Granulomatous Lung Disorder Research Articles

Detection of autoreactive CD4+ T cells by MHC class II multimers in HLA-linked human autoimmune diseases.

Recognition of self-peptides in association with distinct HLA class II alleles by autoreactive CD4+ T cells is central for loss of immunological tolerance leading to autoimmune disease. However, identifying immunodominant self-peptides and characterizing autoreactive T cells is challenging. In this issue of the JCI, Falta et al. identify a disease-associated complementarity-determining region 3β motif specific for beryllium-modified C-C motif ligand 4 (CCL4) and CCL3 self-peptides in patients with chronic beryllium disease (CBD), a granulomatous lung disorder with a known HLA class II allelic association. Detection of these antigen-specific CD4+ T cells by beryllium-pulsed HLA-DP2 tetramers presenting CCL4/CCL3 confirms these autoantigens in humans and mice and enables monitoring in the progress of disease. Detection of autoreactive CD4+ T cells by peptide-MHC class II multimers allows for the detailed characterization of disease-promoting T cells. This knowledge has profound implications for the monitoring and development of targeted therapies in human autoimmune disorders.

Beryllium-specific CD4+ T cells induced by chemokine neoantigens perpetuate inflammation.

Discovering dominant epitopes for T cells, particularly CD4+ T cells, in human immune-mediated diseases remains a significant challenge. Here, we used bronchoalveolar lavage (BAL) cells from HLA-DP2-expressing patients with chronic beryllium disease (CBD), a debilitating granulomatous lung disorder characterized by accumulations of beryllium-specific (Be-specific) CD4+ T cells in the lung. We discovered lung-resident CD4+ T cells that expressed a disease-specific public CDR3β T cell receptor motif and were specific to Be-modified self-peptides derived from C-C motif ligand 4 (CCL4) and CCL3. HLA-DP2-CCL/Be tetramer staining confirmed that these chemokine-derived peptides represented major antigenic targets in CBD. Furthermore, Be induced CCL3 and CCL4 secretion in the lungs of mice and humans. In a murine model of CBD, the addition of LPS to Be oxide exposure enhanced CCL4 and CCL3 secretion in the lung and significantly increased the number and percentage of CD4+ T cells specific for the HLA-DP2-CCL/Be epitope. Thus, we demonstrate a direct link between Be-induced innate production of chemokines and the development of a robust adaptive immune response to those same chemokines presented as Be-modified self-peptides, creating a cycle of innate and adaptive immune activation.

