Circulating KL-6 predicts the outcome of rapidly progressive idiopathic pulmonary fibrosis

TLR9 differentiates rapidly from slowly progressing forms of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is characterized by diffuse alveolar damage and severe fibrosis, resulting in a steady worsening of lung function and gas exchange. Because idiopathic pulmonary fibrosis is a generally progressive disorder with highly heterogeneous disease progression, we classified affected patients as either rapid or slow progressors over the first year of follow-up and then identified differences between the two groups to investigate the mechanism governing rapid progression. Previous work from our laboratory has demonstrated that Toll-like receptor 9 (TLR9), a pathogen recognition receptor that recognizes unmethylated CpG motifs in bacterial and viral DNA, promotes myofibroblast differentiation in lung fibroblasts cultured from biopsies of patients with idiopathic pulmonary fibrosis. Therefore, we hypothesized that TLR9 functions as both a sensor of pathogenic molecules and a profibrotic signal in rapidly progressive idiopathic pulmonary fibrosis. Indeed, TLR9 was present at higher concentrations in surgical lung biopsies from rapidly progressive patients than in tissue from slowly progressing patients. Moreover, fibroblasts from rapid progressors were more responsive to the TLR9 agonist, CpG DNA, than were fibroblasts from slowly progressing patients. Using a humanized severe combined immunodeficient mouse, we then demonstrated increased fibrosis in murine lungs receiving human lung fibroblasts from rapid progressors compared with mice receiving fibroblasts from slowly progressing patients. This fibrosis was exacerbated by intranasal CpG challenges. Furthermore, CpG induced the differentiation of blood monocytes into fibrocytes and the epithelial-to-mesenchymal transition of A549 lung epithelial cells. These data suggest that TLR9 may drive the pathogenesis of rapidly progressive idiopathic pulmonary fibrosis and may serve as a potential indicator for this subset of the disease.

Acute exacerbation of idiopathic interstitial pneumonia following lung surgery in 3 of 68 consecutive patients: a retrospective study

BACKGROUND

Acute exacerbation (AE) of idiopathic interstitial pneumonia (IIP) is occasionally observed after lung surgery. However, the risk of lung surgery in patients with IIPs is not yet clearly known.

SUBJECTS AND METHODS

We conducted a retrospective study of consecutive patients who underwent lung surgery for cancer or for the diagnosis of interstitial pneumonia (IP) between 2000 and 2006. Patients who developed AE following the lung operation were assessed.

RESULTS

The data of 68 consecutive patients (males: 56, females: 12) with IP who underwent lung surgery were analyzed. The lung surgery included lobectomy for lung cancer in 48 patients [idiopathic pulmonary fibrosis (IPF) 31, non-IPF 17], and lung biopsy in 20 patients [IPF 8, non-specific interstitial pneumonia (NSIP) 8, unclassified 4]. Three patients with IPF (4.4% in total) developed AE after the operation (2 lobectomy, 1 biopsy). The triggers of AE were considered to be prolonged ventilation at a large tidal volume with oxygen supplementation at a high concentration. At the time of the AE, the extent of parenchymal involvement on the HRCT images was greater on the non-operated side. All three patients died of respiratory failure 12 to 82 days after the onset of AE despite corticosteroid therapy.

CONCLUSION

It is essential to be aware of the risk of AE of IPF following lung operation. Intraoperative respiratory management, such as oxygen supplementation at a high concentration and/or prolonged mechanical ventilation are likely possible etiologic factors.

A Normal Range of KL-6/MUC1 Independent of Elevated SP-D Indicates a Better Prognosis in the Patients with Honeycombing on High-Resolution Computed Tomography

Both SP-D and KL-6/MUC1 are established biomarkers of the interstitial pneumonias, including idiopathic pulmonary fibrosis (IPF), but the causes and clinical outcomes based on their independent effects are not known. Eleven asymptomatic patients, detected with honeycombing on high-resolution computed tomography (HRCT), were compared with 17 other IPF outpatients having slight respiratory symptoms and honeycombing as well. Although SP-D was increased in both groups, KL-6 was significantly higher in the symptomatic IPF group. When the patients (n = 11) having both biomarkers elevated were compared with the other patients (n = 6) with only SP-D elevated, the distribution of fibrotic lesions with honeycombing on HRCT was larger and the survival time was shorter in the patients having both biomarkers elevated. Immunohistochemical analysis also differentiated these biomarkers in the lung. These results suggest both a cause and the prognostic value of dissociation of these biomarkers.

Mucins carrying selectin ligands as predictive biomarkers of disseminated intravascular coagulation complication in ARDS

BACKGROUND

ARDS patients present with intrapulmonary and systemic coagulation abnormalities. We previously demonstrated that circulating KL-6/MUC1 could predict complications of disseminated intravascular coagulation (DIC) in ARDS. Recent studies indicate that circulating mucin can induce intravascular coagulation via interactions with selectin. We, therefore, investigated whether circulating mucins carrying selectin ligands are associated with DIC in ARDS.

METHODS

We evaluated newly diagnosed patients with ARDS (n = 46) or bacterial pneumonia (n = 17), and healthy control subjects (n = 60). Using serum collected at diagnosis, circulating levels of KL-6/MUC1, KL-6/MUC1 carrying sialyl Lewis(a) (SLAK), KL-6/MUC1 carrying sialyl Lewis(x) (SLXK), and P-selectin glycoprotein ligand-1 (PSGL-1) were measured.

RESULTS

Serum mucins with selectin ligands were significantly elevated in patients with ARDS compared with healthy control subjects. Significantly elevated levels of SLAK and SLXK were found in patients with ARDS subsequently complicated with DIC, as compared with those without DIC. In contrast, serum PSGL-1 levels were significantly decreased in ARDS patients with DIC. Furthermore, SLAK was discovered to be an independent predictor of DIC complication in ARDS. Using cutoff levels obtained by receiver operating characteristic curves, we found that these mucins can be used to distinguish between patients with ARDS with and without subsequently occurring DIC. Among the analyzed mucins, SLAK has the highest sensitivity and specificity for predicting future DIC development.

CONCLUSIONS

These results suggest that mucins with selectin ligands are novel markers for ARDS with future complications of DIC, and KL-6/MUC1 carrying selectin ligands may be involved in the pathogenesis of DIC in patients with ARDS.

Clinical use of biomarkers of survival in pulmonary fibrosis

Background

Biologic predictors or biomarkers of survival in pulmonary fibrosis with a worse prognosis, more specifically in idiopathic pulmonary fibrosis would help the clinician in deciding whether or not to treat since treatment carries a potential risk for adverse events. These decisions are made easier if accurate and objective measurements of the patients' clinical status can predict the risk of progression to death.

