Chitotriosidase: a biomarker of activity and severity in patients with sarcoidosis.

BACKGROUND: Serum chitotriosidase is a promising biomarker that has shown high specificity and sensitivity in patients with sarcoidosis. The aim of this study was to investigate correlations between serum chitotriosidase, clinical phenotypes, disease localizations and different radiological lung involvement and to identify clinical features associated with over-expression of chitotriosidase in a large cohort of sarcoidosis patients. METHODS: Chitotriosidase activity was evaluated in a population of 694 consecutive patients (males 39%, age 55.8 ± 12.8 years). Clinical and respiratory functional characteristics, Clinical Outcome Scale (COS) classification, clinical phenotypes proposed by the GenPhenResA project, and radiological assessment, including CT scan, were collected. Serum sampling and clinical and functional assessments at follow-up were also included. RESULTS: Significantly higher chitotriosidase activity was observed in sarcoidosis patients than in healthy controls (p < 0.0001). Evidence of lung fibrosis with reticular abnormalities and traction bronchiectasis at High resolution CT, presence of multiple extrapulmonary sarcoid localizations and increased 24-h urinary excretion of calcium were associated with significantly higher chitotriosidase activity (p < 0.005). Patients with remitted or minimal disease had lower values of chitotriosidase than patients with persistent disease. At follow-up, patients who required an increase in steroid dose showed an increase in its activity. CONCLUSIONS: Chitotriosidase is a reliable biomarker of sarcoidosis. It is increased in patients with sarcoidosis correlating with disease activity, severity and multiorgan dissemination. Steroid therapy tended to reduce chitotriosidase expression, however it responded in cases of disease relapse.

Increased Risk of Atherosclerosis in Patients with Sarcoidosis.

Sarcoidosis is a systemic granulomatous disease of unknown etiology. Recent studies demonstrated that its pathogenesis is related with enhanced oxidative stress (protein carbonylation and lipid peroxidation) and alterations in the circulating lipid profile. Alterations of lipid metabolism (including the reduction in high-density lipoprotein cholesterol levels and apolipoprotein A1 concentrations) induce plasma membrane, bronchial and lung capillary endothelial cell damage in sarcoidosis patients. Dyslipidemia is associated with increased oxidative stress, diminished overall antioxidative protection and increased risk for atherosclerosis. Very recently increased cardiovascular biomarkers (in particular alterations of lipoprotein A and d-dimer concentrations) were observed in sarcoidosis patients, mainly in those with a high risk of atherosclerosis. Chitotriosidase, a biomarker of sarcoidosis activity and macrophage activation, is increased in serum and bronchoalveolar lavage fluid of patients with sarcoidosis as well as in patients with atherosclerosis. Lipidomics and other recent methodologies allowed the discovery of proteins involved in lipid metabolism and sarcoidosis pathogenesis, such as serum amyloid A, a biomarker of sarcoidosis activity, involved in innate immune response, inflammation and apolipoprotein metabolism. In this review lipid metabolism alteration and atherosclerosis risk in sarcoidosis patients were discussed in order to contribute to this novel and interesting research topic.

Diagnostic Utility of Angiotensin-Converting Enzyme in Sarcoidosis: A Population-Based Study.

