Monoclonal antibodies against human pulmonary surfactant apoproteins: specificity and application in immunoassay

Combining Oxidative Stress Markers and Expression of Surfactant Protein A in Lungs in the Diagnosis of Seawater Drowning

BACKGROUND AND OBJECTIVES

The diagnosis of seawater drowning (SWD) remains one of the most complex and contentious. It is one of the leading causes of unintentional death around the world. In most cases, the forensic pathologist must reach an accurate diagnosis from the autopsy findings and a series of complementary tests such as histopathological, biological, and chemical studies. Despite the lung being the most affected organ in death by submersion, there are few studies on this type of death's impact on this organ. The aim was to investigate human lung cadavers of forensic cases due to different causes of death, the concentration of the oxidative stress markers malondialdehyde (MDA) and γ-glutamyl-l-cysteinyl glycine (GSH), and the relationship with the expression of surfactant protein A (SP-A) to try to discriminate SWD from other types of causes of death.

MATERIALS AND METHODS

A total of 93 forensic autopsy cases were analyzed. Deaths were classified into three major groups based on the scene, cause of death, and autopsy findings (external foam, frothy fluid in airways, overlapping medial edges of the lungs): (a) drowning in seawater (n = 35), (b) other asphyxia (n = 33), such as hangings (n = 23), suffocations (n = 6), and strangulation (n = 4), and (c) other causes (n = 25), such as multiple suffocations. Oxidative stress markers (MDA and GSH) and the immunohistochemical expression of SP-A were determined in both lungs.

RESULTS

MDA levels were statistically higher in both lungs in cases of SWD than in other causes of death (p = 0.023). Similarly, significantly higher levels of GSH were observed in SWD compared to the rest of the deaths (p = 0.002), which was more significant in the right lung. Higher immunohistochemical expression of SP-A was obtained in the cases of SWD than in the other causes of death, with higher levels in both lungs. The correlation analysis between the levels of oxidative stress (MDA and GSH) in the lung tissue and the expression level of SP-A showed positive and significant results in SWD, both in the alveolar membrane and the alveolar space.

CONCLUSIONS

Determining the levels of MDA and GSH in lung tissue and the expression level of SP-A can be of great importance in diagnosing SWD and the circumstances of death. A better understanding of the physiology of submersion is essential for its possible repercussions in adopting measures in the approach to patients who have survived a submersion process. It is also necessary for forensic pathology to correctly interpret the events that lead to submersion.

Surfactant protein A down-regulates epidermal growth factor receptor by mechanisms different from those of surfactant protein D

We recently reported that the lectin surfactant protein D (SP-D) suppresses epidermal growth factor receptor (EGFR) signaling by interfering with ligand binding to EGFR through an interaction between the carbohydrate-recognition domain (CRD) of SP-D and N-glycans of EGFR. Here, we report that surfactant protein A (SP-A) also suppresses EGF signaling in A549 human lung adenocarcinoma cells and in CHOK1 cells stably expressing human EGFR and that SP-A inhibits the proliferation and motility of the A549 cells. Results with ¹²⁵I-EGF indicated that SP-A interferes with EGF binding to EGFR, and a ligand blot analysis suggested that SP-A binds EGFR in A549 cells. We also found that SP-A directly binds the recombinant extracellular domain of EGFR (soluble EGFR or sEGFR), and this binding, unlike that of SP-D, was not blocked by EDTA, excess mannose, or peptide:N-glycosidase F treatment. We prepared a collagenase-resistant fragment (CRF) of SP-A, consisting of CRD plus the neck domain of SP-A, and observed that CRF directly binds sEGFR but does not suppress EGF-induced phosphorylation of EGFR in or proliferation of A549 cells. These results indicated that SP-A binds EGFR and down-regulates EGF signaling by inhibiting ligand binding to EGFR as well as SP-D. However, unlike for SP-D, SP-A lectin activity and EGFR N-glycans were not involved in the interaction between SP-A and EGFR. Furthermore, our results suggested that oligomerization of SP-A is necessary to suppress the effects of SP-A on EGF signaling.

Pulmonary collectins protect macrophages against pore-forming activity of Legionella pneumophila and suppress its intracellular growth

Pulmonary collectins, surfactant proteins A (SP-A) and D (SP-D), play important roles in innate immunity of the lung. Legionella pneumophila is a bacterial respiratory pathogen that can replicate within macrophages and causes opportunistic infections. L. pneumophila possesses cytolytic activity, resulting from insertion of pores in the macrophage membrane upon contact. We examined whether pulmonary collectins play protective roles against L. pneumophila infection. SP-A and SP-D bound to L. pneumophila and its lipopolysaccharide (LPS) and inhibited the bacterial growth in a Ca(2+)-dependent manner. The addition of LPS in the culture blocked the inhibitory effects on L. pneumophila growth by the collectins, indicating the importance of LPS-collectin interaction. When differentiated THP-1 cells were infected with L. pneumophila in the presence of SP-A and SP-D, the number of permeable cells was significantly decreased, indicating that pulmonary collectins inhibit pore-forming activity of L. pneumophila. The number of live bacteria within the macrophages on days 1-4 after infection was significantly decreased when infection was performed in the presence of pulmonary collectins. The phagocytosis experiments with the pH-sensitive dye-labeled bacteria revealed that pulmonary collectins promoted bacterial localization to an acidic compartment. In addition, SP-A and SP-D significantly increased the number of L. pneumophila co-localized with LAMP-1. These results indicate that pulmonary collectins protect macrophages against contact-dependent cytolytic activity of L. pneumophila and suppress intracellular growth of the phagocytosed bacteria. The promotion of lysosomal fusion with Legionella-containing phagosomes constitutes a likely mechanism of L. pneumophila growth suppression by the collectins.

Therapeutic effects for hypersensitivity pneumonitis induced by Japanese mushroom (Bunashimeji)

BACKGROUND

Bunashimeji-related hypersensitivity pneumonitis is found among workers who cultivate the mushroom in indoor facilities. An evaluation of protective measures was initiated using the outcomes of clinical, immunological, and radiological findings.

METHODS

Twenty-two patients presented with symptoms of HP; all were employed cultivating Bunashimeji mushrooms in indoor facilities. After hospitalization, 6 of 22 patients quit their job to avoid exposure to spores (Avoidance group). Sixteen patients continued to work used a mask for 3 months, and were then divided into two subgroups: Mask alone (seven patients) and mask plus oral prednisolone (Mask + PSL) (nine patients). The erythrocyte sedimentation rate (ESR), serum Krebs von der Lungen-6 (KL-6), surfactant protein-D (SP-D), lymphocyte stimulation test (LST), ground-glass scores in chest high-resolution computed tomography (HRCT), and bronchoalveolar lavage (BAL) were assessed before and after treatment.

RESULTS

Complete avoidance resulted in a significant decrease in LST. There was a significant decrease after PSL treatment in serum KL-6, SP-D, and total cell counts in the BAL fluid in the Mask + PSL group. In the Mask alone group, serum KL-6, SP-D, ground-glass scores in chest HRCT and total cell counts in BAL fluid showed high levels compared with the other two groups.

CONCLUSIONS

Complete cessation was the best treatment for hypersensitivity pneumonitis. The use of a mask was ineffective for patients with a high serum KL-6 and SP-D concentration and severe ground-glass opacity on chest HRCT. Initial treatment with PSL is recommended for these patients with high levels of total cell counts in BAL fluid.