Method

A literature review is given on different biomarkers of survival in interstitial lung disease, mainly in IPF, since this disease has the worst prognosis.

Conclusion

Serum biomarkers, and markers measured by medical imaging as HRCT, pertechnegas, DTPA en FDG-PET are not ready for clinical use to predict mortality in different forms of ILD. A baseline FVC, a change of FVC of more than 10%, and change in 6MWD are clinically helpful predictors of survival.

Plasma biomarker profiles in acute exacerbation of idiopathic pulmonary fibrosis

Little is known about the pathobiology of acute exacerbation of idiopathic pulmonary fibrosis (IPF), a condition that shares clinical and histopathological features with acute lung injury. Plasma biomarkers have been well studied in acute lung injury and have provided insight into the underlying disease mechanism. The objective of this study was to determine the plasma biomarker profile of acute exacerbation of IPF and compare this profile with that of stable IPF and acute lung injury. Plasma was collected from patients with stable IPF, acute exacerbation of IPF, and acute lung injury for measurement of biomarkers of cellular activity/injury (receptor for advanced glycation endproducts, surfactant protein D, KL-6, von Willebrand factor), systemic inflammation (IL-6), and coagulation/fibrinolysis (protein C, thrombomodulin, plasminogen activator inhibitor-1). Plasma from patients with acute exacerbation of IPF showed significant elevations in markers of type II alveolar epithelial cell injury and/or proliferation, endothelial cell injury, and coagulation. This profile differed from the biomarker profile in patients with acute lung injury. These findings support the hypothesis that type II alveolar epithelial cells are centrally involved in the pathobiology of acute exacerbation of IPF. Furthermore, they suggest that acute exacerbation of IPF has a distinct plasma biomarker profile from that of acute lung injury.

Plasma biomarker profiles in acute exacerbation of idiopathic pulmonary fibrosis

Little is known about the pathobiology of acute exacerbation of idiopathic pulmonary fibrosis (IPF), a condition that shares clinical and histopathological features with acute lung injury. Plasma biomarkers have been well studied in acute lung injury and have provided insight into the underlying disease mechanism. The objective of this study was to determine the plasma biomarker profile of acute exacerbation of IPF and compare this profile with that of stable IPF and acute lung injury. Plasma was collected from patients with stable IPF, acute exacerbation of IPF, and acute lung injury for measurement of biomarkers of cellular activity/injury (receptor for advanced glycation endproducts, surfactant protein D, KL-6, von Willebrand factor), systemic inflammation (IL-6), and coagulation/fibrinolysis (protein C, thrombomodulin, plasminogen activator inhibitor-1). Plasma from patients with acute exacerbation of IPF showed significant elevations in markers of type II alveolar epithelial cell injury and/or proliferation, endothelial cell injury, and coagulation. This profile differed from the biomarker profile in patients with acute lung injury. These findings support the hypothesis that type II alveolar epithelial cells are centrally involved in the pathobiology of acute exacerbation of IPF. Furthermore, they suggest that acute exacerbation of IPF has a distinct plasma biomarker profile from that of acute lung injury.

Predictive factors for postoperative acute exacerbation of interstitial pneumonia combined with lung cancer

PURPOSE

Postoperative acute exacerbation (AE) of usual interstitial pneumonia (UIP) is a serious complication in the surgical treatment for primary lung cancer combined with UIP. The purpose of this study was to determine the predictors of AE of UIP after a major lung resection.

METHODS

We retrospectively collected data for 40 patients who had been operated on for lung cancer and were diagnosed as UIP based on postoperative histopathological diagnosis. We then evaluated some predictive factors related to the AE of UIP.

RESULTS

The incidence of postoperative AE of UIP was 15% (6/40 patients). No correlation between patients who developed AE of UIP and those who did not, in terms of preoperative C-reactive protein, white blood cell count, percentage lymphocytes, forced expiratory volume in 1 s, percentage total lung capacity, percentage diffusing capacity of lung for carbon monoxide, and the alveolar partial pressures of oxygen and carbon dioxide. Preoperative serum lactate dehydrogenase (LDH) and serum KL-6 were significantly higher and the percent vital capacity (%VC) was significantly lower in patients who developed AE of UIP than in those who did not. Furthermore, recursive descent partition analysis revealed that %VC (<80.6%) and LDH (>or=241 IU/l) could distinguish patients with AE from those without AE.

CONCLUSION

Preoperative %VC plus serum LDH values were considered the predictive factors for AE of UIP after surgery for lung cancer.

[Acute exacerbation of idiopathic pulmonary fibrosis]

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease. Its natural history may have episodes of acute exacerbation (AE-IPF), whose best accepted definition would be a clinically significant acute worsening, without identified cause, in patients with an underlying IPF. The incidence of AE-IPF ranges from 5%-19% of patients per year. It is estimated that acute deterioration of the respiratory status occurred in 47% of these patients before death. A rapidly progressive dyspnoea is the most prominent symptom, with associated cough, fever and flu-like symptoms. The diagnosis is strengthened by the presence of leukocytosis on the blood count, neutrophilia on the bronchoalveolar lavage, and development of new diffuse bilateral ground-glass opacities superimposed on the pre-existing radiographic findings. The major histological finding is diffuse alveolar damage. Methylprednisolone seems to be the best therapeutic option, although the treatment response is usually poor.

Elevated levels of thioredoxin 1 in the lungs and sera of idiopathic pulmonary fibrosis, non-specific interstitial pneumonia and cryptogenic organizing pneumonia

OBJECTIVE

Oxidant stress is thought to be involved in the establishment of idiopathic interstitial pneumonia (IIP). Thioredoxin 1 (TRX1) plays a role as a strong antioxidant in vivo, suggesting that TRX1 may be involved in the pathogenesis of IIPs. However, there is no report on TRX1 levels in the sera of IIPs. In addition, TRX1 expression in the lungs of non-specific interstitial pneumonia (NSIP) and cryptogenic organizing pneumonia (COP) patients also has not been reported. Here, we investigated whether or not TRX1 levels are altered in the lungs and sera of patients with idiopathic pulmonary fibrosis (IPF), NSIP, and COP.

METHODS

Immunohistochemical analysis was performed to examine the expression of TRX1. TRX1 levels in sera were measured using an ELISA kit.

