Immunohistochemical distribution of SP-D, compared with that of SP-A and KL-6, in interstitial pneumonias

A case of pleural mesothelioma with immunohistochemical staining positive for Krebs von den Lungen-6

A 71-year-old male visited a hospital with a chief complaint of exertional dyspnea. A chest CT revealed multiple nodular lesions on the parietal pleura. Thoracoscopic pleural biopsy was performed resulting in a diagnosis of pleural mesothelioma with epithelioid type. When chemotherapy was initially initiated, his serum level of Krebs von den Lungen-6 (KL-6) was high. However, once chemotherapy was started, the serum KL-6 level gradually decreased with tumor shrinkage. Immunohistochemical staining revealed the expression of KL-6 from the tumor cells. This is the first report of KL-6 production directly from tumor cells in epithelial-type pleural mesothelioma.

Japanese clinical practice guide 2022 for hypersensitivity pneumonitis

Considering recently published two guidelines for the diagnosis of hypersensitivity pneumonitis (HP), the Japanese Respiratory Society (JRS) has now published its own Japanese clinical practice guide for HP. Major types of HP in Japan include summer-type, home-related, bird-related, farmer's lung, painter's lung, humidifier lung, and mushroom grower's lung. Identifying causative antigens is critical for increasing diagnostic confidence, as well as improving prognosis through appropriate antigen avoidance. This guide proposes a comprehensive antigen questionnaire including the outbreak sources reported in Japan. Drawing on the 2021 CHEST guideline, this guide highlights the antigen identification confidence level and adaptations for environmental surveys. The detection of specific antibodies against causative antigens is an important diagnostic predictor of HP. In Japan, the assessments of bird-specific IgG (pigeons, budgerigars) and the Trichosporon asahii antibody are covered by medical insurance. Although this guide adopts the 2020 ATS/JRS/ALAT guideline diagnostic criteria based on the combination of imaging findings, exposure assessment, bronchoalveolar lavage lymphocytosis, and histopathological findings, it added some annotations to facilitate the interpretation of the content and correlate the medical situation in Japan. It recommends checking biomarkers; seasonal changes in the KL-6 concentration (increase in winter for bird-related HP/humidifier lung and in summer for summer-type HP) and high KL-6 concentrations providing a basis for the suspicion of HP. Antigen avoidance is critical for disease management of HP. This guide also addresses the pharmacological management of HP, highlighting the treatment strategy for fibrotic HP including combination therapies with anti-inflammatory/immunosuppressive and antifibrotic drugs.

Diagnosis of Fibrotic Hypersensitivity Pneumonitis: Is There a Role for Biomarkers?

Hypersensitivity pneumonitis is a complex interstitial lung syndrome and is associated with significant morbimortality, particularly for fibrotic disease. This condition is characterized by sensitization to a specific antigen, whose early identification is associated with improved outcomes. Biomarkers measure objectively biologic processes and may support clinical decisions. These tools evolved to play a crucial role in the diagnosis and management of a wide range of human diseases. This is not the case, however, with hypersensitivity pneumonitis, where there is still great room for research in the path to find consensual diagnostic biomarkers. Gaps in the current evidence include lack of validation, validation against healthy controls alone, small sampling and heterogeneity in diagnostic and classification criteria. Furthermore, discriminatory accuracy is currently limited by overlapping mechanisms of inflammation, damage and fibrogenesis between ILDs. Still, biomarkers such as BAL lymphocyte counts and specific serum IgGs made their way into clinical guidelines, while others including KL-6, SP-D, YKL-40 and apolipoproteins have shown promising results in leading centers and have potential to translate into daily practice. As research proceeds, it is expected that the emergence of novel categories of biomarkers will offer new and thriving tools that could complement those currently available.

Serum Biomarkers in a Radiological Pattern of Non-Fibrotic Hypersensitivity Pneumonitis: Implications for Mechanistic Difference and Differential Diagnosis

Hypersensitivity pneumonitis (HP) is a consequence of immune-mediated reactions caused by recurrent exposure to environmental agents. Recently, clinical practice guidelines for the diagnosis of HP were published and increased interest in HP. On the other hand, novel therapies have recently emerged for various diseases, and the management of drug-related pneumonitis (DRP) has become increasingly important. Among DRP, the HP pattern (DRP-HP) shows small, poorly defined centrilobular nodules with or without widespread areas of ground-glass opacity or lobular areas of decreased attenuation and vascularity. A similar radiological pattern of non-fibrotic HP can be induced, irrespective of inhalation (non-fibrotic HP) or intravenous administration (DRP-HP). However, their difference has not been well described, although the distribution of lesions in the lungs was slightly different between these two conditions. In this review, we focus on serum biomarkers of lung epithelial cells in order to investigate the difference between DRP-HP and non-fibrotic HP (common-HP). Serum levels of Krebs von den Lungen 6 (KL-6) might be relatively lower (occasionally normal) in DRP-HP than in common-HP, implying a mechanistic difference. KL-6 could be useful in discriminating between DRP and non-fibrotic HP (common type).

