performance is externally validated.

Purpose

To explore how signal-related parameter tuning affects the ability of DL approaches to diagnose AF and validate the optimal approach internally and externally.

Methods

We applied two dedicated DL models (InceptionTime and MINIROCKET) on a set of 7,966 AF and non-AF (normal or with other abnormalities) ambulatory ECG samples, originating from the MIT-BIH AF, MIT-BIH Normal Sinus Rhythm and Long Term AF databases. We tested the effect of different sample lengths (30sec (s), 10s, 30/10s -30s with a "sliding window" of 10s-), sampling frequencies (200, 100, 50 Hz) and lead numbers (two-, single-), and the role of denoising (Discrete Wavelet Transformation, no denoising) on the ability to diagnose AF, by measuring ROC AUC and sensitivity (SEN) after repeated model training and testing. Under the optimal configuration, we trained 10 replicas of both models on 90% of the data and tested their performance on the remaining 10% (internal validation). Finally, we applied both pre-trained models on a separate dataset (MIT-BIH Arrhythmia) to determine their external validity.

Results

Although the diagnostic performance did not differ between 30s and 10s signals, the 30/10s setting displayed significantly higher median AUC (0.98) and sensitivity (97.3%, p&lt;0.05 for all comparisons). Signals sampled at 50Hz performed poorer (AUC=0.88, SEN=79.9%) than those at 100Hz (AUC=0.92, SEN=88.7%) and 200Hz (AUC=0.93, SEN=89.2%), although this difference slightly failed to reach statistical significance. Despite denoised signals showing a higher median AUC (0.95 vs. 0.92) and sensitivity (92.8% vs. 88.7%), the difference was not found significant. Similarly, two-lead signals performed better than single-lead ones (AUC=0.92 vs. 0.9 and SEN=88.7% vs. 84.1%, respectively), but without crossing the significance threshold. The internal validation with denoised, 30/10s, two-lead signals, at 100Hz, yielded similarly high performance metrics for both InceptionTime and MINIROCKET (AUC=0.98, SEN=96.9% and AUC=0.98, SEN=97.4%, respectively). In contrast, the performance on the external set dropped significantly (AUC=0.79, SEN=81.4% and AUC=0.72, SEN=83.7%, respectively, p&lt;0.001 for all comparisons).

Conclusions

Both DL approaches can effectively detect AF in ambulatory ECG signals, with only 3 out of 100 cases missed, designating their promising utility as screening tools for automated AF detection. While optimising tunable parameters can enhance the internal performance of such efforts, their external validation is necessary to establish their robustness "in the wild", since their performance on "unseen" data can be, similarly to our case, notably lower.

Association between excessive supraventricular ectopic activity and future diagnosis of atrial fibrillation in patients with cryptogenic stroke

Funding Acknowledgements

Type of funding sources: None.

Background

The relationship between the excessive supraventricular ectopic activity (ESVEA) and the subclinical atrial fibrillation (AF) in patients with cryptogenic stroke is yet not fully understood.

Purpose

The aim of this study is to examine the prognostic significance of ESVEA for the development of AF in those patients.

Methods

The study retrospectively included 124patients, hospitalized for a cryptogenic stroke between 2014 and 2015. Twenty-four hour inpatient Holter monitoring, was used to define ESVEA as the presence of ≥20 premature atrial complexes per hour (PACs/h), along with a duration of the longest run of supraventricular tachycardia (LSVR) ≥5 seconds. After approximately 5 years of follow-up, the patients were examined for AF.

Results

The remaining 111 patients(12 died and 1 was lost during follow-up) had a median age of 56 and 13 (11.71%) of them were diagnosed with AF (AF patients). The median value of CHA2DS2-VASc score was 3 and was similar for the two groups (p=0.252). Patients with AF had a significantly higher number of PACs/h and a longer duration of LSVR compared to nonAF patients (16.67 vs. 0.21, p&lt;0.001 and 3 vs. 0 seconds, p&lt;0.001, respectively). The existence of ESVEA was also significantly more prevalent among the AF patients (46.15%, 95% CI: 17.78% - 74.22%) compared to non-AF ones (6.1%, 95% CI: 1.3% - 10.7%, p&lt;0.001). ROC analysis revealed the high diagnostic test accuracy of both PACs/h and LSVR for AF. The area under the curve was 97.2% (p&lt;0.001) for PACs/h and 81.1% (p&lt;0.001) for LSVR.

Conclusions

Excessive atrial ectopy, detected with 24h inpatient Holter monitoring, is a significant indicator of future development of AF, in patients presenting originally with a cryptogenic stroke.

Tissue microRNA expression in aortic aneurysm dissection

Background

Dissection and other complications of ascending aortic aneurysms are potentially life-threatening. Several factors may be implicated in aneurysm progression and dissection. The role of tissue microRNAs may be of interest.

Purpose

To examine how serum biomarkers and tissue expression of microRNAs are associated with thoracic aortic aneurysms and dissection.

Methods

We compared three groups of patients; 21 patients with aneurysm of the aortic root, ascending aorta or aortic arch undergoing scheduled repair, 11 patients with acute Stanford type A aortic dissection who underwent emergency surgery and 18 patients with normal aortic diameter undergoing other cardiac surgery (control group). Prior to surgery, peripheral blood samples were obtained from patients, to assess osteoprotegerin and adiponectin levels with the ELISA method. Tissue samples from ascending aortic wall were obtained from patients during surgery. Following appropriate storage and homogenization, tissue Matrix Metalloproteinases (MMPs) 2 and 9 were measured with the ELISA method, while tissue microRNAs 29 and 195 were measured using qrtPCR, after RNA extraction.

Results

There was no significant difference among control, aneurysm and dissection groups in terms of age (62±10 years vs 66±12 years vs 59±12 years, p=0.052), gender distribution (77.8% male vs 81% male vs 90% male, p=0.28) or BMI (28.51±2.92 kg/m2 vs 25.72±3.09 kg/m2 vs 27.02±3.2 kg/m2, p=0.76). There was also no difference among control, aneurysm and dissection groups regarding hypertension (72% vs 62% vs 73%, p=0.73), diabetes mellitus (22% vs 19% vs 36%, p=0.54), smoking (44% vs 29% vs 46%, p=0.09) or dyslipidemia (78% vs 43% vs 55%, p=0.08). The groups of control subjects, aneurysms and dissections did not differ in osteoprotegerin [44 (28, 52) pmol/l vs 31 (28, 37) pmol/l vs 45 (24, 71) pmol/l, p=0.17], adiponectin [6,65 (2,39, 9,79) μg/ml vs 5,28 (2,34, 6,98) μg/ml vs 4,13 (2,49, 7,52) μg/ml, p=0.43], tissue MMP2 [0.97 (0.42, 27.66) ng/ml vs 9.12 (1.72, 61.49) ng/ml vs 2.51 (0.22, 235.72) ng/ml, p=0.34] and tissue MMP9 levels [0.96 (0.29, 8.56) ng/ml vs 10.31 (1.18, 25.58) ng/ml vs 2.76 (0.63, 54.83) ng/ml, p=0.09] (Figure 1). Importantly, tissue expression of mir29 was 2.11-fold higher in the dissection group (p=0.001) and 2.99-fold higher in the aneurysm group (p&lt;0.001) compared to the control group. Tissue expression of mir195 was 2.72-fold higher in the dissection group (p&lt;0.001) and 2.00-fold lower in the aneurysm group (p=0.08) compared to the control group (Figure 2).

