Diffuse pulmonary alveolar fibrosis

Current concepts and dilemmas in idiopathic interstitial pneumonias

Idiopathic interstitial pneumonias comprise approximately one-third of interstitial lung diseases (also called diffuse parenchymal infiltrative lung diseases). The classification of idiopathic interstitial pneumonias has undergone several revisions since the initial description of 40 years ago, and the most recent version was published in 2013. Although some aspects have been clarified, this group of heterogeneous disorders continues to be a source of confusion and misunderstanding in clinical applications. In this article, we explore several topical themes in the evaluation and management of patients with idiopathic interstitial pneumonias.

Histopathology of the idiopathic interstitial pneumonias (IIP): A review

The 2013 American Thoracic Society/European Respiratory Society consensus classification update of the idiopathic interstitial pneumonias (IIP) included several important modifications to the organization and spectrum of the diseases that were proposed in an earlier multidisciplinary consensus document in 2002. The histopathology of the now 'major' and 'rare' IIP is presented here with exposition of the newly included entity of a distinctive upper lobe fibrotic lung disease referred to as idiopathic pleuroparenchymal fibroelastosis. The 'rare histological patterns' of acute fibrinous and organizing pneumonia and bronchiolocentric patterns of interstitial pneumonia are illustrated and discussed.

Cough, sarcoidosis and idiopathic pulmonary fibrosis: raw nerves and bad vibrations

Cough is a common symptom in people who develop interstitial lung diseases (ILD). The pathological features of the ILDs are many and varied suggesting that the cause of cough may also vary with each disease. This article reviews what is currently known about cough in sarcoidosis and idiopathic pulmonary fibrosis; two of the commonest ILDs. It also outlines some of the theories which have been proposed to explain why cough develops in these conditions and describes what little is known about how to treat it.

Therapies for interstitial lung disease: past, present and future

As our understanding of the pathobiology and natural history of the various forms of interstitial lung disease (ILD) has evolved, so have our approaches to treating this heterogeneous group of lung disorders. The earliest pharmacologic agents used to treat various forms of ILD were corticosteroids, and corticosteroids are currently the mainstay of therapy for many forms of ILD. However, it has become clear that corticosteroids and other anti-inflammatory agents lack efficacy for many forms of ILD, such as idiopathic pulmonary fibrosis (IPF), and newer therapies that are in clinical trials target the fibrogenic process and/or secondary pulmonary hypertension (PH) that is present in various forms of fibrotic lung disease. Novel therapies, such as the use of biologic agents (antibodies and cell cycle inhibitors) or stem cell therapies will undoubtedly evolve as new research is performed and clinical trials are undertaken. Lung transplantation remains an option for advanced lung disease that is progressive and unresponsive to non-surgical therapies.

Clinical advances in the diagnosis and therapy of the interstitial lung diseases

The last century experienced remarkable advances in the classification, diagnosis, and understanding of the pathogenesis of the interstitial lung diseases. Technological advances, particularly physiologic testing, lung imaging studies, bronchoalveolar lavage, surgical lung biopsy, and histopathologic assessment, improved our understanding of these entities. In particular, the advent of high-resolution computed tomography, the narrowed pathologic definition of usual interstitial pneumonia, and recognition of the prognostic importance of separating usual interstitial pneumonia from other idiopathic interstitial pneumonia patterns have profoundly changed the approach to these processes. Most recently, genetic medicine, the use of new technologies (e.g., microarrays, mass spectroscopic analysis of proteins, and laser capture microdissection), and the development of animal models have had a major impact on understanding the pathogenesis and potential molecular targets for interfering with fibrogenesis. This article highlights some of the advances and changes in clinical practice that took place in the management of patients with interstitial lung diseases over the last century.

Effects of cigarette smoking on diagnostic tests for work-related hypersensitivity pneumonitis: data from an outbreak of lung disease in metalworkers

BACKGROUND

It is widely believed that development of hypersensitivity pneumonitis (HP) is forestalled in cigarette smokers. We encountered the largest outbreak of HP in metalworkers yet reported [Hodgson et al. (2001): Am J Ind Med 39:616-628] and subsequently did a chart review of the 61 patients seen in connection with the outbreak [Dangman et al. (2002a): Am J Resp Crit Care Med 165(8):A528; Dangman et al. (2002b): Am J Ind Med 42:150-162], developing a diagnostic index for this disease.