Role of serum surfactant protein-D as a prognostic predictor in fibrotic hypersensitivity pneumonitis

BACKGROUND

Serum Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) are candidate diagnostic and activity markers for fibrotic hypersensitivity pneumonitis (HP), although their correlation with prognosis remains unclear. We aimed to evaluate the prognostic usefulness of serum KL-6 and SP-D in patients with fibrotic HP.

METHODS

This was a retrospective medical record review of 185 patients with fibrotic HP at a single center from 2005 to 2019. The baseline and minimum serum KL-6 and SP-D levels over two years were recorded. The contribution of KL-6 and SP-D levels to the incidence of progressive fibrosing interstitial lung disease (PF-ILD) and mortality were evaluated using multivariate analysis.

RESULTS

The respective baseline and minimum levels were 1441 and 808 U/ml for KL-6 and 254 and 132 ng/mL for SP-D. A high minimum SP-D level was significantly associated with a high incidence of PF-ILD by logistic regression, independent of baseline forced vital capacity and honeycombing. Similarly, a high minimum SP-D level was significantly associated with high mortality by Cox proportional hazard model analysis. The stratified minimum SP-D levels of <100, 100-200, and >200 revealed significantly distinct groups in the entire cohort, with PF-ILD incidence rates of 28%, 48%, and 74% and median survival times of 120, 74, and 45 months, respectively.

CONCLUSIONS

High minimum SP-D levels over two years were correlated with an unfavorable prognosis in our cohort. Patient with consistently high SP-D levels during the clinical course may have a poor prognosis and be a candidate for early treatment intensification.

Serum vasohibin-1 levels: A potential marker of dermal and pulmonary fibrosis in systemic sclerosis

Vasohibin-1 (VASH-1) is a potent anti-angiogenic factor mainly produced by endothelial cells. In addition, VASH-1 prevents TGF-β-dependent activation of renal fibroblasts. Since systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy and fibrosis of multiple organs, VASH-1 may be involved in the development of this disease. In this study, we investigated the potential role of VASH-1 in SSc by evaluating the clinical correlation between serum VASH-1 levels and the expression of VASH-1 in SSc-involved skin. Serum VASH-1 levels were higher in SSc patients, especially those with diffuse cutaneous involvement, than in healthy controls and positively correlated with skin score. Furthermore, SSc patients with interstitial lung disease had significantly elevated levels of serum VASH-1 as compared to those without. Importantly, serum VASH-1 levels correlated inversely with both the percentage of predicted vital capacity and the percentage of predicted diffusion lung capacity for carbon monoxide and positively with serum KL-6 levels, but not serum surfactant protein D levels. In SSc-involved skin, VASH1 mRNA was remarkably upregulated compared with healthy control skin, but the major source of VASH-1 was not clear. Fli1 deficiency, a predisposing factor inducing SSc-like endothelial properties, did not affect VASH-1 expression in human dermal microvascular endothelial cells. Collectively, these results suggest that VASH-1 upregulation in the skin and sera is linked to dermal and pulmonary fibrotic changes in SSc, while the contribution of VASH-1 to SSc vasculopathy seems to be limited.

Changes in serum KL-6 levels during short-term strict antigen avoidance are associated with the prognosis of patients with fibrotic hypersensitivity pneumonitis caused by avian antigens

BACKGROUND

Bird-related hypersensitivity pneumonitis (BRHP) is the most common type of fibrotic hypersensitivity pneumonitis (HP). Antigen avoidance (AA) is a key step in the diagnosis and management of HP, but not all fibrotic HP patients improve through AA. Because of the poor prognosis of fibrotic HP, predictive biomarkers to identify patients showing rapid progression during AA are urgently needed.

METHODS

From a retrospective review of the medical records of 1941 patients with interstitial lung disease, 75 cases of fibrotic BRHP confirmed by a provocation test or surgical lung biopsy were identified. To identify potential prognostic markers obtained at or around diagnosis, physiological and serological variables at diagnosis and the relative changes in those variables during strict AA were evaluated. Cox proportional hazards models with log-rank testing were used to compare the associations between these variables and survival.