A FRESH LOOK AT OLD GRANULOMAS: 16 YEARS OF HOT TUB LUNG

SESSION TITLE: Medical Student/Resident Occupational and Environmental Lung Disease SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Hot Tub Lung is a hypersensitivity pneumonitis provoked by contaminated water exposure. Here we present a case of a man with rapid resolution of 16 years of clinical symptoms and functional disability after removal of his hot tub. CASE PRESENTATION: A 56-year-old man presented for a second opinion for progressive exertional limitation and interstitial lung disease. A surgical lung biopsy performed 16 years previously showed interstitial noncaseating granulomatous inflammation with eosinophils and bronchiolitis obliterans with organizing pneumonia - interpreted as suggestive of hypersensitivity pneumonitis or sarcoidosis. He was told he likely had sarcoidosis and was intermittently treated with steroids. He initially required intermittent oxygen therapy and after 5 years progressed to continuous use at 3 liters per minute. Further history obtained when we saw him was pertinent in that he enjoyed regular use of his hot tub at home. A chest CT scan showed diffuse ground glass opacities without evidence of fibrosis. Sputum cultures were positive for Mycobacterium avium complex (MAC), Mycobacterium fortuitum, Mycobacterium mageritense and Nocardia farcinica. Pathology re-review of his lung biopsy suggested Hot Tub Lung as a potential etiology given well-formed granulomas in a peribronchiolar distribution. On subsequent evaluation 3 months after removing his hot tub, a repeat CT scan showed his bilateral ground glass changes had resolved, sputum cultures were negative and he had no need for supplemental oxygen. His FEV1 in 3 months increased from 1.32 liters (33% predicted) to 2.49 liters (60% predicted) - an 89% improvement. On further discussion 7 months after hot tub removal, our patient felt “let out of prison,” was no longer disabled and was preparing to return to work as an electrician. DISCUSSION: Hot Tub Lung is diagnosed by characteristic findings, including persistent respiratory symptoms like cough and dyspnea, diffuse lung infiltrates on imaging, hot tub exposure and isolation of MAC species on respiratory culture, lung biopsy or hot tub water sample. It is characterized as a hypersensitivity pneumonitis rather than an infectious process as avoidance of antigen exposure is often sufficient to resolve symptoms. To our knowledge, this patient’s long duration of exposure is unique in the literature for Hot Tub Lung. Chronic hypersensitivity pneumonitis is often associated with fibrosis which was not seen here. This suggests that Hot Tub Lung can “smolder” over many years without irreversible change taking place. CONCLUSIONS: Hot Tub Lung should be considered when evaluating a granulomatous lung disorder. This case also highlights the importance of fresh clinicopathologic re-evaluation when diagnoses are in doubt. Reference #1: Mukhopadhyay S, Gal AA. Granulomatous Lung Disease: An Approach to the Differential Diagnosis. Arch Pathol Lab Med. 2010;134:667-690. Reference #2: Hanak V, Kalra S, Aksamit TR, Harman TE, Tazelaar HD, Ryu JH. Hot tub lung: Presenting features and clinical course of 21 patients. Respir Med. 2006;100:610-615. Reference #3: Vourlekis JS, Schwarz MI, Cherniack RM, Curran-Everett D, Cool CD, Tuder RM, et al. The Effect of Pulmonary Fibrosis on Survival in Patients with Hypersensitivity Pneumonitis. Am J Med. 2004;16:662-668. DISCLOSURES: No relevant relationships by Derek Hupp, source=Web Response No relevant relationships by Chris Jensen, source=Web Response No relevant relationships by Jeff Wilson, source=Web Response

Identification of Jak-STAT signaling involvement in sarcoidosis severity via a novel microRNA-regulated peripheral blood mononuclear cell gene signature

Sarcoidosis is a granulomatous lung disorder of unknown cause. The majority of individuals with sarcoidosis spontaneously achieve full remission (uncomplicated sarcoidosis), however, ~20% of sarcoidosis-affected individuals experience progressive lung disease or cardiac and nervous system involvement (complicated sarcoidosis). We investigated peripheral blood mononuclear cell (PBMC) microRNA and protein-coding gene expression data from healthy controls and patients with uncomplicated or complicated sarcoidosis. We identified 46 microRNAs and 1,559 genes that were differentially expressed across a continuum of sarcoidosis severity (healthy control → uncomplicated sarcoidosis → complicated sarcoidosis). A total of 19 microRNA-mRNA regulatory pairs were identified within these deregulated microRNAs and mRNAs, which consisted of 17 unique protein-coding genes yielding a 17-gene signature. Pathway analysis of the 17-gene signature revealed Jak-STAT signaling pathway as the most significantly represented pathway. A severity score was assigned to each patient based on the expression of the 17-gene signature and a significant increasing trend in the severity score was observed from healthy control, to uncomplicated sarcoidosis, and finally to complicated sarcoidosis. In addition, this microRNA-regulated gene signature differentiates sarcoidosis patients from healthy controls in independent validation cohorts. Our study suggests that PBMC gene expression is useful in diagnosis of sarcoidosis.

In-silico modeling of granulomatous diseases.

