Downregulation of type III interferons in patients with severe COVID-19

Coronavirus disease 2019 (COVID-19) is globally rampant, and to curb the growing burden of this disease, in-depth knowledge about its pathophysiology is needed. This was an observational study conducted at a single center to investigate serum cytokine and chemokine levels of COVID-19 patients, based on disease severity. We included 72 consecutive COVID-19 patients admitted to our hospital from March 21 to August 31, 2020. Patients were divided into Mild-Moderate I (mild) and Moderate II-Severe (severe) groups based on the COVID-19 severity classification developed by the Ministry of Health, Labor and Welfare (MHLW) of Japan. We compared the patient characteristics as well as the serum cytokine and chemokine levels on the day of admission between the two groups. Our findings indicated that the severe group had significantly higher levels of serum fibrinogen, d-dimer, lactate dehydrogenase, C-reactive protein, ferritin, Krebs von den Lungen-6, surfactant protein (SP)-D, and SP-A than the mild group. Strikingly, the levels of interleukin (IL)-28A/interferon (IFN)-λ2 were significantly lower in the severe group than in the mild group. We believe that reduced levels of type III interferons (IFN-λs) and alterations in the levels of other cytokines and chemokines may impact the severity of the disease.

Krebs von den Lungen-6 and surfactant protein-A in interstitial pneumonia with autoimmune features

Interstitial pneumonia with autoimmune features (IPAF) is a special subtype of interstitial lung disease that has received worldwide attention. Krebs von den Lungen-6 (KL-6) and surfactant protein-A (SP-A) can be used as an important biomarker of interstitial lung disease, but its exact relationship with IPAF is poorly understood.A total of 65 IPAF patients were included in the study and were followed up for 52 weeks. The KL-6 and SP-A were evaluated by chemiluminescence enzyme immunoassay. The above indicators were tested at 2 time points, baseline (the first admission of patients) and 52 weeks. We also collected the indicators of antinuclear antibodies and rheumatoid factor. Based on high-resolution computed tomography evaluations, patients were divided into: aggravation, stable, and improvement group. At same time, 30 age-matched normal people as normal control were recruited, the same information was collected. Correlations among the groups were compared and analyzed.The KL-6 and SP-A level in IPAF patients were significantly higher than normal controls (fold increase = 11.35 and 1.39, both P < .001) and differed significantly at baseline and 52 weeks in IPAF (difference ratio = 37.7% and 21.3%, P < .05, both). There were significant differences at baseline and 52 weeks (r values of aggravation, improvement, and stable groups for KL-6 were 0.705, 0.770, and 0.344, P = .001, .001, and .163, and for SP-A the r value were 0.672, 0.375, and 0.316, P = .001, .126, and .152). In aggravation group, KL-6 and SP-A were correlated with CT scores (both P < .05). Diffusing capacity of the lung for carbon monoxide (DLCO) and forced vital capacity (FVC), % predicted showed a progressive downward trend, with a significant difference at baseline and 52 weeks in IPAF patients (difference ratio = 23.8% and 20.6%, both P < .05). There was a significant correlation between KL-6 and FVC % predicted and DLCO (both P < .05), SP-A showed negatively correlated with DLCO, but not significantly correlated with FVC % predicted (P < .05 and .47).This study demonstrated that KL-6 and SP-A can reflect disease progression, and both 2 play a key role at reflection of lung epithelial cell injury and fibrosis degree in IPAF.

Human arsenic exposure and lung function impairment in coal-burning areas in Guizhou, China

To evaluate the effect of coal-burning arsenic (As) exposure on lung function and the potential underlying mechanisms, a total of 217 As-exposed subjects and 75 reference subjects were recruited into this study. Hair arsenic (H-As), pulmonary function tests, and serum inflammatory markers CC16, SP-A, MMP-9, and TIMP-1 were evaluated. Residents from As-exposed areas showed higher H-As concentrations (median 0.25 μg/g) than subjects from the reference area (median 0.14 μg/g). Large reductions in lung function parameters were noted in the As-exposed group. A significant negative correlation was observed between H-As concentrations and lung function. Specifically, monotonic negative dose-response relationships were observed between H-As and FEV1(%), FEV1/FVC (%) and FEF75 (%) (all P < 0.05), while the associations between H-As and FVC (%), FEF25 (%), and FEF50 (%) were nonlinear (P for nonlinearity = 0.03, 0.001, 0.01, respectively). In addition, there was a direct positive relationship between H-As and the inflammatory response. Alterations in inflammatory biomarkers (CC16, SP-A, MMP-9, and MMP-9/TIMP-1) were significantly associated with As-induced lung function impairment. Thus, this population-based study revealed that As exposure has significant toxic effects on lung function and increased inflammation may occur during this toxic process. We provide scientific evidence for an As-induced alteration in inflammatory biomarkers and pulmonary damage in an As-exposed population. The results of this study can inform risk assessment and risk control processes in relation to human As exposure in coal-burning arsenicosis areas.

Plasma Surfactant Protein-A Levels In Healthy Subjects And Chronic Obstructive Pulmonary Disease Patients

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is the leading cause of morbidity and mortality across the globe. Currently, there is a dearth of biomarkers which can accurately diagnose and evaluate the prognosis of the disease. Systemic Surfactant Protein- A (SP-A) levels are generally higher in smokers compared to non-smokers as well as elevated in COPD patients as compared to controls. The objective of the study was to estimate and compare plasma surfactant protein-A levels in male and female COPD patients and healthy subjects and to evaluate the role of SP-A as a possible bio-marker for COPD patients.

METHODS

A Comparative study, conducted at the department of Physiology & Cell Biology, University of Health Sciences, Lahore between August 2013 and April 2015. A total of 84 subjects of both sexes between 30-80 years of age were included in this study. Subjects were taken from local community and were divided into four groups (A- D). COPD was diagnosed on the basis of relevant history and spirometry showing post bronchodilator FEV1/FVC <0.70.

RESULTS

Plasma SP-A levels were not different between controls and COPD patients and between male and female COPD patients. However, SP-A levels were directly correlated with cotinine levels (r= 0.503, p=0.001). Female patients were usually more symptomatic than males and developed COPD at an earlier age compared with male patients.

CONCLUSION

Plasma SP-A levels were not significantly different between groups. Plasma cotinine levels (an indication of the tobacco use) were positively correlated with plasma SP-A levels in study subjects. Female patients developed COPD at an early age compared to male counterparts with similar tobacco exposure.

Change of surfactant protein D and A after renal ischemia reperfusion injury

Acute kidney injury (AKI) is associated with widespread effects on distant organs, including the lungs. Surfactant protein (SP)-A and SP-D are members of the C-type lectin family, which plays a critical role in host defense and regulation of inflammation in a variety of infections. Serum levels of SP-A and SP-D are markers to reflect lung injury in acute respiratory distress syndrome, idiopathic pulmonary fibrosis, and sarcoidosis. We investigated the change of lung-specific markers, including SP-A and SP-D in an AKI mice model. We studied C57BL/6J mice 4 and 24 hours after an episode of ischemic AKI (23 min of renal pedicle clamping and then reperfusion); numerous derangements were present, including SP-A, SP-D, and lung tight-junction protein. Neutrophil infiltration and apoptosis in the lungs increased in ischemic AKI. Receptor for advanced glycation end products (RAGE) in the lungs, a marker of pneumocyte I, was not changed. Lung tight-junction proteins, particularly claudin-4, claudin-18, and anti-junctional adhesion molecule 1 (JAMA-1), were reduced in 24 hours after AKI. Serum SP-A and SP-D significantly increased in ischemic AKI. SP-A and SP-D in the lungs did not increase in ischemic AKI. The immunohistochemistry showed that the expression of SP-A and SP-D was intact in ischemic AKI. SP-A and SP-D in the kidneys were significantly higher in AKI than in the sham. These patterns of SP-A and SP-D in the kidneys were similar to those of serum. AKI induces apoptosis and inflammation in the lungs. Serum SP-A and SP-D increased in ischemic AKI, but these could have originated from the kidneys. So serum SP-A and SP-D could not reflect lung injury in AKI. Further study is needed to reveal how a change in lung tight-junction protein could influence the prognosis in patients with AKI.