RESULTS

Univariate analyses showed that gender, smoking status, and the relative change in the serum levels of Krebs von den Lungen-6 (KL-6) were associated with prognosis (P = 0.02, 0.04, and 0.02, respectively), but the presence of honeycombing and the forced vital capacity were not associated with survival. The relative change in KL-6 levels (greater than vs. less than a 10% decrease) was significantly associated with survival in a stratified analysis (73.9 vs. 34.9 months; P = 0.04).

CONCLUSIONS

The relative change in KL-6 levels is associated with the prognosis of patients with fibrotic BRHP independent of previously identified prognostic biomarkers. This finding could help pulmonologists identify fibrotic BRHP patients that are likely to show rapid progression.

Serum Krebs von den Lungen-6 level in the disease progression and treatment of Mycobacterium avium complex lung disease

BACKGROUND AND OBJECTIVE

The lack of useful biomarkers reflecting the disease state limits the management of Mycobacterium avium complex lung disease (MAC-LD). We clarified the associations between serum KL-6 level, disease progression and treatment response.

METHODS

Resected lung tissues from MAC-LD patients were immunostained for KL-6. We compared serum KL-6 levels between MAC-LD and healthy control or bronchiectasis patients without nontuberculous mycobacterial lung disease (NTM-LD). Serum KL-6 level was assessed in a prospective observational study at Keio University Hospital between May 2012 and May 2016. We investigated associations between serum KL-6 level and disease progression and treatment response in patients untreated for MAC-LD on registration (n = 187).

RESULTS

The KL-6⁺ alveolar type 2 cell population in the lung and serum KL-6 level were significantly higher in MAC-LD patients than in controls. Serum KL-6 level in bronchiectasis patients without NTM-LD showed no significant increase. Of the 187 patients who did not receive treatment on registration, 53 experienced disease progression requiring treatment. Multivariable Cox analysis revealed that the serum KL-6 level (aHR: 1.18, P = 0.005), positive acid-fast bacilli smear (aHR: 2.64, P = 0.001) and cavitary lesions (aHR: 3.01, P < 0.001) were significantly associated with disease progression. The change in serum KL-6 (ΔKL-6) was significantly higher in the disease progression group; it decreased post-treatment, reflecting the negative sputum culture conversion.

CONCLUSION

Serum KL-6 level is associated with disease progression and treatment response. Longitudinal assessment combined with AFB smear status and presence of cavitary lesions may aid MAC-LD management.

A retrospective clinical research of relapsed organizing pneumonia

BACKGROUND

Organizing pneumonia (OP) usually responds spectacularly well to initial treatment, but relapses can occur and some cases run a fatal course. Still, the issue of relapse has been addressed in relatively few studies, and predictors have not been clarified. The purpose of this study was to examine the pattern of relapses in OP, to determine whether relapse affects morbidity and mortality, and to identify possible predictors of relapse.

METHODS

Blood sampling, pulmonary function testing, computed tomography (CT) of the chest, and bronchofiberscopy were performed for all patients and were retrospectively reviewed along with clinical information. Periodical chest CT was conducted and additional chest CT was performed when relapse of OP was clinically suspected. All patients were followed regarding treatment response, treatment duration, and presence of relapse. Results were compared between two groups based on serum concentrations of surfactant protein (SP)-D: normal SP-D and high SP-D.

RESULTS

Twenty-two patients were analyzed in this study. SP-D showed a negative correlation with percutaneous oxygen saturation and positive correlations with serum lactate dehydrogenase, Krebs von den Lungen (KL)-6, and percentage of lymphocytes in bronchoalveolar lavage (BAL). Prognosis was good for all patients, but relapse was significantly more frequent in the high SP-D group (6 cases) than in the normal SP-D group (0 cases; P = 0.049). Serum KL-6 and percentage of monocytes in BAL were significantly higher, and pulmonary vital capacity and forced expiratory volume in 1 s were significantly lower in the high SP-D group than in the low SP-D group.

CONCLUSIONS

When treating cases of OP with high serum concentrations of SP-D, attention should be paid to the possibility of relapse.

Importance of serial changes in biomarkers in idiopathic pulmonary fibrosis

The clinical significance of serial changes in serum biomarkers in patients with idiopathic pulmonary fibrosis (IPF) remains to be established. This retrospective study was conducted to clarify the associations of serial changes in serum Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) with changes in physiological indices and overall mortality in IPF. The study subjects were 75 patients with IPF. The 6 month change in serum KL-6 was significantly correlated with changes in the percentage of the predicted forced vital capacity (FVC % pred) and the percentage of the predicted diffusing capacity of the lung for carbon monoxide (% D_LCO), while the 6 month change in serum SP-D was correlated only with % D_LCO. During the mean follow-up period of 647 days, 22 (29.3%) patients died. An increase in serum KL-6 over a 6 month period was a significant predictor of mortality even after adjustment for %FVC, % D_LCO and serum KL-6 at the baseline (hazard ratio 1.10 per 100 U·mL^-1, 95% CI 1.01-1.18, p=0.03), whereas the 6 month increase in serum SP-D was not significant. Serial measurements of serum KL-6 may provide additional prognostic information compared to that provided by physiological parameters in patients with IPF.