The pathogenesis of genetically complex granulomatous diseases, such as sarcoidosis and latent tuberculosis, remains largely unknown. With the recent advent of more powerful research tools, such as genome-wide expression platforms, comes the challenge of making sense of the enormous data sets so generated. This manuscript will provide demonstrations of how in-silico (computer) analysis of large research data sets can lead to novel discoveries in the field of granulomatous lung disease. The application of in-silico research tools has led to novel discoveries in the fields of noninfectious (e.g., sarcoidosis) and infectious granulomatous diseases. Computer models have identified novel disease mechanisms and can be used to perform 'virtual' experiments rapidly and at low cost compared with conventional laboratory techniques. Granulomatous lung diseases are extremely complex, involving dynamic interactions between multiple genes, cells, and molecules. In-silico interpretation of large data sets generated from new research platforms that are capable of comprehensively characterizing and quantifying pools of biological molecules promises to rapidly accelerate the rate of scientific discovery in the field of granulomatous lung disorders.

Identification of metal sensitization in sarcoid-like metal-exposed patients by the MELISA® lymphocyte proliferation test — a pilot study

BackgroundPulmonary function is often affected by the inhalation of metal particles. The resulting pathology might trigger various lung diseases, e.g., parenchymal lung fibrosis and granulomatous lung disorders. We previously demonstrated that 6 % of tissue-proven sarcoid patients had a positive beryllium lymphocyte proliferation test (BeLPT), thus correcting the diagnosis to chronic beryllium disease. The aim of this study was to examine if MEmory Lymphocyte Immnuno Stimulation Assay (MELISA®), currently used for non-pulmonary diseases, can identify metals other than beryllium that can also trigger sensitization and induce granulomatous disease.MethodsThis pilot study included 13 sarcoid-like patients who underwent MELISA®. Eleven patients also underwent BeLPT. Biopsy samples were tested for metal content by scanning electron microscope. Eleven study patients had been exposed to metals at the workplace and 2 had silicone implants.ResultsTwo patients who had undergone BeLPT were positive for beryllium. MELISA® detected 9 patients (9/13, 69 %) who were positive for at least one of the tested metals: 4 reacted positively to nickel, 4 to titanium, 2 to chromium, 2 to beryllium, 2 to silica, and one each to palladium, mercury and lead.ConclusionIt is proposed that MELISA® can be exploited to also identify specific sensitization in individuals exposed to inhaled particles from a variety of metals.

Beryllium-Induced Hypersensitivity: Genetic Susceptibility and Neoantigen Generation.

Chronic beryllium (Be) disease is a granulomatous lung disorder that results from Be exposure in a genetically susceptible host. The disease is characterized by the accumulation of Be-responsive CD4(+) T cells in the lung, and genetic susceptibility is primarily linked to HLA-DPB1 alleles possessing a glutamic acid at position 69 of the β-chain. Recent structural analysis of a Be-specific TCR interacting with a Be-loaded HLA-DP2-peptide complex revealed that Be is coordinated by amino acid residues derived from the HLA-DP2 β-chain and peptide and showed that the TCR does not directly interact with the Be(2+) cation. Rather, the TCR recognizes a modified HLA-DP2-peptide complex with charge and conformational changes. Collectively, these findings provide a structural basis for the development of this occupational lung disease through the ability of Be to induce posttranslational modifications in preexisting HLA-DP2-peptide complexes, resulting in the creation of neoantigens.

CpG promoter methylation status is not a prognostic indicator of gene expression in beryllium challenge