PURPOSE: Sarcoidosis is a disease with heterogenous clinical presentations. Diagnosis of sarcoidosis is often challenging with the lack of gold standard tests. In this study, we investigated the diagnostic utility of angiotensin-converting enzyme (ACE) for diagnosis of sarcoidosis. METHODS: A cohort of Olmsted County, Minnesota residents who were diagnosed with sarcoidosis between January 1, 1984 and December 31, 2013 was identified based on individual medical record review. ACE levels recorded in the medical records of all subjects at the time of diagnosis were extracted. Comparator subjects were residents of Olmsted County, Minnesota who had ACE levels tested the same time period but did not have a diagnosis of sarcoidosis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the c-statistic of high versus low/normal ACE to diagnose sarcoidosis were calculated. RESULTS: A total of 3277 Olmsted County residents age ≥18 years had at least one ACE test in 1984-2013. The sarcoidosis incidence cohort contained 295 Olmsted County residents diagnosed with sarcoidosis in 1984-2013. Of these, ACE tests were obtained in 251. The sensitivity and specificity of high ACE for diagnosis of sarcoidosis were 41.4 % (95 % CI 35.3-47.8 %) and 89.9 % (95 % CI 88.8-91.0 %), respectively. The PPV and NPV in this population were 25.4 % (95 % CI 21.3-29.9 %) and 94.9 % (95 % CI 85.0-87.4 %). CONCLUSIONS: This study demonstrated a poor sensitivity and insufficient specificity of high ACE for diagnosis of sarcoidosis suggesting a limited role of ACE in clinical practice.

The serum angiotensin converting enzyme and lysozyme levels in patients with ocular involvement of autoimmune and infectious diseases.

BACKGROUND: Increased serum levels of angiotensin converting enzyme and lysozyme are considered as inflammatory markers for diagnosis of sarcoidosis which is an autoimmune inflammatory disease. The purpose of this study is to evaluate the significance of differences in serum angiotensin converting enzyme and lysozyme levels of patients with ocular involvement of other autoimmune inflammatory and infectious diseases. METHODS: This is a prospective study involving patients with ankylosing spondylitis, behcet's disease, presumed sarcoidosis, presumed latent tuberculosis, presumed latent syphilis, and control group. The serum levels of angiotensin converting enzyme and lysozyme were analyzed by enzyme-linked immunosorbent assay. Bonnferoni analysis was used to assess pairwise comparisons between the groups. RESULTS: There was a significant increase in serum angiotensin converting enzyme level in patients with presumed sarcoidosis compared to ankylosing spondylitis (p = 0.0001), behcet's disease (p = 0.0001), presumed latent tuberculosis (p = 0.0001), presumed latent syphilis (p = 0.0001), and control group (p = 0.0001). The increase in serum lysozyme level was significant for patients with presumed sarcoidosis with respect to ankylosing spondylitis (p = 0.0001), behcet's disease, (p = 0.0001) presumed latent tuberculosis (p = 0.001), presumed latent syphilis (p = 0.033), and control group (p = 0.0001). CONCLUSION: Elevated serum angiotensin converting enzyme levels are significant for patients with presumed sarcoidosis compared to ocular involvement of other autoimmune diseases such as behcet's disease and ankylosing spondylitis, and ocular involvement of infectious diseases such as presumed latent tuberculosis and presumed latent syphilis. However, elevated serum lysozyme level might be also detected in ocular involvement of infectious diseases such as presumed latent tuberculosis and presumed latent syphilis. TRIAL REGISTRATION NUMBER: NCT02627209. Date of registration: 12/09/2015.

Tartrate-resistant acid phosphatase 5a in sarcoidosis: further evidence for a novel macrophage biomarker in chronic inflammation.

BACKGROUND/PURPOSE: Tartrate-resistant acid phosphatase (TRACP) 5a is expressed strongly in inflammatory macrophages (MΦ). Serum TRACP5a is elevated in rheumatoid arthritis patients with extra-articular manifestations of rheumatoid nodules, in a percentage of patients with end-stage chronic kidney disease, and may be a risk marker for acute myocardial infarction. This proof-of-concept study was undertaken in patients with sarcoidosis to further substantiate our hypothesis that TRACP5a protein is a biomarker for macrophages in other chronic inflammatory diseases. METHODS: Immunohistochemical staining for TRACP5a and CD68 was performed in tissues of 19 patients with sarcoidosis. We also measured circulating TRACP5a protein and other inflammation biomarkers including interkeukin-6, angiotensin-converting enzyme, and C-reactive protein in 13 patients. Twenty healthy age-matched nonsmoking individuals were used as the reference group. RESULTS: All sarcoidosis tissues showed strong staining for TRACP5a and CD68 in the non-caseating granulomatous lesions and localized specifically to MΦ, multinucleate giant cells, and epithelioid MΦ. Serum TRACP5a protein was elevated significantly in active sarcoidosis patients compared with the control group, and levels fluctuated with disease activity in one patient studied longitudinally. CONCLUSION: TRACP5a protein is expressed abundantly in the granulomatous tissues and may be elevated in a significant proportion of sarcoidosis patients. These findings further support our hypothesis that serum TRACP5a is derived from systemic inflammatory MΦ and thereby may be a biomarker of inflammation for sarcoidosis and also reflect its disease activity.

