A comparative study of the prognosis for Japanese patients with idiopathic interstitial pneumonia or BOOP based on histopathologic subsets]

We explored the prognosis for 123 patients with either idiopathic interstitial pneumonia (IIP) or bronchiolitis obliterans organizing pneumonia (BOOP). All patients underwent either open lung biopsy or thoracoscopic lung biopsy procedures. The histopathologic diagnosis of IIP included patients with usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), and desquamative interstitial pneumonia with respiratory bronchiolitis-associated interstitial lung disease. The prognosis was poorest for patients with a histologic diagnosis of UIP, and excellent for those who received a diagnosis of BOOP. Although the prognosis is generally considered to be good for patients with NSIP, some NSIP patients in our study died. Histopathologic diagnosis based on surgical lung biopsy is useful in evaluating the prognosis for patients with IIP.     

Classification and recent advances in idiopathic interstitial pneumonia

Idiopathic interstitial pneumonia (IIP) is a heterogeneous group of diseases comprising acute interstitial pneumonia, bronchiolitis obliterans organizing pneumonia (BOOP), nonspecific interstitial pneumonia, desquamative interstitial pneumonia, and idiopathic pulmonary fibrosis and usual interstitial pneumonia (IPF/UIP). We review the clinicopathological spectrum of IIP and introduce recent advances in classification, treatment, and prognosis. BOOP can be clinically categorized as an interstitial pneumonia, though prominent granulation tufts are seen in the airspaces. Though differences between the nonspecific interstitial pneumonia and other lips can be histopathologically clarified, the focus of clinical research on NSIP is differentiation from BOOP, or from IPF and UIP. IIP can be categorized into two groups: groups with acute or subacute lung injuries or fibrosis, such as in acute interstitial pneumonia, BOOP and nonspecific interstitial pneumonia, and groups with chronic injuries or fibrosis, such as IPF/UIP. This classification accords well with the maturity of fibrosis, CT findings, bronchoalveolar lavage fluid cell findings, and prognosis. The most critical problem is the treatment of IPF/UIP, because of its high mortality.     

Role of surgical lung biopsy in separating chronic hypersensitivity pneumonia from usual interstitial pneumonia/idiopathic pulmonary fibrosis: analysis of 31 biopsies from 15 patients

BACKGROUND: Lung biopsy has been proposed as a criterion for diagnosis of chronic hypersensitivity pneumonia (HP), especially in patients without proven antigen exposure. Histologic findings in some suspected HP patients overlap with usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). We reviewed our experience to determine the specificity of histologic findings in surgical lung biopsies from patients with clinical diagnoses of HP. METHODS: Surgical lung biopsies from patients with chronic HP, idiopathic pulmonary fibrosis, and idiopathic NSIP were reviewed retrospectively without knowledge of the clinical diagnosis. Each specimen was assigned a histologic diagnosis, and selected histologic findings were tabulated. Clinical data were abstracted from medical records. RESULTS: Fifteen patients with clinical diagnoses of chronic HP underwent biopsy of one to three lobes. Ten showed features diagnostic of HP in all specimens. Two had discordant findings that included HP in one specimen and UIP or nonspecific changes in others. Biopsies from two showed only UIP, and one showed NSIP. Diagnostic features were present in all samples from 9 of the 11 patients with more than one biopsy site (81.8%). Three patients died of disease, including both patients from whom biopsies showed only UIP. CONCLUSIONS: Most patients with a clinical diagnosis of chronic HP have supportive histologic findings in surgical lung biopsies. A subset of HP patients has findings indistinguishable from UIP. Sampling from more than one lobe may be helpful in separating HP from idiopathic pulmonary fibrosis.     