Conclusions

These findings highlight the role of epigenetic modifications through altered microRNA tissue expression in aortic wall synthesis, extracellular matrix degradation and progress of aneurysm formation and dissection. The exact role of microRNA expression in aortic dilatation and dissection, as well as their role as potential biomarkers, merit further validation.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Multiplex immune serum biomarker profiling in sarcoidosis and systemic sclerosis

Multiplex protein technology has the potential to identify biomarkers for the differentiation, classification and improved understanding of the pathogenesis of interstitial lung disease. The aim of this study was to determine whether a 30-inflammatory biomarker panel could discriminate between healthy controls, sarcoidosis and systemic sclerosis (SSc) patients independently of other clinical indicators. We also evaluated whether a panel of biomarkers could differentiate between the presence or absence of lung fibrosis in SSc patients. We measured 30 circulating biomarkers in 20 SSc patients, 21 sarcoidosis patients and 20 healthy controls using Luminex bead technology and used Fisher's discriminant function analysis to establish the groups of classification mediators. There were significant differences in median concentration measurements between study groups for 20 of the mediators but with considerable range overlap between the groups, limiting group differentiation by single analyte measurements. However, a 17-analyte biomarker model correctly classified 90% of study individuals to their respective group and another 14-biomarker panel correctly identified the presence of lung fibrosis in SSc patients. These findings, if they are corroborated by independent studies in other centres, have potential for clinical application and may generate novel insights into the modulation of immune profiles during disease evolution.

Disseminated gonococcal infection in a homosexual man diagnosed by nucleic acid amplification testing from a skin lesion swab

Disseminated gonococcal infection (DGI) often presents a diagnostic challenge. Through the novel application of molecular technology, a case is presented that suggests how the diagnostic sensitivity for this systemic complication of gonococcal infection can be improved. In a typical case of DGI seen in a homosexual man in whom all mucosal and blood specimens were culture negative, nucleic acid amplification testing (NAAT) helped to confirm the diagnosis. Both throat and skin lesion specimens tested positive for gonococcal DNA and this was confirmed with a supplementary porA pseudogene NAAT. The use of adjuvant NAAT assessment is recommended as part of the diagnostic work-up for suspected DGI cases.

Intracellular cytokine profiles and T cell activation in pulmonary sarcoidosis

In granulomatous inflammatory lung diseases such as sarcoidosis, the balance of cytokine production by activated T cells in the lungs may influence clinical disease outcome. To investigate the potential of T lymphocytes to produce cytokines and contribute to this process, T cells from bronchoalveolar lavage (BAL) and PB from 19 patients with active lung disease were stimulated, stained, and analysed by flow cytometry for intracellular production of cytokines and expression of the activation marker CD69. Higher proportions of BAL cells expressed CD69 compared with PB, in the absence of in vitro stimulation. The expression of IFN-gamma was similar in unstimulated BAL and PB T cells, and there was no association between the expression of CD69 and IFN-gamma. Following stimulation, there were increased numbers of IFN-gamma(+) T cells. A similar trend was found with IL-2(+) T cells, but there were lower levels of IL-4(+) T cells in BAL compared with PB, and similar levels of IL-10(+) T cells. The presence of activated T lymphocytes in BAL samples from patients with sarcoidosis, with the potential to produce Th1 type 1 cytokines may contribute to the inflammatory processes in this granulomatous lung disease. The use of intracellular flow cytometry to investigate cytokine production by BAL T cells could help to indicate potential targets for future therapy.

Single-nucleotide polymorphisms in the SPARC gene are not associated with susceptibility to scleroderma

OBJECTIVE

SPARC (secreted protein, acidic and rich in cysteine) is a matricellular protein that modulates cell-cell and cell-extracellular matrix interactions. SPARC expression is restricted mainly to sites of tissue remodelling and wound repair, and is prominent in fibrotic disorders. Single-nucleotide polymorphisms (SNPs) in the SPARC gene are reportedly linked to scleroderma in four ethnic groups: Choctaw Indians, Caucasians, African Americans and Mexican Americans. We set out to reproduce and to positionally clone these disease associations in a set of UK Caucasian scleroderma patients and ethnically matched controls.

METHODS

One hundred and twenty-one scleroderma subjects and 200 controls were genotyped by polymerase chain reaction with sequence-specific primers differing only in the 3' nucleotide corresponding to each allele of the biallelic SNPs. Scleroderma patients were analysed against controls and on the basis of their fibrosing alveolitis status as judged by high-resolution computed tomography evaluation and the extent of cutaneous involvement.

RESULTS

Eight biallelic SNPs were genotyped: three from the last untranslated exon, which had been described previously, and an additional five novel SNPs: two in the promoter region, one in exon three and two in the 3' untranslated region. Six major haplotypes were constructed across all eight SNP positions. No significant differences in genotype, allele or haplotype frequency were observed between scleroderma and controls or within scleroderma subgroups.

CONCLUSIONS

SNPs in the SPARC gene are not associated with susceptibility to scleroderma. This research adds to the genetic knowledge of the SPARC gene by identifying five novel SNPs spanning the whole gene and inserting these within the context of clearly defined haplotypes.

BAL findings in idiopathic nonspecific interstitial pneumonia and usual interstitial pneumonia

Idiopathic pulmonary fibrosis (IPF), which has the histological pattern of usual interstitial pneumonia (UIP), is a progressive interstitial lung disease with a poor prognosis. Idiopathic interstitial pneumonias with a histological pattern of nonspecific interstitial pneumonia (NSIP) have a better prognosis than UIP, and may present with a clinical picture identical to IPF. The authors hypothesised that bronchoalveolar lavage (BAL) findings may distinguish between UIP and NSIP, and have prognostic value within disease subgroups. BAL findings were studied retrospectively in 54 patients with histologically proven (surgical biopsy) idiopathic UIP (n=35) or fibrotic NSIP (n=19), all presenting clinically as IPF. These findings were also compared with the BAL profile of patients with other categories of idiopathic interstitial pneumonias. BAL total and differential cell counts did not differ between the two groups. Survival was better in NSIP. In neither group were BAL findings predictive of survival or changes in lung function at 1 yr, even after adjustment for disease severity, smoking and treatment. BAL differential counts in fibrotic NSIP differed from respiratory bronchiolitis-associated interstitial lung disease, but not from desquamative interstitial pneumonia or cellular NSIP. The authors conclude that bronchoalveolar lavage findings do not discriminate between usual interstitial pneumonia and nonspecific interstitial pneumonia in patients presenting with clinical features of idiopathic pulmonary fibrosis, and have no prognostic value, once the distinction between the two has been made histologically.