Surfactant Protein A Directly Interacts with TLR4 and MD-2 and Regulates Inflammatory Cellular Response

The purpose of the current study was to examine the binding of pulmonary surfactant protein A (SP-A) to TLR4 and MD-2, which are critical signaling receptors for lipopolysaccharides (LPSs). The direct binding of SP-A to the recombinant soluble form of extracellular TLR4 domain (sTLR4) and MD-2 was detected using solid-phase binding, immunoprecipitation, and BIAcore. SP-A bound to sTLR4 and MD-2 in a Ca2+-dependent manner, and an anti-SP-A monoclonal antibody whose epitope lies in the region Thr184-Gly194 blocked the SP-A binding to sTLR4 and MD-2, indicating the involvement of the carbohydrate recognition domain (CRD) in the binding. SP-A avidly bound to the deglycosylated forms of sTLR4 and MD-2, suggesting a protein/protein interaction. In addition, SP-A attenuated cell surface binding of smooth LPS and smooth LPS-induced NF-kappaB activation in TLR4/MD-2-expressing cells. To know the role of oligomerization in the interaction of SP-A with TLR4 and MD-2, the collagenase-resistant fragment (CRF), which consisted of CRD plus neck domain of SP-A, was isolated. CRF assembled as a trimer, whereas SP-A assembled as a higher order oligomer. Although CRD was suggested to be involved in the binding, CRF exhibited approximately 600- and 155-fold higher KD for the binding to TLR4 and MD-2, respectively, when compared with SP-A. Consistently significantly higher molar concentrations of CRF were required to inhibit smooth LPS-induced NF-kappaB activation and tumor necrosis factor-alpha secretion. These results demonstrate for the first time the direct interaction between SP-A and TLR4/MD-2 and suggest the importance of supratrimeric oligomerization in the immunomodulatory function of SP-A.

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.

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.

Hypersensitivity Pneumonitis due to Bunashimeji Mushrooms in the Mushroom Industry

BACKGROUND

Detection of hypersensitivity pneumonitis (HP) in employees involved in the Bunashimeji mushroom industry is difficult. The level of precipitating antibody is not related with the prediction of progression and resolution of HP. The aims of this study were to examine the actual prevalence of HP in the Bunashimeji industry and the clinical differences among selected employees.

METHODS

One hundred and fourteen employees worked in Bunashimeji enterprises. These subjects were divided into the following subgroups: office workers, pickers/packers with mask and pickers/packers without mask. We measured serum Krebs von der Lungen-6 (KL-6), surfactant protein (SP)-A and SP-D, and examined the stimulation index (SI) due to Bunashimeji spores. Chest high-resolution computed tomography (HRCT), pulmonary function tests and bronchoalveolar lavage (BAL) were performed for select employees who showed positive SI values (>200%) to examine the clinical differences.

RESULTS

The proportion of respiratory symptoms was significantly higher in the pickers/packers than that in the office workers. The picker/packer group had high serum KL-6 concentrations and SI compared with the office worker group. Thirty select employees were divided into the following three subgroups: HP, select employees without HP, and SI <400% and KL-6 <500 U/ml , using high SI levels (>400%) and positive serum KL-6 concentration (>500 U/ml). Four exhibited ground glass opacities with centrilobular fine nodules on HRCT, and 8 had high numbers of lymphocytes in the BAL fluid. The BAL findings and serum KL-6 concentrations showed significant differences among the three groups.

CONCLUSIONS

Four employees were evaluated as having HP. Serum KL-6 and SP-D may be related to the resolution of HP in addition to SI and chest HRCT.

Surfactant protein A binds Mycoplasma pneumoniae with high affinity and attenuates its growth by recognition of disaturated phosphatidylglycerols

Surfactant Protein A (SP-A) is an abundant, multifunctional lectin that resides within the bronchoalveolar compartment of the lung and plays an important role in the innate immunity of the organ. Mycoplasma pneumoniae is a human pathogen that resides in the same compartment as SP-A, and we examined the interaction between the two. Preparations of human and rat SP-A recognized the mycoplasma with high affinity in the presence of Ca(2+), exhibiting apparent K(')(d) values in the nanomolar range. Membranes prepared from the microbe also bound human and rat SP-A with similar characteristics and affinity to the intact cells. The ligand for SP-A was insensitive to proteolysis. Lipid extracts prepared from the mycoplasma, bound SP-A with high affinity when examined by ligand blot analysis. These lipid extracts were also potent competitive inhibitors (IC(50) = 0.2 nM) of human SP-A binding to mycoplasma membranes. The major lipid ligands for the protein identified by mass spectrometry are a group of disaturated phosphatidylglycerols. The addition of SP-A to cultures of M. pneumoniae markedly attenuated the growth of the organism assessed by colony formation, metabolic activity, and DNA replication. The bacteriostatic effects of SP-A were reversed by dipalmitoylphosphatidylglycerol. These findings demonstrate that human SP-A can play a direct role in antibody-independent immunity to M. pneumoniae by interacting with lipid ligands expressed on the surface of the organism and implicate SP-A in the immediate host response to the bacteria.

Surfactant lipid synthesis and lamellar body formation in glycogen-laden type II cells

Pulmonary surfactant is a lipoprotein complex that functions to reduce surface tension at the air liquid interface in the alveolus of the mature lung. In late gestation glycogen-laden type II cells shift their metabolic program toward the synthesis of surfactant, of which phosphatidylcholine (PC) is by far the most abundant lipid. To investigate the cellular site of surfactant PC synthesis in these cells we determined the subcellular localization of two key enzymes for PC biosynthesis, fatty acid synthase (FAS) and CTP:phosphocholine cytidylyltransferase-alpha (CCT-alpha), and compared their localization with that of surfactant storage organelles, the lamellar bodies (LBs), and surfactant proteins (SPs) in fetal mouse lung. Ultrastructural analysis showed that immature and mature LBs were present within the glycogen pools of fetal type II cells. Multivesicular bodies were noted only in the cytoplasm. Immunogold electron microscopy (EM) revealed that the glycogen pools were the prominent cellular sites for FAS and CCT-alpha. Energy-filtering EM demonstrated that CCT-alpha bound to phosphorus-rich (phospholipid) structures in the glycogen. SP-B and SP-C, but not SP-A, localized predominantly to the glycogen stores. Collectively, these data suggest that the glycogen stores in fetal type II cells are a cellular site for surfactant PC synthesis and LB formation/maturation consistent with the idea that the glycogen is a unique substrate for surfactant lipids.