Histologic spectrum of idiopathic interstitial pneumonias

Histopathologic classification plays a key role in separating multiple forms of idiopathic interstitial pneumonia into clinically meaningful categories with important differences in natural history, prognosis, and treatment. Microscopic criteria in diagnosis of these entities include the pattern and microanatomic distribution of inflammation, fibroblast proliferation, collagen deposition, and architectural remodeling. Usual interstitial pneumonia (UIP) defines idiopathic pulmonary fibrosis and is the most common of the idiopathic interstitial pneumonias. UIP has distinctive morphologic features that allow precise diagnosis in classical cases. Other forms of idiopathic interstitial pneumonia include desquamative interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, acute interstitial pneumonia, and nonspecific interstitial pneumonia. These latter categories differ from UIP in that the histopathologic findings do not, by themselves, allow specific diagnosis in most cases and require careful correlation with clinical and radiologic findings.     

BAL findings in idiopathic nonspecific interstitial pneumonia and usual interstitial pneumonia.

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

Proliferative characteristics of fibroblast lines derived from open lung biopsy specimens of patients with IPF (UIP).

We compared the doubling time of fibroblasts derived from idiopathic pulmonary fibrosis (usual interstitial pneumonia) (IPF [UIP]) lung tissues and control fibroblasts, cultured in usual growth medium, and examined the response of these fibroblasts to platelet-derived growth factor (PDGF) and prostaglandin E2 (PGE2). Ten fibroblast lines from open lung biopsy specimens of patients with IPF (UIP) and ten control fibroblast lines from surgically resected lung tissue of patients with limited lung diseases were established. The average doubling time of fibroblast lines was 32.0 +/- 6.0 h (mean +/- SD) in UIP and 33.2 +/- 10.4 h in controls, showing no difference between the two groups. To examine the responses of fibroblasts to PDGF and PGE2 and the differences between fibroblasts derived from fibrotic tissues with different intensity of fibrosis, lung specimens from five patients with IPF were subdivided into two groups, higher-intensity fibrotic lesions (H) and lower-intensity fibrotic lesions (L). The fibroblast lines were established separately. 3H-thymidine uptake with or without PDGF or PGE2 was examined. Results were expressed as the index of thymidine incorporation into the fibroblasts. There were no differences in the doubling times and the responses to PDGF and PGE2 between H and L. There were no differences between control and H regarding their response to PDGF. In response to PGE2, the growth inhibition for H was significantly decreased compared with the control (p less than 0.05). There was no difference in growth inhibition between H and L. The finding that PGE2 inhibits fibroblast proliferation less in UIP lung tissue suggests that fibroblasts from UIP were functionally altered cells or, to some extent, out of normal regulation. These results suggest an abnormal proliferation of fibroblasts observed in IPF (UIP).     

Interstitial lung disease in primary Sjögren syndrome

BACKGROUND: Primary Sj?gren syndrome (pSS) has been associated with various histologic patterns of interstitial lung disease (ILD). METHODS: We retrospectively identified 18 patients with pSS and suspected ILD who underwent lung biopsies (14 surgical biopsies and 9 bronchoscopic biopsies) at our institution during a 13-year period from 1992 through 2004. Histopathologic findings were analyzed and correlated with radiologic features and outcome. RESULTS: Median age was 62 years (range, 34 to 78 years), and 15 patients (83%) were women. Most patients presented with dyspnea and cough. Chest radiographs demonstrated bilateral infiltrates, and high-resolution CT revealed abnormalities of various types including ground-glass, consolidation, reticular, and nodular opacities. The major histopathologic patterns included nonspecific interstitial pneumonia (NSIP) [five patients], organizing pneumonia (OP) [four patients], usual interstitial pneumonia (UIP) [three patients], lymphocytic interstitial pneumonia (three patients), primary pulmonary lymphoma (two patients), and diffuse interstitial amyloidosis (one patient). In four patients (three with OP and one with amyloidosis), the diagnosis was established on transbronchial biopsy results. Treatment commonly included prednisone with or without another immunosuppressive agent. During the follow-up period (median, 38 months), most patients improved or remained stable except three patients with UIP, one patient with NSIP, and one patient with amyloidosis. Seven patients (39%) died, including three deaths from acute exacerbation of interstitial pneumonia. CONCLUSIONS: A variety of histologic patterns can be seen in patients with pSS-associated ILD. Those with UIP tended to have progression of lung disease. Death from acute exacerbation of interstitial pneumonia may occur in patients with pSS-associated ILD.     