Human chitotriosidase: a sensitive biomarker of sarcoidosis.

BACKGROUND: Sarcoidosis is a multisystem granulomatous disease of unknown etiology. No suitable biomarkers are available to evaluate the evolution of this disease, which still has an unpredictable clinical course. Some years ago our research group proposed chitotriosidase as a potential biomarker with prognostic value, that however needed to be validated. AIMS AND METHODS: The aims of this study were to evaluate the sensitivity and specificity of chitotriosidase in a population of 232 sarcoidosis patients under the observation of our Sarcoidosis Regional Referral Centre in Siena and to analyse enzyme concentrations in different disease phenotypes (as defined by the recently published COS classification) to define its prognostic value. RESULTS: Serum chitotriosidase concentrations were significantly higher in patients than in healthy controls (p<0.0001) and were directly correlated with ACE levels (r=0.25, p<0.0001). ROC curve analysis revealed 88.6 % sensitivity and 92.8 % specificity. Enzyme concentrations were significantly higher in stage 3 sarcoidosis than in stage 0 (p=0.02). The lowest concentrations of chitotriosidase were found in untreated patients in remission (COS-1), while the highest enzyme concentrations were found in symptomatic patients with persistent disease on steroids and with functional deterioration in the last year (COS-9). In COS-9 subgroup, chitotriosidase decreased significantly after the increasing of steroid dose or the introduction of a new immunosuppressant therapy (p<0.01). CONCLUSION: Chitotriosidase proved to be a biomarker with good sensitivity and specificity that is easily detected in serum. It can be proposed in clinical practice to identify progressive patients requiring close follow-up, to detect relapses and to evaluate the effects of therapy.

Expression of cathepsin K and tartrate-resistant acid phosphatase is not confined to osteoclasts but is a general feature of multinucleated giant cells: systematic analysis.

OBJECTIVE: Cathepsin K and tartrate-resistant acid phosphatase (TRAP) are two proteins expressed in osteoclastic giant cells. Recently we showed that lesional multinucleated giant cells (MNGs) in pulmonary granulomatosis with polyangiitis expressed these proteins. We aimed to clarify whether the expression of these two proteins has any specificity or is a general feature of MNGs associated with multiple types of granulomatous inflammation. METHODS: In total, 7 Crohn's disease (CD), 5 GCA, 5 giant cell myocarditis (GCM), 11 sarcoidosis and 6 tuberculosis cases were examined for expression of cathepsin K and TRAP using immunohistochemistry (IHC). Protein expression was semi-quantitatively classified as none, weak, moderate or strong. In addition, tissue TRAP activity was examined using an enzymatic reaction. RESULTS: The expression of cathepsin K was robust in >95% of MNGs of all examined disease groups, whereas TRAP expression varied; CD, GCA and tuberculosis showed strong TRAP expression. TRAP expression in sarcoidosis and GCM was weaker (CD vs GCM, P = 0.04; CD vs sarcoidosis, P = 0.06). Compared with IHC, TRAP detection using an enzymatic colour reaction had limited sensitivity. CONCLUSION: Expression of TRAP and cathepsin K is a general feature of MNGs and their expression might be related to histopathological pattern.

Angiotensin-converting enzyme inhibitors in the treatment of sarcoidosis and association with ACE gene polymorphism: case series.

Angiotensin-converting enzyme (ACE) is used as a marker for sarcoid disease activity. We present an observational study of four African-American patients all of whom demonstrated improvement in their sarcoidosis after treatment with ACE inhibitors for hypertension.