Individuals exposed to beryllium (Be) may develop Be sensitization (BeS) and progress to chronic beryllium disease (CBD). Recent studies with other metal antigens suggest epigenetic mechanisms may be involved in inflammatory disease processes, including granulomatous lung disorders and that a number of metal cations alter gene methylation. The objective of this study was to determine if Be can exert an epigenetic effect on gene expression by altering methylation in the promoter region of specific genes known to be involved in Be antigen-mediated gene expression. To investigate this objective, three macrophage tumor mouse cell lines known to differentially produce tumor necrosis factor (TNF)-α, but not interferon (IFN)-γ, in response to Be antigen were cultured with Be or controls. Following challenges, ELISA were performed to quantify induced TNFα and IFNγ expression. Bisulfate-converted DNA was evaluated by pyrosequencing to quantify CpG methylation within the promoters of TNFα and IFNγ. Be-challenged H36.12J cells expressed higher levels of TNFα compared to either H36.12E cells or P388D.1 cells. However, there were no variations in TNFα promoter CpG methylation levels between cell lines at the six CpG sites tested. H36.12J cell TNFα expression was shown to be metal-specific by the induction of significantly more TNFα when exposed to Be than when exposed to aluminum sulfate, or nickel (II) chloride, but not when exposed to cobalt (II) chloride. However, H36.12J cell methylation levels at the six CpG sites examined in the TNFα promoter did not correlate with cytokine expression differences. Nonetheless, all three cell lines had significantly more promoter methylation at the six CpG sites investigated within the IFNγ promoter (a gene that is not expressed) when compared to the six CpG sites investigated in the TNFα promoter, regardless of treatment condition (p < 1.17 × 10−9). These findings suggest that, in this cell system, promoter hypo-methylation may be necessary to allow expression of metal-induced TNFα and that promoter hyper-methylation in the IFNγ promoter may interfere with expression. Also, at the dozen CpG sites investigated in the promoter regions of both genes, beryllium had no impact on promoter methylation status, despite its ability to induce pro-inflammatory cytokine expression.

Metal-specific CD4+ T-cell responses induced by beryllium exposure in HLA-DP2 transgenic mice.

Chronic beryllium disease (CBD) is a granulomatous lung disorder that is associated with the accumulation of beryllium (Be)-specific CD4+ T cells into the lung. Genetic susceptibility is linked to HLA-DPB1 alleles that possess a glutamic acid at position 69 (βGlu69), and HLA-DPB1*02:01 is the most prevalent βGlu69-containing allele. Using HLA-DP2 transgenic (Tg) mice, we developed a model of CBD that replicates the major features of the human disease. Here, we characterized the T cell receptor repertoire of Be-responsive CD4+ T cells derived from the lungs of Be oxide-exposed HLA-DP2 Tg mice. The majority of Be-specific T cell hybridomas expressed TCR Vβ6, and a subset of these hybridomas expressed identical or nearly identical β-chains that were paired with different α-chains. We delineated mimotopes that bind to HLA-DP2 and form a complex recognized by Be-specific CD4+ T cells in the absence of Be. These Be-independent peptides possess an arginine at p5 and a tryptophan at p7 that surround the Be-binding site within the HLA-DP2 acidic pocket and likely induce charge and conformational changes that mimic those induced by the Be2+ cation. Collectively, these data highlight the interplay between peptides and Be in the generation of an adaptive immune response in metal-induced hypersensitivity.

A Case of Hypercalcemia Secondary to Hot Tub Lung

Hypersensitivity pneumonitis (HP) is a diffuse granulomatous lung disease resulting from inhalation of an antigen to which an individual has been previously sensitized. Hot tub lung is an increasingly common form of HP associated with inhalation of water aerosols containingMycobacterium aviumcomplex organisms that contaminate hot tub water. Granulomatous lung disorders, most classically sarcoidosis, have been associated with unregulated 1-α-hydroxylase expression by macrophages present in the granulomas, causing conversion of 25-OH-vitamin D to the active form of vitamin D, 1,25(OH)2 vitamin D, and, thus, hypercalcemia. To our knowledge, this is the first confirmed case of hypercalcemia secondary to elevated 1,25(OH)2 vitamin D levels associated with HP.

