Serum and lavage lactate dehydrogenase isoenzymes in pulmonary alveolar proteinosis

Serum lactate dehydrogenase and its isoenzymes as predictors of clinical outcomes in acute exacerbation of chronic obstructive pulmonary disease: a retrospective analysis of a hospitalized cohort

We aimed to test the relationship between serum lactate dehydrogenase (LDH) and its isoenzymes and treatment outcomes during hospitalization for acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Thirty-eight AECOPD patients were recruited from a tertiary hospital from December 2017 to June 2018. Serum LDH and LDH isoenzymes were measured on venous blood collected at admission. Treatment outcomes included duration of hospital stay, initiation of mechanical or non-invasive ventilation (NIV), initiation of antipseudomonal antibiotics, change in empirical antibiotic treatment, need for intravenous corticosteroids or methylxanthines, and percentage of change in C-reactive protein from admission to the third day. Multivariate linear and binary logistic regression analyses were used to test the study's objectives. We found that, after adjusting for age, gender, comorbidities, COPD severity, level of hypoxemia, and inflammation markers, each 10 U/L increase in serum LDH was associated with prolongation of the hospital stay by 0.25 (0.03, 0.46) days, 42% higher odds [odds ratio (OR) 1.42 (1.00, 2.03)] for need of NIV, and 25% higher odds [OR 1.25 (1.04, 1.49)] for initiation of antipseudomonal treatment. LDH1 and LDH2 were the LDH isoenzymes that mainly drove these relationships. LDH release in the context of an AECOPD could originate from lung, muscle, or heart tissue damage due to airway inflammation, respiratory muscle recruitment, and myocardial stress. Myocardial injury and aerobic adaptation in respiratory muscles may explain the predominance of LDH1 and LDH2 isoenzymes in these associations.

CYFRA21-1 is a more sensitive biomarker to assess the severity of pulmonary alveolar proteinosis

Background

Serum lactate dehydrogenase (LDH), carcinoembryonic antigen (CEA) and CYFRA21-1 are the commonly used biomarkers to identify patients with autoimmune pulmonary alveolar proteinosis (APAP). However, it is not clear which of the biomarkers is more sensitive to the severity of the patient’s condition.

Methods

APAP patients numbering 151 were enrolled in this study. All patients’ severity was assessed through the severity and prognosis score of PAP (SPSP). According to the respective laboratory upper limits of serum levels of LDH, CEA and CYFRA21-1, APAP patients were divided into higher and lower-level groups. Patients were divided into five groups based on SPSP. 88 patients had completed six months of follow-up. We calculated sensitivity, specificity, and critical point of LDH, CEA and CYFRA21-1 between APAP patients and normal control group, and between grade 1–2 and 3–5 through receiving operating characteristics (ROC) curve.

Results

Serum LDH, CEA and CYFRA21-1 levels of patients with PAP were higher and distinctly related to PaO₂, FVC, FEV₁, DLCO, HRCT scores and SPSP. The SPSP of patients in higher-level LDH, CEA and CYFRA21-1 groups were higher than those of corresponding lower-level groups. Based on SPSP results, the patients were divided into five groups (grade I, 20; grade II, 37; grade III, 40; grade IV, 38; grade V, 16). The serum level of CYFRA21-1 of patients with APAP in grade II was higher than that of patients in grade I and lower than that of patients in grade III. Serum CYFRA21-1 of patients with APAP after six months were higher than the baseline among the aggravated group. Serum LDH, CEA and CYFRA21-1 levels after six months among patients in the relieved group of patients with APAP were lower than the baseline. ROC correlating LDH, CEA and CYFRA21-1 values with APAP severity (between grade 1–2 and 3–5) showed an optimal cutoff of LDH of over 203 U/L (< 246 U/L), CEA of over 2.56 ug/L (< 10 ug/L), and CYFRA21-1 of over 5.57 ng/ml (> 3.3 ng/ml) (AUC: 0.815, 95% CI [0.748–0.882], sensitivity: 0.606, specificity: 0.877).