Contribution of T cell subset analysis in induced sputum in diagnosing ocular sarcoidosis.

OBJECTIVE: The aim of this study was to establish a correlation between the diagnosis of ocular sarcoidosis and the presence of an elevated CD4/CD8 ratio in the induced sputum(IS) of patients with uveitis and no other systemic symptoms. METHODS: This retrospective chart review study included all newly diagnosed uveitis patients treated between 1998-2006. IS examinations and determination of angiotensin-converting enzyme (ACE) levels were carried out. A CD4/CD8 ratio > 2.5 and an ACE level > 145 Cd/ml/min were considered abnormal. The etiology of uveitis was retrieved from the medical records. RESULTS: Twenty males and 26 females (mean age 47 +/- 16.1 years) were enrolled. The CD4/CD8 ratio was elevated in 26 (56.5%) patients, and five (10.9%) were diagnosed as having sarcoidosis by the end of follow-up. The sensitivity and specificity of the T lymphocytes CD4/CD8 ratio in diagnosing sarcoidosis were 100% and 48.8%, respectively. CD4/CD8 ratios were not significantly different between the sarcoid and non-sarcoid groups (p > 0.05), but the former tended to have higher levels (p = 0.0991). The mean ACE level of the sarcoid patients was significantly higher than that of the non-sarcoid patients (p < 0.001). CONCLUSION: CD4/CD8 lymphocytes ratios obtained by IS were sensitive in uveitis patients with concomitant sarcoidosis, suggesting that analysis of T cells subsets in IS may rule out an etiology of sarcoidosis in newly diagnosed uveitis patients.

ACE gene I/D polymorphism and risk of sarcoidosis development in Turkish patients.

INTRODUCTION: Etiology of sarcoidosis is unknown but the prevalence of disease in different ethnic groups and identical twins, family characteristics indicate that genetic predisposition is a possible factor. The angiotensin-converting enzyme (ACE) has been implicated in the pahophysiology of sarcoidosis. The aim of this study is to investigate the influence of a polymorphism in I/D (Insertion/Deletion) of the ACE gene on the susceptibility to sarcoidosis. PATIENTS AND METHODS: Our study included 70 Turkish patients who had histopathological diagnosis of sarcoidosis and 69 healthy age and sex matched control subjects. Polymerase chain reaction was used for analysing an I/D polymorphism in the gene coding for ACE. Genotyping was done according to bands that were formed on the agarose gel electrophoresis. Chi-square test was used for statistical analysis and p< 0.05 was accepted as significance. RESULTS: Although the D allele was more frequent in the sarcoidosis patients group, the frequency of the D allele was 67% and 54% respectively in the sarcoidosis and the control group. No significant difference in allele frequencies of I/I, I/D, D/D polymorphisms was observed between the sarcoidosis and control group (p> 0.05). Similarly allele frequencies of I/I, I/D, D/D polymorphisms was not different between sarcoidosis patients with extrapulmonary involvement and sarcoidosis patients without extrapulmonary involvement (p> 0.05). CONCLUSION: Our findings have showed that contribution of ACE gene polymorphisms to susceptibility of disease development in Turkish sarcoidosis patients is not different from the healthy control subjects.

Autophagy and Mitophagy-Related Pathways at the Crossroads of Genetic Pathways Involved in Familial Sarcoidosis and Host-Pathogen Interactions Induced by Coronaviruses.