Beryllium activates innate pattern recognition receptors, promotes migration and activation of dendritic cells from the lung to draining lymph nodes and drives development of memory CD4 T cells (P3129)

Abstract Beryllium exposure results in chronic beryllium disease, a granulomatous lung disorder characterized by the presence of a beryllium-specific adaptive immune response. The impact of beryllium on the innate immune system is poorly understood. The aim of this study was to determine whether beryllium promotes activation of innate pattern recognition receptors that drive the development of pathological CD4 T cell responses. Similar to aluminum hydroxide, a common vaccine adjuvant, beryllium particles induce IL-1β secretion in an Nlrp3-dependent manner and the release of host DNA during inflammation. Unlike aluminum, beryllium-induced IL-1β secretion requires TLR4. A single beryllium exposure in the lungs of mice promotes migration of DCs to the draining lymph nodes and upregulation of DC costimulatory molecules in a MyD88-dependent manner. Beryllium enhances priming and maintenance of memory CD4 T cells to conventional protein antigen and can generate beryllium-specific CD4 T cell responses in HLA-DP2 transgenic mice in the absence of an additional adjuvant. Together, these data suggest that beryllium activates multiple innate immune receptors and promotes pathological immune responses in susceptible individuals by promoting activation of DCs that drive long-lived CD4 T cell responses. Future work is aimed at understanding which innate receptors are required for beryllium to activate DC in vivo and drive CD4 T cell effector and memory function.

Beryllium-specific CD4 + T cells in blood as a biomarker of disease progression

CD4(+) T cells are responsible for the progressive lung damage seen in patients with chronic beryllium disease (CBD), a granulomatous lung disorder in which antigen-specific, T(H)1-type, cytokine-secreting T cells have been characterized. Compared with those seen in beryllium (Be)-sensitized subjects, increased numbers of Be-responsive T cells are present in the blood of patients with CBD. The aim of this study was to determine whether the number of Be-specific T cells in blood predicted the development of CBD in a cohort of Be-exposed subjects. Using IFN-γ ELISpot and proliferation-based assays, we determined the frequency and proliferative capacity of Be-responsive T cells in blood. Compared with the Be lymphocyte proliferation test, which detected an abnormal Be-induced proliferative response in 11 (4.2%) of 260 workers from a Be-machining facility, the IFN-γ ELISpot detected a sensitization rate of 10% (χ(2) = 55.7, P < .0001). A significant positive correlation was also noted between the number of Be-responsive CD4(+) T cells in the blood and lung tissue of patients with CBD. Importantly, the transition from Be sensitization to CBD was associated with an increased number of antigen-specific T cells in blood. These findings have important implications for Be-induced disease and potentially other immune-mediated disorders, suggesting that the frequency of antigen-specific T cells in blood can serve as a noninvasive biomarker to predict disease development and severity of the Be-specific CD4(+) T-cell alveolitis.

Linking Genetic Susceptibility and T Cell Activation in Beryllium-induced Disease

Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by beryllium (Be) exposure in the workplace. It is characterized by the accumulation of Be-specific CD4(+) T cells in the lung as well as persistent lung inflammation, culminating in the development of lung fibrosis. CBD occurs in 2 to 16% of Be-exposed workers depending on the individuals' genetic susceptibility and the characteristics of the exposure. Genetic susceptibility to Be-induced disease has been linked to major histocompatibility complex class II molecules. In particular, HLA-DP alleles possessing a glutamic acid at the 69th position of the beta-chain (betaGlu69) are most strongly linked to disease susceptibility. The HLA-DP alleles that present Be to T cells match those implicated in the genetic susceptibility, suggesting that the HLA contribution to disease is based on the ability of those molecules to bind and present Be to T cells. However, the structural features of betaGlu69-containing HLA-DP molecules that explain the disease association remain unknown. We have recently crystallized HLA-DP2, which is the most prevalent of the betaGlu69-containing HLA-DP molecules. Its unique structure, which includes surface exposure of betaGlu69, provides an explanation of the genetic linkage between betaGlu69-containing HLA-DP alleles and Be-induced disease.