A single round PCR method for genotyping human surfactant protein (SP)-A1, SP-A2 and SP-D gene alleles

The genes coding for the human surfactant proteins (SP)-A and SP-D are located on chromosome 10q22-q23.1. SP-D is the product of a single gene whereas SP-A is the product of two highly homologous genes SP-A1 and SP-A2. Several single nucleotide polymorphisms (SNP) are present in the SP-A1, SP-A2 and SP-D genes. Because of this high degree of sequence homology between the SP-A1 and SP-A2 genes, current genetic analysis studies employ a nested PCR/radioactive hybridization or restriction fragment length polymorphism approach to initially isolate the genes and subsequently to detect the SNP in these isolates. In this manuscript, we report the primers and conditions of a sequence specific primer-PCR methodology that enables the identification of SP-A1, SP-A2 and SP-D gene allelic variants directly on genomic DNA material.

Increased vitronectin and endothelin-1 in the breath condensate of patients with fibrosing lung disease

BACKGROUND

Non-specific interstitial pneumonia (NSIP) and fibrosing alveolitis associated with systemic sclerosis (FASSc) are diseases of unknown aetiology that are characterised by the accumulation of mononuclear cells, followed by the progressive deposition of collagen within the interstitium and subsequent destruction of lung airspace. Better understanding of mediators involved in fibrosis may be useful for early diagnosis and in clinical monitoring of disease progression.

OBJECTIVE

The aim of this study was to investigate the presence of two profibrotic markers, the vitronectin and the endothelin-1 (ET-1) in the airways of NSIP and FASSc patients.

METHODS

Ten NSIP (6 males, age 57 +/- 2 years) and 15 FASSc (8 males, age 55 +/- 4 years) patients were recruited along with 10 normal subjects (4 male, age 52 +/- 2 years). Vitronectin and ET-1 concentrations were measured in their breath condensate, using a specific enzyme immunoassay.

RESULTS

Higher levels of vitronectin and ET-1 were observed in NSIP and FASSc patients [median 92.8 (91.7-93.9) microg/ml; median 8.3 (7.9-9.3) pg/ml] than in control subjects [median 80.3 (89.3-91.4) microg/ml; p < 0.01; median 5.3 (4.9-5.9) pg/ml, p < 0.0001]. We also found increased concentrations of vitronectin in patients with clinical deterioration compared to those remaining stable and in ex-smokers compared to non-smokers and, increased vitronectin and ET-1 in patients treated with steroids compared to untreated patients.

CONCLUSION

These findings justify further studies of vitronectin and ET-1 levels in exhaled breath condensate, as a means of monitoring activity and predicting progression of pulmonary fibrosis.

Single-cell analysis: a novel approach to tumour necrosis factor-alpha synthesis and secretion in sarcoidosis

Tumour necrosis factor (TNF)-alpha is thought to be a key early cytokine in the pathogenesis of sarcoidosis, despite conflicting data. Largely the product of mononuclear phagocyte activation, it is unclear whether TNF-alpha production at disease sites is a feature of all mononuclear phagocytes that accumulate there or whether it is secreted by a subset of these cells. Using the reverse haemolytic plaque assay, the aims of this study were to determine if the upregulation of TNF-alpha could be confirmed and to investigate whether this was monocyte or macrophage specific. The reverse haemolytic plaque assay allows the measurement of cytokine production at a single cell level. A greater number of alveolar macrophages produced TNF-alpha compared to autologous monocytes in sarcoidosis but not in controls and, based on cell size, it was confirmed that this was the product of more mature macrophages and that the secretion of TNF-alpha by monocytes and macrophages was heterogeneous: not all monocytes and macrophages secrete TNF-alpha. No differences in the average levels of TNF-alpha secretion by peripheral blood monocytes or alveolar macrophages were observed. This study has demonstrated that a subset of mononuclear phagocytes, mature macrophages, are responsible for tumour necrosis factor secretion and this could have implications for targeted management in sarcoidosis in the future.

Extended genetic alterations in a patient with pulmonary sarcoidosis, a benign disease

BACKGROUND

Genetic alterations at the microsatellite level have been detected in various human malignant tissues, but have also been found in chronically inflamed tissues. Sarcoidosis is a benign disease of unknown etiology characterized by chronic inflammation, which may be associated with an increased incidence of developing malignancy.

METHODS

We examined the microsatellite alterations in a sputum cytological specimen of a patient with sarcoidosis. The DNA electrophoretic pattern of sputum was compared with that of the peripheral blood. Thirty-two microsatellite markers located at chromosomes 2p, 3p, 8p, 9p, 9q, 17p, 17q were used to reveal genetic alterations.

RESULTS

Loss of heterozygosity (LOH) was detected in eleven markers in loci 2p, 9p, 9q and 17q. LOH was observed in all four markers spanning the chromosomal arm 17q11.2-q21, suggesting a potential chromosomal deletion.

CONCLUSION

The observation of LOH in all four markers spanning the chromosomal arm 17q11.2-q21 may suggest a potential for malignancy development in this patient, or may be linked to the aetiopathogenesis of sarcoidosis. Further microsatellite fine mapping and clinical follow up of this patient are needed to clarify this.

Human leukocyte antigen-DRB1 position 11 residues are a common protective marker for sarcoidosis

Genetic factors, in particular human leukocyte antigens (HLAs) are important determinants of susceptibility to sarcoidosis, a chronic granulomatous disease of undetermined etiology. To clarify the role of HLA in sarcoidosis we determined HLA-DR and -DQ alleles in case-control samples from three European populations (United Kingdom, Czech, and Polish) and compared these results with those published for three additional populations (Italian, Japanese, and Scandinavian) to determine whether the HLA-DR and/or -DQ alleles act as ethnic-dependent, or ethnic-independent modifiers of disease risk. Although variations were apparent in the alleles associated with susceptibility, reductions in the frequency of alleles associated with protection were remarkably consistent in the six populations. Previously detected associations between single-nucleotide polymorphisms at the TAP2 locus and sarcoidosis were shown to be due to linkage disequilibrium with the HLA-DR locus. The protective HLA-DR alleles, which encode the DR1 and DR4 antigens, were found to share characteristic small hydrophobic residues at position 11, which were replaced by small hydrophilic residues in the remaining, nonprotective, HLA-DR alleles. This residue position is within a pocket of the HLA-DR complex antigen binding groove (designated P6), where it is the only variable amino acid and therefore determines the peptide binding preferences of this pocket. A highly significant reduction in the frequency of individuals carrying HLA-DR alleles with a hydrophobic residue at position 11 was observed in the sarcoidosis cases in the three populations we examined. This suggests this HLA-DR residue is an important protective marker in sarcoidosis.