Conclusion

Serum CYFRA21-1 level was more sensitive in revealing the severity of APAP than LDH and CEA levels among mild to moderate forms of disease.

Pentoxifylline decreases serum LDH levels and increases lymphocyte count in COVID-19 patients: Results from an external pilot study

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Pentoxifylline could be beneficial for the treatment of COVID-19.

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Serum lactate dehydrogenase and lymphocyte count are accessible biomarkers that correlate with the severity of COVID-19.

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Pentoxifylline treatment was associated with an increase in the lymphocyte count and decreased LDH levels.

We have previously hypothesized that pentoxifylline could be beneficial for the treatment of COVID-19 given its potential to restore the immune response equilibrium, reduce the impact of the disease on the endothelium and alveolar epithelial cells, and improve the circulatory function. Serum lactate dehydrogenase (LDH) and lymphocyte count are accessible biomarkers that correlate with the severity of COVID-19, the need for hospitalization, and mortality, reflecting the host immune response’s contribution to the seriousness of SARS-CoV-2 infection.

We carried out this external pilot study on 38 patients with moderate and severe COVID-19 to test the effect pentoxifylline on parameters such as LDH, lymphocyte count, days of hospitalization, mortality, and proportion of patients requiring intubation. Twenty-six patients were randomized to receive 400 mg of pentoxifylline t.i.d. plus standard therapy (pentoxifylline group), while the rest received the standard treatment (control group). Linear regression models were built for statistically significant parameters.

Pentoxifylline treatment was associated with a 64.25% increase (CI95% 11.83, 116.68) in lymphocyte count and a 29.61% decrease (CI95% 15.11, 44.10) in serum LDH. Although a trend towards reduced days of hospitalization, mortality, and proportion of patients requiring intubation was observed, no statistically significant difference was found for these parameters.

Our findings open the possibility of pentoxifylline being repositioned as a drug for COVID-19 treatment with the advantages of a proven safety profile, availability, and no risk of immunosuppression; however, this evidence needs to be confirmed in a pragmatic randomized controlled trial.

Clinical significance of cigarette smoking and dust exposure in pulmonary alveolar proteinosis: a Korean national survey

BACKGROUND

This study aimed to investigate clinical characteristics of Korean PAP patients and to examine the potential risk factors of PAP.

METHODS

We retrospectively reviewed medical records of 78 Korean PAP patients diagnosed between 1993 and 2014. Patients were classified into two groups according to the presence/absence of treatment (lavage). Clinical and laboratory features were compared between the two groups.

RESULTS

Of the total 78 PAP patients, 60% were male and median age at diagnosis was 47.5 years. Fifty three percent were ever smokers (median 22 pack-years) and 48% had a history of dust exposure (metal 26.5%, stone or sand 20.6%, chemical or paint 17.7%, farming dust 14.7%, diesel 14.7%, textile 2.9%, and wood 2.9%). A history of cigarette smoking or dust exposure was present in 70.5% of the total PAP patients, with 23% having both of them. Patients who underwent lavage (n = 38) presented symptoms more frequently (38/38 [100%] vs. 24/40 [60%], P < 0.001) and had significantly lower PaO₂ and DL_CO with higher D(A-a)O₂ at the onset of disease than those without lavage (n = 40) (P = 0.006, P < 0.001, and P = 0.036, respectively). Correspondingly, the distribution of disease severity score (DSS) differed significantly between the two groups (P = 0.001). Based on these, when the total patients were categorized according to DSS (low DSS [DSS 1-2] vs. high DSS [DSS 3-5]), smoking status differed significantly between the two groups with the proportion of current smokers significantly higher in the high DSS group (11/22 [50%] vs. 7/39 [17.9%], P = 0.008). Furthermore, current smokers had meaningfully higher DSS and serum CEA levels than non-current smokers (P = 0.011 and P = 0.031), whereas no difference was found between smokers and non-smokers. Regarding type of exposed dust, farming dust was significantly associated with more severe form of PAP (P = 0.004).