Rice Consumption and Subclinical Lung Disease in US Adults: Observational Evidence From the Multi-Ethnic Study of Atherosclerosis

Rice accumulates arsenic, an established lung toxicant. Little is known about the association of rice consumption with arsenic-related health effects, particularly interstitial lung disease. Between 2000 and 2002, 6,814 white, black, Hispanic, and Chinese adults from 6 US cities were enrolled in the Multi-Ethnic Study of Atherosclerosis. We included 2,250 participants who had spirometry data, 2,557 with full-lung computed tomography (CT) scans, and 5,710 with cardiac CT scans. Rice consumption and 310 participants with urinary arsenic were assessed at baseline. Spirometry and full-lung CT-derived measures of total lung capacity and high attenuation area (HAA), and interstitial lung abnormalities were measured at examination 5. Cardiac CT-derived HAA was measured at 1-3 visits. Twelve percent of participants reported eating at least 1 serving of rice daily. Comparing data between that group with those who ate less than 1 serving weekly, the mean difference for forced vital capacity was -102 (95% confidence interval (CI): -198, -7) mL, and for forced expiratory volume in 1 second was -90 (95% CI: -170, -11) mL after adjustment for demographics, anthropometrics, dietary factors, and smoking. The cross-sectional adjusted percent difference for total lung capacity was -1.33% (95% CI: -4.29, 1.72) and for cardiac-based HAA was 3.66% (95% CI: 1.22, 6.15). Sensitivity analyses for urinary arsenic were consistent with rice findings. Daily rice consumption was associated with reduced lung function and greater cardiac-based HAA.

Pirfenidone Improves Familial Idiopathic Pulmonary Fibrosis without Affecting Serum Periostin Levels

Background: Antifibrotic agents have been approved for the treatment of idiopathic pulmonary fibrosis (IPF). However, the efficacy of these drugs in the treatment of familial IPF (FIPF) has not been previously reported. Case presentation: We report the case of a 77-year-old man with FIPF, successfully treated with pirfenidone. His uncle died due to IPF, and his niece was diagnosed with the disease. He had worsening dyspnea two months prior to admission to our hospital. Upon admission, he had desaturation when exercising and broad interstitial pneumonia. Administration of pirfenidone improved his dyspnea, desaturation, and the reticular shadow on his chest radiograph. Increased fibrotic marker levels KL-6 and SP-D were also normalized in six months; treatment had no effect on his serum periostin level. Pirfenidone has been effective for over two years. Conclusion: Antifibrotic agents such as pirfenidone may be useful for the management of FIPF, as well as cases of sporadic IPF.

Significance of molecular biomarkers in idiopathic pulmonary fibrosis: A mini review

Idiopathic pulmonary fibrosis (IPF) is a chronic, irreversible condition with poor prognosis that is characterized by a variable clinical course in each patient, which renders it a complex disease with unknown causes. Despite the proven efficacy of novel antifibrotic therapies, including pirfenidone and nintedanib, the diagnosis and follow-up of IPF remain challenging. Hence, the identification of molecular biomarkers for early detection of IPF and to predict biologically determined individual clinical courses, has recently piqued the interest of researchers. Previous studies have demonstrated the diagnostic and prognostic efficacy of blood proteins such as KL-6, Surfactant protein (SP)-A, and SP-D, in patients with IPF. Due to their use in clinical practice in Japan, for approximately twenty years, a significant amount of data about these biomarkers has been accumulated. This paper reviews the recent literature on molecular biomarkers for IPF that have been developed in Japan as well as other potential molecular biomarkers.

The Serum Level of KL-6 Is Associated with the Risk of Insulin Resistance and New-onset Diabetes Mellitus: The Tanno-Sobetsu Study

Objective Inflammatory cytokines generated in visceral fat have been shown to contribute to the development of insulin resistance. The involvement of pulmonary inflammation in insulin resistance remains unclear, but smoking is known to be a risk factor for diabetes as well as chronic obstructive pulmonary disease. We herein examined the hypothesis that increased serum levels of lung interstitial injury biomarkers [surfactant protein (SP)-A, SP-D and Krebs von den Lungen (KL)-6] are associated with the risk of diabetes development. Methods For cross-sectional and longitudinal analyses, we enrolled 750 apparently healthy non-diabetic subjects who received annual examinations in 2011 or 2012 in the Tanno-Sobetsu cohort. Results A cross-sectional analysis showed that distinct clinical parameters were associated with SP-A, SP-D and KL-6. In a multiple regression analysis, independent explanatory variables were Brinkman index and brain natriuretic peptide (BNP) for SP-A, sex (women), BNP and body mass index (BMI) for SP-D, and age and BMI for KL-6. A longitudinal analysis of 415 subjects who received annual examinations in both 2011 and 2014 showed that 13 (3.1%) of the patients developed type 2 diabetes during the 3-year follow-up. A multiple logistic regression analysis showed the KL-6 levels, systolic blood pressure and homeostasis model assessment of insulin resistance (HOMA-IR) in 2011 to be independently associated with new-onset diabetes. In a multiple regression analysis for HOMA-IR in 2014, the KL-6 level and BMI in 2011 were selected as explanatory variables. Conclusion A modest elevation of the serum KL-6 level is therefore considered to be associated with the risk for insulin resistance development and new-onset diabetes mellitus in a general population.

Impact of serum SP-A and SP-D levels on comparison and prognosis of idiopathic pulmonary fibrosis: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Idiopathic pulmonary fibrosis (IPF) has a poor prognosis in general; however, it is heterogeneous to detect relative biomarkers for predicting the disease progression. Serum biomarkers can be conveniently collected to detect and help to differentially diagnose IPF and predict IPF prognosis. This meta-analysis aimed to evaluate the use of serum surfactant proteins A and D (SP-A and SP-D) for differential diagnosis and prognosis of IPF.

METHODS

Relevant articles were searched in PubMed, Embase, and Chinese National Knowledge Infrastructure databases and reviewed by 2 independent readers. Standard mean difference (SMD) and 95% confidence interval (CI) were calculated to assess the difference in serum levels of SP-A/D among patients with IPF, when compared to patients with non-IPF interstitial lung disease (ILD), pulmonary infection, and healthy control. Hazard ratio (HR) and 95% CI were used to compare the relative risk of mortality.

RESULTS

Twenty-one articles (totalling 1289 IPF patients) were included in final meta-analysis. Serum SP-A levels were significantly higher in patients with IPF than in patients with non-IPF ILD (SMD: 1.108 [0.584, 1.632], P < .001), or pulmonary infection (SMD: 1.320 [0.999, 1.640], P < .001) and healthy controls (SMD: 2.802 [1.901, 3.702], P < .001). There was no significant difference in serum SP-D levels between patients with IPF and those with non-IPF ILD patients (SMD: 0.459 [-0.000, 0.919], P = .050). Serum SP-D levels were significantly higher in patients with IPF than in patients with pulmonary infection (SMD: 1.308 [0.813, 1.803], P < .001) and healthy controls (SMD: 2.235 [1.739, 2.731], P < .001). Risk of death in patients with IPF and elevated serum SP-A was increased 39% compared to patients with low SP-A groups. Elevated SP-D increased risk by 111% when compared to low SP-D. In acute exacerbation of IPF, serum SP-A/D were higher than those in stable stage. The comparisons and prognosis might be different in Asian and Caucasian patients.

CONCLUSIONS

Serum SP-A/D detection might be useful for differential diagnosis and prediction of survival in patients with IPF.

Association of Serum Levels of Pentraxin-3, M-ficolin, and Surfactant Protein A with the Severity of Ischemic Stroke

Stroke is one of the most leading causes of death and disability in the world. Complement system activation contributes to pathogenesis and neuronal damage following stroke. There are no defined biological serum markers to determine the severity of stroke in acute phases. The purpose of current study was to determine the association of three complement activators, namely Pentraxin-3 (PTX3),M-ficolin, and Surfactant protein A (SPA) with the severity of ischemic stroke. This cross-sectional study was done on 82 patients diagnosed with ischemic stroke at 24-96 hours of initiation of the clinical symptoms during 2014-2015. The serum levels of PTX3, M-ficolin, and SPA were measured by enzyme-linked immunosorbent assay ( ELISA). The patients were divided in three stroke severity groups according to modified National Institute of Health Stroke Scale mNIHSS. The results showed that the more severity of the stroke was, the higher serum levels of three evaluated molecules (p<0.001) were. The correlation of serum level of PTX3, M-ficolin, and SPA with stroke severity was 0.732, 0.736, and 0.731, respectively. There is a strong association between serum levels of PTX3, M-ficolin, and SPA with the severity of ischemic stroke. Clinically, such association may be considered to evaluate the severity of the ischemic stroke.