Alveolar macrophages and T cells from sarcoid, but not normal lung, are permissive to adenovirus infection and allow analysis of NF-kappa b-dependent signaling pathways

Adenovirus (Adv)-mediated gene transfer requires efficient infection of target cells. The objective of this study was to establish whether alveolar macrophages (AM) and T cells (AT) from sarcoid patients were permissive to infection with Adv vectors and if this property could be used to investigate cytokine gene regulation. Sarcoid and normal bronchoalveolar lavage (BAL) specimens infected with Adv vectors expressing either beta-galactosidase or a green fluorescent protein were analyzed for transgene expression by fluorescence-activated cell sorter (FACS) and direct immunofluorescence, respectively. Expression of surface antigens previously associated with Adv infection, the coxsackie/adenovirus receptor (CAR), alpha v beta 3, and alpha v beta 5 integrins, was also assessed using FACS analysis. Sarcoid AM and AT were found to efficiently express Adv transgenes, unlike AM from normal volunteers, peripheral blood monocytes, and peripheral blood T cells. Cells permissive to Adv infection expressed the CAR and alpha v beta 5 integrin (also alpha v beta 3 integrin for AM). The data indicate that the upregulation of Adv receptors and the ability to infect sarcoid AM and AT are related to the inflammatory environment within the lung. Having demonstrated efficient Adv-mediated transgene delivery to sarcoid AM and AT, a construct encoding porcine I kappa B alpha was then used to investigate the requirement for nuclear factor (NF)-kappa B in the regulation of cytokine gene expression in pulmonary sarcoidosis. Overexpression of I kappa B alpha in sarcoid BAL specimens indicated that tumor necrosis factor-alpha and interleukin (IL)-6 production by AM and interferon (IFN)-gamma production by AT is NF-kappa B dependent, whereas IL-4 production by AT is NF-kappa B independent. This is the first occasion that the requirement for NF-kappa B in IFN-gamma gene expression within primary human T cells has been demonstrated. The results of this study have implications for the future investigation of molecular pathways in inflammatory lung disease.

Ace gene I/D polymorphism and sarcoidosis pulmonary disease severity

Previous studies of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene in sarcoidosis have revealed both ethnic heterogeneity of I/D frequencies and controversy surrounding the association between the polymorphism and severity of disease. The objective of this study was, therefore, to clarify the role of the ACE I/D polymorphism in (1) disease susceptibility, (2) pulmonary disease severity (with particular reference to pulmonary fibrosis), and (3) pulmonary disease progression, in two distinct European sarcoidosis populations. Standard chest radiographic staging was performed on 118 UK and 56 Czech white patients with sarcoidosis at 2 yr from presentation. Pulmonary function data were analyzed, and patients were then categorized according to disease severity. A PCR-SSP assay was used to determine the ACE I/D genotype of each patient studied. The I/D allele frequencies from these patients were compared with frequencies from ethnically matched UK (n = 386) and Czech (n = 179) control subjects using a chi-square contingency table. No significant differences were seen in the distribution of the ACE I/D genotypes, allele frequencies or phenotype frequencies. Furthermore, no association was found between the ACE I/D polymorphism and pulmonary disease severity, fibrosis, and progression. We conclude that the ACE I/D polymorphism has no role in sarcoidosis susceptibility in European whites and that it is not a regulatory variant in this disease.

Analysis of tumor necrosis factor-alpha, lymphotoxin-alpha, tumor necrosis factor receptor II, and interleukin-6 polymorphisms in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterized by chronic inflammation that is associated with structural damage of the lung and fibrosis. Although the etiology of IPF is unknown, it is likely to involve an interaction between environmental and multiple genetic components. Animal models of pulmonary fibrosis have shown that proinflammatory mediators are critical at both the inflammatory and fibrotic stages of the disease. Genetic variants exist in genes encoding proinflammatory mediators, as well as in genes encoding their receptors, which makes these genes candidates for the pathogenesis of IPF. In the present study, we examined 12 biallelic polymorphisms in the genes for tumor necrosis factor (TNF)-alpha (+488[G/A], -238[G/A], -308[G/A]), lymphotoxin (LT)-alpha (+720[C/A], +365[C/G], and +249[A/G], determining haplotypes LT-alpha1 to LT-alpha4), tumor necrosis factor-receptor 2 (TNF-RII) (gb:M32315: 676[T/G], 1663[A/G], 1668[T/G], 1690[C/T]), and interleukin- (IL)-6 (promoter -174[G/C], intron 4[A/G]). We also examined the haplotypes determined by the three biallelic polymorphisms in each of the TNF-alpha and LT-alpha genes. As compared with a normal control population, the IPF group showed no significant deviations in genotype, allele, or haplotype frequencies. Surprisingly, in the IPF population, but not in the control population, an increased frequency of cocarriage of the IL-6 intron 4G and the TNF-RII 1690C alleles was observed, despite the location of the two genes on different chromosomes. Moreover, using impairment of carbon monoxide transfer (DL(CO)) adjusted for duration of dyspnea as a marker of rapidity of disease progression, we found that the IL-6 intron 4GG genotype was the only genotype independently associated with lower DL(CO) levels. These findings, if independently confirmed, will be the first to suggest that disease progression in IPF may be linked to a particular genetic marker or to functional polymorphisms in other genes near that marker.

Distribution of novel polymorphisms of the interleukin-8 and CXC receptor 1 and 2 genes in systemic sclerosis and cryptogenic fibrosing alveolitis

OBJECTIVE

To search for single-nucleotide polymorphisms in the interleukin-8 (IL-8) and IL-8 receptor CXCR-1 and CXCR-2 genes, and to compare their distribution among patients with systemic sclerosis (SSc) with fibrosing alveolitis (FASSc) or without fibrosing alveolitis (NFASSc), or patients with cryptogenic fibrosing alveolitis (CFA), and normal healthy subjects.

METHODS

Fifty control subjects were screened for potential polymorphisms by using polymerase chain reaction in association with sequence-specific primers incorporating mismatches at the 3' end. The novel polymorphisms were subsequently examined in British Caucasian subjects, including 194 healthy controls, 71 patients with CFA, and 128 patients with SSc who were further subdivided into 78 FASSc patients and 50 NFASSc patients.