RESULTS

TRX1 was expressed in the bronchiole-alveolar epithelium, especially with regenerative or metaplastic feature, and in alveolar macrophages in usual interstitial pneumonia (UIP) and fibrotic NSIP. TRX1 was weakly expressed in the lungs of cellular NSIP and COP. TRX1 producing cells in UIP (n=16), fibrotic NSIP (n=15), cellular NSIP (n=4), and COP (n=5) were significantly increased when compared to nonsmokers (n=7). TRX1 producing cells in UIP and fibrotic NSIP were significantly increased when compared to cellular NSIP and COP. TRX1 levels in the sera of the patients with IPF (n=32; 74.2 ± 7.5 ng/mL), fibrotic NSIP (n=7; 82.5 ± 18.4 ng/mL), cellular NSIP (n=3; 62.2 ± 3.2 ng/mL) and COP (n=17; 88.8 ± 19.7 ng/mL) were significantly higher than those of control subjects (n=74; 35.3 ± 2.7 ng/mL). Furthermore, TRX1 levels in the sera of IPF patients who later showed acute exacerbation (n=7; 106.6 ± 16.3 ng/mL) were significantly higher than those of IPF patients without acute exacerbation (n=25; 65.1 ± 7.6 ng/mL).

CONCLUSION

Overproduction of TRX1 in the lungs and sera may play an important role in the pathogenesis of IIPs.

Acute exacerbation of interstitial pneumonia associated with collagen vascular diseases

Background

Acute exacerbation (AE) is currently established as a distinct condition with acute deterioration of respiratory status in idiopathic pulmonary fibrosis (IPF). Recently, several studies have reported that AE also occurred in interstitial pneumonias other than IPF, such as collagen vascular disease-associated interstitial pneumonia (CVD-IP). However, the incidence of AE in CVD-IP and its clinical characteristics remain to be fully determined. This study was conducted to elucidate cumulative incidence of AE in CVD-IP and its clinical features.

Methods

We reviewed 83 biopsy-proven CVD-IP patients, estimated cumulative incidence of AE, and examined its clinical characteristics.

Results

Among 83 CVD-IP patients, six patients with a mean age of 65.7 years developed AE (overall incidence, 7.2%; 1-year incidence, 1.25%). Underlying CVDs included rheumatoid arthritis (RA) (n = 5; overall incidence, 20.0%) and primary Sjögren syndrome (n = 1; overall incidence, 5.9%). Patients with AE showed acute respiratory deterioration with severe hypoxemia (mean PaO₂/FiO₂ ratio, 131). Radiologically, ground-glass opacity was superimposed on the underlying reticular abnormalities. Preexisting histological patterns included three usual interstitial pneumonia (UIP) and two non-specific interstitial pneumonia (NSIP). Five (83.3%) of six patients died of respiratory failure despite intensive therapy. Univariate Cox's proportional hazards analysis showed that age and RA diagnosis were significantly associated with AE. Multivariate Cox's proportional hazards analysis indicated that age was an independent significant factor predicting AE.

Conclusions

These data suggest that AE can occur in CVD-IP, and this condition is closely similar to that of IPF with poor prognosis. AE is most common in RA, and associated with higher ages.

Differential cytokine secretion and early treatment response in patients with pulmonary tuberculosis

Biomarkers for treatment response would facilitate the testing of urgently needed new anti-tuberculous drugs. The present study investigated the profiles of 30 proinflammatory, anti-inflammatory and angiogenic factors [epidermal growth factor, eotaxin, fractalkine, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interleukin (IL)-1alpha, IL-1beta, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p40, IL-12p70, IL-13, IL-15, IL-17, interferon-gamma, interferon-inducible protein-10, Krebs von den Lungen-6, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, sCD40L, transforming growth factor-alpha, tumour necrosis factor-alpha and vascular endothelial growth factor] in the plasma of 12 healthy tuberculin skin test-positive community controls and 20 human immunodeficiency virus-negative patients with active tuberculosis (TB) and identified potential biomarkers for early treatment response. We showed differences in the level of circulating cytokines between healthy controls and TB patients, but also between fast responders and slow responders to anti-tuberculosis treatment. The general discriminant analysis based on pre-treatment and week 1 measurements identified 10 sets of three-variable models that could classify fast and slow responders with up to 83% accuracy. Overall, this study shows the potential of cytokines as indicators of anti-tuberculosis treatment response.

Comparison of pulmonary CT findings and serum KL-6 levels in patients with cryptogenic organizing pneumonia

The aim of this study was to retrospectively compare high-resolution CT findings among cryptogenic organizing pneumonia (COP) patients with normal and elevated serum KL-6 levels. Chest CT scans performed between April 1999 and April 2007 in 20 COP patients with a normal KL-6 level and 17 COP patients with an elevated KL-6 level were evaluated retrospectively by two chest radiologists. The CT findings in the COP patients with either a normal or an elevated KL-6 level mainly consisted of consolidation (n = 17 and n = 13, respectively) followed by ground-glass opacity (n = 11 and n = 13, respectively). Traction bronchiectasis and architectural distortion were significantly more frequent in patients with an elevated KL-6 level than in those with normal levels (n = 7 and n = 1, and n = 13 and n = 3, respectively) (p = 0.0077 and p = 0.00017, respectively). In follow-up CT scans, a relapse within 1 year after initial treatment with steroids, performed in 16 patients with a normal KL-6 level and 16 with an elevated KL-6 level, occurred in 2 (12.5%) patients with a normal KL-6 level and in 6 (37.5%) with an elevated KL-6 level. The frequency of relapse in patients with an elevated KL-6 level was higher than in those with a normal KL-6 level; however, no significant difference between the two groups was observed (p = 0.103). In conclusion, CT findings of traction bronchiectasis and architectural distortion in COP patients are associated with increased serum KL-6 levels, which might be related to a relapse after treatment.

MMP1 and MMP7 as potential peripheral blood biomarkers in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic lung disease associated with substantial morbidity and mortality. The objective of this study was to determine whether there is a peripheral blood protein signature in IPF and whether components of this signature may serve as biomarkers for disease presence and progression.

METHODS AND FINDINGS

We analyzed the concentrations of 49 proteins in the plasma of 74 patients with IPF and in the plasma of 53 control individuals. We identified a combinatorial signature of five proteins-MMP7, MMP1, MMP8, IGFBP1, and TNFRSF1A-that was sufficient to distinguish patients from controls with a sensitivity of 98.6% (95% confidence interval [CI] 92.7%-100%) and specificity of 98.1% (95% CI 89.9%-100%). Increases in MMP1 and MMP7 were also observed in lung tissue and bronchoalveolar lavage fluid obtained from IPF patients. MMP7 and MMP1 plasma concentrations were not increased in patients with chronic obstructive pulmonary disease or sarcoidosis and distinguished IPF compared to subacute/chronic hypersensitivity pneumonitis, a disease that may mimic IPF, with a sensitivity of 96.3% (95% CI 81.0%-100%) and specificity of 87.2% (95% CI 72.6%-95.7%). We verified our results in an independent validation cohort composed of patients with IPF, familial pulmonary fibrosis, subclinical interstitial lung disease (ILD), as well as with control individuals. MMP7 and MMP1 concentrations were significantly higher in IPF patients compared to controls in this cohort. Furthermore, MMP7 concentrations were elevated in patients with subclinical ILD and negatively correlated with percent predicted forced vital capacity (FVC%) and percent predicted carbon monoxide diffusing capacity (DLCO%).