Relationship between Fractional Exhaled Nitric Oxide Level and Efficacy of Inhaled Corticosteroid in Asthma-COPD Overlap Syndrome Patients with Different Disease Severity

This study explored the relationship between the fractional exhaled nitric oxide (FeNO) level and the efficacy of inhaled corticosteroid (ICS) in asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) patients with different disease severity. A total of 127 ACOS patients with ACOS (case group) and 131 healthy people (control group) were enrolled in this study. Based on the severity of COPD, the ACOS patients were divided into: mild ACOS; moderate ACOS; severe ACOS; and extremely severe ACOS groups. We compared FeNO levels, pulmonary function parameters including percentage of forced expiratory volume in 1 second (FEV1) to predicted value (FEV1%pred), ratio of FEV1 to forced vital capacity (FEV1/FVC), inspiratory capacity to total lung capacity (IC/TLC) and residual volume to total lung capacity (RV/TLC), arterial blood gas parameters, including PH, arterial partial pressure of oxygen (PaO₂) and arterial partial pressure of carbon dioxide (PaCO₂), total serum immunoglobulin E (IgE), induced sputum eosinophil (EOS), plasma surfactant protein A (SP-A), plasma soluble receptor for advanced glycation end products (sRAGE), sputum myeloperoxidase (MPO), sputum neutrophil gelatinase-associated lipocalin (NGAL) and Asthma Control Test (ACT) scores, and COPD Assessment Test (CAT) scores. Compared with pre-treatment parameters, the FeNO levels, RV/TLC, PaCO₂, total serum IgE, induced sputum EOS, plasma SP-A, sputum MPO, sputum NGAL, and CAT scores were significantly decreased after 6 months of ICS treatment, while FEV1%pred, FEV1/FVC, IC/TLC, PH, PaO2, plasma sRAGE, and ACT scores were significantly increased in ACOS patients with different disease severity after 6 months of ICS treatment. This finding suggests that the FeNO level may accurately predict the efficacy of ICS in the treatment of ACOS patients.

Prognostic significance of surfactant protein A, surfactant protein D, Clara cell protein 16, S100 protein, trefoil factor 3, and prostatic secretory protein 94 in idiopathic pulmonary fibrosis, sarcoidosis, and chronic pulmonary obstructive disease

BACKGROUND

Identification of serum and bronchoalveolar lavage fluid (BALF) biomarkers may facilitate diagnosis and prognostication in various lung disorders.

OBJECTIVE

Serum and BALF levels of surfactant protein A (SP-A), surfactant protein D (SP-D), Clara cell protein 16 (CC16), S100 protein, trefoil factor 3 (TFF3), and prostatic secretory protein 94 (PSP94) were evaluated in 94 consecutive patients (idiopathic pulmonary fibrosis (IPF; n=18), sarcoidosis (n=25), chronic obstructive pulmonary disease (COPD; n=51)), and in 155 healthy controls.

METHODS

Biomarkers were measured at diagnosis and compared with disease characteristics. Both uniparametric and multiparametric analyses were used.

RESULTS

Seven significant correlations were found: 1) BALF PSP94 level correlated with prognosis of sarcoidosis (P=0.035); 2) BALF SP-D level with pulmonary functions in IPF (P=0.032); 3) BALF SP-D and TFF3 with IPF mortality (P=0.049 and 0.017, respectively); 4) serum TFF3 level with COPD mortality (P=0.006,); 5) serum SP-A with pulmonary functions impairment in IPF (P=0.011); 6) serum SP-D level was associated with HRCT interstitial score in IPF (P=0.0346); and 7) serum SP-A was associated with staging of COPD according to spirometry (P<0.001). Moreover, our analysis showed that some biomarker levels differed significantly among the diseases: 1) BALF SP-D level differed between sarcoidosis and IPF; 2) serum SP-A level differed among IPF, sarcoidosis, COPD and was also different from healthy controls; 3) serum S100A6, S100A11 levels differed among IPF, sarcoidosis, COPD from healthy controls 4) serum SP-D, CC16, TFF-3 levels distinguished IPF patients from healthy controls; and 5) serum CC16, TFF3, PSP94 distinguished COPD patients from healthy controls. Our study shows that some of selected biomarkers should have prognostic value in the analysed lung disorders. On the other hand, these biomarkers do not appear to be unequivocally suitable for differential diagnosis of these disorders.

A pediatric patient with interstitial pneumonia due to enterovirus D68

Enterovirus D68 (EV-D68) infection is associated with upper and lower respiratory tract symptoms such as fever, cough, and wheezing. Pediatric patients with EV-D68 infection easily develop more severe respiratory complications compared to patients infected with other species of enterovirus, and consequently, have a higher rate of hospitalization and admission to intensive care units. Therefore, the clinical picture of respiratory complications associated with EV-D68 infection needs to be elucidated. Here, we report a 4-year-old girl of EV-D68 infection that required artificial respiration management within 24 h from the onset of cold symptoms. The patient was diagnosed with interstitial pneumonia on the basis of chest imaging findings with patchy, funicular and frosted glassy shadows, increased blood markers of surfactant protein-A, surfactant protein-D and sialylated carbohydrate antigen KL-6, and increased neutrophils and lymphocytes in the bronchoalveolar lavage. Steroids showed a remarkable effect in her treatment. Further investigations are needed to confirm the efficacy of steroids for interstitial pneumonia due to EV-D68 infection. As rapid deterioration of respiratory status is observed in EV-D68 infection, the possibility of interstitial pneumonia may be considered.

Airway inflammation among compost workers exposed to actinomycetes spores

OBJECTIVES

To study the associations between exposure to bioaerosols and work-related symptoms, lung function and biomarkers of airway inflammation in compost workers.

MATERIALS AND METHOD

Personal full-shift exposure measurements were performed on 47 workers employed at five windrow plants (n=20) and five reactor plants (n=27). Samples were analyzed for endotoxins, bacteria, fungal and actinomycetes spores. Health examinations were performed on workers and 37 controls before and after work on the day exposure was measured. The examinations included symptoms recorded by questionnaire, lung function by spirometry and nasal dimensions by acoustic rhinometry (AR). The pneumoproteins CC16, SP-D and SP-A were measured in a blood sample drawn at the end of the day.

RESULTS

The levels of endotoxins (median 3 EU/m(3), range 0-730 EU/m(3)) and actinomycetes spores (median 0.2 × 10(6) spores/m(3), range 0-590 × 10(6) spores/m(3)) were significantly higher in reactor plants compared to windrow plants. However, windrow composting workers reported more symptoms than reactor composting workers, probably due to use of respiratory protection. Exposure-response relationships between actinomycetes spores exposure and respiratory effects, found as cough and nose irritation during a shift, was significantly increased (OR 4.3, 95% CI 1.1-16, OR 6.1, 95% CI 1.5-25, respectively, p<0.05) among workers exposed to 0.02-0.3 × 10(6) actinomycetes spores/m3, and FEV1/FVC% decreased cross shift (b=-3.2, SE=1.5%, p<0.01). Effects were weaker in the highest exposed group, but these workers used respiratory protection, frequently limiting their actual exposure. No relationships were found between exposure and pneumoprotein concentrations.

CONCLUSIONS

The major agent in the aerosol generated at compost plants was actinomycetes spores which was associated with work related cough symptoms and work-shift lung function decrease.

[Comparison of biomarkers of pulmonary tuberculosis activity --serum surfactant proteins A and D, KL-6, C-reactive protein, and erythrocyte sedimentation rate]

OBJECTIVE

To evaluate serum surfactant proteins A and D (SP-A and SP-D), KL-6, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) as biomarkers for monitoring the activity of pulmonary tuberculosis.