Sarcoidosis is a multisystem disease characterized by the development and accumulation of granulomas, the hallmark of an inflammatory process induced by environmental and/or infectious and or genetic factors. This auto-inflammatory disease mainly affects the lungs, the gateway to environmental aggressions and viral infections. We have shown previously that genetic predisposition to sarcoidosis occurring in familial cases is related to a large spectrum of pathogenic variants with, however, a clustering around mTOR (mammalian Target Of Rapamycin)-related pathways and autophagy regulation. The context of the COVID-19 pandemic led us to evaluate whether such genetic defects may increase the risk of a severe course of SARS-CoV2 infection in patients with sarcoidosis. We extended a whole exome screening to 13 families predisposed to sarcoidosis and crossed the genes sharing mutations with the list of genes involved in the SARS-CoV2 host-pathogen protein-protein interactome. A similar analysis protocol was applied to a series of 100 healthy individuals. Using ENRICH.R, a comprehensive gene set enrichment web server, we identified the functional pathways represented in the set of genes carrying deleterious mutations and confirmed the overrepresentation of autophagy- and mitophagy-related functions in familial cases of sarcoidosis. The same protocol was applied to the set of genes common to sarcoidosis and the SARS-CoV2-host interactome and found a significant enrichment of genes related to mitochondrial factors involved in autophagy, mitophagy, and RIG-I-like (Retinoic Acid Inducible Gene 1) Receptor antiviral response signaling. From these results, we discuss the hypothesis according to which sarcoidosis is a model for studying genetic abnormalities associated with host response to viral infections as a consequence of defects in autophagy and mitophagy processes.

Conformational fingerprinting of the angiotensin I-converting enzyme (ACE). 1. Application in sarcoidosis.

Fine epitope mapping of monoclonal antibodies (mAbs) to 16 epitopes on human angiotensin I-converting enzyme (ACE) revealed that the epitopes of all mAbs contained putative glycosylation sites. ACE glycosylation is both cell- and tissue-specific and, therefore, the local conformation of ACE produced by different cells could be also unique. The pattern of ACE binding by a set of mAbs to 16 epitopes of human ACE - "conformational fingerprint of ACE" - is the most sensitive marker of ACE conformation and could be cell- and tissue-specific. The recognition of ACEs by mAbs to ACE was estimated using an immune-capture enzymatic plate precipitation assay. Precipitation patterns of soluble recombinant ACE released from Chinese hamster ovary (CHO)-ACE cells was influenced by conditions that alter ACE glycosylation. This pattern was also strongly cell type specific. Patients with sarcoidosis exhibited conformational fingerprints of tissue ACE (lungs and lymph nodes), as well as blood ACE, which were distinct from controls. Conformational fingerprinting of ACE may detect ACE originated from the cells other than endothelial cells in the blood and when combined with elevated blood ACE levels in patients with sarcoidosis may potentially reflect extrapulmonary sarcoidosis involvement (bone marrow, spleen, liver). If proven true, this would serve as a biomarker of enormous potential clinical significance.

A case of neurosarcoidosis with necrotizing granuloma expressing angiotensin-converting enzyme.

We described a case of neurosarcoidosis with necrotizing sarcoid granulomatosis in a 22-year-old man. Contrast-enhanced brain computed tomography scan and magnetic resonance imaging showed intracerebral multiple nodular lesions. Noncaseating and partial necrotizing granulomas were detected in the specimen resected by neurosurgery. In addition, immunohistochemical examination revealed the expression of angiotensin-converting enzyme in necrotizing granuloma. Thus, these findings were consistent with neurosarcoidosis. Clinical and pathological presentation, immunological features, and treatment modalities of neurosarcoidosis are discussed.

Angiotensin convertase activities in human alveolar macrophages: effects of cigarette smoking and sarcoidosis.

Angiotensin I convertase activity has been found in human alveolar macrophages from normal volunteers and patients with pulmonary sarcoidosis. This activity is higher in the alveolar macrophages from smokers than from nonsmokers, and is even more elevated in sarcoid patients. The activity can be detected with both angiotensin I and bradykinin analogs and appears to require protein synthesis, but the enzyme is not secreted by alveolar macrophages in culture.

Chitotriosidase activity in sarcoidosis and some other pulmonary diseases.