CONCLUSIONS

Our experiments provide the first evidence for a peripheral blood protein signature in IPF to our knowledge. The two main components of this signature, MMP7 and MMP1, are overexpressed in the lung microenvironment and distinguish IPF from other chronic lung diseases. Additionally, increased MMP7 concentration may be indicative of asymptomatic ILD and reflect disease progression.

Circulating KL-6/MUC1 as an independent predictor for disseminated intravascular coagulation in acute respiratory distress syndrome

OBJECTIVES

Acute respiratory distress syndrome (ARDS) patients show high levels of circulating mucin including KL-6/MUC1 (soluble MUC1 mucin). Because cancer mucin can bind vascular endothelial cells and platelets via selectins, mucin-selectin interactions are reported to trigger platelet aggregation and intravascular coagulation. Therefore, we hypothesized that KL-6/MUC1 is involved in the pathogenesis of disseminated intravascular coagulation (DIC) in ARDS. The aim of the current study is to evaluate the association between circulating KL-6/MUC1 and DIC in ARDS patients.

DESIGN

Observational study with structured follow-up.

SETTING

Intensive care unit in Hiroshima University Hospital.

SUBJECTS

Fifty-six newly diagnosed patients with ARDS.

INTERVENTIONS

Circulating levels of KL-6/MUC1 were measured during diagnosis and serially measured during the clinical course along with indices of respiratory failure, inflammation, coagulation and fibrinolysis and multiple organ dysfunction.

RESULTS

Acute respiratory distress syndrome patients complicated with DIC showed significantly higher levels of serum KL-6/MUC1 than patients without DIC during the clinical course. Amongst the parameters analysed at diagnosis of ARDS, KL-6/MUC1 was an independent predictor for DIC complication. The baseline level of circulating KL-6/MUC1 at diagnosis of ARDS was significantly correlated with an increased DIC score following ARDS diagnosis. Using an optimum cutoff level of KL-6/MUC1 obtained by a receiver operating characteristic curve, the sensitivity and specificity for predicting future DIC development in ARDS patients were 88.9% and 55.3%, respectively.

CONCLUSIONS

These results suggest that KL-6/MUC1 is associated with DIC development in ARDS patients. Elevated levels of KL-6/MUC1 at diagnosis could be a predictor of DIC complication in ARDS.

Circulating thymus- and activation-regulated chemokine/CCL17 is a useful biomarker for discriminating acute eosinophilic pneumonia from other causes of acute lung injury

BACKGROUND

The presentation of acute eosinophilic pneumonia (AEP) closely resembles that of acute lung injury (ALI)/ARDS, including its idiopathic form, acute interstitial pneumonia (AIP). AEP usually lacks peripheral eosinophilia at the acute phase; therefore, the establishment of serum biomarkers for AEP would be clinically useful.

METHODS

We measured the levels of thymus- and activation-regulated chemokine (TARC)/CCL17, eotaxin/CCL11, KL-6, and surfactant protein-D (SP-D) in serum for patients with acute parenchymal lung diseases including AEP (n = 17), AIP (n = 13), pneumonia-associated ALI/ARDS (n = 12), and alveolar hemorrhage (n = 7). To evaluate diagnostic ability, each marker was estimated by measuring the area under the receiver operating characteristic curve (AUC).

RESULTS

Serum TARC/CCL17 levels of AEP patients were much higher than those of patients in other disease groups. More importantly, high circulating TARC/CCL17 levels were observed in AEP even at acute phase when peripheral eosinophilia was absent. TARC/CCL17 showed the largest AUC, and the TARC/CCL17 levels with cutoff points from 6,259 to 7,039 pg/mL discriminated AEP from other syndromes with sensitivity and specificity of 100%. The KL-6 level was low in most patients with AEP, and the sensitivity was 81.6% in cutoff with 100% specificity. The AUC for eotaxin/CCL11 and SP-D was small, with values of 0.73 (95% confidence interval [CI], 0.60 to 0.86) and 0.53 (95% CI, 0.31 to 0.64), respectively.

CONCLUSIONS

This study indicates that the measurement of circulating TARC/CCL17 and KL-6 is useful for discriminating AEP from other causes of ALI.

Acute exacerbations of idiopathic pulmonary fibrosis

The natural history of idiopathic pulmonary fibrosis (IPF) has been characterized as a steady, predictable decline in lung function over time. Recent evidence suggests that some patients may experience a more precipitous course, with periods of relative stability followed by acute deteriorations in respiratory status. Many of these acute deteriorations are of unknown etiology and have been termed acute exacerbations of IPF. This perspective is the result of an international effort to summarize the current state of knowledge regarding acute exacerbations of IPF. Acute exacerbations of IPF are defined as acute, clinically significant deteriorations of unidentifiable cause in patients with underlying IPF. Proposed diagnostic criteria include subjective worsening over 30 days or less, new bilateral radiographic opacities, and the absence of infection or another identifiable etiology. The potential pathobiological roles of infection, disordered cell biology, coagulation, and genetics are discussed, and future research directions are proposed.

Loss of caveolin-1 in bronchiolization in lung fibrosis

Bronchiolization is a key process in fibrosing lung in which the proliferative status of bronchiolar epithelium changes, leading to abnormal epithelial morphology. Within the context that caveolin-1 acts to suppress epithelial proliferation, we postulated that stimulating epithelial injury would lead to caveolin-1 downregulation and encourage proliferation. The present study evaluates the expression of caveolin-1, especially in bronchiolization, in C57BL/6J mice with bleomycin-induced lung fibrosis and in various types of re-epithelialization in human interstitial pneumonias (IPs). Immunohistochemically, levels of caveolin-1 decreased in the bronchiolar epithelium of mice treated with bleomycin. Levels of caveolin-1 mRNA in the whole lung were decreased at 7 and 14 days. Caveolin-1 mRNA was also decreased in laser-capture microdissection- retrieved bronchiolar epithelial cells at 7 days. Among patients with 12 IPs, including four usual IPs (UIPs) and eight nonspecific IPs (NSIPs), whole lung caveolin-1 was significantly decreased compared with 12 controls at both mRNA and protein levels. By scoring immunointensity, caveolin-1 was significantly reduced in bronchiolization and squamous metaplasia as well as in bronchiolar epithelium in 23 IPs (12 UIPs and 11 NSIPs) compared with bronchiolar epithelium from seven controls. These data suggested that loss of caveolin-1 is associated with abnormal re-epithelialization in lung fibrosis.