RESULTS

Three novel biallelic polymorphisms were identified in the IL-8 gene (all in noncoding areas of the gene), 1 was found in the CXCR-1 gene (resulting in a conservative amino acid change), and 3 were observed in the CXCR-2 gene, of which the first resulted in a silent codon change and the others were in the 3' untranslated area of exon 3. Compared with controls, a significant increase in the frequency of the CXCR-2 +785 CC homozygote and of the CXCR-2 +1208 TT homozygote was found in the SSc patients (37% versus 22% [P = 0.01] and 33% versus 17% [P = 0.003], respectively). A subgroup analysis revealed this association to be significant both in the FASSc patients and in the NFASSc patients.

CONCLUSION

This report describes an association between SSc and 2 polymorphisms occurring close to each other in the CXCR-2 gene. This finding and its functional significance need to be confirmed and analyzed in future studies.

Distribution of novel polymorphisms of the interleukin-8 and CXC receptor 1 and 2 genes in systemic sclerosis and cryptogenic fibrosing alveolitis

OBJECTIVE

To search for single-nucleotide polymorphisms in the interleukin-8 (IL-8) and IL-8 receptor CXCR-1 and CXCR-2 genes, and to compare their distribution among patients with systemic sclerosis (SSc) with fibrosing alveolitis (FASSc) or without fibrosing alveolitis (NFASSc), or patients with cryptogenic fibrosing alveolitis (CFA), and normal healthy subjects.

METHODS

Fifty control subjects were screened for potential polymorphisms by using polymerase chain reaction in association with sequence-specific primers incorporating mismatches at the 3' end. The novel polymorphisms were subsequently examined in British Caucasian subjects, including 194 healthy controls, 71 patients with CFA, and 128 patients with SSc who were further subdivided into 78 FASSc patients and 50 NFASSc patients.

RESULTS

Three novel biallelic polymorphisms were identified in the IL-8 gene (all in noncoding areas of the gene), 1 was found in the CXCR-1 gene (resulting in a conservative amino acid change), and 3 were observed in the CXCR-2 gene, of which the first resulted in a silent codon change and the others were in the 3' untranslated area of exon 3. Compared with controls, a significant increase in the frequency of the CXCR-2 +785 CC homozygote and of the CXCR-2 +1208 TT homozygote was found in the SSc patients (37% versus 22% [P = 0.01] and 33% versus 17% [P = 0.003], respectively). A subgroup analysis revealed this association to be significant both in the FASSc patients and in the NFASSc patients.

CONCLUSION

This report describes an association between SSc and 2 polymorphisms occurring close to each other in the CXCR-2 gene. This finding and its functional significance need to be confirmed and analyzed in future studies.

The effect of lung biopsy on lung function in diffuse lung disease

The aim of this study was to investigate the effect on lung function of lung biopsy used in the diagnosis of diffuse lung disease carried out by an open procedure or by video-assisted thoracoscopy. One hundred and sixteen patients with diffuse lung disease who attended the Royal Brompton Hospital were studied retrospectively. Thirty five patients underwent open lung biopsy, and 33 video-assisted thoracoscopic biopsy and 48 had their diagnosis made without biopsy. All patients underwent lung function tests before and after surgery, or at an interval of 3-6 months in those who did not undergo biopsy. No significant differences were found in changes in lung function between those who had and had not undergone biopsy, and the proportions of patients whose lung function improved or deteriorated were similar. Lung biopsy by an open procedure or by video-assisted thoracoscopy did not differ in its effects on lung function. The results for older patients, those with severe disease and those with fibrosing alveolitis were the same as for the whole group. Open lung biopsy for the diagnosis of diffuse lung disease does not deleteriously affect lung function whether carried out by an open or a minimally invasive procedure.

Identification of four novel interleukin-13 gene polymorphisms

The development of allergic asthma is thought to involve environmental and inherited genetic components and has pathophysiological features reflecting in part the activity of T cell cytokines. Interleukin-13, a product primarily of activated lymphocytes, is considered to be a critical effector molecule in allergic airway response and has been found to be overexpressed in the airways of patients with asthma. The IL-13 gene is located on chromosome 5q31, one of the major loci to be linked to asthma susceptibility, and amongst a cluster of genes which dominate the immunopathology of allergic disease. Recently, an IL-13 promoter polymorphism was found to be associated with allergic asthma. In the present study we report the identification of four novel biallelic polymorphisms in the IL-13 gene, two intronic and two exonic, one of which results in a basic to hydrophilic amino acid change. We characterised the frequencies of these four biallelic polymorphisms and the frequencies of the haplotypes, resulting from the combination of these four biallelic polymorphisms, in a population of 196 UK Caucasoid healthy individuals.

Mannose-binding lectin promoter and structural gene variants in sarcoidosis

BACKGROUND

Sarcoidosis is a chronic granulomatous disease of unknown aetiology. Studies have suggested that the causative agent may be an infectious micro-organism. The mannose binding lectin (MBL) is involved in innate immunity to a wide range of micro-organisms. Mutations in the promoter region and exon 1 of the MBL gene occur with high frequency and are associated with reduced serum levels of MBL and increased susceptibility to microbial diseases. This study investigated whether MBL variants predispose to sarcoidosis by increasing their susceptibility to micro-organisms.

METHODS

MBL gene promoter and exon 1 variants were detected by sequence specific primer polymerase chain reaction (SSP-PCR) in 167 UK Caucasian sarcoidosis patients and 164 control subjects. Severity of pulmonary disease outcome among patients was assessed by radiography after a minimum of 4 years from disease onset and classified as mild, moderate, and severe disease categories, accordingly.

RESULTS

MBL variant frequencies were similar in patients and controls studied. Among sarcoidosis patients, the frequencies of variants were similar regardless of severity of disease outcome. The average patient ages at time of diagnosis were similar for all MBL genotypes.

CONCLUSIONS

MBL gene variants do not appear to influence susceptibility to sarcoidosis, age of disease onset, or severity of disease.