BACKGROUND: Patients with sarcoidosis have elevated levels of several markers of inflammation. Particularly high levels have been reported for chitotriosidase. In this study, we evaluate whether determining chitotriosidase in serum would be useful in the diagnosis and clinical management of patients with sarcoidosis. METHODS: Patients with newly diagnosed sarcoidosis and patients with asthma, fibrosis, asbestosis, lung cancer or chronic obstructive pulmonary disease (n=190) were recruited from an outpatient department. Individuals with no disease (n=26) served as controls. An X-ray was taken, diffusion capacity was measured and blood samples were taken for analysis of chitotriosidase, soluble receptor for interleukin-2, tumour necrosis factor alpha and angiotensin converting enzyme. In most patients with sarcoidosis, the analyses were done before and after regular treatment with corticosteroids over 6 months. RESULTS: Some patients with sarcoidosis had markedly high activities of chitotriosidase, but activities above controls were also found among patients with asbestos, fibrosis and lung cancer. There were significant relationships between chitotriosidase and interleukin-2 receptor and angiotensin-converting enzyme. After treatment, chitotriosidase activity decreased in 52 of 69 patients. CONCLUSIONS: The results confirm that chitotriosidase activity is markedly increased in some cases of sarcoidosis. As increased activities are also found in other diseases, chitotriosidase cannot be considered a specific marker of sarcoidosis. In cases of sarcoidosis where high CTO activities are found, this enzyme could serve as a useful marker supporting the diagnosis of sarcoidosis when following the effects of treatment and in surveillance for recurrence of the disease.

Association of the 3050G>C polymorphism in the cyclooxygenase 2 gene with systemic sarcoidosis.

BACKGROUND: We investigated the potential association between cyclooxygenase-2 (COX-2) gene polymorphisms and clinical manifestations of sarcoidosis. METHODS: This observational cross-sectional study involved seven hospitals in Spain. We diagnosed patients with sarcoidosis according to the International Criteria. The following variables were recorded: age, gender, initial diagnostic methods, serum angiotensin-converting enzyme (ACE) levels, pulmonary function tests, radiological stage, and clinical findings at diagnosis. Manifestations of sarcoidosis were classified as systemic vs. nonsystemic. Genotyping of four COX-2 polymorphisms (COX2.5909T>G, COX2.8473T>C, COX2.926G>C, and COX2.3050G>C) was undertaken on DNA extracted from peripheral blood lymphocytes using fluorescent hybridization probes and melting curves. RESULTS: A total of 131 sarcoid patients (63 males, mean age: 47 +/- 15 years) were studied. One hundred twenty-six of these patients had one or more positive biopsies. The results demonstrated that genotype distribution for the COX2.3050G>C polymorphism was significantly different between patients with systemic sarcoidosis and those with nonsystemic forms (p = 0.046). After adjustment for age, gender, and serum ACE levels, a significant association between the carriage of at least one C allele of the COX2.3050G>C polymorphism and systemic sarcoidosis was observed (odds ratio [OR]: 2.3; 95% confidence interval [CI]: 1.03-5.12, p = 0.031). Other polymorphisms were not associated with either clinical manifestations of the disease or serum ACE levels. CONCLUSIONS: Our results indicate for the first time that the C allele of the COX2.3050G>C polymorphism is associated with systemic sarcoidosis.

Chitotriosidase and soluble IL-2 receptor: comparison of two markers of sarcoidosis severity.

BACKGROUND: Sarcoidosis is a multisystemic granulomatous disease with an unpredictable clinical course characterized by accumulation of activated proliferating T lymphocytes and mononuclear phagocytes in affected organs. AIMS AND METHODS: The aims of this study were to describe the clinical, radiological and immunological features of a population of sarcoidosis patients followed at the Sarcoidosis Regional Centre in Siena and to analyse chitotriosidase and sIL-2R concentrations in serum of these patients in order to understand their potential as disease markers. RESULTS: Chitotriosidase and sIL-2R concentrations in serum of sarcoidosis patients were found to be significantly higher than in healthy controls (p<0.01) and a positive correlation between the two markers was documented for the first time. Moreover, chitotriosidase and sIL-2R were expressed differently in different radiographic stages of the disease. CONCLUSION: Chitotriosidase and sIL-2R are two markers of sarcoidosis of different origin, the values of which show a correlation in these patients; they are easily detectable in serum and could be useful clinical markers of progression.

