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.     

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.     

The clinical significance of histopathologic subgroups in idiopathic interstitial pneumonia: is surgical lung biopsy essential?

For many years, the clinical entity of idiopathic interstitial pneumonia (IIP) has been a source of confusion for physicians. There has been much debate over the utility of subclassifying this condition histopathologically. It now appears that such classification is useful, and the most important distinction is the presence or absence of usual interstitial pneumonia (UIP). Unlike the other histopathologic subgroups, UIP has a grave prognosis and responds poorly to traditional therapies. To emphasize this clinical difference, the diagnosis of idiopathic pulmonary fibrosis (IPF), once used synonymously with IIP, is now reserved for only those patients with the histopathologic pattern of UIP. Although the gold standard for the diagnosis of IPF/UIP remains surgical lung biopsy, recent studies suggest that careful clinical and radiographic evaluation can identify IPF/UIP with a specificity of 90% or more. In the absence of a clear clinical diagnosis, we recommend pursuing surgical lung biopsy. Knowledge of the underlying histopathology will allow for more accurate prognosis, help guide therapy, and make possible the clinical investigation of novel therapeutic agents for patients with IIP.     

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.     

Myofibroblasts and S-100 protein positive cells in idiopathic pulmonary fibrosis and rheumatoid arthritis-associated interstitial pneumonia.

The aim of this study was to investigate whether idiopathic pulmonary fibrosis (IPF) can be distinguished from rheumatoid arthritis (RA)-associated interstitial pneumonia (RA-IP) by means of quantitatively assessing myofibroblasts and S-100 protein positive dendritic cells. Seven patients with IPF and twelve with RA, in whom the pathological findings were consistent with usual interstitial pneumonia (UIP) were studied. Antibodies to vimentin, alpha-smooth muscle actin (alpha-SMA) and S-100 protein were used for immunohistochemical studies performed using the streptavidin/biotin/peroxidase complex method, applied to dewaxed sections from each case. In fibrosis of RA-IP, appearance of both vimentin- and alpha-SMA-positive cells, namely myofibroblasts, was widely observed, together with the pathological patterns of honeycombing, UIP and bronchiolitis obliterans-organizing pneumonia (BOOP). Fibrosis, in cases of chronic IPF, was found to be characterized mainly by vimentin-positive but alpha-SMA-negative fibroblasts. Pulmonary tissues from RA-IP patients especially when associated with a BOOP pattern, contained many cells positive for S-100 protein. However, such cells were generally hard to find in cases of IPF. These findings suggests that idiopathic pulmonary fibrosis and rheumatoid arthritis-associated interstitial pneumonia can be differentiated from each other, to some extent, based on the appearance of myofibroblasts and the presence of S-100-positive dendritic cells.     

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.     

Fibrosing interstitial pneumonia and idiopathic pulmonary fibrosis

The most reasonable classification for diffuse interstitial pneumonia/fibrosis is described according to the clinical course, histopathological findings and responses to steroids. Idiopathic pulmonary fibrosis (IPF) represents the most prevalent, most chronic form of the disease with the worst prognosis. The histopathological findings of IPF are usual interstitial pneumonia (UIP) which microscopically is recognized as patchy lesions. In UIP diffuse alveolar inflammation does not change to diffuse alveolar fibrosis, rather the disease progresses via an increase in the number of localized fibrosis lesions. Steroids are ineffective in the treatment of IPF. Lung transplantation is the only effective treatment. The question of when such transplantation should be undertaken constitutes the subject of further study.     

Histopathologic variability in usual and nonspecific interstitial pneumonias.

