Prognostic significance of histopathologic subsets in idiopathic pulmonary fibrosis

Tenascin mRNA expression at the foci of recent injury in usual interstitial pneumonia

To elucidate which cells are synthesizing tenascin in usual interstitial pneumonia (UIP) we have analyzed thoracoscopic or open lung biopsies from 30 patients with UIP by mRNA in situ hybridization, using (35)S-labeled tenascin RNA probes. The phenotype of the cells expressing tenascin mRNA was confirmed by immunohistochemical stainings of serial sections with antibodies against alpha-smooth muscle actin and human cytokeratin. The results demonstrate that tenascin is expressed at the foci of recent lesions consisting of intralumenal or incorporating loose fibrotic buds. The cells expressing tenascin mRNA were located in and underneath the newly formed epithelium. Immunohistochemical stainings showed that the cells in the newly formed epithelium were strongly cytokeratin positive, and thus evidently regenerating type 2 pneumocytes, while the cells underneath the newly formed epithelium were alpha-smooth muscle actin positive and apparently myofibroblasts. Tenascin mRNA expression was clearly stronger and more frequent in myofibroblasts than in type 2 pneumocytes, however. Weak tenascin mRNA expression was also found in metaplastic bronchiolar-type epithelium and alveolar macrophages. Our results are thus in good agreement with the previous studies showing that tenascin is actively synthesized at the early fibrotic lesions in UIP. Furthermore, results demonstrate that the interaction between the epithelium and the underlying connective tissue plays a significant role in tenascin synthesis and that myofibroblasts are mainly responsible for its synthesis in fibroblastic foci of UIP.

Idiopathic nonspecific interstitial pneumonia: prognostic significance of cellular and fibrosing patterns: survival comparison with usual interstitial pneumonia and desquamative interstitial pneumonia

Nonspecific interstitial pneumonia (NSIP) has been proposed as a histologic subtype of idiopathic interstitial pneumonia with lung biopsy findings that are inconsistent with those of other idiopathic interstitial pneumonias. NSIP has a broad spectrum of histologic findings and a variable prognosis. The aim of this study was to determine whether it would be preferable to subdivide NSIP into cellular and fibrosing patterns. The authors classified lung biopsies from 101 patients with idiopathic interstitial lung disease as having histologic patterns of desquamative interstitial pneumonia (DIP), usual interstitial pneumonia (UIP), or cellular or fibrosing NSIP. Survival analysis was performed using the Kaplan-Meier method. Due to histologic, clinical, and survival similarities, the patients with idiopathic NSIP with lung biopsies that showed fibrosing as well as fibrosing and cellular patterns were combined into a single group of NSIP, fibrosing pattern. Of the 101 patients, 16 patients (9 women, 7 men) had idiopathic DIP; 56 patients (17 women, 39 men) had idiopathic UIP; 22 patients (7 women, 15 men) had idiopathic NSIP, fibrosing pattern; and 7 patients (2 women, 5 men) had idiopathic NSIP, cellular pattern. The patients had a mean age of 42, 51, 50, and 39 years respectively. Patients with idiopathic NSIP, cellular pattern had a better 5- and 10-year survival than those with idiopathic NSIP, fibrosing pattern (100% vs 90% and 100% vs 35% respectively, p = 0.027). Survival of patients with idiopathic UIP was worse than that of patients with idiopathic NSIP, fibrosing pattern (p = 0.014). The difference, however, was more evident at 5 years (43% vs 90%) than at 10 years (15% vs 35%). The 5- and 10-year survival of patients with idiopathic NSIP, cellular pattern and DIP was 100%, which was significantly better than that of patients with idiopathic UIP (p <0.0001). Based on these data, NSIP should be separated into cellular and fibrosing patterns, because these histologic patterns are associated with different clinical characteristics and prognoses.

Anti-cytokine therapy in fibrosing alveolitis: where are we now?

Idiopathic pulmonary fibrosis (IPF) is a condition that has a poor prognosis, with a median survival of 4-5 years irrespective of treatment. Ziesche et al (N Engl J Med 1999, 341: 1264-1269) describe an open randomised trial of 18 patients with IPF, unresponsive to corticosteroid treatment at high dose. Nine patients were treated with continued corticosteroid and nine with prednisolone plus interferon-gamma 1b (IFN-gamma). Significant benefits in physiological parameters are reported in the IFN-gamma-treated group. An analysis of lung tissue by reverse-transcriptase-mediated polymerase chain reaction showed corresponding decreases in the transcription of transforming growth factor-beta1 and connective tissue growth factor. This is the first report of treatment showing efficacy in this disease, albeit in a very preliminary study, but the data should be viewed with caution. This study is discussed in the context of other published studies of treatment for IPF and the scientific rationale on which it was based.