CD27 Expression on CD4+ T Cells Differentiates Effector from Regulatory T Cell Subsets in the Lung

Beryllium exposure in the workplace can result in chronic beryllium disease, a granulomatous lung disorder characterized by CD4(+) T cell alveolitis and progressive lung fibrosis. A large number of the CD4(+) T cells recruited to the lung in chronic beryllium disease recognize beryllium in an Ag-specific manner and express Th1-type cytokines following T cell activation. Beryllium-responsive CD4(+) T cells in the bronchoalveolar lavage (BAL) express an effector memory T cell phenotype and recognize beryllium in a CD28-independent manner. In this study, we show that the majority of beryllium-responsive CD4(+) T cells in BAL have lost CD27 expression, whereas a subset of beryllium-responsive cells in blood retains expression of this costimulatory molecule. In addition, loss of CD27 on BAL CD4(+) T cells inversely correlates with markers of lung inflammation. A small population of BAL CD4(+) T cells retains CD27 expression, and these CD4(+)CD27(+) T cells contain the FoxP3-expressing, naturally occurring regulatory T (T(reg)) cell subset. Coexpression of CD27 and CD25 identifies the majority of FoxP3-expressing T(reg) cells in blood and BAL, and these cells express potent suppressor function. Taken together, these findings suggest that CD27 is differentially expressed between effector T cells from the inflamed lung and can be used in conjunction with CD25 to isolate T(reg) cells and assess their functional capacity in an ongoing adaptive immune response in a target organ.

Metal-Induced Diffuse Lung Disease

The number of metals that are associated with the development of diffuse parenchymal lung disease continues to expand. In addition to lung fibrosis, inhalation of metal particulates can induce a wide range of lung pathology, including reactive airways disease and cancer. This article focuses on diffuse parenchymal diseases resulting from the inhalation of beryllium and cobalt. More is known regarding the immunopathogenesis of beryllium-induced disease than is known for disease induced by any other metal. Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by beryllium exposure in the workplace and is characterized by the accumulation of beryllium-specific CD4 (+) T cells in the bronchoalveolar lavage. Genetic susceptibility markers associated with increased risk have been identified for both CBD and hard metal lung disease. The mechanism for the genetic susceptibility of CBD lies in the ability of certain human leukocyte antigen (HLA)-DP molecules to bind and present beryllium to pathogenic CD4 (+) T cells. Whether the same is true for hard metal lung disease is unknown. In contrast, no HLA allelic association has been identified in nickel allergic subjects. The study of metal-induced lung disease allows the investigation of the relationship between environmental exposure and genetic susceptibility. These studies will enhance our understanding of the immunopathogenesis of metal-induced disease and how exposure to these metals results in irreversible lung fibrosis.

Decreased expression of haem oxygenase-1 by alveolar macrophages in idiopathic pulmonary fibrosis

Haem oxygenase (HO)-1 is an oxidative stress responsive protein that may be involved in the pathogenesis of interstitial lung disease. HO-1 expression in alveolar macrophages from bronchoalveolar lavage was investigated in 24 patients with idiopathic pulmonary fibrosis (IPF), 16 with sarcoidosis, 14 with hypersensitivity pneumonitis (HP) and 13 controls. Using immunocytochemistry, HO-1 expression in macrophages was scored semiquantitatively from 0-3 according to increasing intensity. The mean score of 100 macrophages was calculated. Macrophages were cultured and levels of interleukin (IL)-12 and IL-18 in the culture supernatants were measured by ELISA. The mean score of HO-1 was significantly lower in IPF (67) than in sarcoidosis (105), HP (106) or controls (106). There was no significant difference between sarcoidosis, HP and controls. The score of HO-1 correlated positively with the lymphocyte percentage in sarcoidosis and HP. Positive correlations were found between the score of HO-1 and the release of IL-12 and IL-18 by macrophages in IPF. The expression of haem oxygenase-1, a critical defender against oxidative stress, is decreased in macrophages of idiopathic pulmonary fibrosis patients compared with those with granulomatous lung disorders. This supports the hypothesis of an oxidant-antioxidant imbalance in the pathogenesis of idiopathic pulmonary fibrosis.