Findings of surgical lung biopsy (SLB) are important in categorizing patients with idiopathic interstitial pneumonia (IIP). We investigated whether histologic variability would be evident in SLB specimens from multiple lobes in patients with IIP. SLBs from 168 patients, 109 of whom had multiple lobes biopsied, were reviewed by three pathologists. A diagnosis was assigned to each lobe. A different diagnosis was found between lobes in 26% of the patients. Patients with usual interstitial pneumonia (UIP) in all lobes were categorized as concordant for UIP (n = 51) and those with UIP in at least one lobe were categorized as discordant for UIP (n = 28). Patients with nonspecific interstitial pneumonia (NSIP) in all lobes were categorized as having fibrotic (n = 25) or cellular NSIP (n = 5). No consistent distribution of lobar histology was noted. Patients concordant for UIP were older (63 +/- 9 [mean +/- SD] yr; p < 0.05 as compared with all other groups) than those discordant for UIP (57 +/- 12 yr) or with fibrotic NSIP (56 +/- 11 yr) or cellular NSIP (50 +/- 9 yr). Semiquantitative high-resolution computed tomography demonstrated a varied profusion of fibrosis (p < 0.05 for all group comparisons), with more fibrosis in concordant UIP (2.13 +/- 0.62) than in discordant UIP (1.42 +/- 0.73), fibrotic NSIP (0.83 +/- 0.58), or cellular NSIP (0.44 +/- 0.42). Survival was better for patients with NSIP than for those in both UIP groups (p < 0.001), although survival in the two UIP groups was comparable (p = 0.16). Lobar histologic variability is frequent in patients with IIP, patients with a histologic pattern of UIP in any lobe should be classified as having UIP.     

Fibrotic idiopathic interstitial pneumonia: high-resolution computed tomography considerations

The fibrotic idiopathic interstitial pneumonias comprise usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). The characteristic high-resolution computed tomography findings of UIP are reticular abnormality and honeycombing with basal and peripheral predominance. Honeycombing is the strongest predictor of UIP. The extent of fibrosis on computed tomography (CT) is an important prognostic indicator in idiopathic pulmonary fibrosis (IPF). When ground-glass attenuation is seen in IPF it commonly progresses to fibrosis and honeycombing. Imaging may help to detect complications of IPF, including accelerated progression, lung cancer, and secondary infection. Our understanding of the clinical and radiological features of NSIP is still evolving. The CT finding of extensive ground-glass abnormality and some reticular abnormality, with basal and peripheral predominance, is strongly suggestive of NSIP. However, the CT appearances of NSIP overlap with those of UIP, organizing pneumonia (OP), and desquamative interstitial pneumonia (DIP), and biopsy may be necessary to sort this out. Other idiopathic pneumonias that may be associated with CT evidence of lung fibrosis include DIP, OP, acute interstitial pneumonia, and lymphoid interstitial pneumonia.     

Desquamative interstitial pneumonia and respiratory bronchiolitis-associated interstitial lung disease

Our understanding of the various types and patterns of diffuse lung disease that might result in fibrosis has evolved considerably over the last 50 years. Many entities now regarded as distinct had been previously "lumped' together as a single disease, "lung fibrosis,' and more recently misdiagnosed as idiopathic pulmonary fibrosis (IPF, synonymous with cryptogenic fibrosing alveolitis). In 1965 desquamative interstitial pneumonia (DIP) was first described, and later it was clearly demonstrated that the clinical and pathological features of DIP and IPF were different, particularly in terms of survival and response to therapy. They are not part of the same disease spectrum nor does DIP evolve into usual interstitial pneumonia (UIP). Later, in the mid-1980s, RBILD was described as a distinct clinicopathologic syndrome with features consistent with an interstitial lung disease among current or former smokers. In the recent histopathological classification of idiopathic interstitial pneumonia (IIP), DIP and RBILD have been included as separate entities, although there is some evidence that suggests they may lie at the two ends of a single spectrum. The debate bears similarities with the debate about DIP and UIP and is as yet unresolved. This article will give a broad and current overview of these two rarer forms of IIP, including issues that relate to diagnosis, imaging, histopathology, treatment, and prognosis.     

Cyclosporin treatment in steroid-resistant and acutely exacerbated interstitial pneumonia