METHODS

Patients with recently diagnosed and sputum smear-positive pulmonary tuberculosis were consecutively recruited between February and April 2013 at the Kanagawa Cardiovascular and Respiratory Center. Serum levels of SP-A, SP-D, KL-6, and CRP, and ESR were measured twice before treatment initiation and after confirmation of disease improvement (indicated by two consecutive negative smears or one negative sputum culture). The relationship of those biomarkers with disease activity was evaluated by comparing the baseline values with the biological and radiological disease severities and by assessing the changes in those values before and after treatment.

RESULTS

Twenty-seven patients with pulmonary tuberculosis were enrolled in the study. The median age was 66 years, and the male/female ratio was 19/8 for the entire cohort. The baseline levels of most biomarkers significantly or relatively increased in patients with severe biological and radiological outcomes, which were indicated by findings such as long-term positive sputum culture, and the presence of cavities and shadows on chest radiographs. A second measurement of these biomarkers was performed after a median treatment period of 56 days. The changes in the median levels for these biomarkers were as follows (before/after treatment): SP-A (ng/mL), 55.3/ 39.2 (p < 0.01); SP-D (ng/mL), 71.5/38.5 (p = 0.03); KL-6 (U/ mL), 365/374 (p = 0.43); CRP (mg/dL), 3.8/0.4 (p < 0.01); ESR (mm/hr), 69/46 (p = 0.27). After treatment, the levels of SP-A, SP-D, and CRP significantly decreased.

CONCLUSION

The levels of SP-A, SP-D, and CRP reflected not only the baseline values but also the chronological disease activity. Therefore, these biomarkers could be useful for the management of pulmonary tuberculosis.

[Determination and clinical significance of serum surfactant proteins A and D in children with bronchiolitis]

OBJECTIVE

To study the variation and clinical significance of serum levels of surfactant proteins A (SP-A) and D (SP-D) among children with different degrees of bronchiolitis.

METHODS

Seventy children with bronchiolitis were divided into acute (n=42) and recovery phase groups (n=28). According to the severity of symptoms, the acute phase group was further divided into severe (n=12) and mild subgroups (n=30). Another 26 children who were hospitalized in the same period due to non-infectious diseases and had not undergone surgery were used as the control group. Competitive enzyme-linked immunosorbent assay was performed to measure serum levels of SP-A and SP-D in each group.

RESULTS

The acute phase group had significantly higher serum levels of SP-A and SP-D compared with the recovery phase (P<0.01) and control groups (P<0.01). Compared with the control group, the recovery phase group had elevated levels of SP-A and SP-D (P<0.01). Within the acute phase group, serum levels of SP-A and SP-D in the severe subgroup were significantly higher than in the mild subgroup (P<0.01).

CONCLUSIONS

Serum levels of SP-A and SP-D are significantly elevated in children with acute bronchiolitis, and severe cases have higher serum levels of SP-A and SP-D than mild cases. Even after the relief of clinical symptoms, serum levels of SP-A and SP-D remain high. These findings suggest that serum levels of SP-A and SP-D might be useful biomarkers for evaluating the severity of bronchiolitis among children.

[Alterations of SP-A, SP-D and KL-6 in serum and bronchoalveolar lavage fluid in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To study the alterations and relationship of surfactant protein (SP)-A, SP-D and KL-6 in serum and bronchoalveolar lavage fluids (BALF) in children with Mycoplasma pneumoniae pneumonia (MPP).

METHOD

Self-control method was used for the study on SP-A, SP-D and KL-6 in serum, infected and non-infected BALFs in 32 MMP children with only one side of MPP.

RESULT

The contents of SP-A, SP-D and KL-6 in infected BALF were [mg/L;M (IQR) ]: 243 (90-468) , 187 (43-333) , 148 (47-426) ;104 (37-257) , 56 (25-131) , 35 (12-147) in non-infected BALF; 35 (25-69) , 33 (9-149) and 24 (15-62) in serum. The correlation coefficient of KL-6 between serum and infected BALF were -0.534 and -0.378 (P < 0.05).

CONCLUSION

There were significant correlation between the alterations of SP-A, SP-D and KL-6 in serum and lung infection in children with CAP. KL-6 in serum may be more sensitive than SP-A and SP-D.

Advances in the study of biomarkers of idiopathic pulmonary fibrosis in Japan

Idiopathic pulmonary fibrosis is an intractable disease with a median survival time of 2 to 3 years. Serum levels of Krebs von den Lungen-6 (KL-6), surfactant protein A (SP-A), and surfactant protein D (SP-D) are useful biomarkers for idiopathic pulmonary fibrosis and they are widely used in Japan. Based on clinical use in Japan, a combination of KL-6, SPA, and SP-D is useful at diagnosing interstitial lung diseases and predicting the prognoses for patients with these diseases. However, the differential diagnosis of idiopathic pulmonary fibrosis from other interstitial lung diseases is still challenging. Several other biomarkers have been identified and are being studied in Japan.

[Surfactant proteins-A and D as important serum markers for interstitial lung disease in patients with polymyositis or dermatomyositis]

OBJECTIVE

To explore the possible diagnostic values of serum surfactant protein-A (SP-A) and surfactant protein-D (SP-D) for interstitial lung diseases (ILD) in patients with polymyositis or dermatomyositis (PM/DM).

METHODS

Serum MCP-1 concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in 100 adult PM/DM patients, 20 patients with pulmonary infection and 42 healthy controls. And the association with their clinical features and serum levels of SP-A and SP-D was analyzed.

RESULTS

The serum levels of SP-A and SP-D in the PM/DM patients with ILD were both significantly higher than those without ILD and healthy controls (all P < 0.01) while there were no significance differences with those with infectious lung diseases (P > 0.05). The sensitivity of serum abnormal levels of SP-A, SP-D and combination of SP-A and SP-D for ILD in PM/DM patients were 66.1%, 64.3% and 80.0% and the specificity 72.7%, 72.7% and 70.2% respectively. The serum levels of SP-A were positively correlated with serum ferritin and C-reactive protein (CRP) and negatively with percent carbon monoxide diffusing capacity (DLCO%) (r = -0.474, P < 0.05), VC% (r = -0.404, P < 0.05) while the serum levels of SP-D were negatively correlated with circulating CD3+T cells (r = -0.244, P < 0.05) and CD4+T cells (r = -0.277, P < 0.05) in PM/DM patients. Furthermore, SP-A was an independent risk factor for death of ILD in PM/DM (OR 1.032, 95%CI 1.006 - 1.059, P < 0.05).

CONCLUSION

SP-A and SP-D may be potential useful serum markers for the diagnosis of ILD in PM/DM patients. And the combined detection of SP-A and SP-D offers a higher sensitivity than either marker alone. As a risk factor, serum SP-A can predict the prognosis of PM/DM patients with ILD.

Determinants of serum levels of surfactant proteins A and B and Clara cell protein CC16

Increased leakage of surfactant proteins A and B (SP-A and SP-B) and Clara cell secretory protein (CC16) from the air spaces into the circulation occurs in a range of respiratory conditions. However, circulating levels depend not only on the rate of entry into the circulation, but also on the rate of clearance. In order to clarify the role of the kidney in the clearance of these proteins, serum levels were related to markers of glomerular filtration in 54 non-smoking patients with varying degrees of renal dysfunction, none of whom had respiratory disease or were receiving dialysis at the time of sampling. Serum SP-A was related to SP-B (r = 0.53, p < 0.001) and to CC16 (r = 0.33, p < 0.02). Similarly, SP-B was related to CC16 (r = 0.39, p < 0.004). Stepwise multiple linear regression analysis suggested that serum SP-A and SP-B are influenced by age (approximately 20 and approximately 25% of variance, respectively), whereas CC16 is determined by renal function and, to a lesser extent, by body weight (approximately 63% of variance in total). We conclude that CC16 is cleared from blood by the renal route, whereas SP-A and SP-B are not. Serum SP-A and SP-B are influenced by age, which we speculate reflects increased damage to the alveolocapillary barrier.