Nonspecific interstitial pneumonia: a real clinical entity?

Based on the current multidisciplinary classification of idiopathic interstitial pneumonia (IIP) organized by ATS/ERS, nonspecific interstitial pneumonia (NSIP) is considered as one type of IIP. An incidence of idiopathic NSIP is relatively small and possesses clinical features that are different than idiopathic pulmonary fibrosis (IPF) and usual interstitial pneumonia (UIP). Because there is little evidence of a long-term prognosis in patients with NSIP, some of them have an unfavorable prognosis similar to IPF/UIP. We review the significance of prognostic factors that have been reported in patients with IPF/UIP by applying them to patients with NSIP. The association with collagen vascular diseases focuses on etiologic background. Finally, the article discusses whether NSIP could be an early lesion of UIP based on the reported evidence and our own professional experiences.     

Unique characteristics of systemic sclerosis sine scleroderma-associated interstitial lung disease

STUDY OBJECTIVES: To describe the characteristics of systemic sclerosis sine scleroderma (ssSSc)-associated interstitial lung disease (ILD) presenting as idiopathic interstitial pneumonia (IIP). DESIGN: Retrospective review of six patients with ssSSc-associated ILD diagnosed after referral for evaluation of IIP. MEASUREMENT AND RESULTS: All patients were white, their mean age was 56 years (range, 37 to 86), and gender was evenly divided. Sclerodactyly, skin thickening, and digital edema were absent in all patients. All patients had scattered telangiectasia, and four patients had Raynaud phenomenon with abnormal nailfold capillaroscopy findings. All described gastroesophageal reflux, and three patients had esophageal dysmotility by esophagography. All had restrictive pulmonary physiology and a reduced diffusion capacity. High-resolution CT revealed nonspecific interstitial pneumonia (NSIP) or usual interstitial pneumonia (UIP) radiographic patterns. Of the three patients who underwent surgical lung biopsy, two patients had NSIP and one patient had UIP pathologic patterns. Five patients had asymptomatic pericardial effusions and elevated pulmonary artery pressures by echocardiography. All patients had nucleolar-staining anti-nuclear antibodies (ANAs), and one patient was anti-Scl-70 positive. All five anti-Scl-70-negative patients were anti-Th/To positive, and the anti-Scl-70-positive patient was anti-Th/To negative. CONCLUSIONS: In the presentation of an IIP, the presence of a nucleolar-staining ANA, telangiectasia, Raynaud phenomenon with abnormal capillaroscopy findings, gastroesophageal reflux, or pericardial disease suggests underlying systemic sclerosis. These findings should aid clinicians in the evaluation and treatment of patients with otherwise undefined ILD.     

High-BAL fluid concentrations of RANTES in nonspecific interstitial pneumonia compared with usual interstitial pneumonia

Chemokines such as regulated on activation, normal T-cell expressed and secreted (RANTES), monocyte chemoattractant protein (MCP)-1, monocyte inflammatory protein (MIP)-lalpha have been reported to play an important role in the pathogenesis of interstitial lung diseases. Among idiopathic interstitial pneumonia (IIP), nonspecific interstitial pneumonia (NSIP) has elevated percentages of Lymphocytes in bronchoalveolar lavage (BAL) fluid compared with usual interstitial pneumonia (UIP). These chemokines are candidate mediators for lymphocyte attraction to the lung in NSIR Therefore, we measured the BAL fluid levels of RANTES, MCP-1 and MIP1-alpha in 15 patients with idiopathic NSIP, 20 with idiopathic UIP, 22 with sarcoidosis and 12 healthy volunteers to evaluate the contribution of these chemokines using enzyme-linked immunosorbent assays. The levels of RANTES in BAL fluid were significantly higher in patients with NSIP compared with healthy volunteers (P < 0.01), UIP and sarcoidosis (P < 0.05). In MCP-1, the levels in BAL fluid of NSIP and UIP patients were significantly elevated compared with healthy volunteers and sarcoidosis patients (P < 0.01). These results suggest that RANTES and MCP-1 in BAL fluid may play an important role in inflammatory cell recruitment to the lung in idiopathic NSIP as well as other interstitial lung diseases.     