Intermittent intravenous cyclophosphamide pulse therapy for the treatment of active interstitial lung disease associated with collagen vascular diseases

The availability of intravenous cyclophosphamide (CYC) pulse therapy for collagen vascular diseases (CVD)-associated interstitial lung disease (ILD) has been indicated. However, the standard protocol concerning the dosage and the interval of CYC infusion has not yet been established. The aim of this study is to elucidate the efficacy and the safety of our "divided administration" protocol of CYC for the treatment of CVD-ILD. The treatment protocol consists of two steps: step 1, CYC 400-500 mg at 10-day intervals for at least 30 days, and step 2, CYC 500 mg at 14-day intervals for at least 4 weeks. The ILD activities were monitored by respiratory symptoms, serum levels of KL-6 (a serological marker of IP), chest computed tomography (CT), and pulmonary function tests. Seventeen patients [nonspecific interstitial pneumonia (NSIP), 12 patients; usual interstitial pneumonia (UIP), 4; lymphocytic interstitial pneumonia (LIP), 1] accomplished the study protocol. The sessions of CYC infusion ranged from 5 to 20 (mean, 8.3). In all patients, respiratory symptoms were improved and the serum levels of KL-6 were decreased (from 1572 +/- 904 to 978 +/- 392 U/ml; P < 0.01). Chest CT findings were improved in 4 patients (23.5%): they were all classified as NSIP; not deteriorated, 13 patients (76.5%). An improvement in the vital capacity percentage (%VC) was recognized in 10 patients (78.6%) and in diffusing capacity of carbon monoxide (%DLco) in 8 patients (61.5%). Nevertheless, mean %VC and mean %DLco did not change significantly. No major adverse event(s) occurred. The efficacy and safety of our "divided administration" protocol of CYC for CVD-ILD was demonstrated.

Role of galectin-3 in human pulmonary fibrosis

BACKGROUND

Galectin-3 is a beta-galactoside-binding protein which is implicated in diverse physiological and pathological processes including human liver cirrhosis and a mouse lung fibrosis model. The aim of this study is to determine whether galectin-3 is involved in human lung fibrosis.

METHODS

We measured galectin-3 concentration in bronchoalveolar lavage fluid (BALF) and examined its expression in alveolar macrophages from patients with interstitial lung disorders using ELISA and immunohistochemical staining, respectively. Using monocyte/macrophage cell lines in vitro, we examined the effect of cytokines on galectin-3 expression, and the opposite similarly by RT-PCR and Western blotting. Finally, we performed Micro Boyden chamber assay and Sircoll assay to determine whether galectin-3 induces migration and collagen synthesis, respectively, in fibroblasts.

RESULTS

Galectin-3 was specifically increased in BALF from patients with idiopathic pulmonary fibrosis (IPF) and interstitial pneumonia associated with collagen vascular disease (CVD-IP). Galectin-3 levels in BALF seemed to be lower in IPF and CVD-IP patients receiving corticosteroid therapy. Alveolar macrophages from IPF patients expressed more galectin-3 compared with those from control. Galectin-3 expression was induced by tumor necrosis factor-alpha (TNF-alpha) and interferon (IFN)-gamma in a monocytic cell line U937. Galectin-3 also induced mRNA expression and protein production of TNF-alpha and interleukin (IL)-8 in a macrophage cell line THP-1. This lectin stimulated NIH-3T3 fibroblast to induce migration and collagen synthesis in vitro.

CONCLUSIONS

These results suggest that galectin-3 is involved in the pathogenesis of human IPF and CVD-IP by activating macrophages and fibroblasts.

[Quantifying plasma levels of transforming growth factor beta1 in idiopathic pulmonary fibrosis]

OBJECTIVE

Transforming growth factor ss1 (TGF-ss1) is one of the key profibrotic mediators in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The purpose of this study was to investigate the prognostic value of quantifying TGF-ss1 levels in patients with IPF.

PATIENTS AND METHODS

We conducted a prospective study of 29 IPF patients and 27 healthy controls. Enzyme-linked immunosorbent assays were used to quantify TGF-ss1 levels.

RESULTS

Mean (SD) TGF-ss1 levels were significantly higher in the IPF patients than in the control subjects (11.1 [7.5] ng/mL vs 4 [2.4] ng/mL; P< .01). Weak inverse correlations were observed between TGF-ss1 levels and both forced vital capacity and total lung capacity. Thirteen IPF patients were evaluated at 8 (1.2) months (range, 5-9 months). The mean TGF-ss1 level was 18.2 (15) ng/mL and there were no significant differences with respect to the initial measurement of 11.1 (7.5) ng/mL. No correlation was observed between changes in respiratory function and changes in TGF-ss1 levels.

CONCLUSIONS

Although plasma levels of TGF-beta1 were high in the patients with IPF, they do not appear to be a useful prognostic marker of disease activity or therapeutic response.

Health-related quality of life in patients with idiopathic pulmonary fibrosis--cross-sectional and longitudinal study

OBJECT

To validate the cross-sectional and longitudinal use of the Medical Outcome Study Short Form 36 (SF-36) for measuring health-related quality of life (HRQL) in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

Patients were administered the SF-36 and concomitantly underwent laboratory and physiologic tests and high-resolution computed tomography (HRCT). Forty-six patients participated in the initial cross-sectional study, and 32 patients who were available more than one year later again underwent these studies under the same conditions.

RESULTS

Patients with IPF had significantly lower scores across all 8 domains of the SF-36 when compared with the general population. Significant decline of HRQL was observed in 2 physical domains. There were significant differences in within-subject changes in a few domains according to worsening of the physiologic parameters. Vital capacity as percent of predicted was significantly correlated with the results of 6 subscales and its changes were significantly correlated with those of 4 subscales. The 6-min-walk distance was correlated significantly with 3 subscales and its changes were significantly correlated with those of 4 subscales. Changes in the HRCT ground-glass score were significantly correlated with those of 3 subscales. No significant correlations between changes in 3 domains and those of any clinical parameters were observed.

CONCLUSION

Patients with IPF had significantly impaired HRQL in both physical and psychological functions. This disease clearly decreased the physical aspects of HRQL over time. HRQL instruments should be incorporated into routine evaluations of IPF patients, since they measure dimensions not fully estimated by clinical assessment.