METHODS

A re-examination of data from the chart review was carried out to explore possible effects of cigarette smoking on the clinical tests used to diagnose HP [Hodgson et al. (2001): Am J Ind Med 39:616-628].

RESULTS

Cigarette smokers with HP were less likely than non-smokers with HP to develop crackles in the lungs, elevated erythrocyte sedimentation rates (ESRs), and restrictive spirometry. Smoking habits had little effect on diffusion capacity and alveolar-arterial oxygen gradients in the patients with HP. Smokers were more likely to have abnormal gallium scans than non-smokers.

CONCLUSIONS

It appears that cigarette smoking can affect the physical examination findings, spirometry, and ESR changes associated with HP, making these tests less sensitive and specific, and potentially obscuring the diagnosis. Such changes may contribute to the apparent "protective" effect of smoking on the development of HP.

Interstitial lung disease in systemic sclerosis: comparison of BALF lymphocyte phenotype and DLCO impairment

Patients with scleroderma (systemic sclerosis-SSc) frequently develop an interstitial lung disease. The role of lymphocytes in fibrosing alveolitis preceding lung fibrosis has been established. The purpose of this work was to evaluate cell profiles and lymphocyte phenotypes in the bronchoalveolar lavage (BAL) fluid and to correlate them with depression in lung function tests detected by depletion of diffusing capacity (DLCO). BAL was carried out in 25 untreated, non-smoking patients suffering from diffuse scleroderma and in 12 healthy non-smoking volunteers. For the analysis of lymphocyte sub-sets flow cytometry and monoclonal antibodies were used. The following cell sub-types were counted: T lymphocytes, B lymphocytes, helper lymphocytes, suppressor/cytotoxic lymphocytes, natural killer cells, cytotoxic T lymphocytes and activated T lymphocytes. The total cell count was higher in the group of patients with mild and moderate impairment in DLCO. The percentage of lymphocytes was greater in patients with DLCO lower than 65% of the predicted value since neutrophilia was found in patients with severe DLCO depletion, i.e. significant when compared with healthy subjects. The proportions of suppressor/cytotoxic lymphocytes and of activated T lymphocytes were higher in patients than in controls. The statistical analysis revealed significant differences between patients with moderate and mild changes in DLCO and the healthy volunteers. A decreased helper/suppressor ratio was noticed in these patients. We concluded that the BALF lymphocyte phenotype analysis may reflect the features of alveolitis in patients with SSc.

Persistent interleukin-2 activity and molecular evidence for expression of lymphotoxin in the hapten-immune model for pulmonary interstitial fibrosis

The hapten-immune model for pulmonary fibrosis shows that a specific T-cell-mediated immune response is essential for the induction of a nonresolving fibrosis. Here, we report results from studies that identify soluble factors released by activated T lymphocytes that might mediate long-lasting fibrosis. Pulmonary fibrosis was induced by priming hamsters for contact hypersensitivity responses with an epicutaneous application of 2,4,6-trinitro-1-chlorobenzene (TNCB) in carrier and challenging intratracheally (IT) 5 days later with a single dose of the soluble form of the immunizing hapten. Bronchoalveolar lavage fluid was harvested at various time points after IT challenge and assayed for tumor necrosis factor (TNF) and interleukin-2 (IL-2) bioactivity. After IT challenge with the sensitizing hapten, only the immune animals contained IL-2 activity in the bronchoalveolar lavage fluid. TNF activity was detected in lungs of both immune and nonimmune animals. Interestingly, the TNF activity was significantly higher (P less than 0.05) in nonimmune challenged than in immune challenged animals on day 5. Molecular hybridization studies showed that a similar amount of TNF-alpha mRNA was expressed in adherent cells from both groups. The nonadherent subpopulation of mononuclear cells harvested from challenged-immune animals expressed TNF-beta (lymphotoxin) mRNA. These data show, for the first time, an association of lymphotoxin with the appearance of pulmonary fibrotic disease in an animal model for pulmonary fibrosis. These observations are consistent with the postulates that lymphotoxin and IL-2 participate in the immunopathogenesis of hapten-immune induced pulmonary fibrosis and that TNF-alpha is associated with the healing of the fibrotic process initiated by toxic lung injury.