Clinical Impact of the KL-6 Concentration of Pancreatic Juice for Diagnosing Pancreatic Masses

Background and Aim. Pancreatic juice cytology (PJC) is considered optimal for differentially diagnosing pancreatic masses, but the accuracy of PJC ranges from 46.7% to 93.0%. The aim of this study was to evaluate the clinical impact of measuring the KL-6 concentration of pancreatic juice for diagnosing pancreatic masses. Methods. PJC and the KL-6 concentration measurements of pancreatic juice were performed for 70 consecutive patients with pancreatic masses (39 malignancies and 31 benign). Results. The average KL-6 concentration of pancreatic juice was significantly higher for pancreatic ductal adenocarcinomas (PDACs) (167.7 ± 396.1 U/mL) and intraductal papillary mucinous carcinomas (IPMCs) (86.9 ± 21.1 U/mL) than for pancreatic inflammatory lesions (17.5 ± 15.7 U/mL, P = 0.034) and intraductal papillary mucinous neoplasms (14.4 ± 2.0 U/mL, P = 0.026), respectively. When the cut-off level of the KL-6 concentration of pancreatic juice was 16 U/mL, the sensitivity, specificity, and accuracy of the KL-6 concentration of pancreatic juice alone were 79.5%, 64.5%, and 72.9%, respectively. Adding the KL-6 concentration of pancreatic juice to PJC when making a diagnosis caused the values of sensitivity and accuracy of PJC to increase by 15.3% (P = 0.025) and 8.5% (P = 0.048), respectively. Conclusions. The KL-6 concentration of pancreatic juice may be as useful as PJC for diagnosing PDACs.

Peritoneal Malignant Mesothelioma with Epithelioid Type, Demonstrating High Serum and Ascitic KL-6 Levels: Immunohistochemical Analyses

We report a case of KL-6 producing peritoneal malignant mesothelioma. A 56-year-old woman was referred to our hospital on November 2005 with severe abdominal distention. Peritoneal malignant mesothelioma with epithelioid type was diagnosed by clinical symptoms, laboratory investigations, imaging studies, and immunohistochemical examination of known tumor markers. In addition, high serum and ascitic KL-6 levels were observed and the immunostaining of the tumor for KL-6 was evident. We thus consider KL-6 to be a potential novel marker for peritoneal malignant mesothelioma with epithelioid type.

Early Stages of Hyaline Membrane Formation Detected in Alveolar Mouths in Diffuse Alveolar-Damage-Associated Diseases: A Detailed Immunohistochemical Study

To study the early stages of hyaline membrane (HM) formation, diffuse alveolar damage (DAD) was thoroughly investigated using immunohistochemical methods in 15 autopsy cases, which consisted of various types of interstitial pneumonias and pulmonary diseases derived from nonmalignant or malignant diseases. Alveolar mouths (AMs) that were presumed to be normal were ultrastructurally examined in detail, by using pulmonary tissues in the pneumothorax. It is interesting to note that during the initial stages of HM formation in AMs, fragmented eosinophilic masses were closely attached to AMs as irregular fragments or by a cap-like structure. The ultrastructure revealed some distance between the capillary spaces and surface epithelium of the AMs, indicating that the epithelial cells at the AMs might be often easily damaged even by minor stimuli; they can be considered as "locus minoris resistentiae." HMs were found to be formed initially at the site of AMs derived from fragmented eosinophilic masses in not only pulmonary but also extrapulmonary diseases, including both nonmalignant and malignant diseases. These irregular eosinophilic masses, representing the early shape of HMs, were immunohistochemically positive for the epithelial membrane antigens, namely, surfactant protein A and factor VIII antigen, and occasionally for KL-6 and cytokeratins. These results suggested that fragmented irregular masses represent the initial phase of HM formation. Five of 15 cases were focally negative for KL-6 at the initial irregular mass of HMs. Because KL-6 is one of the fundamental components of pulmonary surface elements, it needs to be studied further by detailed clinicopathological examination.