Fibrinolysis-inhibitory capacity of clot-embedded surfactant is enhanced by SP-B and SP-C

Incorporation of pulmonary surfactant into fibrin inhibits its plasmic degradation. In the present study we investigated the influence of surfactant proteins (SP)-A, SP-B, and SP-C on the fibrinolysis-inhibitory capacity of surfactant phospholipids. Plasmin-induced fibrinolysis was quantified by means of a (125)I-fibrin plate assay, and surfactant incorporation into polymerizing fibrin was analyzed by measuring the incorporation of (3)H-labeled L-alpha-dipalmitoylphosphatidylcholine into the insoluble clot material. Incorporation of a calf lung surfactant extract (Alveofact) and an organic extract of natural rabbit large surfactant aggregates (LSA) into a fibrin clot revealed a stronger inhibitory effect on plasmic cleavage of this clot than a synthetic phospholipid mixture (PLX) and unprocessed LSA. Reconstitution of PLX with SP-B and SP-C increased, whereas reconstitution with SP-A decreased, the fibrinolysis-inhibitory capacity of the phospholipids. The SP-B effect was paralleled by an increased incorporation of phospholipids into fibrin. We conclude that the inhibitory effect of surfactant incorporation into polymerizing fibrin on its susceptibility to plasmic cleavage is enhanced by SP-B and SP-C but reduced by SP-A. In the case of SP-B, increased phospholipid incorporation may underlie this finding.

Assessment of differentiation in adenocarcinoma cells from pleural effusion by peripheral airway cell markers and their diagnostic values

Ultrastructural studies have shown that Clara cell-type is a more common type of adenocarcinoma than alveolar type II cell-type, and that both types may provide better prognosis than other types, indicating an importance of differentiation toward peripheral airway cells. Pulmonary surfactant protein (SP)-A is a specific marker for both alveolar type II cells and Clara cells in peripheral lung tissues, while SP-C and Clara cell 10 kD protein (CC10) may be particularly and highly specific to alveolar type II cells and Clara cells, respectively. The aims of this study were to assess the differentiation of adenocarcinoma cells in pleural effusions by evaluating the expression of these cell markers and to evaluate their values as diagnostic tools for judging the cause of pleural effusion. We examined pleural effusions from 52 patients; 20 with primary lung adenocarcinomas, 6 with small cell lung carcinomas, 11 with metastatic malignant tumors and 15 with non-neoplastic diseases. The cell pellets from effusions were subjected to immunocytochemical staining for SP-A, proSP-C, a precursor of SP-C, and CC10. By this immunocytochemical study for SP-A and proSP-C, 10 (50%) and 6 (30%) of 20 adenocarcinomas, respectively, showed a positive immunoreactivity in their effusion cells, while none of them expressed CC10. Alveolar type II cells therefore may be the main progenitor cells of some adenocarcinomas. In pleural effusions from patients with primary lung adenocarcinomas, reverse transcriptase-polymerase chain reaction (RT-PCR) for SP-A mRNA showed a sensitivity of 83%, while, in all remaining patients, these assays were negative. In conclusion, we demonstrated that lung adenocarcinomas, which are partially differentiated toward alveolar type II cells, are not as rare as previously thought, and that both the RT-PCR and immunocytochemical analyses for SP-A and pro-SP-C could be worthy indicators of differential diagnosis.

Use of thyroid transcription factor 1, PE-10, and cytokeratins 7 and 20 in discriminating between primary lung carcinomas and metastatic lesions in fine-needle aspiration biopsy specimens

BACKGROUND

The distinction of a primary lung carcinoma from a metastatic lesion is important, because the treatment and prognosis differ for patients with these malignancies. Such a distinction can be difficult because of overlapping cytologic features. It has been shown that antibodies to thyroid transcription factor 1 (TTF-1) and PE-10 are fairly specific markers for primary lung tumors in histologic specimens. TTF-1 regulates the expression of surfactant protein production, and PE-10 is a monoclonal antibody against components of human surfactant proteins. The combination of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) immunoprofiling has been helpful in the identification of the primary site of origin of lung tumors.

METHODS

In the current study, the authors evaluated the utility of TTF-1 and PE-10 immunostaining and also compared the staining with expression of CK7 and CK20 in the discrimination between primary lung tumors and metastatic lesions in 55 specimens from fine-needle aspiration (FNA) biopsies of the lung. Formalin fixed, paraffin embedded cell blocks from 35 primary lung tumors (16 adenocarcinomas, 8 squamous cell carcinomas, 6 large cell undifferentiated carcinomas, and 5 small cell carcinomas) and 20 metastatic carcinomas (6 breast lesions, 6 colon lesions, 3 urinary bladder lesions, 2 kidney lesions, 1 biliary tract lesion, 1 endometrial lesion, and 1 thyroid lesion) were immunostained with monoclonal antibodies to TTF-1, PE-10, CK7, and CK 20. Positive immunostaining for CK7, CK20, and PE-10 was based on cytoplasmic staining, whereas TTF-1 positive staining was based on nuclear staining of the neoplastic cells.

RESULTS

Positive immunostaining with TTF-1 and PE-10 was noted in six primary lung tumors (17%). One metastatic lesion (5%) and two metastatic lesions (10%) were positive for TTF-1 and PE-10, respectively. The CK7 positive/CK20 negative immunophenotype was noted in 30 primary lung tumors (86%) and in 11 metastatic lesions (55%). The CK7 negative/CK20 negative immunophenotype was seen in four metastatic lesions and in the remaining five primary lung tumors. The CK7 negative/CK20 positive and CK7 positive/CK20 positive immunophenotypes were seen in two and three metastatic lesions, respectively, but in none of the primary lung tumors. When a CK7 positive/CK20 negative adenocarcinoma also demonstrated either TTF-1 positive or PE-10 positive staining, it was likely that the adenocarcinoma was of pulmonary origin (P < 0.035; Fisher exact test). The specificity of such a combination for discriminating between primary and metastatic adenocarcinomas was 94%.

CONCLUSIONS

The results suggest that TTF-1, PE-10, or CK7/CK20 alone did not distinguish reliably between primary pulmonary tumors carcinomas and metastatic neoplasms of the lung in FNA biopsy specimens because of low sensitivity and specificity. The use of a panel of antibodies that includes CK7/CK20, TTF-1, and PE-10 may be helpful in discriminating between primary and metastatic adenocarcinomas of the lung. An adenocarcinoma is likely a primary lung tumor when it is of the CK7 positive/CK20 negative phenotype and demonstrates either TTF-1 positive or PE-10 positive staining.

Prognostic significance of frequent acidophilic nuclear inclusions in adenocarcinoma of the lung with immunohistochemical and ultrastructural studies

BACKGROUND

Adenocarcinoma of the lung occasionally has acidophilic nuclear inclusions (ANIs). Some studies have reported that the incidence of ANIs was higher in well differentiated tumor types and have suggested that adenocarcinoma patients with ANIs might have a more favorable prognosis; however, to the authors' knowledge, statistically significant prognostic findings were not reported. The objective of the current study was to assess the prognostic significance of ANI in patients with pulmonary adenocarcinoma and, moreover, to characterize ANI immunohistochemically and ultrastructurally.

METHODS

Surgically resected tumor specimens from 147 patients with primary pure adenocarcinoma of the lung were examined. Only obvious ANIs surrounded by a clear halo on hematoxylin and eosin-stained slides were counted; the authors classified cases with > or = 10 ANIs per 10 high-power fields (/10 HPF) as frequent-ANI cases, cases with < 10 ANIs/10 HPF as infrequent-ANI cases, and cases without ANIs as non-ANI cases in the current study.