Idiopathic interstitial fibrosis

The lung has only a limited pattern of response to injury. Idiopathic interstitial fibrosis is a descriptive term, describing the end stage of one pattern of pulmonary fibrosis in which the inflammation lies within the structure of the alveolar walls and around vessels and bronchioli, in the interstitium. The disease is characteristically subpleural in distribution and provides a marked restrictive consequence on pulmonary function which progresses to hypoxic core pulmonale. This is despite the apparent normality of much of the lung at autopsy. Six to fifteen percent develop lung cancer, the proportion depending on the autopsy rate. A nonspecific nature of the changes limits the diagnostic value of transbronchial biopsy, open lung biopsy may be of value in assessing and grading the disease in relationship to therapy.

Class II antigens of the major histocompatibility complex are increased in lungs of bleomycin-treated rats

The expression of class II molecules (Ia) of the major histocompatibility complex by isolated alveolar macrophages (AM) and alveolar type II cells from the lungs of rats with bleomycin-induced pulmonary fibrosis was examined. The percentage of Ia-positive AM and type II cells from rats treated with bleomycin as detected by flow cytometry was increased three times and two times, respectively, over the values obtained from control rats. The relative density of Ia expression, determined with a radioimmunoassay technique, showed a 50% increase in Ia density on AM and a 35% increase on type II cells. Recombinant interferon-gamma increased the expression of Ia on type II cells in vitro by 35% to the level obtained on type II cells in bleomycin-induced lung disease. We conclude that the increase of Ia expression on cells of the immune system and on pulmonary epithelial cells may have an important role in the initiation and/or amplification of inflammatory reactions in the lung and may contribute to the development of pulmonary fibrosis.

Idiopathic pulmonary fibrosis: cellular and molecular pathogenesis

Diffuse involvement of the pulmonary interstitium with abnormal fibrous tissue is a process that occurs in many settings. There are many possible etiologies for pulmonary fibrosis, but in the majority of individuals, a clear cause cannot be determined and a diagnosis of idiopathic pulmonary fibrosis (IPF) results. Despite limited knowledge concerning the etiology, recent advances in biomedical technology offer great promise for increasing our understanding of IPF. This review will focus on current concepts of the pathogenesis and therapy of IPF.

Cellular events in alveolitis and the evolution of pulmonary fibrosis

"Alveolitis", as opposed to "pneumonia" sensu strictiori, is a term used to denote diffuse inflammatory changes of the pulmonary parenchyma, excluding those that result from local bacterial, fungal or other extracellular microbial growth. The various types of alveolitis are classified according to their histological characteristics and range from "luminal phagocytic" or "mural lymphoplasmacellular" and "exudative" to "fibrosing" alveolitis. In this overview, various exogenous and endogenous causes of different types of alveolitis, and the cellular events in their pathogenesis are briefly discussed to illustrate the complex mechanisms involved. Particular emphasis is placed on the possible transition from diffuse exudative to fibrosing alveolitis. It appears that pulmonary fibrosis, which is usually patchy rather than truly diffuse, does not have a uniform pathogenesis. Besides the possibility of a certain degree of a diffuse fibrosis three major pathways are evident: (1) granulation tissue budding into alveolar lumina (luminal fibrosis) (2) exudate incorporation into alveolar walls (mural fibrosis) and--at least equally important--(3) so-called collapse (atelectatic) induration (obliterative-interseptal fibrosis), a process that has largely been neglected so far.

[Changes in the lung connective tissue framework in sudden infant death (SIDS)]

Light microscopy findings are reported on the interstitial connective tissue framework of 45 lungs from babies who died within the first 2 years of life. Thirty were confirmed cases of SIDS and 15 were controls of similar age who died of known causes. The stains applied were H & E, PAS, Prussian blue, Elastica van Gieson, Trichrom (Masson-Goldner), Gomori's silver methenamine and Picro-Sirius polarization (modified). Particular attention was paid to type I and type III collagen, reticulin fibers and ground substance. All investigated cases showed evidence of chronic recurrent interstitial edema in a highly significant frequency and intensity in contrast to the controls. Areas of recent and persistent lymphedema were observed, some of them with reactive fibroplastic activity, which tended towards gradual fibrosis. These changes were irregularly distributed and frequently involved the mural interstitium. Considering the effects of such changes on expansibility, ventilation and perfusion of the lungs, as well as the impairment of gas diffusion, the findings described could be significant in the forensic evaluation of the signs of asphyxia found in most cases of SIDS.