CONCLUSION

A considerable proportion of PAP patients had a history of cigarette smoking and/or dust exposure, suggestive of their possible roles in the development of PAP. Active cigarette smoking at the onset of PAP is associated with the severity of PAP.

The Clinical Clues of Pulmonary Alveolar Proteinosis: A Report of 11 Cases and Literature Review

Pulmonary alveolar proteinosis (PAP) is a rare interstitial lung disease characterized by the abnormal alveolar accumulation of surfactant components. The diagnosis of PAP can be easily missed since it is rare and lacks specific clinical symptoms. It is of great importance to have a better understanding of the crucial clue to clinically diagnose PAP and take PAP into consideration in the differential diagnosis of interstitial pulmonary diseases or other diseases with similar manifestations. Here, we analyze the clinical characteristics of 11 cases of PAP patients in local hospital and review the relevant literature in order to provide more information in diagnosis and management of PAP. In our observation, cyfra21-1 and neuron-specific enolase (NSE) known as tumor markers probably can be useful serum markers for diagnosis of PAP. As for the method of pathologic diagnosis, open-lung biopsy was the gold standard but now it is less required because findings on examination of bronchoalveolar lavage fluid (BALF) can help to make the diagnosis. We also have deep experience about when and how to carry out lung lavage.

Expanded CURB-65: a new score system predicts severity of community-acquired pneumonia with superior efficiency

Aim of this study was to develop a new simpler and more effective severity score for community-acquired pneumonia (CAP) patients. A total of 1640 consecutive hospitalized CAP patients in Second Affiliated Hospital of Zhejiang University were included. The effectiveness of different pneumonia severity scores to predict mortality was compared, and the performance of the new score was validated on an external cohort of 1164 patients with pneumonia admitted to a teaching hospital in Italy. Using age ≥ 65 years, LDH > 230 u/L, albumin < 3.5 g/dL, platelet count < 100 × 10⁹/L, confusion, urea > 7 mmol/L, respiratory rate ≥ 30/min, low blood pressure, we assembled a new severity score named as expanded-CURB-65. The 30-day mortality and length of stay were increased along with increased risk score. The AUCs in the prediction of 30-day mortality in the main cohort were 0.826 (95% CI, 0.807–0.844), 0.801 (95% CI, 0.781–0.820), 0.756 (95% CI, 0.735–0.777), 0.793 (95% CI, 0.773–0.813) and 0.759 (95% CI, 0.737–0.779) for the expanded-CURB-65, PSI, CURB-65, SMART-COP and A-DROP, respectively. The performance of this bedside score was confirmed in CAP patients of the validation cohort although calibration was not successful in patients with health care-associated pneumonia (HCAP). The expanded CURB-65 is objective, simpler and more accurate scoring system for evaluation of CAP severity, and the predictive efficiency was better than other score systems.

One-year, simultaneous combined exposure of CDMA and WCDMA radiofrequency electromagnetic fields to rats

PURPOSE

We investigated whether one-year, long-term, simultaneous exposure to code division multiple access (CDMA; 849 MHz) and wideband code division multiple access (WCDMA; 1.95 GHz) radiofrequencies (RF) would induce chronic illness in Sprague-Dawley (SD) rats.

MATERIALS AND METHODS

Two groups of 40 SD rats (50% males and females in sham and exposed groups) were exposed to CDMA and WCDMA RF simultaneously at 2.0 W/kg for 45 min/day (total 4.0 W/kg), 5 days per week for a total of one year. Body and organ weight measurements, urinalysis, haematological and blood biochemical analysis, and histopathological evaluations were performed.

RESULTS

The mortality patterns in male and female rats exposed to RF were compared with those found in gender-matched sham control animals. No significant alteration in body weight was observed with the simultaneous combined RF exposure. Most RF-exposed rats showed no significant alteration, based on urinalysis, haematology, blood biochemistry, or histopathology. However, some altered parameters of the complete blood count and serum chemistry were seen in RF-exposed rats. The total tumour incidence was not different between sham-exposed and RF-exposed animals.