OBJECTIVE: The aim of this study was to evaluate the efficacy of cyclosporin A (CsA) in patients with interstitial pneumonia (IP). DESIGN: Retrospective comparative study. PATIENTS: We reviewed 33 patients (23 males and 10 females with a mean age of 62.5 years) with histologically-proven progressive IP who were treated with CsA. All patients had corticosteroid-resistant IP or developed acute exacerbation of IP in their courses. RESULTS: The underlying systemic diseases were: idiopathic interstitial pneumonias (IIPs) in 19 patients, and collagen vascular diseases (CVDs) in 14. The histopathological patterns and underlying diseases of IP were classified as usual interstitial pneumonia (UIP)/idiopathic pulmonary fibrosis (IPF) in 10 patients, cellular-nonspecific interstitial pneumonia (NSIP)/IIPs in 3, fibrotic-NSIP/IIPs in 5, organizing pneumonia (OP)/IIP in 1, UIP/CVDs in 4, cellular-NSIP/CVDs in 7, fibrotic-NSIP/CVDs in 2, and diffuse alveolar damage (DAD)/CVD in 1, respectively. They received a low dosage of CsA combined with corticosteroids. The prognoses after treatment with CsA were well correlated with histopathological patterns. Cellular-NSIP and OP showed better prognoses than fibrotic-NSIP, UIP or DAD. In addition, CVDs had better prognoses than IIPs, when compared on the basis of the same histopathological patterns. Furthermore, the prognoses in the CsA-treated group were significantly better than in those without CsA treatment in regard to acute exacerbation of UIP/IPF. CONCLUSIONS: CsA combined with corticosteroids may be an efficacious treatment for corticosteroid-resistant IP and for acute exacerbation of IPF.     

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.     

Interstitial lung disease in polymyositis and dermatomyositis. Clinical features and prognosis as correlated with histologic findings

Open lung biopsies from 14 patients and autopsy tissue from one patient with polymyositis/dermatomyositis were reviewed in an attempt to correlate histologic features with clinical, radiographic, and prognostic variables. Three major groups based on histologic patterns were identified: bronchiolitis obliterans organizing pneumonia (BOOP), usual interstitial pneumonia (UIP), and diffuse alveolar damage (DAD). Patients with BOOP had a more favorable prognosis than did patients with UIP. Patients with DAD had a uniformly poor prognosis. One patient had a cellular interstitial pneumonia and did well. Histologic subclassification of the interstitial lung disease proved to be a better predictor of survival than did the radiographic appearance or the clinical presentation. These findings suggest that there is a broader range of histologic findings in polymyositis-dermatomyositis than is suggested in the literature and subclassification may be useful for prognosis.     

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.     

Cyclosporin A treatment of interstitial pneumonia]

To assist in making prognoses for patients with interstitial pneumonia (IP) who were treated with cyclosporin A (CsA), we conducted a review of forty-nine patients (32 men and 17 women with a mean age of 62 yrs) with progressive IP during the period from 1997 through 2001. All patients were steroid-resistant or acutely exacerbated cases. They received a low dosage of CsA (100-130 mg/day) combined with corticosteroids. Before and after the CsA therapy, blood gas analysis and HRCT scans were evaluated. Twenty-five patients underwent video-assisted thoracoscopic surgery (VATS) or autopsy for a histopathological evaluation. Among the 49 patients with IP, the documented underlying systemic diseases were of unknown etiology (IPF or IIP) in 26 and were collagen vascular diseases (CVD) in 23. The chest CT pattern and underlying systemic diseases of IP were classified as a usual interstitial pneumonia (UIP) pattern/IPF in 16 cases, a non-UIP pattern/IIP in 10 cases, a UIP pattern/CVD in 7 cases, and a non-UIP pattern/CVD in 16 cases. The prognoses after CsA treatment were improved or unchanged in 27% of cases with a UIP pattern/IPF, 78% of cases with a non-UIP pattern/IIP, 71% of cases with a UIP pattern/CVD and 75% of cases with a non-UIP pattern/CVD; deteriorated in 73%, 22%, 29% and 25% of cases, respectively, with these patterns and underlying diseases. At present, four out of thirteen (31%) patients with acute exacerbation of UIP pattern/IPF have survived for four to twelve months (mean: 7.5 months). Four patients revealed re-exacerbation of IP after the dose of CsA was tapered. Among the 25 patients with IP, the histopathological patterns of IP were classified as usual interstitial pneumonia (UIP) in 10 cases, nonspecific interstitial pneumonia (NSIP) in 14 cases (group I, 2; group II, 5; group III, 7) and diffuse alveolar damage (DAD) in 1 case. The prognoses were improved or unchanged in all cases of NSIP group I, in 80% of cases with NSIP group II, in 29% of cases of NSIP group III and in 20% of cases of UIP; and deteriorated in the case of DAD, in 80% of cases of UIP, in 71% of cases of NSIP group III, and in 20% of cases of NSIP group II. It should be emphasized that CsA combined with corticosteroids may be effective for the treatment of steroid-resistant or acute exacerbation cases of IP. Further studies are required to determine long-term outcome with this treatment.     