Interstitial pneumonitis following bone marrow transplantation: pathogenesis and therapeutic considerations

High-dose chemo-radiotherapy followed by allogeneic bone marrow transplantation has become standard treatment for a variety of hematological malignancies. Interstitial pneumonitis (IP) is a major complication after bone marrow transplantation, the incidence being approximately 50% (range 20-65%). Cytomegalovirus (CMV) is found in about half of these cases. If no infectious cause can be detected, the interstitial pneumonitis is labeled 'idiopathic'. The occurrence of CMV IP is related to the state of severe immunosuppression in combination with graft-vs-host disease (GvHD) in these patients. The most important factors contributing to idiopathic IP seem to be: chemotherapy, total-body irradiation, agents to prevent GvHD and GvHD itself. For preventing CMV IP hyperimmune globulin seems to be the most promising method at this moment. As long as the etiology of idiopathic IP remains unclear, no measures can be taken to prevent or treat this disease.

Asbestosis and cryptogenic fibrosing alveolitis: a radiological and functional comparison

This study compares the relationship between lung function and radiological abnormality in 46 subjects with asbestosis and 38 subjects with cryptogenic fibrosing alveolitis. Radiographs were graded separately by two observers according to the 1980 International Labour Organisation criteria for classification of the pneumoconioses. The correlation between the transfer factor of the lungs and the radiographic profusion of small parenchymal opacities was found to be greater in subjects with asbestosis than in subjects with cryptogenic fibrosing alveolitis. At any level of radiological profusion transfer factor was higher in cases with asbestosis than in cases with fibrosing alveolitis. As pleural thickening is seen commonly in asbestosis and may influence lung volumes and the ratio of transfer factor to effective alveolar volume, the results of these measurements were compared only in the cases showing absent or minimal pleural thickening. Both of these variables were higher in the subjects with asbestosis. The results indicate that despite pathological, functional and radiographic similarities, lung function for a given degree of radiographic parenchymal abnormality is better in subjects with asbestosis than in subjects with cryptogenic fibrosing alveolitis, and that changes in the plain chest x-ray appearances in asbestosis correlate more closely with the results of lung function tests.

Mechanisms of pulmonary fibrosis. Spontaneous release of the alveolar macrophage-derived growth factor in the interstitial lung disorders

Interstitial lung disorders are characterized both by a chronic inflammation of the lower respiratory tract that includes increased numbers of activated alveolar macrophages and by increased numbers of fibroblasts within the alveolar wall. Since alveolar macrophages from normal individuals can be activated to release a growth factor for lung fibroblasts (alveolar macrophage-derived growth factor [AMDGF]), we hypothesized that the activated alveolar macrophages within the lower respiratory tract of patients with fibrotic lung disorders might be spontaneously releasing AMDGF. To evaluate this hypothesis, alveolar macrophages (suspension culture, 4 h, 37 degrees) from 65 patients with interstitial lung disorders and 30 control subjects were examined for the spontaneous release of fibroblast growth-promoting activity, with human lung fibroblasts as the target. Whereas none of the controls had macrophages spontaneously releasing a growth-promoting activity for fibroblasts, 82% of the patients with interstitial lung disease had alveolar macrophages that were spontaneously releasing a growth-promoting activity for fibroblasts. In common with AMDGF, the fibroblast growth-promoting activity released by these macrophages eluted from DEAE cellulose at 270 mM NaCl, had a partition coefficient of 0.3 by gel filtration on Sephadex G-50, was distinct from other characterized growth factors, and acted as a progression factor for fibroblast replication in a serum-free complementation test. These data suggest that the expansion of fibroblast numbers within the alveolar structures in interstitial lung disorders may result, in part, from the release of AMDGF by alveolar macrophages stimulated in vivo.

Interstitial lung disease in primary biliary cirrhosis

A 51-year-old woman with a 5-1/2 year history of primary biliary cirrhosis (PBC) developed interstitial lung disease (ILD). The initial pulmonary infiltrate consisted of unilateral nodules mimicking neoplastic disease and later progressed to involve both lungs with a diffuse interstitial process. Tissue obtained by open lung biopsy was compatible with lymphoid interstitial pneumonia. The pulmonary infiltrates cleared spontaneously but recurred on two more occasions with subsequent resolution. This pulmonary disease activity appeared unrelated to the chemical activity of the PBC, which progressed to a fatal termination. The association of ILD, especially of a recurrent nature, with PBC is rare.