RESULTS

Nineteen frequent-ANI cases (12.9%) and 16 infrequent-ANI cases (10.9%) were found; the remaining 112 cases (76.2%) were considered to be non-ANI cases. The majority of ANIs immunohistochemically contained surfactant apoprotein and ultrastructurally corresponded to invagination of the inner nuclear membrane, showing a tubular or amorphous configuration. Frequent-ANI patients showed significantly better prognosis than the other two groups on both overall univariate analysis and univariate analysis limited to patients with International Union Against Cancer Stage I disease (P = 0.0096 and P = 0.0095, respectively). However, on the multivariate analysis only disease stage was shown to be a significant prognostic factor and frequent-ANI showed borderline significance (P = 0.0956).

CONCLUSIONS

Frequent ANIs appear to be of limited value in clarifying the prognosis of patients with lung adenocarcinoma.

Diagnostic significance of surfactant proteins A and D in sera from patients with radiation pneumonitis

Radiation pneumonitis (RP) is the most common complication of radiotherapy for thoracic tumours. The aim of this study was to evaluate the significance of pulmonary surfactant proteins (SP)-A and SP-D as new serum markers for RP. Twenty-five patients with lung tumour, who had received radiotherapy, were studied. At the completion of radiotherapy, the presence of RP was judged by chest plain radiography and chest high resolution computed tomography (HRCT). RP findings detected on chest plain radiography were seen in only three of 12 patients in whom RP was detected by HRCT. Nevertheless, both SP-A and SP-D concentrations in sera from the patients with RP were significantly higher than those from the 13 patients without RP (p = 0.0065, p = 0.0011, respectively). As with SP-A, ratios of SP-D at the completion, compared to at the initiation (1 week post/pre ratio), were also significantly higher in patients with RP than in patients without RP. When a post/pre ratio > 1.6 was considered positive, the SP-A and SP-D assays showed an 83% and 85% specificity, respectively. In conclusion, serum assays of surfactant proteins A and D may be of diagnostic value for detection of radiation pneumonitis, even when the radiographic change is faint.

Tumor uptake of radioiodinated anti-human pulmonary surfactant-associated protein monoclonal antibody PE10 in nude mice bearing human pulmonary adenocarcinoma in combination with an unlabeled preload

This study assessed the potential use of radioimmunoscintigraphy of pulmonary alveolar Type II cells tumor with the radiolabeled anti-human surfactant-associated protein (SP) monoclonal antibody (MAb) PE 10 in combination with preloads of unlabeled MAb. The in vitro binding of iodine-125 ((125)I)-labeled MAb PE 10 (1 microg), which had a specific radioactivity of 400 MBq/mg, on human pulmonary papillary adenocarcinoma NCI-H441 cells that produced SP was investigated. In NCI-H441 tumor-bearing nude mice, the tumor uptake of (125)I-MAb PE 10 (5 microg) was examined in combination with preloads of unlabeled MAb PE 10 (0, 5, 10, and 50 microg). An isotype-matched unassociated murine MAb was used as a control both in vitro and in vivo. (125)I-MAb PE 10 showed specific cell binding compared with (125)I-control MAb. Tumor uptake of (125)I-MAb PE 10 in vivo reached a peak of 4.97+/-0.33% injected dose per gram (%ID/g) at 48 h postinjection. Preloads of 5 and 10 microg unlabeled MAb PE 10 significantly enhanced tumor uptake at 48 h postinjection ( 5.94+/-0.29% ID/g and 5.72+/-0.29% ID/g, respectively), whereas preload of 50 microg unlabeled MAb PE 10 significantly decreased tumor uptake ( 2.75+/-0.32% ID/g) at 48 h. Preload of 5 microg unlabeled MAb PE 10 significantly increased the tumor-to-blood radioactivity ratio at 48 h ( 2.39+/-0.16). Preloads of unlabeled control MAb did not cause any significant change in tumor uptake. Immunohistochemistry showed the intracellular and pericellular patterns of SP expression in tumor cells. In conclusion, radioimmunoscintigraphy with MAb PE 10 labeled with a gamma-emitting radioiodine such as (123)I might be a useful means of targeting pulmonary alveolar Type II tumor cells in combination with preloading with an optimal dose of the unlabeled MAb.

Hyperplasia of type II pneumocytes in pulmonary lymphangioleiomyomatosis

BACKGROUND

Little is known of the morphology of the pneumocytes lining the parenchymal cysts in lymphangioleiomyomatosis (LAM).

OBJECTIVE

To evaluate the structural characteristics of the alveolar epithelial cells in LAM.

METHODS

Immunohistochemical and electron microscopic studies were performed on lung tissue from 22 women with pulmonary LAM.

RESULTS

Epithelial cells that reacted with PE-10 (a mouse monoclonal antibody that recognizes the surfactant apoprotein A in type II pneumocytes) and TTF-1 (an antibody that identifies nuclear transcription factor found in type II pneumocytes) were the predominant cell type lining the surfaces of lesions of LAM and normal areas of lung. Scanning and transmission electron microscopic studies confirmed that these cells were type II pneumocytes as demonstrated by (1) apical microvilli, (2) electron-dense lamellar bodies, and (3) cytoplasmic projections that extended from the basal surfaces into the underlying connective tissue, where they made extensive contact with interstitial connective tissue cells. A few cells had morphologic characteristics of type I pneumocytes, including large flat surfaces lacking microvilli. Cells that appeared intermediate between type I and type II pneumocytes were observed occasionally.

CONCLUSIONS

These observations and the reactivity of these cells with antibody to proliferating cell nuclear antigen demonstrate that extensive hyperplasia of type II pneumocytes is a major characteristic of LAM.

Serum surfactant proteins A and D as prognostic factors in idiopathic pulmonary fibrosis and their relationship to disease extent

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening, interstitial lung disease of unknown etiology. For optimal therapeutic management of IPF an accurate tool is required for discrimination between reversible and irreversible types of the disease. However, such noninvasive tools are few, and even with high-resolution computed tomography (HRCT), which is the most trusted method for doing so, the nature of the disease activity in IPF cannot always be accurately predicted. The aims of the present study were to assess the values of surfactant protein (SP)-A and SP-D in semiquantifying the extent of disease in IPF and in predicting deterioration in restrictive pulmonary function and survival over a follow-up period of 3-yr. SP-A and SP-D in sera were measured with enzyme-linked immunosorbent assays as previously described. Fifty-two IPF patients were studied to evaluate the association between serum SP-A and SP-D and disease extent on HRCT, deterioration in pulmonary function, and survival during 3 yr of follow-up. Both SP-A and SP-D concentrations were significantly correlated with the extent of alveolitis (a reversible change), whereas they did not correlate with the progression of fibrosis (an irreversible change). The SP-D concentration, unlike that of SP-A, was also related to the extent of parenchymal collapse and the rate of deterioration per year in pulmonary function. The concentrations of SP-A and SP-D in patients who died within 3 yr were significantly higher than in patients who were still alive after 3 yr. We propose that assays of SP-A and SP-D in sera from IPF patients are useful tools for understanding some pathologic characteristics of the disease, that SP-D may be a good predictive indicator of the rate of decline in pulmonary function, and that a combination of the assays for SP-A and SP-D may be helpful in predicting the outcome of patients with IPF.