T cell recognition in chronic beryllium disease

Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by beryllium exposure in the workplace and is characterized by the accumulation of beryllium-specific CD4 + T cells. Depending on genetic susceptibility and the nature of the exposure, CBD occurs in up to 20% of exposed workers. Genetic susceptibility has been associated with particular HLA-DP alleles, especially those possessing a negatively charged glutamic acid residue at the 69th position of the β-chain. The mechanism for this association lies in the ability of these HLA-DP molecules to bind and present beryllium to pathogenic CD4 + T cells. Large numbers of effector memory, beryllium-specific CD4 + T cells are recruited to the lung of these subjects and secrete Th1-type cytokines upon beryllium recognition. The presence of circulating beryllium-specific CD4 + T cells directly correlates with the severity of lymphocytic alveolitis. With the presence of a known antigenic stimulus, CBD serves as an important model of immune-mediated, organ destruction. Thus, our findings in CBD have important implications for studies in autoimmune diseases, in particular those with an unknown inciting antigen and an inaccessible target organ.

Chronic Beryllium Disease

In Brief Chronic beryllium disease is an immune-mediated granulomatous lung disease seen predominantly in workers exposed to beryllium. It is thought to be mediated by a hypersensitivity reaction to beryllium. Disease risk is a function of intensity of beryllium exposure and genetic immune susceptibility. A specific immunophenotype, human leukocyte antigen-DPglu69 has been strongly associated with development of the disease. The presence of noncaseating granulomas, in vitro lymphocyte proliferation on beryllium challenge, and a history of exposure are necessary for diagnosis. Current treatment entails cessation of exposure; additionally, systemic corticosteroids may be required. The natural history and optimal treatment strategies are poorly defined at present. Chronic beryllium disease is an occupational granulomatous lung disorder. It is thought to be mediated by a hypersensitivity reaction to beryllium. Disease risk is imparted by both beryllium exposure and genetic susceptibility. This article reviews clinical and epidemiologic features of the disease and provides an overview of recent advances in genetic and pathophysiologic aspects of chronic beryllium disease.

Immunological features of lung lavage cells from patients with primary biliary cirrhosis may reflect those seen in pulmonary sarcoidosis.

To investigate the basis of subclinical alveolitis in patients with primary biliary cirrhosis, 10 primary biliary cirrhosis patients were studied by bronchoalveolar lavage. Both bronchoalveolar lavage lymphoid and non-lymphoid cell populations were analysed using immunocytological methods to determine their proportions and phenotypic features in an attempt to gain information as to possible immune mechanisms active in the lung of these patients. Six of the 10 patients in our study showed evidence of an alveolitis (raised lymphocyte count: 27.6 (4.3)% of total count) on lavage. The results were compared with control groups of normal volunteers and patients with active pulmonary sarcoidosis. The six primary biliary cirrhosis patients with lymphocytosis had a raised CD4/CD8 T-cell ratio (4.13:1), similar to the sarcoid patients (5.60:1). A proportion of these T-lymphocytes expressed markers of activation (HLA-DR+ 7.5 (2.1)%); CD25 + 2.3 (0.9)%; CD7 + 5.8 (1.5)%. This increased T-cell activation was also seen in the sarcoid groups (HLA-DR+ 10.0 (1.9)%; CD25 + 3.0 (1.1)%; CD7 + 5.0 (0.2)%). This was not seen in the primary biliary cirrhosis patients without lymphocytosis and the normal volunteers. Within the non-lymphoid cell population, an increase in dendritic (RFD1+) cells was seen in primary biliary cirrhosis patients with lymphocytosis (31.2 (1.9)%) and sarcoid patients (46.3 (5.1)%) in contrast with the normal and primary biliary cirrhosis group without lymphocytosis. The primary biliary cirrhosis patients without lymphocytes had a relatively greater proportion of mature phagocytes (RFD7+). We postulate that these observations suggest the emergence in the lung of a granuloma producing mechanism similar to that occurring in the liver. By comparison, the alveolitis found in primary biliary cirrhosis is consistent with that observed in interstitial granulomatous lung disorders such as sarcoidosis.

Type III and type IV allergy: granulomatous lung disorders

Type III and type IV allergy: granulomatous lung disorders