Serum pneumoproteins and biomarkers of exposure to urban air pollution: a cross-sectional comparison of policemen and foresters

Very few biomarkers are available for the non-invasive detection of effects of urban air pollution on the respiratory tract. The objective was to evaluate whether Clara cell protein (CC16) and surfactant-associated protein-A (SP-A), two pulmonary secretory proteins, were useful in the detection of effects of urban air pollutants on the pulmonary epithelium. These proteins were determined in the serum of 53 policemen working in Brussels, Belgium, and a control group of 59 foresters working in the countryside. Except for ozone (O(3)), annual concentrations of the main air pollutants (PM(10), NO(2), CO, SO(2) and benzene) were significantly higher in Brussels than in the country. The proportion of smokers was lower in urban policemen compared with foresters, but they smoked on average a similar number of cigarettes per day as confirmed by their urinary excretion of cotinine. Muconic acid, a marker of benzene exposure, was significantly higher in urban policemen than in foresters, in both smokers and non-smokers. Multiple regression analysis showed that the type of work, smoking habits and time spent outdoors and in a car were significant determinants of benzene uptake. Tobacco smoking impaired lung function to a similar extent in urban policemen and foresters. The serum levels of SP-A were significantly increased in smokers but were not different between policemen and foresters. Serum CC16 was significantly reduced by tobacco smoking and slightly decreased in policemen compared with foresters. Interestingly, the reduction of serum CC16 was more pronounced in the subgroup of traffic compared with survey policemen, the latter being also less exposed to benzene. The results suggest that serum pneumoproteins and especially serum CC16 could be useful in the detection of chronic effects of urban air pollutants on the respiratory epithelium of populations particularly at risk.

Surfactant protein A, exposure to endotoxin, and asthma in garbage collectors and in wastewater workers

Endotoxin causes an inflammation at the bronchial and alveolar level. The inflammation-induced increase in permeability of the bronchoalveolar epithelial barrier is supposed to cause a leakage of pneumoproteins. Therefore, their concentrations are expected to increase in the bloodstream. This study aimed at examining the association between occupational exposure to endotoxin and a serum pneumoprotein, surfactant protein A, to look for nonoccupational factors capable of confounding this association, and examine the relation between surfactant protein A and spirometry. There were 369 control subjects, 325 wastewater workers, and 84 garbage collectors in the study. Exposure to endotoxin was assessed through personal sampling and the Limulus amebocytes lysate assay. Surfactant protein A was determined by an in house sandwich enzyme-linked immunosorbent assay (ELISA) in 697 subjects. Clinical and smoking history were ascertained and spirometry carried out according to American Thoracic Society criteria. Multiple linear regression was used for statistical analysis. Exposure was fairly high during some tasks in wastewater workers but did not influence surfactant protein A. Surfactant protein A was lower in asthmatics. Interindividual variability was large. No correlation with spirometry was found. Endotoxin has no effect on surfactant protein A at these endotoxin levels and serum surfactant protein A does not correlate with spirometry. The decreased surfactant protein A secretion in asthmatics requires further study.

Pneumoproteins as markers of paraquat lung injury: a clinical case

OBJECTIVE

To describe the changes in lung-specific secretory proteins in biological fluids in a fatal case of paraquat ingestion and to present immunostaining data obtained on postmortem lung tissue specimens.

METHODS

A 20-year-old man committed suicide by ingesting 100ml of a 20% paraquat solution. Surfactant associated proteins A (SP-A), B (SP-B) and Clara cell 16kDa protein (CC16) were determined in the serum and on broncho-alveloar lavage performed 18h after admission. Renal failure progressed rapidly and the patient died from refractory hypoxia. Immunostaining studies using antibodies directed against CC16, SP-A and SP-B were performed on postmortem lung tissue specimens.

RESULTS

Serum CC16 seemed to increase gradually with the progression of renal impairment. Serum SP-A and SP-B levels increased before any significant changes in pulmonary gas exchanges. The immunostaining study showed that the labeling for SP-A and SP-B was reduced or absent following paraquat toxicity, while Clara cells were relatively preserved.

CONCLUSIONS

The elevation of serum CC16 with paraquat toxicity is probably mainly related to a reduced renal clearance. The increase of serum SP-A and SP-B could reflect an increased lung to blood leakage, independently of the alteration of the renal function.

Elevated serum surfactant protein A and D in pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by widespread localization of calcispherites in the alveolar spaces. The authors report two cases of PAM, with markedly elevated sera concentrations of surfactant protein-A and surfactant protein-D, which showed a tendency to increase as the disease progressed. Therefore, surfactant protein-A and surfactant protein-D may function as serum markers to monitor the disease activity and progression of PAM.

Gefitinib-induced interstitial lung disease showing improvement after cessation: disassociation of serum markers

Gefitinib (ZD1839), a small-molecule epidermal growth factor receptor tyrosine kinase inhibitor, is an anticancer agent for patients with non-small cell lung carcinoma. Recently, however, as a result of accumulating evidence, it has been recognized that gefitinib can give rise to lethal lung toxicity. The authors report a case of interstitial lung disease (ILD) induced by gefitinib, which improved promptly following cessation of the administration of the agent. Clinical signs suggesting a good prognosis were noted, namely, findings similar to acute eosinophilic pneumonia on CT and a disassociation in the elevation of specific serum markers of ILD. At the time of onset of ILD, serum concentrations of surfactant protein (SP)-A and SP-D were significantly increased, whereas that of KL-6 was not increased. A previous study of three cases of lethal lung toxicity resulting from gefitinib administration revealed a significant and almost equal increase in KL-6, SP-A and SP-D. These results suggest that SP-A and SP-D may be indicators of gefitinib-induced ILD and that KL-6 is a predictor of outcome. Using a combination of these markers may help to establish a differential prognosis in patients with gefitinib-induced ILD.

The influence of gestation and mechanical ventilation on serum clara cell secretory protein (CC10) concentrations in ventilated and nonventilated newborn infants

Clara cell secretory protein (CC10) is an important anti-inflammatory mediator in the adult lung, but its role in newborn pulmonary protection is uncertain. We examined the early postnatal behavior of CC10 in newborn serum and tracheal fluid and hypothesized that CC10 production is positively influenced by gestation. Blood from 165 infants from the first, third/fourth, and seventh days of life (gestational ages: 23-29 wk, 30-36 wk, >36 wk) and tracheal fluid (TF) from the first day of life from 32 ventilated infants were analyzed for CC10. Surfactant proteins A (SPA) and B (SPB) were also analyzed from the blood of a subgroup of infants. Serum CC10 on day 1 was highest in term infants (69.4 ng/mL), followed by moderately preterm (55.8 ng/mL), and then extremely preterm infants (median 42.1 ng/mL). Term infants also had higher tracheal fluid CC10 than preterm infants. (20.152 ng/mL versus 882 ng/mL). Mechanical ventilation increased serum CC10 only in moderately preterm infants, and only on d 1 [68.4 ng/mL versus 42.1 ng/mL (nonventilated moderately preterm infants)]. Serum CC10 decreased progressively by the end of the first week in all infants, in contrast to SPA and SPB, which increased. Our results show that CC10 is detectable in the blood of newborn infants and that a production surge occurs at birth. This surge is more pronounced in term infants and may confer them with superior extrauterine pulmonary protection compared with preterm infants.

Monitoring markers of disease activity for interstitial lung diseases with serum surfactant proteins A and D

OBJECTIVES

Surfactant protein (SP) A and D are specific serum markers for interstitial lung diseases including idiopathic pulmonary fibrosis (IPF). The authors evaluated the critical roles of these markers on the prognoses of patients with IPF and the mechanisms of their elevation in sera.

METHODOLOGY

The authors evaluated the relationship between prognosis and the serum markers in 82 IPF patients. The protein content and mRNA expression of the markers were evaluated using rats with interstitial pneumonia induced by bleomycin administration.

RESULTS

Higher levels of serum SP-D at the time of the initial visit to the Sapporo Medical University Hospital were associated with poorer prognoses, while SP-A showed no significant affect on survival. Causes of the elevation in sera were due to the acceleration of, not only production in the lungs, leakage into the circulation. The elevation was associated with alveolitis but not fibrosis.