Serum levels of surfactant proteins A and D are useful biomarkers for interstitial lung disease in patients with progressive systemic sclerosis

To find a less-invasive and lung-specific clinical biomarker, we measured serum levels of surfactant proteins A and D (SP-A and SP-D) by sandwich enzyme-linked immunosorbent assays in 42 patients with progressive systemic sclerosis (PSS) to evaluate their significance in relation to the presence of interstitial lung disease (ILD) and to assess their diagnostic merits. The patients were divided into two groups based on findings by chest computed tomography (CT): 30 patients with ILD (CT-positive ILD group), and 12 patients without any lung abnormalities (CT-negative ILD group). The CT-positive ILD group was further divided into two groups: 24 patients with ILD detectable by chest plain radiography (X-ray-positive ILD group) and six patients with ILD showing no abnormality (X-ray-negative ILD group). The levels of SP-A and SP-D in sera were significantly higher in the CT-positive ILD group than in the CT-negative ILD group. They were also significantly higher in the X-ray-positive ILD group than in the CT-negative ILD group. In the X-ray-negative ILD group, their levels were higher than those of the CT-negative ILD group. We next estimated sensitivity and specificity of SP-A, SP-D, and X-ray for detecting ILD on CT. Sensitivity of SP-D was high (77%) as well as that of X-ray (80%), whereas SP-A showed a low sensitivity (33%). Remarkably, five of six patients in the X-ray-negative ILD group showed SP-D concentrations over its cut-off level, thereby demonstrating that an SP-D assay contributes to the detection of ILD overlooked by X-ray. Moreover, a combination of X-ray and SP-D dramatically increases sensitivity to 97%. Specificity of SP-A, SP-D, and X-ray to the CT-negative ILD group was 100%, 83%, and 100%, respectively. In conclusion, this study indicates that elevated levels of serum SP-A and SP-D reflect well the presence of ILD and that the combination of SP-D and X-ray contributes to reduce the risk of clinicians overlooking ILD complicated by PSS, although a repetition in another set of subjects is needed to confirm these indications.

Pulmonary surfactant-associated protein A levels in cadaveric sera with reference to the cause of death

Pulmonary surfactant-associated protein A (SP-A) is an exclusively lung specific protein, and is considered to leak into the blood stream in alveolar septal damage. In this study we examined the serum SP-A level in forensic autopsy materials using an enzyme immunoassay with monoclonal antibodies to assess the postmortem level in relation to the cause and mode of death. Although a gradual postmortem degradation should be taken into consideration, topological relationship of serum level seemed to be fairly stable (arterial> or =venous blood in most cases), indicating no evident influence of postmortem diffusion. Significant elevation of serum SP-A (76.7-250 ng/ml in left heart blood) was observed in hyaline membrane diseases from various causes independent of the postmortem intervals (<30 h). However, mean SP-A levels in postmortem heart blood were usually low in asphyxia including hanging, strangulation and choking (left, 25.5 ng/ml; right, 22.3 ng/ml), polytrauma (left, 13.1 ng/ml; right, 9.0 ng/ml) and stab wound to the neck (left, 34.1 ng/ml; right, 29.4 ng/ml). Prominent elevation was noted in a case of fatal strangulation with complication of idiopathic interstitial pneumonia, and also in some deaths due to drowning, burns in fires, blunt and gunshot chest injuries. These findings indicated that postmortem elevation of serum SP-A levels was associated with alveolar septal damage due to inflammation, mechanical and physical stresses, which caused leakage of SP-A into the bloodstream.

Surfactant protein A and D expression in the porcine Eustachian tube

Surfactant proteins A and D are collectins which are considered to play an important role in the innate immunity of lungs. Our aim was to investigate whether surfactant protein A or D is expressed in the porcine Eustachian tube originating from the upper airways. Both surfactant proteins A and D were present in the epithelial cells of the Eustachian tube, as shown by strong immunostaining. Using RT-PCR and Northern hybridization, these collectins were detected in the Eustachian tube. The present study is the first report demonstrating surfactant protein gene expression in the Eustachian tube. Surfactant proteins A and D may be important in the antibody-independent protection of the middle ear.

Immunohistochemical and ultrastructural studies of basal cells, Clara cells and bronchiolar cuboidal cells in normal human airways

Immunohistochemical studies were made of the distribution of various cytokeratins (CK), Clara cell secretory protein (CC10), surfactant protein A (SP-A) and type VII collagen in normal human airways. Electron microscopic studies were made to identify hemidesmosomes and anchoring fibrils on the basal surfaces of the epithelial cells. CK19 was detected in all epithelial cells, and CK17 in all basal cells. CK14 was coexpressed in a few basal cells, and this coexpression was decreased in the distal airways. Two types of basal cells were recognized. One type, found mainly in large airways, was characterized by abundant intermediate filaments and well-developed hemidesmosomes and anchoring fibrils. The second type contained few intermediate filaments and poorly developed hemidesmosomes and anchoring fibrils. Reactivity for type VII collagen was found along the basement membrane throughout the airways, but not in the alveoli. Clara cells were reactive for CC10 and CK17, but not for CK14 and SP-A. The bronchiolar cuboidal cells in the respiratory bronchioles were positive only for CK19. Surfactant protein A was present only in type II alveolar epithelial cells. Thus, two types of basal cells are present in airways, and the bronchiolar cuboidal cells appear distinct from these basal cells, Clara cells and type II alveolar epithelial cells.

Surfactant proteins A and D: disease markers

The abundant and restricted expression of surfactant proteins SP-A and SP-D within the lung makes these collectins specific markers for lung diseases. The measurement of SP-A and SP-D in amniotic fluids and tracheal aspirates reflects lung maturity and the production level of the lung surfactant in infants with respiratory distress syndrome (RDS). The SP-A concentrations in bronchoalveolar lavage (BAL) fluids are significantly decreased in patients with acute respiratory distress syndrome (ARDS) and also in patients at risk to develop ARDS. The prominent increase of these proteins in BAL fluids and sputum is diagnostic for pulmonary alveolar proteinosis (PAP). The concentrations of SP-A and SP-D in BAL fluids from patients with idiopathic pulmonary fibrosis (IPF) and interstitial pneumonia with collagen vascular diseases (IPCD) are rather lower than those in healthy controls and the SP-A/phospholipid ratio may be a useful marker of survival prediction. SP-A and SP-D appear in the circulation in specific lung diseases. Their serum concentrations significantly increase in patients with PAP, IPF and IPCD. The successive monitoring of serum levels of SP-A and SP-D may predict the disease activity. The serum SP-A levels increase in patients with ARDS. SP-A is also a marker for lung adenocarcinomas and can be used to differentiate lung adenocarcinomas from other types and metastatic cancers from other origins, and to detect metastasis of lung adenocarcinomas.

Comparative ultrastructural study of atypical adenomatous hyperplasia and adenocarcinoma of the human lung

Atypical adenomatous hyperplasia (AAH) of the human lung is considered a possible precursor of pulmonary adenocarcinoma. However, its true biological significance remains to be clarified. The authors studied the ultrastructure of AAH in surgically resected lungs and compared it with that of coexisting adenocarcinoma in an effort to define the characteristic features of AAH. Ultrastructurally, AAH possessed oval to irregular nuclei with high nucleo-cytoplasmic ratio and large nucleoli. Development of cytoplasmic organelles was generally poorer in AAH than in adenocarcinoma. However, these differences became less apparent as the degree of atypia of AAH advanced. Both lamellar bodies and electron-dense granules were found in AAH as well as in adenocarcinoma. These results suggest a close relation of AAH with adenocarcinoma of type 2 pneumocyte or Clara cell type. Further, the results of immunohistochemical studies for surfactant apoprotein A, urine protein 1, cytochrome P-450s, CEA, p53, c-erbB-2, Ki67, and bcl-2 well reflected the ultrastructural findings. These results suggest, in accordance with previous studies, that AAH is a lesion closely related to adenocarcinoma. Further, AAH shares some characteristics of type 2 pneumocytes and Clara cells, implying that it might be derived from their common precursor.