Polymorphic analysis of the high-affinity tumor necrosis factor receptor 2

The tumor necrosis factor receptor 2 (TNF-RII, CD120b, TNF-R p75/80) gene has recently been characterised. It is located on chromosome 1p362 and consists of 10 exons and 9 introns A number of biallelic polymorphisms have been found in exons 4, 6, 9 and 10 based on differences between published sequences. In this study we have used polymerase chain reaction methodology in association with sequence-specific primers (PCR-SSP) incorporating mismatches at the 3' end to identify these polymorphisms. We were able to confirm the presence of a single biallelic polymorphism in exon 6 corresponding to a (T/G) at nucleotide 676 of TNF-RII mRNA (gb:M32315) which results in an amino acid change and three biallelic polymorphisms in exon 10 (in the3'UTR) corresponding to (A/G) at nucleotide 1663, (T/G) at nucleotide 1668 and a (C/T) at nucleotide 1690 of gb:M32315, whereas no polymorphisms were observed in exons 4 and 9. Here we report that in 192 unrelated UK Caucasian individuals the allele frequencies determined by direct counting were: 676-T (0.77), 1663-G (0.51), 1668-T (0.95), and 1690-T (0.64) and the calculated gene frequencies were; 676-T (0.52), 676-G (0.12); 1663-G (0.30), 1663-A (0.28); 1668-T (0.77), 1668-G (0.025); and 1690-T (0.40), 1690-C (0.20). Furthermore, the presence of an A allele at nucleotide position 1663 was found to be strongly associated with the presence of a C allele at nucleotide position 1690 and a G allele at nucleotide position 1668 whereas the presence of a G allele at position 1663 was associated with the absence of a C allele at nucleotide position 1690.

Different cytokine profiles in cryptogenic fibrosing alveolitis and fibrosing alveolitis associated with systemic sclerosis: a quantitative study of open lung biopsies

Differences in the inflammatory response and prognosis of cryptogenic fibrosing alveolitis (CFA) and that associated with systemic sclerosis (FASSc) are beginning to emerge. It is hypothesized that these differences may be reflected in a distinct pattern of T-helper (Th)-1 and Th-2-type cytokines. Open lung biopsies were obtained from clinically well-documented cases of CFA and FASSc and, as a control, compared with grossly and histologically normal parenchyma obtained from smokers whose lungs were resected for cancer (n=5 in each group). In situ hybridization (ISH) was applied to the samples using anti-sense and sense 35S-labelled riboprobes to detect messenger ribonucleic acid (mRNA) for interleukins (IL)-2, IL-4, IL-5 and interferon (IFN)-gamma. Between 52-91% of cells expressing the cytokines studied were present in the alveolar interstitium rather than in lumenal cells or the alveolar epithelial lining. The highest values for all four cytokines were present in the patients with FASSc, i.e., 22-39 ISH positive cells x mm(-2) alveolar tissue compared with 1-19 cells x mm(-2) and 4-5 cell x mm(-2) in CFA and control subjects, respectively. Whereas the proportions of the four cytokines in FASSc were similar to the control subjects, IL-4 and IL-5 predominated significantly in CFA (p<0.001). For example, the ratio of IL-5 to IFN-gamma was 22:1 in CFA, significantly higher than in the cases with FASSc (2:1) or the control subjects (4:1) (p<0.05). In conclusion, cryptogenic fibrosing alveolitis is an inflammatory condition which is characterized, like asthma, by a predominance of gene expression for T-helper-2-type regulatory cytokines, whereas cryptogenic fibrosing alveolitis associated with systemic sclerosis appears to have a distinct mixed T-helper-1/T-helper-2 functional phenotype and a greater number of cells expressing each of these pro-inflammatory cytokines.

Exhaled nitric oxide is increased in active fibrosing alveolitis

STUDY OBJECTIVES

Interstitial inflammation is a major aggravating factor in fibrosing lung disease associated with scleroderma (FASSc) and cryptogenic fibrosing alveolitis (CFA). Exhaled nitric oxide (NO) production is increased in asthma and bronchiectasis and reflects the degree of inflammation. We investigated whether measuring levels of exhaled NO is valuable in assessing disease activity in patients with CFA and patients with FASSc.

MEASUREMENTS AND RESULTS

NO levels were measured in 11 patients with CFA (mean age +/- SEM, 58 +/- 12 years old; 5 were male) and 17 patients with FASSc (mean age, 48 +/- 9 years old; 5 were male), and they were compared to BAL cell counts and lung function. Patients with CFA and FASSe had elevated NO levels (11.2 +/-1.0 parts per billion [ppb] and 9.8 +/- 1.0 ppb, respectively; p > 0.05), whereas in a group of 13 nonsmoking normal subjects, the NO levels were not elevated (6.9 +/- 0.5 ppb; p < 0.05). Patients with FASSc (n = 8) who had active BAL (defined as either lymphocytes > 14%, neutrophils > 4%, or eosinophils > 3%) had significantly higher NO levels (13.2 +/- 1.8 ppb), and neutrophil (16.5 +/- 4.0%) and lymphocyte (26.8 +/- 3.4%) BAL cell counts than did patients with FASSc who had inactive BAL (6.7 +/- 1.2 ppb; 1.3 +/- 1.0% and 7.5 +/- 1.3%, respectively; p < 0.05). There was a significant correlation between exhaled NO and lymphocyte cell count in patients with FASSc (r = 0.58; p < 0.05). All patients with CFA had active BAL; however, those treated with corticosteroids (12.9 +/- 1.0% ppb, p < 0.05) had lower NO levels (9.0 +/- 1 ppb) and higher BAL lymphocyte cell couits (16.6 +/- 2.0%) than did those not treated with corticosteroids (7.2 +/- 1.7%; p < 0.05).

CONCLUSIONS

We conclude that exhaled NO may be a useful addition to BAL cell counts in disease monitoring.

Detection of human retrovirus 5 in patients with arthritis and systemic lupus erythematosus

OBJECTIVE

To examine whether human retrovirus 5 (HRV-5) infection is associated with autoimmune rheumatic disease.

METHODS

DNA from patients with various disorders including inflammatory diseases and from normal subjects was tested by nested polymerase chain reaction (PCR) for HRV-5 proviral DNA. Positive results were confirmed by DNA sequencing.

RESULTS

HRV-5 proviral DNA was detected in 53% of synovial samples from arthritic joints, in 12% of blood samples from patients with rheumatoid arthritis (RA), and in 16% of blood samples from patients with systemic lupus erythematosus. In contrast, it was not detectable by PCR of affected tissues from patients with several other autoimmune diseases and was found in only 1 of >200 tissue specimens obtained at autopsy from non-RA patients. Sequence analysis of the amplified viral segment showed genetic variation between samples with maintenance of the open reading frame, typical of a replicating infectious retrovirus.

CONCLUSION

This is the first report of the frequent detection of HRV-5 in any disease. We propose that the possible involvement of HRV-5 in autoimmune and rheumatic disease should be investigated further.