CONCLUSIONS

SP-D is a good predictor of the prognosis in patients with IPF.

Exhaled metallic elements and serum pneumoproteins in asymptomatic smokers and patients with COPD or asthma

STUDY OBJECTIVES

The aim of this study was to characterize the elemental composition of exhaled breath condensate (EBC) in order to identify new biomarkers of exposure and susceptibility in COPD patients. Serum pneumoproteins were used as lung-specific biomarkers of effect.

DESIGN

EBC was obtained from 50 healthy subjects, 30 healthy smokers, 30 asthmatics, and 50 patients with stable COPD, and was collected by cooling exhaled air. Trace elements and toxic metals in the samples were measured by means of inductively coupled plasma-mass spectrometry and electrothermal atomic absorption spectroscopy. The serum pneumoproteins were immunoassayed.

RESULTS

The EBC of COPD subjects had higher levels of such toxic elements as lead, cadmium, and aluminum, and lower levels of iron and copper, than that of the nonsmoking control subjects. There were no between-group differences in surfactant protein (SP)-A and SP-B levels. Clara-cell protein and SP-D levels were negatively and positively influenced, respectively, by tobacco smoke.

CONCLUSIONS

Our results show that toxic metals and transition elements are detectable in the EBC of studied subjects. We propose new biomarkers of exposure as a means of assessing the target tissue dose of carcinogenic and pneumotoxic substances from tobacco smoke or polluted workplaces, and the use of the transition elements involved in redox systems of oxidative stress as disease biomarkers associated with effect or susceptibility. Together with biomarkers of effect, such as serum pneumoproteins, the elemental composition of EBC may be clinically useful in distinguishing similar diseases.

A case of interstitial pneumonia caused by bucillamine: a study using serological markers

The patient was a 61-year-old man diagnosed with rheumatoid arthritis (RA) in 2001. He initially received treatment at a nearby clinic, but his condition could not be satisfactorily controlled. He subsequently consulted our hospital during the same year. Although his symptoms improved in response to treatment at our hospital, slight fever, cough, and then high fever and dyspnea subsequently developed. A diagnosis of interstitial pneumonia was made on the basis of findings of diagnostic imaging. The time course of changes in serological markers, including surfactant protein A (SP-A), surfactant protein D (SP-D), and KL-6, as well as markers of inflammatory reaction and lactate dehydrogenase was examined to determine the clinical significance of serological markers in the management of interstitial pneumonia.

KL-6 and surfactant proteins A and D in serum and bronchoalveolar lavage fluid in patients with acute eosinophilic pneumonia

OBJECT

The serum levels of KL-6, surfactant protein A (SP-A), and SP-D are useful biomarkers and prognostic factors for the activity of interstitial pneumonias. The aim of this study was to determine the clinical roles of the levels of KL-6, SP-A, and SP-D in the serum and bronchoalveolar lavage fluid (BALF) of patients with acute eosinophilic pneumonia (AEP).

MATERIALS AND METHODS

We researched 5 cases of AEP. The levels of KL-6, SP-A, and SP-D in the sera and BALF of those patients were measured by enzyme-linked immunosorbent assay.

RESULTS

KL-6 levels in BALF did not differ between AEP patients and the healthy control group, while SP-A and SP-D levels in BALF were significantly higher in the AEP patients than in the healthy control group. In sera, AEP patients had significantly higher than normal levels of SP-A and SP-D, but not of KL-6. Only in sera there was a positive correlation between SP-A and SP-D, but no apparent correlations in BALF and also between KL-6 and the others. Furthermore, the BALF levels of SP-D, but not of SP-A or KL-6, statistically correlated with the concentration of albumin in BALF. After clinical improvement, the elevated levels of serum SP-A or SP-D in AEP patients decreased until normal levels were reached within 2 months.

CONCLUSION

These results suggest that the serum or BALF levels of SP-D appear to be more sensitive than those of SP-A or KL-6 at reflecting the inflammatory response in AEP lungs.

Increased levels of interleukin-18 in bronchoalveolar lavage fluid of patients with idiopathic nonspecific interstitial pneumonia

BACKGROUND

Interleukin-18 (IL-18) is a proinflammatory cytokine that can induce interferon-gamma (IFN-gamma), and it plays an important role in T-helper 1 responses. Among idiopathic interstitial pneumonia (IIP), nonspecific interstitial pneumonia (NSIP) has an increased number of lymphocytes in bronchoalveolar lavage (BAL) fluid compared with usual interstitial pneumonia (UIP). However, the difference in their pathogenesis is unclear.

OBJECTIVE

The present study aims to investigate the roles of IL-18 in patients with idiopathic UIP and idiopathic NSIP.

METHODS

We measured the serum and BAL fluid (BALF) levels of IL-18 and IFN-gamma in 22 patients with IIP (12 with UIP, 10 with NSIP) and 9 healthy volunteers.

RESULTS

Lymphocyte proportions in BALF were significantly higher in NSIP than in UIP and healthy subjects. No significant differences were observed in the serum IL-18 levels of all subjects, while the BALF levels of IL-18 in patients with NSIP were significantly higher than in patients with UIP (p < 0.005) and in healthy subjects (p < 0.005). Among all subjects, the levels of IL-18 in BALF correlated significantly with those in serum and the lymphocyte proportions in BALF. The serum IFN-gamma levels of all subjects were below sensitivity, but there was significant reverse correlation between the levels of IFN-gamma and the lymphocyte proportions in BALF.

CONCLUSION

The lymphocytosis in BALF of patients with idiopathic NSIP and a part of idiopathic UIP might be associated with the high levels of IL-18.

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.

Serum surfactant protein-A levels in chronic bronchitis and its relation to smoking

BACKGROUND

Surfactant protein-A (SP-A), which is an important constituent of natural surfactant, occurs physiologically in small amounts in blood. Tobacco smoke induces increased alveolo-capillary leakage of surfactant proteins into blood and its level in blood may help in the assessment of lung injury caused by smoke. Little is known on the SP-A levels in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Prospective analytical study of 30 patients with clinical diagnosis of chronic bronchitis, which was made on the basis of symptoms, signs and chest radiographic findings. Serum SP-A and serum cotinine levels were measured.

RESULTS

Out of 30 patients, 21 were smokers and nine were non-smokers. The serum SP-A level in smokers with chronic bronchitis is significantly higher than the non-smokers. The plasma cotinine levels are also high in smokers. However, there was no correlation between the serum SP-A level and plasma cotinine level (r=0.044). Serum SP-A levels were related to age in smokers (r=0.566, p<0.01) but not in non-smokers with chronic bronchitis (r=0.017, p>0.05).

CONCLUSION

The increase in SP-A level in smokers with chronic bronchitis suggests that tobacco smoking causes a chronic increase in permeability of the lung parenchyma. The SP-A, a lung-specific secretory protein, is a potential marker for non-invasive assessment of the integrity of the lung epithelium. Further studies are required to find out whether SP-A can be used as a marker for early identification of smokers who are at risk of COPD.

[Sivelestat sodium hydrate was effective for ARDS in a patient suffering from chronic rheumatoid arthritis with acute exacerbation after failing to respond to high dose steroid pulse therapy]

Sivelestat sodium hydrate (ELASPOL) was effective for ARDS in a fifty-year-old female patient suffering from chronic rheumatoid arthritis with acute exacerbation, after failing to respond to high dose steroid pulse therapy. In ICU, the patient had bilateral lung opacities, especially of the upper lobes, respiratory acidosis, hypercapnea (PaCO2 89 mmHg), and poor oxygenation (P/F ratio 193). High dose steroid pulse therapy had been performed, but oxygenation was not improved, and a low level of oxygenation (P/F ratio 155) persisted. Sivelestat was started two days after finishing the steroid pulse therapy. The butterfly shadow on chest X ray and impaired oxygenation were markedly improved from the third day of sivelestat administration. Respiratory support was terminated with P/F ratio 300. Plasma concentrations of SP-A and SP-D decreased after sivelestat administration, but concentration of KL-6 was still elevated. In this case, sivelestat was effective for ARDS in the patient not responding to steroid pulse therapy, and clinical finding and plasma concentrations of SP-A and SP-D were correlated well.