Serial high resolution CT findings in nonspecific interstitial pneumonia/fibrosis

PURPOSE

The purpose of this work was to evaluate the radiographic and serial high resolution CT (HRCT) findings in patients with nonspecific interstitial pneumonia/ fibrosis (NSIP).

METHOD

We identified 15 patients with biopsy-proven NSIP. Radiography and initial and follow-up CT findings were reviewed.

RESULTS

Predominant radiographic findings were bilateral infiltrates distributing in the middle and lower lung zones and decreased lung volumes. At initial CT, predominant patterns were peribronchovascular interstitial thickening (n = 6), parenchymal bands (n = 8), intralobular interstitial thickening (n = 12), and traction bronchiectasis (n = 14). Mixed pattern of ground-glass opacity and consolidation (n = 11) were predominant findings of increased lung opacity. At follow-up CT in 14 cases, the abnormalities had disappeared completely in 3, improved in 9, persisted in 1, and worsened in 1.

CONCLUSION

The pulmonary abnormalities observed in NSIP on HRCT can disappear or be diminished in most cases after corticosteroid therapy. Intralobular interstitial thickening and traction bronchiectasis, which have been considered to be indicators of irreversible fibrosis, also show favorable responses.

High-resolution computed tomography in the evaluation of fibrosing alveolitis

High-resolution computed tomography (HRCT) is now widely used in the investigation of patients with suspected or known diffuse lung disease. This article reviews some of the technical aspects of HRCT and the pathologic considerations that should be appreciated in the context of diagnosing fibrosing alveolitis. The precise quantitation of disease extent and characterization of disease pattern on HRCT has been used to provide new insights about the prognosis and pathophysiology of fibrosing lung disease.

The accuracy of the clinical diagnosis of new-onset idiopathic pulmonary fibrosis and other interstitial lung disease: A prospective study

STUDY OBJECTIVES

Presently, surgical (open or thoracoscopic) lung biopsy (SLB) is the gold standard for the diagnosis of new-onset idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs). The accuracy of a clinical diagnosis of IPF and other subsets of ILD has never been established in prospective studies. We investigated the accuracy and validity of a clinical diagnosis of IPF and ILD other than IPF.

DESIGN

Prospective, independent evaluation of patients and clinical data by an ILD expert, of chest radiographic and high-resolution computed tomography (HRCT) features by a chest radiologist, and of histologic features of lung biopsy by a pulmonary pathologist in consecutive patients referred for a diagnostic evaluation of ILD.

SETTING

Tertiary university medical center with recognized expertise in management of ILD.

PATIENTS

Community patients referred for further definitive diagnostic evaluation of new-onset, untreated nonspecific ILD.

INTERVENTION

By comparing the histologic features of SLB in 59 patients consecutively referred for further diagnostic evaluation of new-onset ILD with the clinical and radiologic diagnoses, we determined the sensitivity and specificity of clinical diagnosis and radiologic diagnosis (based on chest radiograph and HRCT features alone) of IPF and ILD other than IPF. A specific clinical diagnosis was independently made by the ILD expert after a thorough clinical assessment that included evaluation of an HRCT scan and bronchoscopic findings. The chest radiographs and HRCT scans were separately reviewed by the chest radiologist, who made a radiologic diagnosis independently. All patients underwent SLB within a month of preoperative "clinical" diagnosis. The clinician's and radiologist's diagnoses were then compared with the gold standard of histologic diagnosis.

MEASUREMENTS AND RESULTS

Prior to the clinical evaluation at our center, 85% of patients who underwent SLB had nondiagnostic transbronchial biopsy. The diagnosis of IPF and ILD other than IPF was accurately made by clinical features alone in 62% of cases. The correct radiographic diagnosis of non-IPF ILD was made in 58% of the cases. The sensitivity and specificity of the clinical diagnosis of ILD other than IPF were 88.8% and 40%, respectively. The sensitivity and specificity of the radiographic diagnosis of ILD other than IPF were 59% and 40%, respectively. However, the sensitivity and specificity of the diagnosis of IPF on clinical grounds were 62% and 97%, respectively. The sensitivity and specificity of the radiologic diagnosis of IPF were 78.5% and 90%, respectively.