Malignant phyllodes tumor of breast with lung metastases mimicking the primary

We report a case of recurrent malignant phyllodes tumor with liposarcomatous transformation metastasizing to the lung. The unusual feature of this case was that the metastases reproduced the primary tumor and contained ductal structures and elements of sarcoma. The origin of the ductal structures in the lung metastases was confirmed to be from the phyllodes tumor, on the basis of their immunophenotype. The epithelial cells were positive for steroid receptors and GCDFP-15, and the myoepithelial cells were positive for anti-smooth-muscle-specific proteins. We also reevaluated by immunohistochemistry a case of phyllodes tumor previously published by West et al., allegedly containing epithelial structures of supposed breast origin within lung metastases. The epithelial component was shown to consist of entrapped alveolar lining cells.

Surfactant protein A2 gene expression by human airway submucosal gland cells

To determine whether human airway submucosal glands produce and secrete surfactant proteins, we examined their protein and gene expression in submucosal glands from trachea and bronchi obtained from operated and autopsied lungs within 4 h of death. Using a monoclonal antibody (PE-10) against surfactant protein A (SP-A), a positive immunoperoxidase stain was observed over serous cells of submucosal glands in histologic sections of airway walls. Measurement of SP-A in culture medium samples using single-step enzyme-linked immunosorbent assay showed a significant secretion of SP-A by isolated submucosal glands (1.2 +/- 0.08 ng/ml/h, SEM, n = 40). In gene expression experiments by reverse transciption-polymerase chain reaction, the SP-A complementary DNA (cDNA) segment was amplified from isolated submucosal glands, indicating the presence of SP-A messenger RNA (mRNA) in airway submucosal glands. Bronchial superficial epithelial cells failed to show the presence of SP-A mRNA. No cDNA segment of SP-B, SP-C, or SP-D cDNA was amplified from isolated submucosal glands or superficial epithelial cells, whereas all were amplified from alveolar tissue. Furthermore, in contrast to the control alveolar tissue, which expressed both SP-A1 and SP-A2 genes, SP-A2 gene transcript alone was detected in isolated submucosal glands by Southern analysis that included the digestion of the amplified SP-A cDNA fragment with the restriction enzyme Apa I. These findings indicate that human airway submucosal gland cells can transcribe the SP-A2 gene and produce SP-A protein in a manner different from peripheral airways and alveoli, playing a role in the airway defense mechanism.

Decreased contents of surfactant proteins A and D in BAL fluids of healthy smokers

Hydrophilic surfactant proteins, surfactant protein A (SP-A) and surfactant protein D (SP-D), have important roles in modulating the host defense functions in the peripheral airways. It has been reported that cigarette smoke may alter the component and function of pulmonary surfactant. In this study, we determined the contents of SP-A and SP-D in BAL fluids of healthy smokers and nonsmokers by enzyme-linked immunosorbent assay using monoclonal antibodies against each protein. The contents of SP-A and SP-D in BAL fluids were significantly (p<0.05) decreased in smokers compared to those in nonsmokers, although there was no significant difference of total phospholipid content between smokers and nonsmokers. These results suggest that the decreased levels of SP-A and SP-D in smokers may impair the host defense functions of surfactant in the peripheral airways and might have a crucial roles in the development of chronic obstructive lung disease.

Immunohistochemical distribution of surfactant apoproteins in hypoplastic lungs of nonimmunologic hydrops fetalis

Forty-three patients with nonimmunologic hydrops fetalis (NIHF), including 32 patients (74%) with hypoplastic lung, were immunohistochemically examined for the expression of surfactant apolipoproteins (SPs), using anti-gamma G immunoglobulins against human SP-A with a molecular weight (MW) of 35 K and SP-B with a MW of 5 K compared with that in 59 patients in a control group and 45 patients with hypoplastic lung induced by causes other than NIHF. In the control group, SP-A was expressed in the lungs from 23 gestational weeks and became more numerous and intense in alveolar type II cells after 31 gestational weeks, whereas SP-B began to be expressed from 20 gestational weeks, and almost all patients showed a diffuse positivity after 26 gestational weeks. In the NIHF group, SP-A expression was generally weak, even after 31 gestation weeks. Moreover, most of the patients showing a weak expression of SP-A were also associated with hypoplastic lung and had a clinical history of persistent intrauterine pleural effusion of more than 2 weeks. Conversely, the immunoreactivity of SP-B was well preserved in NIHF cases either with or without hypoplastic lung. These results suggest that in the NIHF lung, there is a possible delay in the functional maturation or development of SP-A synthesis by alveolar type II cells, and this retardation of the functional maturation in type II cells also participates in the postnatal respiratory insufficiency in NIHF.

Epitope mapping for monoclonal antibody against human surfactant protein A (SP-A) that alters receptor binding of SP-A and the SP-A-dependent regulation of phospholipid secretion by alveolar type II cells

Surfactant protein A (SP-A) is a lung-specific glycoprotein in pulmonary surfactant and has a collagen like sequence on its N-terminal. SP-A has been shown to function as an inhibitor of phospholipid secretion by primary culture of alveolar type II cells via cell surface receptor(s) for SP-A. In a previous report, we showed that the C-terminal non-collagen like domain of human SP-A possessed the biological activities, and that a monoclonal antibody against human SP-A, PE10, abolished the biological activity of SP-A (Murata et al. (1993) Biochem. J. 291, 71-76). In the present study, we investigated an epitope of SP-A for PE10. Western blot analysis with fragmented peptides of human SP-A generated by both lysyl endopeptidase and BrCN showed that PE10 reacted with the peptide corresponding with Glu202 to the C-terminal but that it lacked the ability to bind to the peptide corresponding with Tyr208 to the C-terminal. The antibodies against a synthetic peptide (P1) corresponding with Glu202 to Asn217 of human SP-A inhibited the binding of PE10 to SP-A, suggesting that a similar site was recognized by both PE10 and anti-P1 antibodies. Anti-P1 antibodies as well as PE10 suppressed the biological activity of SP-A. A direct interaction between P1 and rat lung membranes, or between P1 and alveolar type II cell membranes was shown from the measurement of the fluorescence emission spectra of dansyl-labeled P1. These results suggest that an area contiguous to or near the region from Glu202 to Met207 of SP-A is important for expressing the biological activities.

The value of PE-10, a monoclonal antibody against pulmonary surfactant, in distinguishing primary and metastatic lung tumours

A new monoclonal antibody (PE-10) raised against components of pulmonary surfactant has been assessed for its ability to distinguish primary from secondary carcinomas in the lung. We applied this antibody to a series of 107 primary lung carcinomas, 40 adenocarcinomas of other sites, and 26 cases of adenocarcinoma metastatic to lung and pleura. Of the primary lung carcinomas, all the non-mucinous bronchiolo-alveolar carcinomas were positive whereas all the mucinous cases were negative; 60% of other types of adenocarcinoma were positive and 10% of large cell undifferentiated carcinomas, 20% of small cell carcinomas and 40% of atypical carcinoids also showed focal positivity. Squamous cell carcinomas were all negative. Adenocarcinomas of the breast, kidney, large bowel and ovaries were all negative, as were all 26 cases of adenocarcinoma metastatic to the lung and pleura. We conclude that this antibody is highly specific and moderately sensitive for primary tumours of the lung.