[A case of acute eosinophilic pneumonia with a disassociation between the KL-6 level and SP-A and SP-D levels in the serum and BAL fluid]

A 45-year-old Japanese electrical engineer was admitted to our department of internal medicine on August 12, 2003, because of a sudden high fever and severe hypoxic respiratory failure. At a barbecue with his family on August 3 beside a nearby river, he had been exposed to the smoke. From August 4 to 11, he had suffered fatigue, fever, dry cough and progressive dyspnea. On admission, his SpO2 was 84%, and computed tomography scanning showed patchy ground glass opacity, thickened bronchial walls, and bilateral pleural effusions. The eosinophil count in the bronchoalveolar lavage fluid (BALF) was increased to 52.4%. Noticeably, the KL-6, SP-A and SP-D levels in the serum were elevated to 197 U/ml, 188 ng/ml and 137 ng/ml, and their levels in BALF had also increased to 225 U/ml, 890 ng/ml and 1110 ng/ml, respectively. The lymphocyte stimulation test was negative, and the cultures of blood and BALF did not grow any pathogens. The patient had smoked 1 pack of per cigarettes day for 25 years and showed no sign of atopic illness. Acute eosinophilic pneumonia (AEP) was diagnosed, and responded dramatically to treatment with oxygen and corticosteroids. The dissociation between the normal KL-6 levels and the elevated SP-A and SP-D levels in the serum and BAL fluid may play an important role in cases of AEP.

Elevated serum surfactant protein A and D in a case of acute eosinophilic pneumonia

A 29-year-old man was admitted to our hospital because of fever elevation, dry cough, malaise, skin eruption, and dyspnea with hypoxemia. His serum levels of surfactant protein (SP) -A and SP-D were markedly high, but serum KL-6 was not. He was diagnosed as acute eosinophilic pneumonia (AEP) on the basis of CT imaging, bronchoalveolar lavage findings and the clinical course. He showed good response to steroid therapy and serum levels of SP-A and SP-D returned to almost normal levels. Our experience suggested that serum SP-A and SP-D might be helpful markers for monitoring the clinical course in AEP.

Hericium erinaceum (yamabushitake) extract-induced acute respiratory distress syndrome monitored by serum surfactant proteins

This is the first report suggesting a causal relationship between acute respiratory distress syndrome and Hericium erinaceum extract, which is commercialized as a diet food. A 63-year-old man was admitted to our hospital for intensive care of severe acute respiratory failure with diffuse infiltration in both lungs. Bronchoalveolar lavage fluid revealed a high percentage of lymphocytes. Lymphocyte stimulation test showed a strong reactivity against extract formulation of Hericium erinaceum (Yamabushitake), which he had taken four months before onset. He recovered with successful steroid pulse therapy under mechanical ventilation. Concentrations of surfactant protein (SP)-A and SP-D in sera reflected the clinical features.

Plasma surfactant protein levels and clinical outcomes in patients with acute lung injury

BACKGROUND

Because injury to the alveolar epithelial barrier is a characteristic feature of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS), plasma surfactant protein levels may have prognostic value. To test this hypothesis plasma surfactant proteins A and D (SP-A and SP-D) levels were measured in patients with ALI or ARDS enrolled in the NHLBI sponsored multicentre ARDS Network randomised controlled trial of a 6 ml/kg v 12 ml/kg tidal volume strategy.

METHODS

Data from 565 participants in the clinical trial were used. Plasma levels of SP-A and SP-D were measured at baseline and on day 3 after the start of the mechanical ventilation protocol. The longitudinal impact of baseline plasma surfactant protein levels on clinical outcomes was examined by multivariate analysis, controlling for mechanical ventilation group, APACHE III score, and other clinical covariates. The effect of 6 ml/kg tidal volume ventilation on plasma SP-A and SP-D levels was evaluated using analysis of covariance.

RESULTS

Baseline plasma SP-A levels were not related to any clinical outcome. In contrast, higher baseline plasma SP-D levels were associated with a greater risk of death (OR 1.21 per 100 ng/ml increment; 95% CI 1.08 to 1.35), fewer ventilator-free days (mean decrease -0.88 days; p=0.001), and fewer organ failure-free days (mean decrease -1.06 days; p<0.0001). The 6 ml/kg tidal volume strategy had no effect on the rise in plasma SP-A levels (p=0.91) but attenuated the rise in plasma SP-D levels (p=0.0006).

CONCLUSIONS

Early in the course of ALI/ARDS an increased level of plasma SP-D is associated with a worse clinical outcome. The 6 ml/kg tidal volume strategy attenuated the rise of SP-D early in the clinical course. Taken together, these observations indicate that plasma SP-D, a product of alveolar type II cells, is a valuable biomarker in ALI/ARDS.

Serum pneumoproteins: a cross-sectional comparison of firefighters and police

BACKGROUND

Serum pneumoproteins provide a measure of the permeability of the lower respiratory tract, and have shown promise as a biomarker of acute and chronic exposure to respiratory toxicants.

METHODS

To evaluate the effects of chronic occupational smoke exposure, 105 firefighters were compared with 44 police controls in a cross-sectional study using spirometry, diffusing capacity of the lung, serum Clara cell protein (CC16), and serum surfactant-associated protein A (SP-A) measurements.

RESULTS

There were no significant differences in age, gender, height, spirometry (FVC and FEV(1)), and diffusing capacity between the two groups. Serum SP-A was lower in firefighters (260.1 +/- 121.2 microg/L) than police (316.0 +/- 151.4 microg/L, P = 0.019). Serum CC16 was also lower in firefighters (8.39 +/- 3.11 microg/L) than police (10.56 +/- 4.20 microg/L, P < 0.001), although this difference lost statistical significance when adjusted for confounders.

CONCLUSIONS

Firefighters have lower serum concentrations of SP-A than do police. Although the clinical significance of this finding is presently unknown, SP-A deserves further study as a biomarker of toxic exposure to the lower respiratory tract.

Lung hyperpermeability and asthma prevalence in schoolchildren: unexpected associations with the attendance at indoor chlorinated swimming pools

AIMS

To study whether exposure to nitrogen trichloride in indoor chlorinated pools may affect the respiratory epithelium of children and increase the risk of some lung diseases such as asthma.

METHODS

In 226 healthy children, serum surfactant associated proteins A and B (SP-A and SP-B), 16 kDa Clara cell protein (CC16), and IgE were measured. Lung specific proteins were measured in the serum of 16 children and 13 adults before and after exposure to NCl(3) in an indoor chlorinated pool. Relations between pool attendance and asthma prevalence were studied in 1881 children. Asthma was screened with the exercise induced bronchoconstriction test (EIB).

RESULTS

Pool attendance was the most consistent predictor of lung epithelium permeability. A positive dose-effect relation was found with cumulated pool attendance and serum SP-A and SP-B. Serum IgE was unrelated to pool attendance, but correlated positively with lung hyperpermeability as assessed by serum SP-B. Changes in serum levels of lung proteins were reproduced in children and adults attending an indoor pool. Serum SP-A and SP-B were already significantly increased after one hour on the pool side without swimming. Positive EIB and total asthma prevalence were significantly correlated with cumulated pool attendance indices.

CONCLUSIONS

Regular attendance at chlorinated pools by young children is associated with an exposure dependent increase in lung epithelium permeability and increase in the risk of developing asthma, especially in association with other risk factors. We therefore postulate that the increasing exposure of children to chlorination products in indoor pools might be an important cause of the rising incidence of childhood asthma and allergic diseases in industrialised countries. Further epidemiological studies should be undertaken to test this hypothesis.

Prolonged alveolocapillary barrier damage after acute cardiogenic pulmonary edema

OBJECTIVES

To determine whether acute cardiogenic pulmonary edema is associated with damage to the alveolocapillary barrier, as evidenced by increased leakage of surfactant specific proteins into the circulation, to document the duration of alveolocapillary barrier damage in this setting, and to explore the role of pulmonary parenchymal inflammation by determining if circulating tumor necrosis factor-alpha is increased after acute cardiogenic pulmonary edema.

DESIGN

Prospective, observational study.