Fibronectin gene polymorphisms associated with fibrosing alveolitis in systemic sclerosis

Systemic sclerosis (SSc), a multisystem immunologic disease of unknown etiology, is commonly manifested in the lung as fibrosing alveolitis (FASSc). There is evidence to support the role of genetic factors in the predisposition to pulmonary fibrosis in SSc (HLA DR3/DR52a). This association is not complete and other candidate genes are likely involved. Of these, fibronectin is a growth factor known to play a crucial role in lung fibrosis. Our study investigated whether polymorphisms of the fibronectin gene are associated with lung fibrosis in SSc. Using the polymerase chain reaction and the restriction enzymes HaeIII, MspI, HindIII, and TaqI, we assessed the restriction fragment length polymorphisms (RFLPs) in 161 patients with SSc and 253 healthy control subjects from the United Kingdom. For each restriction enzyme, three genotypes were possible corresponding to the presence of the cutting site on neither, one, or both chromosomes (HaeIII AA, AB, BB; MspI CC, CD, DD; HindIII EE, EF, FF; TaqI GG, GH, HH). There was a significant decrease of genotype BB (FASSc: 17%, control: 34%; Pcorr = 0.006) with a reciprocal increase of genotype AB (FASSc: 62%, control: 46%; Pcorr = 0.022) in FASSc with the HaeIII RFLP. A significant decrease of genotype DD was observed in FASSc (FASSc: 28%, control: 41%; Pcorr = 0.038) with the MspI RFLP. The coassociation of genotypes AB (HaeIII RFLP) and CD (MspI RFLP) was present in 45% of the FASSc group (P = 0.0059), with an increased relative risk of developing fibrosing alveolitis of 1.988. We conclude that genotypes of the fibronectin gene are useful prognostic factors in SSc, helping to predict individuals likely to develop pulmonary fibrosis.

8-Isoprostane as a biomarker of oxidative stress in interstitial lung diseases

Oxidative stress contributes to the pathophysiology of interstitial lung diseases, such as cryptogenic fibrosing alveolitis (CFA), fibrosing alveolitis associated with systemic sclerosis (FASSc) and sarcoidosis. F2-isoprostanes are a series of prostaglandin (PG) F2-like compounds produced in vivo independent of cyclooxygenase, as products of the radical-catalyzed lipid peroxidation. Measurement of the concentrations of F2-isoprostanes has proved to be valuable in assessing oxidative stress in vivo. The aim of this study was to measure 8-epi-PGF2alpha concentrations, one of the most abundant F2-isoprostane in humans, in bronchoalveolar lavage (BAL) in normal subjects and to compare them to those observed in patients with CFA (n = 9), FASSc (n = 8) and sarcoidosis (n = 10). 8-epi-PGF2alpha was detectable in BAL fluid in normal subjects (9.6 +/- 0.8 pg/ml) and its concentrations were increased approximately 5-fold in patients with CFA (47.4 +/- 7.0, p < 0.001) and FASSc (43.2 +/- 3.3, p < 0. 001). 8-epi-PGF2alpha was also increased in patients with sarcoidosis, although to a lesser extent (12.0 +/- 0.70 pg/ml, p < 0. 01). No correlation between 8-epi-PGF2alpha and either lung function tests or BAL cell types was observed in any group of patients. Our study shows that the level of oxidative stress is enhanced in patients with interstitial lung diseases as reflected by increased concentrations of 8-epi-PGF2alpha in BAL fluid.

Sequential identification of apoptotic and necrotic cells on individual cytospin preparations

Here, we describe a simple methodology which allows the consecutive differentiation of apoptotic and necrotic cells on the same cytospin preparation of fresh and cultured cells. In this methodology, necrotic cells are initially identified on the cytospin preparations using trypan blue followed by the identification of in situ DNA fragmentation using the TUNEL assay. Identification of trypan blue and TUNEL positive cells in the same section permits the simultaneous assessment of necrotic and apoptotic cells.

The source and role of RANTES in interstitial lung disease

The chemokine "regulated on activation, normal T-cell expressed and secreted" (RANTES) is a potent eosinophil and lymphocyte attractant with particular preference for CD45RO+ T-cells and eosinophils. These cells accumulate in the lungs of patients with sarcoidosis and fibrosing alveolitis. The purpose of this study was to determine whether RANTES mediates the inflammatory cell influx in these diffuse lung diseases. Cell types and number of bronchoalveolar cells expressing RANTES protein were investigated by immunocytochemistry using lavage cells obtained from 22 patients and 11 control subjects. Subsequently, RANTES messenger ribonucleic acid (mRNA) was semiquantitated using reverse transcription polymerase chain reaction (RT-PCR) methodology in unseparated lavage cell pellets in 26 patients and 13 control subjects. Cells expressing RANTES mRNA were identified by in situ hybridization. RANTES protein expression in lower respiratory tract (LRT) cells was identified in all study groups. The percentage of RANTES+ lavage cells in sarcoidosis was higher than in controls. RANTES was localized in the cytoplasm, mainly in alveolar macrophages (CD68+ cells) in sarcoidosis, and both in alveolar macrophages and eosinophils in fibrosing alveolitis. The same cell types which expressed RANTES protein expressed RANTES mRNA, as assessed by in situ hybridization. Sarcoidosis patients had higher levels of RANTES mRNA than the other groups. RANTES protein was higher in individuals with abnormal lymphocyte numbers: RANTES protein and mRNA expression was significantly correlated with lavage CD45RO+ lymphocyte numbers. These results indicate that RANTES may mediate T-lymphocyte influx in diffuse lung disease, particularly sarcoidosis. Moreover, they suggest that the cellular source of RANTES is the alveolar macrophage in sarcoidosis, and both macrophages and eosinophils in fibrosing alveolitis.

Up-regulation of IL-8 secretion by alveolar macrophages from patients with fibrosing alveolitis: a subpopulation analysis

Neutrophil accumulation in the lower respiratory tract of patients with fibrosing alveolitis is thought to be facilitated by IL-8, a neutrophil chemoattractant primarily secreted by mononuclear phagocytes. The aims of this study were: (i) to explore IL-8 secretion by lung and blood mononuclear phagocytes in subjects with cryptogenic fibrosing alveolitis, systemic sclerosis with and without fibrosing alveolitis, sarcoidosis and normal individuals; (ii) to examine IL-8 secretory heterogeneity in alveolar macrophages and peripheral blood monocytes; and (iii) to correlate alveolar macrophage phenotypic profile to IL-8 secretion. We observed that more monocytes secreted IL-8 than autologous macrophages and that there was heterogeneity in the in vitro IL-8 secretion by alveolar macrophages and peripheral blood monocytes. IL-8 secretion by alveolar macrophages was significantly higher in subjects with fibrosing alveolitis compared with subjects without fibrosing alveolitis, due to a higher percentage of IL-8-secreting alveolar macrophages in the fibrotic group both in the absence (P < 0.002) and presence of lipopolysaccharide (LPS) (P < 0.04) and correlated with bronchoalveolar lavage neutrophil percentage. Using the MoAbs RFD1, RFD7 and RFD9, that distinguish subsets of alveolar macrophages, we have been able to identify associations between secretion of IL-8 and smaller cells and the cells identified by the MoAb RFD7. In situ hybridization of the bronchoalveolar lavage cell population revealed that alveolar macrophages are the predominant source of IL-8 in the lung. We conclude that there is an increased number of IL-8-secreting alveolar macrophages in the lungs of patients with fibrosing alveolitis, and IL-8 secretion by these cells is associated with specific phenotypic profile expression.