Serum Angiotensin-Converting Enzyme Has a High Negative Predictive Value in the Investigation for Systemic Sarcoidosis.

PURPOSE: To examine whether measurement of serum angiotensin-converting enzyme (ACE) is useful in diagnosing sarcoidosis in undifferentiated uveitis. DESIGN: Evaluation of a diagnostic test. METHODS: Data collection was performed from 1035 consecutive subjects presenting with uveitis to Moorfields Eye Hospital undergoing measurement of serum ACE as part of baseline investigations for underlying systemic disease. The main outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of elevated serum ACE. RESULTS: Mean age of the sample was 41.7 years and 56.1% of subjects were female. Sarcoidosis was the underlying cause for the uveitis in 110 subjects (10.6%) and was more common in adults, female subjects, black subjects, and subjects with intermediate uveitis or panuveitis. ACE was elevated in 196 subjects (18.9%) and elevated levels were observed in 85 subjects eventually diagnosed with underlying sarcoidosis (true positive 77.3%) and in 111 subjects with an alternate diagnosis (false positive 12.0%). In adult subjects, sensitivity of serum ACE was 78.1%, specificity 90.0%, and PPV 43.6%, but the NPV was 97.0%. The test performed well, with area under curve (AUC) 0.897 (95% confidence interval [CI] 0.854-0.941). Serum ACE performed less well in distinguishing sarcoid uveitis in pediatric subjects, with sensitivity 60.0%, specificity 78.5%, and PPV 10.0%, but again NPV was high at 96.9% and AUC was 0.828 (95% CI 0.571-1.000). CONCLUSIONS: Serum ACE had a very high negative predictive value for sarcoid uveitis, eliminating the need for further screening tests in subjects with normal serum ACE, unless clinical suspicion was high.

Pulmonary alveolar macrophages from patients with active sarcoidosis express type IV collagenolytic proteinase. An enzymatic mechanism for influx of mononuclear phagocytes at sites of disease activity.

Alveolar macrophages (AMs) recovered from the bronchoalveolar lavage (BAL) of 44 patients with sarcoidosis were evaluated for their ability to release type IV collagenolytic metalloproteinase (IV-Case). This enzyme, which is produced by peripheral blood monocytes (PBMs) but not by tissue macrophages, degrades type IV collagen, the major structural component of vessel wall basement membranes, and helps to promote the migration of PBMs from the blood compartment to peripheral tissues. Our results demonstrated that AMs from patients with active sarcoidosis released significantly increased levels of IV-Case with respect to patients with inactive disease and control subjects. After in vitro culture, sarcoid AMs secreted IV-Case during the first 24 h of collection; after that time, AMs progressively lost their ability to release IV-Case. Exposition of both sarcoid and normal AMs to recombinant IL 2 or gamma IFN did not influence their property to release IV-Case. The immunoblot analysis of IV-Case demonstrated complete identity between IV-Case released by AMs and the degradative enzyme obtained from PBMs. The increased property to release IV-Case was significantly related to the increase of the absolute number of AMs and, in particular, of AMs bearing two determinants that are usually expressed by most PBMs (CD11b and CD14). Selective depletion of CD11b+/CD14+ AMs from the entire macrophagic population was associated with the recovery of the IV-Case activity to normal values. A positive correlation was also found between the increase in the absolute number of lung T cells and the enhanced CD4/CD8 pulmonary ratio. A 6-mo follow-up study indicated a significant association between the positivity for the 67Gallium scan and the increased property of AMs to release IV-Case. Our data are consistent with the hypothesis that a IV-Case mediated influx of peripheral monocytes takes place in the lung of sarcoid patients. Furthermore, the correlation found between the IV-Case release and disease activity suggests that this assay could represent a useful tool in sarcoidosis disease staging.