CONCLUSIONS

Our results suggest that one-year chronic exposure to CDMA (849 MHz) and WCDMA (1.95 GHz) RF simultaneously at 2.0 W/kg for 45-min RF exposure periods (total, 4 W/kg) did not increase chronic illness in rats, although there were some altered parameters in the complete blood count and serum chemistry.

LDH concentration in nasal-wash fluid as a biochemical predictor of bronchiolitis severity

OBJECTIVE

Because the decision to hospitalize an infant with bronchiolitis is often supported by subjective criteria and objective indicators of bronchiolitis severity are lacking, we tested the hypothesis that lactate dehydrogenase (LDH), which is released from injured cells, is a useful biochemical indicator of bronchiolitis severity.

PATIENTS AND METHODS

We retrospectively analyzed a study of children <24 months old presenting to the emergency department with bronchiolitis. Demographic, clinical information, nasal wash (NW), and serum specimens were obtained. NW samples were analyzed for respiratory viruses, caspase 3/7 activity, and a panel of cytokines and chemokines. Total LDH activity was tested in NW samples and sera.

RESULTS

Of 101 enrolled children (median age: 5.6 months), 98 had NW specimens available. A viral etiology was found for 82 patients (83.6%), with respiratory syncytial virus (RSV) (66%) and rhinovirus (19%) being the most common viruses detected. Concentrations of LDH in NW specimens were independent from those in sera and were higher in children with RSV infection or with dual infection. Significant correlations were found between NW LDH and NW cytokines/chemokines. Similarly, NW LDH correlated with NW-caspase 3/7 activity (r = 0.75; P < .001). In a multivariate analysis, NW LDH concentration in the upper quartile was significantly associated with a reduced risk of hospitalization (odds ratio: 0.19 [95% confidence interval: 0.05-0.68]; P = .011).

CONCLUSIONS

NW LDH levels in young children with bronchiolitis varied according to viral etiology and disease severity. Values in the upper quartile were associated with approximately 80% risk reduction in hospitalization, likely reflecting a robust antiviral response. NW LDH may be a useful biomarker to assist the clinician in the decision to hospitalize a child with bronchiolitis.

Update in nonneoplastic lung diseases

CONTEXT

Nonneoplastic lung diseases include a wide range of pathologic disorders from asthma to interstitial lung disease to pulmonary hypertension. Recent advances in our understanding of the pathophysiology of many of these disorders may ultimately impact diagnosis, therapy, and prognosis. It is important for the practicing pathologist to be aware of this new information and to understand how it impacts the diagnosis, treatment, and outcome of these diseases.

OBJECTIVE

To update current progress toward elucidating the pathophysiology of pulmonary alveolar proteinosis, idiopathic pulmonary hemosiderosis, and pulmonary arterial hypertension, as well as to present classification systems for pulmonary hypertension, asthma, and interstitial lung disease and describe how these advances relate to the current practice of pulmonary pathology.

DATA SOURCES

Published literature from PubMed (National Library of Medicine) and primary material from the authors' institution.

CONCLUSIONS

Improved understanding of the pathophysiology of pulmonary alveolar proteinosis, pulmonary hypertension, and idiopathic hemosiderosis may impact the role of the surgical pathologist. New markers of disease may need to be assessed by immunohistochemistry or molecular techniques. The classification systems for interstitial lung disease, asthma, and pulmonary hypertension are evolving, and surgical pathologists should consider the clinicopathologic context of their diagnoses of these entities.