Alveolar basement membrane breaks down in diffuse alveolar damage: an immunohistochemical study

Sequential structural changes of the alveoli in diffuse alveolar damage (DAD) were examined by immunohistochemical methods. Lung specimens obtained at autopsy from 52 patients with DAD were stained with antibodies to laminin, 7S collagen (7S) and type IV collagen (type IV) for alveolar basement membrane, to von Willebrand factor, CD-31 and thrombomodulin (TM) for the alveolar capillary endothelial cell, and to epithelial membrane antigen and surfactant apo-protein (PE-10) for the alveolar epithelium. Forty-two of the patients had the exudative form of DAD; 10 of the patients had the proliferative form of DAD. The results were summarized as follows: (i) laminin was most easily impaired both in the epithelial and capillary basement membrane in the early exudative stage; (ii) following laminin, 7S and type IV in the capillary basement membrane were also injured in the early exudative stage, and recovered in the proliferative stage; (iii) subsequently, 7S and type IV in the epithelial basement membrane were also impaired in the late exudative stage, and remained impaired even in the proliferative stage; and (iv) alveolar epithelium regenerated almost completely in the late exudative stage, but staining for TM in the alveolar capillary recovered in the proliferative stage. Because the alveolar basement membrane must govern the homeostasis of alveolar tissue architecture, it was concluded that its preservation is necessary to avoid the abnormal remodeling of the alveoli in the reparative stage of DAD, if the patient survives the acute episodes of the disease.

Monocyte chemoattractant protein-1 in idiopathic pulmonary fibrosis and other interstitial lung diseases

Macrophages play a crucial role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). To examine the mechanisms for increased monocyte/macrophage recruitment in IPF and nonIPF interstitial lung diseases (nonIPF) the localization of monocyte chemoattractant protein-1 (MCP-1) was investigated in 14 cases of IPF, seven cases of nonIPF, and seven normal control lungs (CTRL) by immunohistochemistry using a specific anti-MCP-1 monoclonal antibody, F9. By double immunohistochemical staining using F9 and one of the cell type specific antibodies significant differences in the staining pattern of MCP-1 were observed between IPF and nonIPF. In IPF MCP-1 was observed in cuboidal and flattened metaplastic epithelial cells, alveolar macrophages, and vascular endothelial cells. In contrast, no epithelial cells were stained for MCP-1 in nonIPF cases, although alveolar macrophages and vascular endothelial cells were labeled. Northern hybridization analysis of selected cases showed marked expression of MCP-1 messenger RNA (mRNA) in IPF and nonIPF compared with CTRL. These findings suggest that the MCP-1 production in IPF and nonIPF plays an important role in the recruitment of monocyte/macrophages. Monocyte chemoattractant protein-1 production by epithelial cells in IPF may be caused by the metaplastic nature of the epithelial cells and may be one of the key factors inducing the irreversible progression of IPF.

Rat surfactant apoprotein A (SP-A) exhibits antioxidant effects on alveolar macrophages

The effects of surfactant apoprotein A (SP-A) on the superoxide production of rat alveolar macrophages (AM) were studied. Superoxide production was measured by the ferricytochrome c reduction method. When AM were incubated with SP-A only during the measurement of superoxide production, superoxide production was not influenced by SP-A. However, when AM were preincubated with SP-A at a concentration of 1, 2, and 10 micrograms/ml, superoxide production by AM was significantly inhibited (P < 0.05, P < 0.01, P < 0.01, respectively). The superoxide production of AM stimulated by PMA was significantly inhibited by SP-A at a concentration of 1 microgram/ml (P < 0.01), and superoxide production stimulated by zymosan was also inhibited by SP-A at a concentration of 10 micrograms/ml (P < 0.05). Suppression of superoxide production of unstimulated and PMA-stimulated AM was significantly inhibited by anti-SP-A antibody. Superoxide generation by the xanthine and xanthine oxidase system was not affected by the presence of SP-A. Our results suggest that superoxide production of AM can be inhibited by SP-A and that this inhibitory effect on AM is due to a specific effect of SP-A. From these results, it is speculated that SP-A may have a protective role for oxidant injury by AM in the lung.

Langerhans cells in Langerhans cell histiocytosis and peripheral adenocarcinomas of the lung

The present paper deals with more precise characterization of Langerhans cells (LC) and accompanying lymphocytes in lung LC histiocytosis (LCH) and primary lung peripheral adenocarcinomas using immunohistochemical methods with various kinds of monoclonal antibodies against cell adhesion and activation markers and some cytokines. Tissue specimens were obtained from 4 patients with pulmonary LCH and from 29 patients with primary lung peripheral adenocarcinoma. In florid (exudative and granulomatous) nonfibrotic LCH lesions, LC, particularly those in contact with lymphocytes, were S100, CD1a, MHC Class II, CD11a and c, CD16, and CD54 positive. In this context, LC were CD4+ and CD25+. Lymphocytes around LC were CD3+ with a "memory" phenotype (CD45RO+) and, frequently, CD25+ and HLA-DR+. S100+ and CD1a+ LC were commonly observed in adenocarcinomas subclassified as papillary and as nonmucinous bronchioloalveolar, in both cases mainly where Clara cells and Type II pneumocytes were present. In carcinomas the vast majority of LC were HLA-DR+ and, rarely, weakly CD16+, CD25+, and CD54+. The infiltration of reactive cells in cancer tissue was mainly represented by T lymphocytes (CD3+CD45RO+). These T cells were HLA-DR- and CD25-. The presence of LC was associated with a strong reactivity of epithelial cells with antibodies PE-10 and 439-9B, both recognizing molecules mainly expressed by Type II alveolar cells. Several cells in LCH florid lesions showed immunoreactivity for both IL-1 alpha and beta. Immunostaining for IFN-gamma revealed the presence in the same areas of some positive cells showing lymphoid morphology. No IL-1 or IFN-gamma reactivity was found in adenocarcinomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Surfactant apoprotein A secretion by human tracheobronchial epithelial cells

To determine whether surfactant apoproteins are produced locally by the airway walls, we used a two-site simultaneous immunoassay with monoclonal antibodies and measured the surfactant apoprotein-A (SP-A) content in media cultured with human airway explants or cultured epithelial cells. Tracheobronchial explants were cultured for 2 successive periods (periods I and II). Significant SP-A concentrations were detected in both periods. Methacholine (MCh) or isoproterenol (ISP), added to the medium at the beginning of period II, reduced the ratio of SP-A concentration in period II to that in period I, compared to samples without treatment. The SP-A concentration in the medium at the confluent period of cultured epithelial cells was significantly higher than at the mid-period, indicating that SP-A secretion is dependent on the cell number. The supernatant from explants stimulated by MCh was capable of reducing SP-A secretion from cultured epithelial cells. Immunohistochemical study of SP-A using monoclonal antibody demonstrated positive immunoperoxidase staining in the cytoplasm of epithelial cells. Further, Western blots of electrophoresed proteins from epithelial cells showed the characteristic properties of SP-A. These findings indicate that tracheobronchial epithelium can secrete SP-A.