Diverse cellular TGF-beta 1 and TGF-beta 3 gene expression in normal human and murine lung

A role for transforming growth factor-beta 1, (TGF-beta 1) has been proposed in lung development and in the pathogenesis of pulmonary disease. However, previous studies have not delineated the cells expressing TGF-beta 1 in normal adult lung, nor compared its gene expression with that of other TGF-beta isoforms. We used digoxigenin-labelled riboprobes to localize TGF-beta 1 and TGF-beta 3 gene expression in normal adult human and mouse lung. This procedure was technically simple, providing excellent resolution. TGF-beta 1 and TGF-beta 3 messenger ribonucleic acid (mRNA) transcripts were detected in a wide variety of cells. In human lung, mRNA for both isoforms was localized to bronchiolar epithelium and alveolar macrophages. TGF-beta 1, but not TGF-beta 3 mRNA was detected in mesenchymal and endothelial cells. In murine tissue, TGF-beta 1, mRNA was localized to bronchiolar epithelium, Clara cells, mesenchymal cells, pulmonary endothelium and alveolar cells, including macrophages. TGF-beta 3 mRNA was similarly distributed but not detected in endothelium. In summary, using a nonisotopic technique in lung tissue, we have detailed the cells expressing the transforming growth factor-beta 1 and beta 3 genes in human and murine lung. There was widespread expression of these cytokines in normal lung consistent with autocrine or paracrine roles in regulating cellular turnover, immune defence and matrix protein metabolism.

Neutrophil activation in fibrosing alveolitis: a comparison of lone cryptogenic fibrosing alveolitis and systemic sclerosis

Fibrosing alveolitis complicating systemic sclerosis (FASSc) carries a better prognosis than lone cryptogenic fibrosing alveolitis (CFA). We wanted to determine whether this improved prognosis is associated with differential neutrophil migration and activation in the lower respiratory tract. We therefore compared bronchoalveolar lavage (BAL) neutrophil numbers and levels of neutrophil-derived enzymes in FASSc, CFA and normal individuals. Bronchoalveolar lavage was performed on 45 subjects (FASSc n = 20; CFA n = 15; normals n = 10); cell counts and levels of neutrophil-derived enzymes, myeloperoxidase, elastase (total elastase and elastase/alpha 1 antitrypsin complexes), collagenase and lactoferrin were measured. Lung function testing was performed in subjects with fibrosing alveolitis. Significant differences in the levels of collagenase, myeloperoxidase and elastase/ alpha 1-antitrypsin complexes were present in the BAL fluid from the three groups. Patients with CFA had significantly higher neutrophil percentages and levels of collagenase and myeloperoxidase than those with FASSc. Disease extent, as judged by lung volumes and gas transfer, was comparable in the CFA and FASSc groups. Forced vital capacity (% predicted) was significantly lower in patients with evidence of increased neutrophil enzyme release than those without. We conclude that: 1) increased neutrophil migration to the lung is accompanied by release both of primary and secondary granule enzymes in cryptogenic fibrosing alveolitis; and 2) the lower amounts of neutrophil products in fibrosing alveolitis complicating systemic sclerosis may account for the improved prognosis, even when disease is as extensive as in cryptogenic fibrosing alveolitis.

Interleukin-8. Differential expression in lone fibrosing alveolitis and systemic sclerosis

Fibrosing alveolitis may occur alone (CFA) or in association with systemic sclerosis (FASSc). FASSc was recently shown to have a prognostic advantage over CFA. Because interleukin-8 (IL-8) is likely to be a major determinant of neutrophil alveolitis, we evaluated IL-8 expression in patients with CFA and FASSc and compared it with that in normal individuals and sarcoidosis and systemic sclerosis patients without pulmonary involvement (SSc no FA). IL-8 protein in bronchoalveolar lavage fluid (BALF) was assessed by immunoassay, and IL-8 mRNA expression was assessed using Northern analysis and reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization of lung parenchyma. Compared with normal subjects, IL-8 concentration was significantly greater in both CFA (p < 0.001) and FASSc groups (p < 0.05) but no different in sarcoidosis. The IL-8 concentration in CFA was higher than in FASSc (p < 0.01) and was related to BAL % neutrophils (rs = 0.48, p < 0.01). IL-8 mRNA expression evaluated by Northern analysis was seen only in patients with CFA and FASSc and was related to BAL % neutrophils (rs = 0.63, p < 0.01). We suggest that IL-8 is a key factor in the pathogenesis of fibrosing alveolitis and that the poorer prognosis of CFA compared with FASSc is related to higher levels of IL-8 within the lower respiratory tract.

Activation of peripheral blood mononuclear cells in bronchoalveolar lavage fluid from patients with sarcoidosis: visualisation of single cell activation products

BACKGROUND

Interstitial lung diseases are characterised by the recruitment of mononuclear cells to disease sites where maturation occurs and activation products, including lysozyme (LZM), are released. Analysis of in vitro cell culture supernatants for activation products masks the functional heterogeneity of cell populations. It is therefore necessary to examine the secretion of activation products by single cells to assess whether the activation of newly recruited mononuclear phagocytes at the sites of disease in the lung is uniform and controlled by the local microenvironment.

METHODS

The reverse haemolytic plaque assay was used to evaluate, at a single cell level, the ability of bronchoalveolar lavage (BAL) fluid from seven patients with sarcoidosis to activate Ficoll-Hypaque-separated peripheral blood mononuclear cells by comparison with BAL fluid from six normal volunteers and nine patients with systemic sclerosis. Monolayers of peripheral blood mononuclear cells and sheep red blood cells were cultured either alone or in the presence of 20% (v/v) BAL fluid with a polyclonal anti-LZM antibody. LZM/anti-LZM complexes bound to red blood cells surrounding the secreting cells were disclosed following complement lysis of red blood cells and quantification of plaque dimensions using microscopy and image analysis.

RESULTS

Bronchoalveolar lavage fluid from all the patients with sarcoidosis increased LZM secretion by peripheral blood mononuclear cells compared with unstimulated mononuclear cells. By contrast, BAL fluid from the other individuals had no effect on LZM secretion.

CONCLUSIONS

Single cells activated by BAL fluid can be evaluated by the reverse haemolytic plaque assay. BAL fluid from patients with sarcoidosis, but not from patients with systemic sclerosis or normal individuals, contains components capable of activating mononuclear phagocytes to secrete lysozyme.