Lung biopsy in rheumatoid arthritis

Forty open lung biopsies from patients with rheumatoid arthritis and possible "rheumatoid lung disease" were reviewed in an attempt to correlate histology with radiologic, physiologic, and prognostic variables. A wide variety of histopathologic features was seen, and primary and secondary patterns of injury were recognized. Five different groups based on histologic patterns were identified: pulmonary rheumatoid nodules, usual interstitial pneumonia (UIP), bronchiolitis obliterans with patchy organizing pneumonia (BOOP), lymphoid hyperplasia, and cellular interstitial infiltrates. The finding of rheumatoid nodules as the primary pattern imparted a uniformly good prognosis, whereas the pattern of UIP indicated a poor one. Patients with BOOP had a more favorable prognosis than did patients with UIP, as did patients with lymphoid hyperplasia and/or nonspecific cellular interstitial infiltrates. Consistent correlations between pulmonary function testing and roentgenographic and histologic findings were not found. The term "rheumatoid lung disease" is of no use as a histologic diagnosis because it encompasses a broad spectrum of morphologic changes that carry significantly different prognoses.     

Inflammatory cell phenotyping of the pulmonary interstitium in idiopathic interstitial pneumonia

BACKGROUND: Several studies have implicated the role of inflammation in the pathogenesis of lung damage in idiopathic interstitial pneumonias (IIPs). Investigations of inflammatory cells in IIP have show that eosinophils, neutrophils and T cells may be associated with a poorer prognosis. OBJECTIVES: The aim of our study was to map, by quantitative analysis, the number of inflammatory cells in the lung tissue of patients with non-specific interstitial pneumonia/non-specific interstitial pneumonia (NSIP/NSIP), acute interstitial pneumonia/diffuse alveolar damage (AIP/DAD) and idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) and to correlate them with lung function tests and survival. METHODS: After immunohistochemical staining, we quantified the content of inflammatory cells [macrophages, neutrophils (elastase+), plasma cells, and CD3, CD4 and CD8 T lymphocytes (TLs)] in 20 NSIP, 20 DAD and 20 UIP surgical lung biopsies. RESULTS: The total density of inflammatory cells was significantly increased in DAD and NSIP when compared to UIP (p = 0.04). TLs were increased in DAD and NSIP when compared to UlP lungs (p < 0.05). The density of inflammatory cells in UIP showed significant differences in normal, intervening and dense fibrosis areas (p < 0.05). The most numerous cells infiltrating the mural fibrosis and honeycombing areas were plasma cells, neutrophils (elastase+), CD20+, CD3+, CD4+ and CD8+ (p < 0.05). In UIP, CD3+ TLs were directly correlated with forced expiratory volume in 1 s/forced vital capacity ratio x 100 (p = 0.05). CD68+ cells presented a significant positive correlation with the forced expiratory volume in 1 s (p = 0.04); neutrophil (elastase+) cells significantly correlated with residual volume (p = 0.02), residual volume/total lung capacity (p = 0.04) and carbon monoxide transfer factor (p = 0.03). The most important predictor of survival in UIP was CD3+ TLs (p = 0.05). CONCLUSION: The total density of inflammatory cells and lymphocytes presents a different distribution within the pulmonary parenchyma in AIP/DAD, NSIP/NSIP and IPF/UIP evolutionary adapted responses to injury. There is a localized distribution of inflammation in the normal, intervening and dense fibrosis areas of UIP for CD3+, associated with a lethal deterioration of the pulmonary function and poor survival. Our findings provide further evidence of the importance of inflammation in the pathophysiology of IIPs.     