CONCLUSIONS

In a center with recognized expertise in the management of ILD, the specificity of diagnosis of new-onset IPF based on a thorough clinical assessment or HRCT features alone is very high (97% and 90%, respectively), but the sensitivity is low (62% and 78.5%, respectively). Thus, not all patients with new-onset IPF require SLB for diagnosis, but a diagnosis of IPF will be missed in nearly one third of new-onset IPF cases despite evaluation by experts. The relatively low sensitivity and specificity of the diagnosis of ILD other than IPF also emphasizes that an SLB is indicated in patients with ILD in whom the diagnosis is unclear.

A case of group II non-specific interstitial pneumonia developed during corticosteroid therapy after acute respiratory distress syndrome

Non-specific interstitial pneumonia/fibrosis (NSIP) is a relatively new entity among idiopathic interstitial pneumonias. This disease is pathologically characterized by varying proportions of interstitial inflammation and fibrosis that appear to occur over a single, short period of time, and is clinically characterized by a generally good prognosis. Although corticosteroid therapy is widely considered to be effective for treatment of this disease, we report a case of Group II NSIP which developed during treatment with corticosteroid 4 months after acute respiratory distress syndrome (ARDS). This case suggests that any group of NSIP may be developed after ARDS, and that low-dose corticosteroid treatment is not sufficient to prevent the development of NSIP.

A histologic pattern of nonspecific interstitial pneumonia is associated with a better prognosis than usual interstitial pneumonia in patients with cryptogenic fibrosing alveolitis

This study aimed to investigate whether there was a difference in outcome related to histologic pattern in cryptogenic fibrosing alveolitis (CFA) and to see whether there were correlations between clinical and radiologic findings and histology. One hundred thirteen lung biopsies from consecutive patients taken for the diagnosis of diffuse lung disease were reviewed and reclassified using the Katzenstein and Myers criteria for interstitial pneumonias. Patients lacking full investigational data at presentation and those with conditions predisposing to lung fibrosis were excluded, leaving 15 patients diagnosed with nonspecific interstitial pneumonia (NSIP) and 15 with usual interstitial pneumonia (UIP). Clinical and radiologic findings at presentation and serial lung function information and survival status in November 1998 were compared for the two groups. Survival was found to be significantly greater in the NSIP group compared with the UIP group (p < 0.001). This could not be explained by differences in treatment. Patients with UIP showed a progressive deterioration in lung function whereas those with NSIP remained stable. CT scans of patients with UIP showed more fibrosis than those of patients with NSIP (p < 0.011). A histologic diagnosis of NSIP is associated with a better prognosis than UIP. This subclassification of CFA is clinically useful.

Clinical features of non-specific interstitial pneumonia

The clinical features of 24 patients with non-specific interstitial pneumonia (NIP) were evaluated. The patients consisted of seven men and 17 women, with a median age of 60 years. In seven patients, the disease was idiopathic and eight had collagen vascular diseases. Cough, dyspnoea and fever were frequently observed. The time interval between the onset of symptoms and open lung biopsy was 3 months. Mild increases of IgG, CRP, and LDH were also frequently observed. The average per cent VC was 65.1 +/- 3.2% and the average PaO2 was 71.3 +/- 2.4 Torr. Bronchoalveolar lavage was done in 20 patients, and a moderate increase in lymphocytes (27.8 +/- 6.7%) with a low CD4/CD8 ratio (0.86 +/- 0.22) was observed. Multiple patchy infiltration or diffuse interstitial shadows, located predominantly in the lower fields of both lungs were the characteristic chest CT findings. Lung biopsies in this group were characterized by varying proportions of chronic interstitial inflammation and fibrosis which was temporarily uniform. Patients were given steroid pulse therapy or oral steroids. The results were mild to marked improvements in chest roentgenographic findings and lung functions. Four patients (16.7%) died because of respiratory failure caused by NIP. This is the first report to describe clinical features of NIP since the original report by Katzenstein and Fiorelli.