Increased levels of KL-6 and subsequent mortality in patients with interstitial lung diseases

OBJECTIVES

KL-6 is a specific marker in patients with interstitial lung diseases (ILDs); however, the relationship between elevated levels of KL-6 and subsequent mortality is not well defined. To determine if elevated serum levels of KL-6 are associated with increased mortality, and to identify the most suitable cut-off level of KL-6 by which to distinguish between good prognosis and poor prognosis, we evaluated the prognostic significance of serum KL-6 levels in patients with stable-state ILDs.

METHODS

Two hundred and nineteen patients diagnosed with ILDs (152 with idiopathic interstitial pneumonia and 67 with collagen disease-associated pulmonary fibrosis) at Tsukuba University Hospital from April 1999 to October 2005 were entered in this study. Serum KL-6 levels in patients with ILDs were measured with a commercially available enzyme immunoassay kit, and these patients were then followed up.

RESULTS

During the follow-up period, 58 of the 219 patients died of respiratory failure. Patients who died during this period had higher levels of KL-6 than did those who did not (P = 0.0004). The receiver operating characteristic curve analysis showed 1000 U mL(-1) as the most suitable cut-off level by which to distinguish between the two groups of patients. The 95% specificity serum KL-6 level with poor outcome was 2750 U mL(-1). In univariate and multivariate analysis, elevated serum KL-6 (>1000 U mL(-1)) in the stable state indicated poor prognosis (P = 0.0005, log-rank test; P = 0.0001, Cox proportional hazard model).

CONCLUSIONS

Elevated KL-6 level may provide simple, yet valuable information by which to identify patients with ILDs who are at increased risk for subsequent mortality.

Clinical review: Idiopathic pulmonary fibrosis—Past, present and future

Idiopathic pulmonary fibrosis (IPF) is an important, and devastating, interstitial lung disease. It has a median mortality of only 3 years, worse than many cancers, and its incidence continues to rise. In this article, an overview of key developments in our understanding and clinical management of IPF will be provided.

Plasma KL-6 predicts the development and outcome of bronchopulmonary dysplasia

Circulating KL-6 is a specific indicator of pulmonary injury affecting the alveolar epithelium and interstitium. Our preliminary study suggested the usefulness of plasma KL-6 as a marker of bronchopulmonary dysplasia (BPD). To confirm the diagnostic value of KL-6 for BPD as well as to determine the reference range, we conducted a larger prospective study in 135 preterm infants <32 wk GA. Among the infants without oxygen dependence at a postconceptional age of 36 wk, the plasma KL-6 level showed no significant association with GA at any time. Among 42 infants <28 wk GA, plasma KL-6 levels were significantly higher in those with moderate/severe BPD compared with those with no/mild BPD. A plasma level of 199 U/mL at 1 wk or 232 U/mL at 2 wk was an excellent predictor of moderate/severe BPD <28 wk GA (positive predictive value of 83% and 80%, respectively). Unlike nonspecific markers of inflammation or fibrosis, KL-6 objectively reflects the severity of pulmonary injury irrespective of the treatment or the radiographic changes. Therefore, not only as a good marker, measurement of KL-6 may also help to provide new insights into the pathogenesis of BPD.

Circulating levels of KL-6 in acute respiratory distress syndrome sepsis or traumatic brain injury in critically ill children

KL-6 is a high molecular weight glycoprotein that is expressed on the apical borders of normal secretary alveolar epithelial cells. The aim of our study was to elucidate the potential role of circulating levels of KL-6, related to C-reacting protein (CRP), disease severity (PRISM, TISS), length of stay (LOS) or mechanical ventilation (LOMV), and outcome, in children with acute respiratory distress syndrome (ARDS), sepsis, or traumatic brain injury (TBI). KL-6 concentrations were monitored using solid phase sandwich enzyme-linked immunosorbent assay in plasma of nine patients with ARDS and compared to nine patients with TBI, nine with sepsis, and nine ventilated patients with cancer of matched illness severity on days 1, 3, 5, 7, and 10. Initial respiratory/ventilatory parameters (oxygenation index, plateau pressures) were recorded for ARDS patients. Patients with ARDS had higher early plasma levels of KL-6 (956 +/- 400 U/ml), as compared to patients with TBI (169 +/- 9 U/ml), sepsis (282 +/- 81 U/ml), and ventilated controls (255 +/- 40 U/ml). Significant correlations were demonstrated between plasma KL-6 concentration and oxygenation index, PaO(2): FiO(2) ratio, LOS and LOMV, but not with CRP or PRISM. Only in patients with ARDS, plasma KL-6 levels were higher in non-survivors than survivors (P < 0.03). Plasma KL-6 levels have possible prognostic significance and may provide a useful marker for ARDS in critically ill children.

Extracellular matrix metalloproteinase inducer in interstitial pneumonias☆

Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycosylated transmembrane protein that induces matrix metalloproteinases (MMPs), is minimally expressed in the normal adult lung. We previously reported that it is up-regulated in murine bleomycin-induced lung injury. In this study, we determined the expression of EMMPRIN and its association with MMP-2, MMP-7, and MMP-9 in interstitial pneumonias (IPs). We performed immunohistochemistry for EMMPRIN and MMPs on lung tissue from 22 subjects with various IPs. We did bronchoalveolar lavage (BAL) on 9 of these subjects and 13 others with IPs to measure the soluble EMMPRIN in BAL fluid. For comparison, immunohistochemistry or BAL was done on 14 subjects without IPs. The staining intensity for each protein was scored from 0 to 3 in various epithelial cell types. Soluble EMMPRIN in BAL fluid was measured by an enzyme-linked immunosorbent assay. Extracellular matrix metalloproteinase inducer was prominent in abnormal epithelial cells. It was more prominent in hyperplastic type II cells, compared with epithelium in alveolar bronchiolization. It was also elevated in BAL fluid from the subjects with IPs. Matrix metalloproteinases were expressed in cells expressing EMMPRIN, although the profile of MMPs varied among the different abnormal epithelial cell types with MMP-2 and MMP-7 in hyperplastic type II cells and MMP-7 and MMP-9 in cells showing squamous metaplasia and cells comprising bronchiolization. These results suggest a role of EMMPRIN in reepithelialization in IPs.

Prognostic value of circulating KL-6 in idiopathic pulmonary fibrosis

OBJECTIVE

Circulating levels of KL-6, a high MW glycoprotein (MUC1 mucin), are elevated in a majority of patients with a number of interstitial lung diseases, including idiopathic pulmonary fibrosis (IPF). However, KL-6 levels vary from patient to patient. The aim of the present study was to determine whether the serum KL-6 level at the time of diagnosis predicts prognosis in IPF.