Fine-needle aspiration cytology of sclerosing hemangioma of the lung: case report with immunohistochemical study

Sclerosing hemangioma of the lung (SHL) is a rare benign neoplasm, usually found incidentally on a routine chest X-ray. We present a case of SHL initially diagnosed by fine-needle aspiration cytology. Cytomorphologic characteristics were confirmed by a cell block examination and immunohistochemical findings. The differential diagnoses of the fine-needle aspiration are discussed.

Elevated levels of lung surfactant protein A in sera from patients with idiopathic pulmonary fibrosis and pulmonary alveolar proteinosis

An enzyme-linked immunosorbent assay using monoclonal antibodies to human lung surfactant protein A (SP-A) was applied to sera from patients with lung diseases. We examined whether SP-A appears in the sera of patients with diseases that are known to cause alterations in surfactant composition in bronchoalveolar lavage fluids, and we characterized the SP-A that was found. The level of SP-A in sera from 57 healthy volunteers was 45 +/- 3 ng/ml (mean +/- SEM). The levels in patients with idiopathic pulmonary fibrosis (IPF) (205 +/- 23 ng/ml, n = 32) and pulmonary alveolar proteinosis (PAP) (285 +/- 23 ng/ml, n = 6) were significantly higher than those in healthy control subjects (p < 0.01), whereas those of sarcoidosis (n = 16), pneumonia (n = 14), and tuberculosis (n = 14) were 52 +/- 27 ng/ml, 65 +/- 11 ng/ml, and 49 +/- 23 ng/ml, respectively. Electrophoresis and immunoblotting analysis demonstrated that the fraction isolated from serum of a patient with PAP or IPF by anti-SP-A immunoaffinity column chromatography consisted chiefly of human IgG and IgM, and that it also contained SP-A. Furthermore, IgG was found in preparation of purified human SP-A. SP-A was demonstrated to bind to nonimmune IgG coated onto microtiter wells. Gel filtration analysis revealed that serum SP-A was eluted at fractions of larger molecular size than was the purified SP-A. These findings suggest that SP-A appears in the bloodstream as a complex with immunoglobulin in IPF and in PAP.

Surfactant protein-A concentration in bronchoalveolar lavage fluids of patients with pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is characterized by accumulation of large quantities of lipoproteinaceous materials in alveoli. Surfactant protein A (SP-A) is the predominant phospholipid-associated glycoprotein in pulmonary surfactant and is specific to the lung. The contents of SP-A in bronchoalveolar lavage (BAL) fluids of patients with PAP were measured with an enzyme-linked immunosorbent assay using two monoclonal antibodies to human SP-A to evaluate its usefulness for diagnosis. Concentration of SP-A in BAL fluid in PAP was significantly increased in comparison with that of normal volunteers. The ratio of SP-A to protein in BAL fluid of PAP was at almost the same level as in normal subjects, while the ratio of SP-A to phospholipid in PAP was significantly higher. These results indicate that measurement of BAL fluid SP-A is of clinical value for diagnosis of PAP and should be used as a biochemical diagnostic tool in the clinical laboratory.

Pulmonary surfactant protein A in pleural effusions

Pulmonary surfactant protein A (SP-A) is known to be a major phospholipid-associated glycoprotein in pulmonary surfactant, which is specific to the lung. Immunohistochemically, expression of SP-A in tumor tissues is found in approximately 50% of patients with lung adenocarcinoma but not in the other histologic types of lung cancer of metastatic lung tumors. In this study, the SP-A content of pleural effusions was determined using an enzyme-linked immunosorbent assay. These results showed that approximately 40% of patients with lung adenocarcinomas (27 of 67) had high levels of SP-A (greater than 500 ng/ml) in their pleural effusions. By contrast, patients with other histologic types of lung cancers, adenocarcinomas of different primary sites, and tuberculosis had low levels of SP-A in their pleural effusions. The determination of SP-A in malignant effusions will contribute to distinguishing primary lung adenocarcinoma from adenocarcinomas of miscellaneous origin.

Presence of an 80 kilodalton protein, cross-reacted with monoclonal antibodies to pulmonary surfactant protein A, in the human middle ear

We report the presence of a middle ear protein that has the same epitope as human surfactant protein A. Monoclonal antibodies (PC-6 and PE-10) against human pulmonary surfactant protein A stained faint granules of the mucosal epithelial cell cytoplasm in the orifice of the eustachian tube immunohistochemically. These antibodies also reacted with middle ear effusion of patients with otitis media with effusion by dot immunoassay, and recognized an 80 kd protein by Western blot analysis. These findings indicate that a protein immunoreactive with PC-6 and PE-10 occurs in the mucosal epithelial cells of the middle ear, and is also present in middle ear effusion. It is therefore likely that this 80 kd protein might be secreted from the mucosal epithelial cells to the middle ear cavity.

Pseudomesotheliomatous carcinoma of the lung. An immunohistochemical and ultrastructural study of three cases

The authors report immunohistochemical and electron microscopic studies on three new cases of pseudomesotheliomatous carcinoma of the lung. Although the distinct clinical and histopathologic features of this peripheral lung cancer were described many years ago, its recognition as a distinct variety of lung carcinoma has not gained wide acceptance. Little is known of its incidence and only few cases have been reported until now. In the current study the authors demonstrate the epithelial nature of this tumor by its positive immunohistochemical reactions for epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), Leu-M1, B 72.3, and surfactant apoprotein. The ultrastructural features and staining of nuclear inclusions with surfactant apoprotein indicate differentiation into type II cells as found in other forms of peripheral lung adenocarcinoma. Despite these morphologic similarities, pseudomesotheliomatous carcinoma is characterized by extensive invasion of the pleura and rapidly fatal course. Because of this biologic behavior it deserves recognition as a distinct variant of peripheral lung carcinoma.

Surfactant apoprotein A (SP-A) in tracheal aspirates of newborn infants with RDS

Human pulmonary surfactant contains four groups of apoproteins, SP-A, B, C and D. We determined the concentration of SP-A in the tracheal aspirate of newborn infants by a two-site simultaneous immunoassay with monoclonal antibodies, and used this assay to assess changes in surfactant in various clinical situations. SP-A concentrations were standardized per milligram of albumin in the aspirate. The ratio of SP-A/albumin (micrograms/mg) in tracheal aspirates of 18 preterm infants with respiratory distress syndrome (RDS), in which samples were obtained within 12 hours of birth, was significantly lower (0.2 +/- 0.1 microgram/mg, mean +/- S.D.) compared to a group of 20 non-RDS preterm infants of similar gestational age (15.8 +/- 7.4 micrograms/mg) (p less than 0.05). None of the RDS infants had a SP-A/albumin ratio above 1 microgram/mg within 12 hours of birth, but the ratio exceeded 5 micrograms/mg in all samples from non-RDS infants. The SP-A/albumin ratio significantly increased, however, at 48 to 72 hours after birth in infants with RDS (15.7 +/- 9.5 micrograms/mg). During the recovery phase of RDS, no difference was evident in the SP-A/albumin ratio in babies treated with artificial surfactant compared to those not treated.