Rare lung disease II: pulmonary alveolar proteinosis

The present article is the second in a series on rare lung diseases. It focuses on pulmonary alveolar proteinosis (PAP), a disorder in which lipoproteinaceous material accumulates in the alveolar space. PAP was first described in 1958, and for many years the nature of the material accumulating in the lungs was unknown. Major insights into PAP have been made in the past decade, and these have led to the notion that PAP is an autoimmume disorder in which autoantibodies interfere with signalling through the granulocyte-macrophage colony-stimulating factor receptor, leading to macrophage and neutrophil dysfunction. This has spurred new therapeutic approaches to this disorder. The discussion of PAP will begin with a case report, then will highlight the classification of PAP and review recent insights into the pathogenesis of PAP. The approach to therapy and the prognosis of PAP will also be discussed.

The value of BAL fluid LDH level in differentiating benign from malignant solitary pulmonary nodules

PURPOSE

Serum lactate dehydrogenase (LDH) concentration is an indicator of tissue injury. It may be locally secreted in some conditions. This study was performed in order to investigate the value of LDH levels in bronchoalveolar lavage fluid (BALF) in the differentiation of a bening, from a malignant solitary pulmonary nodules (SPN) and to assess its relationship with serum LDH levels.

METHODS

The study was a prospective clinical study. It included 59 patients with a SPN. They underwent bronchoscopy with bronchoalveolar lavage (BAL). Both total serum and BAL LDH levels were measured.

RESULTS

BALF LDH level was increased in all patients with malignant SPN. The mean BALF LDH level was significantly higher in patients with malignant SPN (342.23 +/- 89.98) as compared to the benign ones (17.62 +/- 7.90) (P < 0.001). There was no correlation between BALF LDH and serum LDH level in patients with SPNs (P = 0.595).

CONCLUSION

BALF LDH levels are increased in patients with malignant SPN, but had no significant rise in benign SPN. This factor is useful in differentiating the benign SPNs from malignant SPNs.

Pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis is a rare syndrome characterized by intra-alveolar accumulation of surfactant components and cellular debris, with minimal interstitial inflammation or fibrosis. The condition has a variable clinical course, from spontaneous resolution to respiratory failure and death due to disease progression or superimposed infections. The standard of care for alveolor proteinosis therapy is represented by whole lung lavage. Important discoveries have been made in the last decade with respect to disease pathogenesis and therapy of both congenital and acquired forms of the disease. Granulocyte-macrophage colony-stimulating factor (GM-CSF) pathway has been shown to be involved in the disease pathogenesis of both acquired and congenital disease. Furthermore, anti-GM-CSF blocking autoantibodies have been found in the serum and bronchoalveolar lavage fluid and seem to interfere with the surfactant clearance by alveolar macrophages in many acquired cases. In the congenital form, the most common defects identified to date are several mutations of the genes encoding GM-CSF receptor subunits or surfactant proteins. Using GM-CSF as a therapeutic tool has also been shown to be effective in at least half of the acquired cases treated, while the importance of quantitative determination of anti-GM-CSF antibodies before and during the course of the therapy, as well as the autoantibody titer-GM-CSF dose relationship are to be elucidated. The congenital form of the disease does not respond to therapy with GM-CSF, consistent with the known primary defects and differences in disease pathogenesis.

[Pulmonary alveolar phospholipoproteinosis]

Pulmonary alveolar phospholipoproteinosis is a rare lung disease of unknown cause characterized by surfactant plugging of the alveoli. At the present time, surgical lung biopsy, long considered as the gold standard, is not necessary for positive diagnosis of pulmonary alveolar phospholipoproteinosis when computed tomography anomalies and analysis of bronchial lavage fluids present a typical pattern. Treatment requires abundant lavage, but the demonstration of anti-GM-CSF antibodies in primary forms opens new therapeutic perspectives.