METHODS

The relationship between clinical variables and prognosis in 27 patients with IPF were analysed retrospectively. The diagnosis was made by histological examination (n = 16) or on clinical findings including high-resolution CT scanning (n = 11). All patients were followed up for at least 3 years. Variables such as age, FVC%, PaO(2) at rest, initial LDH level, C-reactive protein and KL-6 were used for analysis.

RESULTS

At the cut-off level determined by receiver operating characteristic curves, LDH and KL-6 showed a significant correlation with the patient's prognosis by univariate analysis. However, multivariate analysis revealed that only KL-6 was a predictor of prognosis. The patients were categorized by their serum KL-6 levels (as above or below the cut-off level of 1000 U/mL) and their survival estimated using the Kaplan-Meier method. The difference in median survival between the two groups was significant. The median survival of patients with low KL-6 was more than 36 months, whereas that of patients with high KL-6 was only 18 months.

CONCLUSION

These results suggest that initial evaluation of serum KL-6 level can predict survival in patients with IPF.

The Mucin-1 568 Adenosine to Guanine Polymorphism Influences Serum Krebs von den Lungen-6 levels

Krebs von den Lungen (KL)-6 offers a new perspective as a disease marker in pulmonary diseases. The aim of this study was to analyze whether serum KL-6 levels are dependent on the functional adenosine to guanine mucin-1 (MUC1) gene polymorphism at nucleotide position 568 in a well-characterized white population. Polymorphisms were determined in 327 healthy, white individuals and 74 patients with sarcoidosis, using a PCR-sequence-specific primer assay. The serum KL-6 levels were measured by ELISA. Significant differences between serum KL-6 levels of healthy subjects who were grouped according to MUC1 568 genotype were observed (P<0.0001) (mean+/-SEM): AA (195.2+/-9.9 U/ml; 95% confidence interval [CI], 175.7-214.8), AG (246.0+/-8.6 U/ml; 95% CI, 229.0-263.1), and GG (302.6+/-11.8 U/ml; 95%CI, 279.3-326.0). In the patients with sarcoidosis, the results were (mean+/-SD): AA (550.1+/-411.7; 95% CI, 380.2-720.1), AG (716.3+/-452.4; 95% CI, 547.4-885.2), GG (1,151.0+/-1122; 95% CI, 610.1-1692.0); P=0.02. Comparison of the KL-6 levels in which the 568 genotype was ignored rendered 6 out of 74 (7.5%) misclassifications of "elevated" versus "normal" KL-6 levels or vice versa. In conclusion, the MUC1 568 A to G polymorphism may be of interest for diagnostic purposes because our study delivered in vivo evidence that it contributes to interindividual variations in KL-6 levels.

A pilot study of aerosolized N-acetylcysteine for idiopathic pulmonary fibrosis

OBJECTIVE

Idiopathic pulmonary fibrosis poses a significant therapeutic challenge because of its progressive course. Since oxidative stress plays an important role in the pathogenesis of idiopathic pulmonary fibrosis, an open, randomized trial of long-term inhalation therapy with the antioxidant, N-acetylcysteine was conducted.

METHODOLOGY

A total of 30 patients with idiopathic pulmonary fibrosis were randomly assigned to one of the following inhalation therapies: N-acetylcysteine (352 mg per day) or bromhexine hydrochloride (4 mg per day) as the control. Efficacy was assessed by analysing changes occurring from baseline to 12 months in pulmonary function, the 6-min walking test, high-resolution CT, health-related quality of life, and serum KL-6-values.

RESULTS

Four patients (n=2 in each group) died within 12 months due to progression of idiopathic pulmonary fibrosis. A total of 22 patients (control, n=12; N-acetylcysteine, n=10) completed the study. At 12 months there were significant differences between the N-acetylcysteine and control groups in terms of mean changes in lowest SaO(2) during the 6-min walking test (-0.3+/- 2.1% vs -6.8+/-1.8%, P<0.05), serum KL--6 (-482+/-220 U/mL vs 176+/-204 U/mL, P<0.05), and the ground-glass score on high-resolution CT (-1.3+/-1.6 vs 6.7+/-1.5, P<0.01). No significant differences were observed in pulmonary function, 6-min walking distance or quality of life.

CONCLUSIONS

These data suggest that although long-term aerosolized N-acetylcysteine administration did not influence pulmonary function or quality of life, it may delay disease progression as evidenced by exercise desaturation, high-resolution CT, and serum KL-6.

Beneficial effect of polymyxin B-immobilized fiber column (PMX) hemoperfusion treatment on acute exacerbation of idiopathic pulmonary fibrosis

OBJECTIVE

This study was aimed to investigate the effect of polymyxin B-immobilized fiber column (PMX) hemoperfusion treatment on the acute exacerbation of idiopathic pulmonary fibrosis (IPF).

PATIENTS AND METHODS

Six patients with a clinical diagnosis of idiopathic pulmonary fibrosis (IPF) who developed acute exacerbation were included in this study. Although five of six patients were treated with high-dose corticosteroid therapy, mechanical ventilation was necessary for all six patients due to severe respiratory failure. Blood endotoxin levels were undetectable in all patients. PMX treatment was performed on these six patients.

RESULTS

In four of six patients, alveolar-arterial difference of oxygen (AaDO(2)), serum KL-6 and lactate dehydrogenase (LDH) were improved after PMX treatment. These four patients were successfully weaned from mechanical ventilation and survived more than 30 days after the initial PMX treatment.

CONCLUSION

These data suggest a potential beneficial effect of PMX treatment on acute exacerbation of IPF.

KL-6, a human MUC1 mucin, promotes proliferation and survival of lung fibroblasts

The serum level of KL-6, a MUC1 mucin, is a clinically useful marker for various interstitial lung diseases. Previous studies demonstrated that KL-6 promotes chemotaxis of human fibroblasts. However, the pathophysiological role of KL-6 remains poorly understood. Here, we further investigate the functional aspects of KL-6 in proliferation and apoptosis of lung fibroblasts. KL-6 accelerated the proliferation and inhibited the apoptosis of all human lung fibroblasts examined. An anti-KL-6 monoclonal antibody counteracted both of these effects induced by KL-6 on human lung fibroblasts. The pro-fibroproliferative and anti-apoptotic effects of KL-6 are greater than and additive to those of the maximum effective concentrations of platelet-derived growth factor, basic fibroblast growth factor, and transforming growth factor-beta. These findings indicate that increased levels of KL-6 in the epithelial lining fluid may stimulate fibrotic processes in interstitial lung diseases and raise the possibility of applying an anti-KL-6 antibody to treat interstitial lung diseases.