The ultrastructure of human fibrosing alveolitis

This report describes the ultrastructural findings in 37 patients who underwent open lung biopsy which yielded diagnoses of fibrosing alveolitis. A spectrum of lesions are categorized for the capillary endothelium and its basement membrane, the interstitial space and its fibrocellular components, and the alveolar epithelium and its basement membrane. The findings typify the different pulmonary cellular reactions to injury. Evidence for cellular regeneration and death in both epithelial and endothelial cell populations include atypical epithelial cell proliferation, capillary basement membrane multilamination, decrease in capillary lumen size and prominent pericytic ensheathment of pulmonary capillaries. Within the interstitium of the lung, proliferation of collagen and elastic fibers are documented, but in addition, abundant myofibroblasts and smooth muscle cells are present. No ultrastructural evidence of immune complex deposition was found in this study. The morphologic findings of fibrosing alveolitis further support the widespread concept that the lung responds to various injuries in a similar manner and undergoes a common reparative response regardless of etiology.

Mechanisms of neutrophil accumulation in the lungs of patients with idiopathic pulmonary fibrosis

Neutrophils are a characteristic feature of the alveolitis of idiopathic pulmonary fibrosis (IPF). a chronic disorder limited to lung. One mechanism by which neutrophils may be selectively attracted to lung and not other tissues is via the secretion of the neutrophil-specific chemotactic factor by alveolar macrophages. To evaluate the role of alveolar macrophages in modulating the migration of neutrophils to he lung in IPF, alveolar macrophages, obtained by bronchoalveolar lavage of patients with IPF, were evaluated for their ability to release a chemotactic factor for neutrophils. Unstimulated alveolar macrophages from normal individuals did not release the factor. In patients with IPF, there was a significant correlation between the proportions of neutrophils in lavage fluid and the release of a chemotactic factor for neutrophils by alveolar macrophages (p less than 0.001). The chemotactic factor released by IPF alveolar macrophages was of low molecular weight (400-600), at least partially lipid in nature, and preferentially attracted neutrophils compared with monocytes. Several lines of evidence suggested that immune complexes in the lung stimulated alveolar macrophages of patients with IPF to release the chemotactic factor. First, immune complexes stimulated normal macrophages to release the factor.Second, there was a significant correlation between the release of the chemotactic factor by IPF alveolar macrophages and the levels of immune complexes in bronchoalveolar lavage fluid. Third, bronchoalveolar lavage fluid containing immune complexes stimulated normal macrophages to release the factor. Fourth, IPF alveolar macrophages that released large amounts of the chemotactic factor had an apparent suppression of their immunoglobulin (Ig)G Fc receptor function, suggesting that immune complexes were bound to their surface. In contrast, the IgG Fc receptor function of IPF alveolar macrophages that released only small amounts of the factor was similar to that of normal macrophages. These studies suggest that neutrophils are attracted to the lung in patients with IPF by a potent chemotactic factor released by alveolar macrophages that have been stimulated, in vivo, via their IgG Fc receptor by immune complexes.

Needs for animal models of human diseases of the respiratory system

Animal models are of two types those that occur spontaneously and those that the scientist produces by artefact. One value of spontaneously occurring models is that if pathogenetic mechanisms are identified, they give new leads for the study of human disease. There is a need for spontaneously occurring examples of so-called primary or idiopathic pulmonary fibrosis, pulmonary hypertension (arterial or venous), and emphysema. Acquired or artefactual models of each of these conditions are available and have led to better understanding of the pathological changes, but they have not led to identification of the basic or primary abnormality. A naturally occurring model of cystic fibrosis could be a major event in our control of this disease. A spontaneously occurring form of asthma is needed as a bridge between experiment and patient. Artefactual models that are needed are of bronchopulmonary dysplasia and shock lung. There is probably enough agreement--but only just--on the nature of bronchopulmonary dysplasia for specific needs to be identified. Here the questions concern the choice of an appropriate species--or several--in which to study the premature lung and its adaptation to air breathing and supportive therapy. Knowledge of comparative anatomy and physiology must influence choice of species for certain models. For adult respiratory failure, or shock lung, a model is needed that progresses to pulmonary hypertension. Spontaneous models of interstitial pneumonia and of infection, both viral and bacterial, are needed. An animal model of a disease is only as useful as the questions we ask of it.