Pulmonary Alveolar Proteinosis

Pulmonary alveolar proteinosis (PAP) is characterized by the accumulation of surfactant phospholipids and proteins within the lung alveoli. Important advances have been made over the past 8 years in our understanding of this disease, offering new directions for research and patient care. First, genetically altered mice that are homozygous for a disrupted granulocyte-macrophage colony-stimulating factor (GM-CSF) gene developed a lung lesion with histologic resemblance to PAP. The surfactant is thought to be catabolized or cleared mostly by alveolar macrophages, this process being dependent on GM-CSF. Second, a neutralizing autoantibody against GM-CSF was found in serum and bronchoalveolar lavage fluid of patients with idiopathic PAP but not in healthy controls, thereby raising the suspicion that human PAP may be an autoimmune disease. The relationship between the antibody and disease pathogenesis remains unclear but data suggest that the GM-CSF antibody may have a potential role as a diagnostic test. No specific therapy exists for PAP. Sequential whole lung lavage is the standard of care. Exogenous therapy with GM-CSF may improve the lung disease in some patients with PAP but this therapy is still experimental. Interventions directed at treating a relative GM-CSF deficiency by administration of GM-CSF or lowering the antibody level (i.e. by plasmapheresis or immunosuppression) may hold promise as future therapy for this rare disease.

Specific enzyme activities in bronchoalveolar lavage fluid as an aid to diagnosis of tracheobronchitis and bronchopneumonia in dogs

Lactate dehydrogenase (LDH), alkaline phosphatase (ALP), alanine aminotransferase and gamma-glutamyl transferase enzyme activities, and total protein (TP), calcium, inorganic phosphate, urea nitrogen (UN) and creatinine concentrations in bronchoalveolar lavage fluid were investigated for their relative importance in the diagnosis of respiratory diseases in dogs. Bronchoalveolar lavage (BAL) fluid was obtained from 26 dogs (20 with respiratory diseases and six controls) following anaesthesia with sodium pentothal. Enzyme activities and biochemical parameters were measured in BAL fluid. LDH and ALP levels were significantly increased in 12 dogs with bronchopneumonia, but not in eight dogs with tracheobronchitis. Insignificant and variable levels of TP and UN concentrations were found in both groups. It was concluded that LDH and ALP enzyme activities could be considered as pointers to pulmonary inflammation and/or damage while TP and UN measurements in BAL fluid may have a place in the identification of changes in respiratory and vascular permeability.

BN 52021 (a platelet activating factor-receptor antagonist) decreases alveolar macrophage-mediated lung injury in experimental extrinsic allergic alveolitis

Several lines of research indirectly suggest that platelet activating factor (PAF) may intervene in the pathogenesis of extrinsic allergic alveolitis (EAA). The specific aim of our study was to evaluate the participation of PAF on macrophage activation during the acute phase of EAA in an experimental model of this disease developed in guinea pigs. Initially we measured the concentration of PAF in bronchoalvedar lavage fluid, blood and lung tissue. In a second phase we evaluate the participation of PAF on alveolar macrophage activation and parenchymal lung injury. The effect of PAF on parenchymal lung injury was evaluated by measuring several lung parenchymatous lesion indices (lung index, bronchoalvedar lavage fluid (BALF) lactic hydrogenase activity and BALF alkaline phosphatase activity) and parameters of systemic response to the challenge (acute phase reagents). We observed that induction of the experimental EAA gave rise to an increase in the concentration of PAF in blood and in lung tissue. The use of the PAF-receptor antagonist BN52021 decreases the release of lysosomal enzymes (beta-glucuronidase and tartrate-sensitive acid phosphatase) to the extracellular environment both in vivo and in vitro. Furthermore, antagonism of the PAF receptors notably decreases pulmonary parenchymatous lesion. These data suggest that lung lesions from acute EAA are partly mediated by local production of PAF.

The enhanced inflammatory response in non-small cell lung carcinoma is not reflected in the alveolar compartment