Serum biomarkers in interstitial lung diseases

The use of biomarkers in medicine lies in their ability to detect disease and support diagnostic and therapeutic decisions. New research and novel understanding of the molecular basis of the disease reveals an abundance of exciting new biomarkers who present a promise for use in the everyday clinical practice. The past fifteen years have seen the emergence of numerous clinical applications of several new molecules as biologic markers in the research field relevant to interstitial lung diseases (translational research). The scope of this review is to summarize the current state of knowledge about serum biomarkers in interstitial lung diseases and their potential value as prognostic and diagnostic tools and present some of the future perspectives and challenges.

Double-blind, placebo-controlled trial of pirfenidone in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal disorder without an effective therapy to date. In a double-blind, randomized, placebo-controlled trial, 107 patients were prospectively evaluated for efficacy of a novel compound, pirfenidone. The difference in the change in the lowest oxygen saturation by pulse oximetry (SpO2) during a 6-minute exercise test, the primary endpoint, from baseline to 6 months was not significant between the two groups (p = 0.0722). In a prespecified subset of patients who maintained a SpO2 greater than 80% during a 6-minute exercise test at baseline, the lowest SpO2 improved during a 6-minute exercise test in the pirfenidone group at 6 and 9 months (p = 0.0069 and 0.0305, respectively). Positive treatment effect was demonstrated in secondary endpoints: (1) change in VC measurements at 9 months (p = 0.0366) and (2) episodes of acute exacerbation of IPF occurring exclusively in the placebo group during the 9 months (p = 0.0031). Significant adverse events were associated with pirfenidone; however, adherence to treatment regimen was similar between pirfenidone and placebo groups. In conclusion, treatment with pirfenidone improved VC and prevented acute exacerbation of IPF during the 9 months of follow-up. Future long-term studies are needed to clarify the overall safety and efficacy of pirfenidone in IPF.

Serum KL-6 and Surfactant Proteins A and D in Pediatric Interstitial Lung Disease

OBJECTIVE

To determine if serum KL-6, surfactant protein A (SP-A), and surfactant protein D (SP-D) levels are elevated in pediatric interstitial lung disease (ILD) and associated with pulmonary function and disease severity score.

METHODS

Serum KL-6, SP-A, and SP-D levels were measured by enzyme-linked immunosorbent assay in 10 children with ILD and in 10 healthy volunteers. In the ILD group, FEV1 percentage of predicted, FVC percentage of predicted, and ILD disease severity score were measured and correlated with serum KL-6, SP-A, and SP-D levels.

RESULTS

For the ILD and control groups, respectively, mean serum KL-6 was 4,523 U/mL and 206 U/mL (p = 0.007), mean serum SP-A was 133 ng/mL and 21 ng/mL (p = 0.003), and mean serum SP-D was 304 ng/mL and 75 ng/mL (p = 0.004). There was an inverse relationship between SP-A and FVC (p = 0.05), and between SP-D and FEV1 (p = 0.05). There was a direct relationship between SP-D and ILD score (p = 0.05).

CONCLUSIONS

Serum KL-6, SP-D and SP-D levels are elevated in children with ILD. SP-A and SP-D levels appear to correlate with some measures of disease severity.

KL-6: marker for pulmonary involvement in Langerhans cell histiocytosis in infants

The purpose of this study was to investigate serum KL-6 levels in an infant with Langerhans cell histiocytosis (LCH) and pulmonary involvement. The histologic diagnosis of LCH was established by skin biopsy. Imaging of the chest confirmed marked interstitial shadowing throughout both lung fields. Acutely, serum KL-6 was elevated to 9,400 U/mL. Following induction chemotherapy, clinical manifestations of LCH improved and the levels of serum KL-6 returned to within normal limits. During the maintenance therapy phase, there was a resurgence of the LCH, but without involvement of the lungs, and the levels of KL-6 remained normal. The authors conclude that KL-6 may be a useful marker for pulmonary involvement in infants with LCH.

Changes in serum KL-6 after intravenous fosfomycin administration in idiopathic interstitial pneumonia

Changes in serum KL-6 levels after intravenous fosfomycin (FOM) administration in idiopathic interstitial pneumonia (IIP) were studied. Seventeen patients who were diagnosed with usual interstitial pneumonia by surgical lung biopsy were selected as subjects. In these patients, FOM was administered intravenously, at a dose of 2 g twice daily, for 14 days, and serum KL-6 was determined before and after its administration. FOM administration resulted in a reduction of serum KL-6 in all 17 patients (1273 +/- 132 U/ml [mean +/- SEM] to 1023 +/- 101 U/ml; P < 0.01). FOM may reduce serum KL-6 in IIP and may be an appropriate therapeutic drug for this condition.

Circulating KL-6 levels in patients with drug induced pneumonitis

BACKGROUND

The circulating level of KL-6/MUC1 is a sensitive marker for various interstitial lung diseases. Previous case reports have suggested that KL-6 may also be increased in some patients with drug induced pneumonitis. A study was undertaken to determine whether serum KL-6 could be a marker for particular types of drug induced pneumonitis.

METHODS

The findings of high resolution computed tomographic (HRCT) chest scans of 30 patients with drug induced pneumonitis were reviewed separately by two independent observers. The pneumonitis was classified into four predominant patterns: widespread bilateral consolidation (diffuse alveolar damage, DAD; n=7), fibrosis with or without consolidation (chronic interstitial pneumonia, CIP; n=11), consolidation without fibrosis (bronchiolitis obliterans organising pneumonia or eosinophilic pneumonia, BOOP/EP; n=8), and diffuse ground glass opacities without fibrosis (hypersensitivity pneumonitis, HP; n=4). Serum KL-6 levels were measured by a sandwich enzyme linked immunosorbent assay.

RESULTS

The overall sensitivity of serum KL-6 in detecting drug induced lung disease was 53.3%, which was lower than its sensitivity in detecting other interstitial lung diseases. However, the KL-6 level was increased in most patients with a DAD or CIP pattern (16/18; 88.9%) and was closely correlated with their clinical course. In contrast, serum KL-6 levels were within the normal range in all patients with a BOOP/EP or HP pattern.

CONCLUSIONS

Particular patterns detected by HRCT scanning, such as DAD and CIP but not the BOOP/EP or HP patterns, are associated with increased circulating KL-6 levels in drug induced pneumonitis. Serum KL-6 levels may reflect the clinical activity of the particular disorders.