Morphologic-physiologic correlates of the severity of fibrosis and degree of cellularity in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of lung parenchyma characterized by a chronic inflammatory cellular infiltration and varying degrees of interstitial fibrosis. Current data indicate that the severity of fibrosis and the degree of cellularity determine, in part, the prognosis of IPF and the response to therapy. Whereas lung biopsy gives the best assessement of fibrosis and cellularity, physiologic studies are used to stage and monitor the disease process. To determine which physiologic studies correlate best with severity of fibrosis and degree of cellularity, these parameters were graded in lung biopsies of 23 patients with IPF and compared with a variety of physiologic studies. Although vital capacity, total lung capacity, and diffusing capacity are commonly used as objective monitors of the disease process, none of these parameters correlated with either the severity of fibrosis or the degree of cellularity in biopsy specimens. In contrast, almost all parameters of lung distensibility correlated with the morphologic assessment of degree of fibrosis; compliance had the best correlation. Parameters of distensibility, however, correlated poorly with the degree of cellularity. In comparison, gas exchange during exercise correlated with both morphologic parameters; the exercise-induced changes in arterial oxygen pressure per liter of oxygen consumed had a high correlation with the degree of fibrosis (r = 0.89; P less than 0.001) and correlated to a lesser extent with the degree of cellularity (r = 0.56; P = 0.009). In contrast, neither the resting arterial oxygen tension nor the arterial oxygen tension at maximal exercise correlated with the morphologic assessment of degree of fibrosis or the degree of cellularity. These morphologic-physiologic comparisons suggest that (a) lung volumes and diffusing capacity are poor monitors of both the degree of fibrosis and the degree of cellularity; (b) the fibrotic process contributes, at least in part, to parameters of lung distensibility, and both fibrosis and cellularity contribute to gas exchange alterations during exercise; and (c) parameters of lung distensibility and exercise-induced gas exchange alterations may be useful in staging the severity of disease in IPF.

Bird fancier's lung

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Extrinsic allergic alveolitis: a disease commoner in non-smokers

The smoking habits of 18 patients with extrinsic allergic alveolitis, 22 with cryptogenic fibrosing alveolitis, and 75 patients with sarcoidosis were compared with the smoking habits of the normal population of the Prairie Region for 1973. The patients were diagnosed at the same two hospitals over the four-year period November 1971--75 and were of comparable age. Non-smoking was significantly associated with allergic alveolitis in men and the three cases in women were all non-smokers. For the other two diseases, smoking habits were similar to those of the local population.

Small airways in idiopathic pulmonary fibrosis. Comparison of morphologic and physiologic observations

18 patients with idiopathic pulmonary fibrosis were studied to determine if they had morphologic evidence of small airways disease and if physiologic testing could predict morphologic findings. In the presence of normal airway function by standard physiologic studies (forced expiratory volume in 1 s/forced vital capacity and airway resistance by plethysmography), dynamic compliance, maximum expiratory flow-volume curves, and maximum flowstatic recoil curves were measured to detect physiologic alterations consistent with small airways abnormalities. These physiologic data were then compared with estimates of small airways diameter made in lung biopsy specimens.94% (17 of 18) of the patients had peribronchiolar fibrosis or peribronchiolar inflammation or bronchiolitis. 67% (12 of 18) had an overall estimate of small airways diameter of "narrowed," whereas 33% (6 of 18) had airways that overall were "not narrowed." 59% (10 of 17) had frequency-dependent dynamic compliance, 50% (9 of 18) had abnormal maximum expiratory flow-volume curves, and 39% (7 of 18) had abnormal maximum flow-static recoil curves. Comparisons between morphologic and physiologic data revealed a significant correlation between the results of dynamic compliance and the overall estimate of small airways diameter (P = 0.001), and the results of maximum flow-volume curves and the overall estimate of small airways diameter (P = 0.009); there was no significant correlation between the results of maximum flow-static recoil curves and the overall estimate of small airways diameter (P = 0.1). THE RESULTS OF THIS STUDY SUGGEST THAT: (a) idiopathic pulmonary fibrosis is a disease of small airways as well as alveoli; (b) dynamic compliance and the maximum expiratory flow-volume curve can predict the overall status of small airways diameter in idiopathic pulmonary fibrosis; and (c) whereas the maximum flowstatic recoil curve predicts the overall estimate of small airways diameter in most patients with this disease, it is the least sensitive of these three monitors of small airways.

Fibrosing alveolitis with autoimmune haemolytic anaemia: two case reports

Two patients with fibrosing alveolitis and autoimmune haemolytic anaemia are described. One patient also had neurofibromatosis. The haematological associations of fibrosing alveolitis are discussed, and a possible relationship between autoimmune haemolysis and fibrosing alveolitis is suggested.