An inflammatory response has been observed in lung cancer both locally and systemically. The aim of the present study was to investigate whether the alveolar compartment was involved in the inflammatory response in non-small cell lung carcinoma (NSCLC). Both inflammatory mediators in bronchoalveolar lavage fluid (BALF) and cytokines produced by alveolar macrophages (AM) were investigated. Twenty patients with newly detected NSCLC and nine control subjects were studied. The patients had not been treated with chemotherapy, radiotherapy or with systemic or inhaled corticosteroids. All patients and control subjects were current smokers or stopped smoking recently. BAL was performed in the affected lung as well as in the contralateral lung of NSCLC patients, and only unilaterally in control subjects. Comparable results were demonstrated for the levels of the of the inflammatory mediators TNF-a, Interleukin (IL)-6, IL-8, both soluble TNF receptors and the soluble adhesion molecules E-selectin and intercellular adhesion molecule (ICAM)-1 between the affected lung and the contralateral lung in the NSCLC population as well as between the NSCLC population and the control subjects. Moreover, no significant differences in cytokine profiles of AM were found between AM obtained from the affected lung and from the contralateral lung. Although BAL is a useful tool in the diagnostic procedure for NSCLC, the present findings suggest that BAL does not reflect the enhanced inflammatory state, as reported in plasma and in the interstitial compartment around the tumour cells in NSCLC.

Alveolar lipoproteinosis in lung allograft recipients

Three cases of pulmonary alveolar proteinosis developing in lung allograft recipients are reported. In each case, repeated bouts of alveolar damage from harvest/reperfusion injury, rejection, and infection were observed before the development of intraalveolar accumulation of granular, periodic acid-Schiff-positive material in the allograft lungs. It is speculated that iatrogenic immunosuppression combined with defective clearance of alveolar material by alveolar macrophages created a milieu conducive to the accumulation of surfactant, lipoprotein, and fibrinous debris that was morphologically identical to alveolar proteinosis.

Effects of proteinosis surfactant proteins on the viability of rat alveolar macrophages

Pulmonary alveolar proteinosis (PAP) is a disease of unknown etiology that is characterized by the accumulation of protein- and lipid-rich insoluble material in alveoli and terminal bronchioles of the lung. Alveolar macrophages (AM) in PAP are reportedly extremely large and have low viability. We investigated substances in lavaged lung material from patients with PAP that induced these cellular changes in rat AM. Rat AM were incubated for various periods with liposomes prepared from lipids and isolated hydrophobic surfactant apoproteins, and cell size, viability, and lactate dehydrogenase release were determined. Of the hydrophobic apoproteins, a dimeric form of surfactant-associated protein-C ([SP-C]2) had the most marked effects. In addition, [SP-C]2 induced increased superoxide anion release at an early phase (6 to 12 h) and an increase in glutathione content at 24 h of incubation. At 3 d after incubation, cellular glutathione and adenosine triphosphate (ATP) content were significantly decreased in cells treated with [SP-C]2, [SP-C]2 was presumed to cause early cell death through increased formation of superoxide anion and the subsequent derangement of cellular metabolism. [SP-C]2 was not removed from cells, and SP-B and SP-C were removed at slower rates than lipids. The changes in macrophages induced by [SP-C]2 may contribute to establishing PAP.

Serum lactate dehydrogenase and its isoenzyme pattern in ex-coalminers

Serum lactate dehydrogenase (LDH) activity, a marker of cell damage, is increased in several pulmonary disorders, especially when fibrosis is involved. In rats exposed to silica, high levels of LDH activity were found. A rise of serum LDH3 has been associated with lung tissue injury. The aim of this study was to investigate the serum LDH isoenzyme pattern after coal-dust exposure and the possible relation to pulmonary function tests. Ex-coalminers (n = 201), with a history of coal-dust exposure more than 20 yr ago, were admitted to the authors' hospital for a medical check-up and were included in the study. The serum LDH activity was found to be elevated in 79.1% of the ex-coalminers (634 +/- 245 U I-1). Moreover, in 196 of the 201 cases (97.5%), a high LDH3 level (31 +/- 4%) was demonstrated. A moderate negative relation was found between the forced expiratory volume in 1 s (FEV1) and the LDH activity (r = -0.26; P < 0.001), as well as between FEV1 and LDH3 activity (r = -0.23; P < 0.001), even in the subgroup (n = 42) with a normal LDH. All other liver function tests were within normal limits. These results suggest that coal-dust, even many years after the actual exposure, causes an increase in the total serum LDH activity and changes in the LDH-isoenzyme pattern, mainly characterized by a high LDH3 activity.