Lung fibrosis: new classifications and therapy.

The recent American Thoracic Society/European Respiratory Society consensus classification of idiopathic interstitial pneumonia is equally applicable to pulmonary fibrosis associated with connective tissue disease. The most frequent histopathologic entities are usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), which is more prevalent than UIP in systemic sclerosis. The prognostic significance of NSIP is unknown in connective tissue disease, although NSIP has a better prognosis than UIP in idiopathic interstitial pneumonia. The use of computed tomography to distinguish between UIP and NSIP requires further refinement. Recent therapeutic studies have reinforced disenchantment amongst clinicians with corticosteroid and immunosuppressive regimens in UIP. UIP is increasingly regarded an "epithelial-fibrotic" disease rather than a primarily inflammatory disorder, accounting for recent widespread interest in antifibrotic agents. This conclusion should not be extrapolated to NSIP, especially in connective tissue disease. Strong circumstantial evidence of a therapeutic benefit justifies the continued use of cyclophosphamide in progressive lung fibrosis in systemic sclerosis.     

Fibroblast contractility: usual interstitial pneumonia and nonspecific interstitial pneumonia

The aim of this study was to compare the function of lung fibroblasts obtained from surgically biopsied specimens of patients with idiopathic pulmonary fibrosis/usual interstitial pneumonia (UIP; n = 5), nonspecific interstitial pneumonia (NSIP; n = 5), and normal parts of surgically resected lungs (control; n = 5). The results showed that (1) fibroblasts obtained from UIP showed increased contractility compared with those obtained from NSIP or controls (UIP, 72.7 +/- 6.21%; NSIP, 32.8 +/- 5.46; controls, 28.5 +/- 3.51, p < 0.01 in UIP versus NSIP or control); (2) this increase in contractility was consistent with enhanced F-actin content in fibroblasts; (3) conditioned media from UIP fibroblast cultures enhanced control fibroblast contractility, whereas those obtained from NSIP or controls did not; (4) the 180 and 25 kD products representing the contractility in conditioned media were identified as fibronectin (ED-A domain) and TGF-beta1 by immunoblots, respectively; (5) the UIP-conditioned media contained higher amounts of fibronectin or TGF-beta 1 (fibronectin: UIP 289 +/- 47.1 ng/ml, NSIP 121 +/- 23.0, control 118 +/- 16.0; TGF-beta1: UIP 798 +/- 119 pg/ml, NSIP 246 +/- 69.1, control 247 +/- 53.6, p < 0.01 in UIP versus NSIP or control); () the contractility positively correlated with the amount of either fibronectin (r = 0.867, p < 0.001, n = 15) or TGF-beta 1 (r = 0.939, p < 0.001, n = 15), respectively. Thus, UIP fibroblasts showed greater contractility than did NSIP fibroblasts and up-regulated control fibroblasts.     

Proliferative characteristics of fibroblast lines derived from open lung biopsy specimens of patients with the usual interstitial pneumonia form of idiopathic pulmonary fibrosis]