Idiopathic pulmonary fibrosis: current concepts

Idiopathic pulmonary fibrosis (IPF) is generally defined as a progressive, fibrosing inflammatory disease of the lung parenchyma of unknown cause. It is characterized by slowly increasing dyspnea, diffuse interstitial lung infiltrates, restrictive lung dysfunction, and impaired gas exchange. Ultimately, it is fatal in most patients, and treatment options remain unsatisfactory. The advent of high-resolution computed tomography of the chest and modifications in the histopathologic classification of interstitial pneumonias have reshaped the concept of IPF. Although initially thought to be a relatively specific clinicopathologic entity, it seems likely that IPF as previously defined is a heterogeneous disorder consisting of several clinicopathologic entities with differing histopathologic patterns, clinical course, response to therapy, and prognosis. The most common histologic pattern in cases previously defined as IPF is usual interstitial pneumonia, which is associated with a median survival of less than 3 years. For accurate prognosis and optimal management of patients, the clinician should attempt to be as precise as possible in distinguishing various clinicopathologic entities that have been included under the clinical heading of IPF. In the future, we recommend that the use of the term "idiopathic pulmonary fibrosis" be restricted to patients with usual interstitial pneumonia and that clinicians recognize the fact that other idiopathic interstitial pneumonias do not have the same prognostic effect traditionally ascribed to IPF.

Nonspecific interstitial pneumonia. Individualization of a clinicopathologic entity in a series of 12 patients

Nonspecific interstitial pneumonia/fibrosis (NSIP) has recently been individualized within the group of idiopathic interstitial pneumonias mainly based on a pathologic pattern of temporally uniform lesions distinct from usual, desquamative, and acute interstitial pneumonia. We studied 12 consecutive patients with NSIP at lung biopsy done as a diagnostic procedure for idiopathic interstitial lung disease. The patients were six males and six females, aged 52.5 +/- 11.8 yr. In 8 of 12 cases the pathologic lesions consisted of both cellular interstitial inflammation and fibrosis, whereas only cellular inflammation was present in three cases, and fibrosis in one. Dyspnea, cough, inspiratory crackles, and squeaks were the most common symptoms and signs. Six cases were cryptogenic. An associated disorder or a presumed cause was present in the other six patients, including underlying connective tissue disease (n = 3), organic dust exposure (n = 2), and prior acute lung injury (n = 1). Lung function tests found a restrictive ventilatory defect (11/12), impairment of TLCO (11/11), and hypoxemia at rest (7/12). Chest X-ray showed infiltrative opacities in all cases. Computed tomography of the chest in 11 cases mainly showed ground glass opacities (9/11), patchy areas of alveolar consolidation (6/ 11), and thickening of interlobular septas (5/11). All patients were treated with corticosteroids, and seven with immunosuppressive agents. All patients were alive at last follow-up, 50 +/- 40 mo after diagnosis. Ten patients (83%) were clinically improved or stabilized. Thus, despite its heterogeneity, NSIP deserves to be individualized as an original clinicopathologic entity and should be clearly distinguished from usual interstitial pneumonia, especially because of a better prognosis.

Colchicine versus prednisone in the treatment of idiopathic pulmonary fibrosis. A randomized prospective study. Members of the Lung Study Group

Twenty-six symptomatic subjects with clinical evidence plus either high-resolution computed tomography (HRCT, n = 25) or open-lung biopsy (OLB, n = 1) patterns typical for idiopathic usual interstitial pneumonia (idiopathic UIP) were entered into a randomized prospective treatment trial using high-dose prednisone (n = 12) versus colchicine (n = 14). The minimum dose of prednisone used was 60 mg/d for 1 mo, tapered to 40 mg/d over the second month, tapered to 40 mg every other day during the third month, with subsequent doses adjusted as clinically indicated. The dose of colchicine was 0.6-1.2 mg/d, as tolerated. The presence of a rim of subpleural honeycomb change was present in all of the 25 subjects who had HRCT. Subjects treated with high-dose prednisone alone experienced a higher incidence of serious side effects and also exhibited a trend (not statistically significant, p = 0.391) to more rapid decline of pulmonary function and shortened survival than did those treated with colchicine alone. In most subjects with typical clinical and HRCT features of idiopathic UIP, neither prednisone nor colchicine resulted in objective improvement, and the disease continued to progress in the majority. Colchicine appears to be a safer alternative to a trial of high-dose prednisone but may be no different than no therapy.