Is Metalloproteinase-7 Specific for Idiopathic Pulmonary Fibrosis?

BACKGROUND: Matrix metalloproteinase (MMP)-7 was reported to be a key molecule in the pathogenesis of idiopathic pulmonary fibrosis (IPF) based on the result of microarray analysis and knockout mice. However, the role of MMP-7 has not been determined in other types of idiopathic interstitial pneumonia (IIP). The aim of this study was to investigate the role of MMP-7 in IIP by comparing its expression in usual interstitial pneumonia (UIP) and cryptogenic organizing pneumonia (COP). METHODS: Levels of MMP and tissue inhibitors of metalloproteinase in BAL fluid and their expression on lung tissues were compared between normal control subjects (n = 5) and the patients with IPF (n = 6) and COP (n = 11). RESULTS: There was no significant difference in BAL fluid MMP-7 levels between UIP and COP, although it was higher in both diseases compared to normal control subjects. Furthermore, the pattern and the degree of MMP-7 expression in lung tissues were also similar in both IPF and COP, whereas MMP-2 level was higher in COP and MMP-9 level was higher in IPF. CONCLUSION: MMP-7 seems to play an important role in the pathogenesis of not only IPF but also COP; therefore, it may not be the key factor determining the prognosis or reversibility of IIPs.     

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.     

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.     

Nonspecific interstitial pneumonia (NSIP)

Nonspecific interstitial pneumonia (NSIP) represents one histologic subtype of idiopathic interstitial pneumonia (IIP). NSIP is typified by temporal homogeneity and less profusion of fibroblastic foci than is seen with usual interstitial pneumonia (UIP), the most common IIP. Clinically patients with NSIP present with similar symptoms (cough and dyspnea) when compared to patients with UIP. The duration of these symptoms prior to presentation is variable. The finding of fever may be more common in NSIP and clubbing may be more common in UIP; however, both findings can be seen in either UIP or NSIP. Physiological findings typically demonstrate a restrictive ventilatory defect with decreased gas transfer; little difference exists between UIP and NSIP. High resolution computed tomography (HRCT) scans are more likely to show honeycombing with UIP and a ground-glass pattern with NSIP, however, either of these findings can be seen with UIP or NSIP. The most striking differential feature between NSIP and UIP is the markedly better prognosis for patients with NSIP, a finding that cannot be explained by baseline differences in physiology or radiographic features. In this article we explore the clinical, physiological, and radiographic features of NSIP. We also review available information regarding response to therapy and prognosis.     

Anti-endothelial cell antibodies in patients with interstitial lung diseases

BACKGROUND: Anti-endothelial cell antibodies (AECA) are circulating antibodies that bind to endothelial antigens and induce endothelial cell damage. AECA have been detected in patients with collagen vascular disease (CVD) and their presence is associated with interstitial lung disease (ILD) in cases of CVD. However, the prevalence of AECA in patients with idiopathic interstitial pneumonias (IIPs) is not known. METHODS: We investigated the prevalence of AECA in patients with IIPs. We also examined whether the expression of AECA differed among the histologic subgroups usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), and compared the values with those of CVD-associated ILD (CVD-ILD). Twenty patients with IIPs and 24 patients with CVD-ILD were studied. Serum samples were examined for AECA by cellular enzyme-linked immunosorbent assay (ELISA) using human umbilical vein endothelial cells. Values are expressed as ELISA ratios (ER). RESULTS: All sera from patients with idiopathic pulmonary fibrosis (IPF)/UIP were negative for AECA, whereas 5 out of 10 with idiopathic NSIP, 5 out of 14 with CVD-UIP and 4 out of 10 with CVD-NSIP tested positive (p<0.05). ER values were significantly lower in patients with IPF/UIP than idiopathic NSIP, CVD-UIP or CVD-NSIP (p<0.05). Among idiopathic NSIP, CVD-NSIP and CVD-UIP patients, the ER values did not differ. CONCLUSIONS: Among IIP patients, only those with idiopathic NSIP, not IPF/UIP, tested positive for AECA. The prevalence of AECA in idiopathic NSIP patients was similar to that in CVD-ILD patients. These results may provide important information to understand the distinct pathophysiology of each form of IIPs.