One form of idiopathic pulmonary fibrosis (IPF), usual intersitial pneumonia (UIP) is characterized pathologically by patchily distributed fibrotic areas in apparently normal parenchyma. Excessive accumulation of collagen and fibroblasts in fibrotic areas are shown histologically. Fibroblast proliferation is generally evaluated as a process following alveolitis. However, substantial alveolitis with increased inflammatory and immune cells were not observed in our UIP cases. To evaluate the possibility that fibroblasts in UIP are controlled by mechanisms other than normal paracrine regulation, proliferative features of lung fibroblast lines from UIP lung with regular growth medium, platelet derived growth factor (PDGF) and prostaglandin E2 (PGE2) were investigated. Ten fibroblast lines from open lung biopsy specimens of patients with IPF (UIP) and 10 control fibroblast lines from surgically resected lung tissues of patients with limited lung disease were established. The doubling time of fibroblast lines with regular growth medium was UIP:32.0 +/- 6.0 hrs. (mean +/- S.D.), normal control: 33.2 +/- 10.4 hrs. There was no difference between the groups. To examine growth promotion activity by PDGF and growth inhibition by PGE2, lung specimens from 4 patients with IPF were subdivided into tissue with high intensity fibrotic lesion (H) and low intensity fibrotic lesion (L), and the fibroblast lines were established separately. 3H-thymidine uptake with or without PDGF and PGE2 was examined, and results were expressed as the stimulation index. Growth promotion by PDGF was H: 1.97 +/- 1.19, L: 1.89 +/- 0.78, normal control: 2.29 +/- 0.55. There were no differences between groups. Growth inhibition by PGE2 was H: 0.88 +/- 0.24, L: 0.69 +/- 0.49, normal control: 0.44 +/- 0.33. Growth inhibition for H was significantly lower than control (p less than 0.05). Growth inhibition for L was lower than controls, but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum 7S collagen levels in diffuse interstitial lung diseases--an index of the destruction of alveolar structure]

To examine whether alteration of 7S collagen in the alveolar basement membrane is related to the condition and prognosis of diffuse interstitial lung diseases (idiopathic interstitial pneumonia: IIP, collagen vascular diseases, sarcoidosis, and hypersensitivity pneumonitis), we measured serum 7S collagen levels in 123 patients with diffuse interstitial lung disease and other lung diseases. Patients with diffuse lung diseases (diffuse interstitial lung disease, pulmonary emphysema, and diffuse panbronchiolitis: DPB) showed significantly higher serum levels of 7S collagen than healthy normal controls. Serum 7S collagen levels in IIP and collagen vascular diseases were significantly higher than those in pulmonary emphysema and DPB. In cases of IIP, serum 7S collagen levels in the active stage were significantly higher than those in the inactive stage. Furthermore, the prognosis of patients with higher serum 7S collagen levels was significantly poorer than those of patients with lower serum 7S collagen levels. In infectious pulmonary diseases, serum 7S collagen levels of patients with adult respiratory distress syndrome (ARDS) were significantly higher than those of patients without ARDS. Autopsy specimens obtained from patients with positive serum 7S collagen showed diffuse alveolar damage and/or diffuse pulmonary hemorrhage in the alveolar areas. Immunohistochemical staining for 7S collagen showed disruption and/or loss of the alveolar basement membrane. The authors conclude that serum level of 7S collagen is useful for estimating the activity of diffuse interstitial lung diseases as an index of the destruction of alveolar structure.     

Nonspecific interstitial pneumonia and usual interstitial pneumonia: comparison of the clinicopathologic features and prognosis

Background

Nonspecific interstitial pneumonia (NSIP) has recently been proposed as a histologic type of idiopathic interstitial pneumonia (IIP), but its broad spectrum of clinicopathologic findings and variable prognosis are poorly understood. It is particularly unclear how NSIP and usual interstitial pneumonia (UIP) are related. The present study investigated the clinicopathologic features and prognosis of NSIP, and its differential diagnosis from UIP.

Methods

The clinicopathologic findings and prognosis in 21 NSIP and 18 UIP patients who underwent surgical or video-assisted thoracoscopic lung biopsy were reviewed.