Secondary alveolar proteinosis in cancer patients

Pulmonary alveolar proteinosis (AP) is a rare cause of progressive respiratory failure in the normal host. It was first described by Rosen and coworkers in 1958 on the morphological basis of the accumulation of a PAS-positive material in the alveolar space. A couple of years later, AP was found to be unexpectedly associated with malignant diseases, especially with acute or chronic myeloid leukemias. These forms were called secondary AP in opposition to the primary forms observed in normal hosts. Probably because of its morphological definition and late diagnosis by means of histology or autopsy material, secondary AP has been considered to be life-threatening for a long time. However, recent observations show that AP can be diagnosed early in the course of the disease, especially through bronchoalveolar lavage, as long as the pathologist is aware of this possibility. Another point is that secondary AP can be reversible, both clinically and morphologically. This article summarizes the clinical features, morphological findings, and the main malignant diseases associated with secondary AP. We also comment on the hypotheses proposed in the literature to explain the association of AP, malignant disease, and immunosuppression. Alveolar macrophage is likely a key factor in the occurrence of secondary AP.

Role of lysosomal enzymes released by alveolar macrophages in the pathogenesis of the acute phase of hypersensitivity pneumonitis

Hydrolytic enzymes are the major constituents of alveolar macrophages (AM) and have been shown to be involved in many aspects of the inflammatory pulmonary response. The aim of this study was to evaluate the role of lysosomal enzymes in the acute phase of hypersensitivity pneumonitis (HPs). An experimental study on AM lysosomal enzymes of an HP-guinea-pig model was performed. The results obtained both in vivo and in vitro suggest that intracellular enzymatic activity decrease is, at least partly, due to release of lysosomal enzymes into the medium. A positive but slight correlation was found between extracellular lysosomal activity and four parameters of lung lesion (lung index, bronchoalveolar fluid total (BALF) protein concentration, BALF LDH and BALF alkaline phosphatase activities). All the above findings suggest that the AM release of lysosomal enzymes during HP is a factor involved, although possibly not the only one, in the pulmonary lesions appearing in this disease.

Altered adhesion molecule expression and endothelial cell activation accompany the recruitment of human granulocytes to the lung after segmental antigen challenge

Mounting evidence suggests that inflammatory cells recruited to the lung can contribute to the pathogenesis of asthma. The factors governing the activation and recruitment of circulating cells to the lung remain unknown, but an early step in this process is the interaction of adhesion molecules on circulating cells with those on endothelial cells. We used a segmental antigen challenge model followed 18 h later by bronchoalveolar lavage (BAL) to study granulocyte recruitment to the lung in 14 allergic subjects. Using immunofluorescence and flow cytometry, we determined the expression of the adhesion molecules CD11b, L-selectin (LECAM-1), and VLA-4 on BAL and peripheral blood granulocytes. Total cell count and percentages of recovered eosinophils and basophils were significantly increased in BAL fluids from antigen-challenged segments. Compared with their peripheral blood counterparts, CD11b expression was increased 2- to 3-fold on BAL eosinophils, basophils, and neutrophils (n = 9, P less than 0.05). In contrast, L-selectin expression was significantly decreased on BAL cells (n = 3 to 4, P less than 0.05). Similar phenotypic changes were observed on all three cell types, and on neutrophils recovered from saline-challenged control lung segments. In two subjects, VLA-4 alpha (CD49d) expression on BAL eosinophils was 78 +/- 5% of that seen on peripheral blood eosinophils. Because ELAM-1 (endothelial leukocyte adhesion molecule-1, E-selectin) expression occurs during allergic inflammation and is shed after endothelial activation, we used a sensitive enzyme-linked immunosorbent assay to analyze BAL supernatants for a soluble form of this molecule (sELAM-1).(ABSTRACT TRUNCATED AT 250 WORDS)