SETTING

Critical care, cardiac intensive care, and cardiology wards of a tertiary-care university teaching hospital.

PATIENTS

A total of 28 patients presenting with acute cardiogenic pulmonary edema and 13 age-matched normal volunteers.

INTERVENTIONS

Circulating surfactant protein-A and -B and tumor necrosis factor-alpha were measured on days 0 (presentation), 1, 3, 7, and 14. Clinical markers of pulmonary edema were documented at the same times.

MEASUREMENTS AND MAIN RESULTS

Surfactant protein-A and -B were elevated on day 0 compared with controls (367 +/- 17 ng/mL vs. 303 +/- 17 and 3821 +/- 266 ng/mL vs. 2747 +/- 157 [mean +/- sem], p <.05), and although clinical, hemodynamic and radiographic variables improved rapidly (p <.001), surfactant protein-A and -B rose further until day 3 (437 +/- 22, p <.001, 4642 +/- 353, p <.01). Tumor necrosis factor-alpha was elevated at presentation (p <.05), doubled by day 1 (6.98 +/- 1.36 pg/mL, p <.05), remained elevated on day 3 (5.72 +/- 0.96 pg/mL, p <.05), and peak levels were related to chest radiograph extravascular lung water score (r(p) = 0.64, p =.003).

CONCLUSIONS

Although the initial increase in plasma surfactant protein-A and -B may represent hydrostatic stress failure of the alveolocapillary barrier, the prolonged elevation, when hemodynamic abnormalities have resolved, and the delayed elevation of tumor necrosis factor-alpha are consistent with pulmonary parenchymal inflammation, which may further damage the alveolocapillary barrier. This prolonged physiologic defect at the alveolocapillary barrier after acute cardiogenic pulmonary edema may partly account for the vulnerability of these patients to recurrent pulmonary fluid accumulation.

Relationship of anti-GM-CSF antibody concentration, surfactant protein A and B levels, and serum LDH to pulmonary parameters and response to GM-CSF therapy in patients with idiopathic alveolar proteinosis

BACKGROUND

Conventional measures of the severity of alveolar proteinosis (AP) include alveolar-arterial oxygen gradient ([A - a]DO(2)), vital capacity (VC), and carbon monoxide transfer factor (TLCO), but alternative serological measures have been sought. Granulocyte-macrophage colony stimulating factor (GM-CSF) neutralising autoantibody is found in patients with idiopathic acquired AP. We have investigated the interrelationships between the levels of this antibody and those of surfactant protein (SP)-A and -B, lactate dehydrogenase (LDH), and conventional measures of disease severity, and the capacity of these parameters to predict the response to rhGM-CSF treatment.

METHODS

Blood levels of anti-GM-CSF antibodies, SP-A, SP-B, LDH, and [A - a]DO(2), VC, and TLCO were measured before rhGM-CSF treatment and every 2 weeks thereafter in 14 patients with AP.

RESULTS

At baseline, high levels of anti-GM-CSF antibodies and increased SP-A and SP-B levels were seen in all patients, and LDH was raised in 83%. SP-A was highly correlated with [A - a]DO(2), VC, and TLCO (p</=0.02), but other markers were not. Only a normal LDH level was predictive of a response to rhGM-CSF treatment (p=0.03). During treatment a correlation between conventional and serological variables within patients was seen only between SP-A and [A - a]DO(2) (p=0.054), LDH levels and [A - a]DO(2) (p=0.010), and LDH levels and VC (p=0.019).

CONCLUSIONS

Of the serological parameters studied, only SP-A and LDH levels were correlated with conventional measures of disease severity, with LDH most accurately reflecting [A - a]DO(2) and vital capacity. Only a normal LDH level predicted a higher likelihood of response to treatment with GM-CSF.

Possible postmortem serum markers for differentiation between fresh-, saltwater drowning and acute cardiac death: a preliminary investigation

The aim of the present study was to investigate the differences in postmortem blood biochemistry between fresh-, saltwater drowning and acute myocardial infarction/ischemia (AMI) (n=11, n=15 and n=23, respectively; postmortem interval <48 h). Left and right cardiac blood samples were examined for the serum markers: sodium (Na), chloride (Cl), magnesium (Mg), blood urea nitrogen (BUN), creatinine (Cr), pulmonary surfactant-associated protein A (SP-A) and cardiac troponin T (cTn-T). The most efficient markers were the left-right cardiac BUN ratio for determination of drowning (hemodilution) and the left heart blood Mg level for differentiation between fresh- and saltwater aspiration. A characteristic feature of saltwater drowning was a low left-right BUN ratio and a marked elevation in the serum Cl, Mg and Ca levels of the left heart blood. Serum cTn-T level was usually low in drownings, showing a difference from most cases of AMI. Freshwater drowning showed a significant elevation of serum SP-A, although there was considerable overlapping with saltwater drowning and AMI. These findings suggested the usefulness of serum markers in the investigation of death from drownings.

High serum concentrations of surfactant protein A in usual interstitial pneumonia compared with non-specific interstitial pneumonia

BACKGROUND

The pathological diagnosis of interstitial lung diseases (ILD) by surgical lung biopsy is important for clinical decision making. There is a need, however, to use serum markers for differentiating usual interstitial pneumonia (UIP) from other ILD. Surfactant protein (SP)-A, SP-D, KL-6, sialyl SSEA-1 (SLX), and sialyl Lewis(a) (CA19-9) are useful markers for the diagnosis and evaluation of activity of ILD. We have investigated the usefulness of these proteins as markers of UIP.

METHODS

Serum and bronchoalveolar lavage (BAL) fluid levels of the above five markers were measured in 57 patients with various forms of ILD (19 with UIP, 12 with non-specific interstitial pneumonia (NSIP), eight with bronchiolitis obliterans organising pneumonia (BOOP), and 10 with sarcoidosis), eight patients with the control disease (diffuse panbronchiolitis (DPB)), and nine healthy volunteers.

RESULTS

Serum levels of SP-A, SP-D, and KL-6 in patients with UIP and NSIP were significantly higher than in healthy volunteers. In particular, the serum levels of SP-A in patients with UIP were significantly higher than in patients with NSIP (p<0.0001, mean difference -58.3 ng/ml, 95% confidence interval -81.6 to -35.0), and BAL fluid levels of SP-D in patients with UIP were significantly lower than in patients with NSIP (p=0.01, mean difference 322.4 ng/ml, 95% confidence interval 79.3 to 565.5).

CONCLUSION

Serum SP-A levels may be clinically useful as a biomarker to differentiate between UIP and NSIP.

Prognostic value of surfactant proteins A and D in patients with acute lung injury

OBJECTIVE

The primary objective of this study was to test the hypothesis that in patients intubated for acute lung injury, lower concentrations of surfactant proteins A and D in the pulmonary edema fluid and higher concentrations in the plasma are associated with more severe lung injury and worse clinical outcomes.

DESIGN

Observational study.

SETTING

Intensive care unit patients in a tertiary university hospital and a university-affiliated city hospital.

PATIENTS

Thirty-eight intubated, mechanically ventilated intensive care unit patients with acute lung injury or acute respiratory distress syndrome as defined by the North American European Consensus Conference.

INTERVENTIONS

Undiluted pulmonary edema fluid and plasma samples were collected within 24 hrs of endotracheal intubation in all patients.

MEASUREMENTS AND MAIN RESULTS

The concentrations of surfactant proteins A and D were measured in pulmonary edema fluid and in plasma. Plasma surfactant protein A, but not surfactant protein D, was higher in patients with fewer days of unassisted ventilation (p = .03) and in patients with an absence of intact alveolar fluid clearance (p =.03). In contrast, pulmonary edema fluid surfactant protein D, but not surfactant protein A, was lower in patients with worse oxygenation, as measured by the alveolar-arterial oxygen difference (p = .01) and was lower in the patients who died (2646 ng/mL) compared with those who survived (5503 ng/mL; p = .02).

CONCLUSIONS

These results demonstrate that reduced pulmonary edema fluid surfactant protein D and elevated plasma surfactant protein A concentrations at the onset of acute lung injury may be associated with more severe disease and worse clinical outcome and may serve as valuable biochemical markers of prognosis.