Results

NSIP was more frequent in women and showed nonspecific clinical manifestations. High-resolution computed tomography (HRCT) demonstrated ground-glass, net-like, and patchy attenuation in both lungs. Semiquantitative HRCT showed a median fibrosis score of 3 (range, 0 to 7) in NSIP patients and 5 (range, 2 to 7) in UIP patients (P<0.01). On histopathologic examination, NSIP cases were heterogeneous and the findings could be categorized into cellular and fibrosing patterns. The mean age of the NSIP and UIP patients was 48 and 60 years, respectively. The frequencies of fibroblast foci, myogelosis, honeycomb lesions, and pulmonary structural destruction in NSIP and UIP patients were 16.7% and 100% (P<0.001), 22.2% and 85.7% (P<0.05), 16.7% and 92.9% (P<0.001), and 27.8% and 100% (P<0.05), respectively. The responses to glucocorticoid treatment and the prognosis were significantly greater in NSIP than those in UIP.

Conclusions

NSIP was difficult to be differentiated from UIP by general clinical manifestations, but HRCT can be helpful for this purpose. Definitive diagnosis depends on the results of surgical lung biopsy.     

Clinical significance of histological classification of idiopathic interstitial pneumonia.

Patients with idiopathic interstitial pneumonias (IIPs) can be subdivided into groups based on the histological appearance of lung tissue obtained by surgical biopsy. The quantitative impact of histological diagnosis, baseline factors and response to therapy on survival has not been evaluated. Surgical lung biopsy specimens from 168 patients with suspected IIP were reviewed according to the latest diagnostic criteria. The impact of baseline clinical, physiological, radiographic and histological features on survival was evaluated using Cox regression analysis. The predictive value of honeycombing on high-resolution computed tomography (HRCT) as a surrogate marker for usual interstitial pneumonia (UIP) was examined. The response to therapy and survival of 39 patients treated prospectively with high-dose prednisone was evaluated. The presence of UIP was the most important factor influencing mortality. The risk ratio of mortality when UIP was present was 28.46 (95% confidence interval (CI) 5.5-148.0; p=0.0001) after controlling for patient age, duration of symptoms, radiographic appearance, pulmonary physiology, smoking history and sex. Honeycombing on HRCT indicated the presence of UIP with a sensitivity of 90% and specificity of 86%. Patients with nonspecific interstitial pneumonia were more likely to respond or remain stable (9 of 10) compared to patients with UIP (14 of 29) after treatment with prednisone. Patients remaining stable had the best prognosis. The risk ratio of mortality for stable patients compared to nonresponders was 0.32 (95% CI 0.11-0.93; p=0.04) in all patients and 0.33 (95% CI 0.12-0.96; p=0.04) in patients with UIP. The histological diagnosis of usual interstitial pneumonia is the most important factor determining survival in patients with suspected idiopathic interstitial pneumonia. The presence of honeycombing on high-resolution computed tomography is a good surrogate for usual interstitial pneumonia and could be utilized in patients unable to undergo surgical lung biopsy. Patients with nonspecific interstitial pneumonia are more likely to respond or remain stable following a course of prednisone. Patients remaining stable following prednisone therapy have the best prognosis.     

Correlations of histologic classification with clinical features and prognosis in interstitial lung disease associated with collagen disease]

We studied 32 patients with interstitial pneumonia associated with collagen disease. All underwent surgical lung biopsy. Twenty-seven were histologically classified as follows: 8 with usual interstitial pneumonia (UIP), 10 with nonspecific interstitial pneumonia (NSIP), 6 with bronchiolitis obliterans organizing pneumonia (BOOP), and 3 with diffuse alveolar damage (DAD). Twenty-five of the patients were treated with corticosteroid but 4 (3 DAD, 1 NSIP) deteriorated rapidly and died within a month after lung biopsy. At the final follow-up, all 8 UIP patients were alive with residual respiratory impairment, whereas 6 NSIP and 4 BOOP patients had almost completely recovered. These findings suggested that histologic classification can be highly valuable to the therapeutic responsiveness and prognosis in cases of interstitial pneumonia associated with collagen disease.