Usefulness of KL-6 in the subtyping of intraductal papillary mucinous neoplasia of the pancreas, including carcinoma, dysplasia, and hyperplasia

KL-6 is known as a useful serum biomarker of the disease activity in interstitial pneumonias. We investigated its usefulness as a biomarker for subtyping intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. IPMNs are generally divided into 4 subtypes, namely pancreatobiliary (PB), intestinal (INT), gastric (GS), and oncocytic (ONC). Aside from the KL-6 antibody, the MUC1, MUC2, MUC5AC, MUC6, and MIB-1 antibodies were also examined. Eighteen IPMN cases were examined, including 12 cases of intraductal papillary mucinous carcinomas (IPMCs) simultaneously associated with dysplasia (IPMDs) and hyperplasia (IPMHs) and 6 IPMD cases with IPMH. KL-6 antibody was positive in the 8 IPMC cases, corresponding to a MUC2-negative PB subtype, but negative in 4 IPMC cases, corresponding to the INT subtype, which is positive for MUC2. IPMD of moderate-to-severe degree positively stained for the KL-6 antibody in the IPMC cases of the PB subtype but not in those of the INT subtype. The IPMH cases were mostly negative for KL-6, similar to the mild IPMD cases. In the 6 cases of mild IPMD and/or IPMH, KL-6 and MUC2 expressions were mostly negative. In conclusion, the KL-6 antibody is immunohistochemically a good biomarker of the PB subtype of IPMC, but not the INT subtype. Identifying IPMN subtypes based on KL-6 stainability would be useful. Clinicopathological studies with more IPMC cases might be needed for further progress in this field of study.

Idiopathic pleuroparenchymal fibroelastosis is characterized by an elevated serum level of surfactant protein-D, but Not Krebs von den Lungen-6

PURPOSE

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a recently reported rare disease entity characterized by fibrotic thickening of the pleural and subpleural parenchyma predominantly in the upper lobes in idiopathic interstitial pneumonias (IIPs). Because the clinical features of this rare disease are not fully elucidated, we examined the clinical characteristics of IPPFE, especially for serum interstitial biomarkers, surfactant protein-D (SP-D), and Krebs von den Lungen-6 (KL-6).

METHODS AND RESULTS

Four consecutive cases of IPPFE who fulfilled the diagnostic criteria were studied. All cases were more than 60 years of age, and were classified as underweight by body mass index. A severe restrictive ventilatory defect was found in all cases on admission. High-resolution computed tomography showed intense pleural thickening associated with fibrosis predominant in upper lobes. Histopathological findings were also confirmed in three out of four cases. Interestingly, the serum level of SP-D was markedly elevated in all cases, while KL-6 was within normal range in three out of four cases. As compared with major IIPs such as idiopathic pulmonary fibrosis and fibrotic nonspecific interstitial pneumonia, IPPFE significantly showed higher frequency of cases with a unique pattern of serum biomarkers, which is characterized by an elevated level of SP-D with a normal range of KL-6.

CONCLUSIONS

In IPPFE, SP-D might tend to be elevated, while KL-6 was within a normal range. Further study is required to determine the pathogenesis and clinical significance of the elevated SP-D in IPPFE.

The Innate Immune System of the Perinatal Lung and Responses to Respiratory Syncytial Virus Infection

The response of the preterm and newborn lung to airborne pathogens, particles, and other insults is initially dependent on innate immune responses since adaptive responses may not fully mature and require weeks for sufficient responses to antigenic stimuli. Foreign material and microbial agents trigger soluble, cell surface, and cytoplasmic receptors that activate signaling cascades that invoke release of surfactant proteins, defensins, interferons, lactoferrin, oxidative products, and other innate immune substances that have antimicrobial activity, which can also influence adaptive responses. For viral infections such as respiratory syncytial virus (RSV), the pulmonary innate immune responses has an essential role in defense as there are no fully effective vaccines or therapies for RSV infections of humans and reinfections are common. Understanding the innate immune response by the preterm and newborn lung may lead to preventive strategies and more effective therapeutic regimens.

Immunohistochemical and fluorescence in situ hybridization studies on noninvasive and invasive extramammary Paget's disease

To determine useful immunohistochemical markers for tumor cells in extramammary Paget's disease (EMPD), immunohistochemical (IHC) examinations in 17 patients with EMPD, including 4 patients with dermal invasion, were performed. Among the antibodies examined, cytokeratin 7 (CK7) and CK19 were strongly positive for both intraepidermal and dermally invasive tumor cells in all patients. CAM5.2 and mucin 1 (MUC1) were also good markers. Although IHC examination revealed positive for HER-2 in 4 EMPD patients with dermal invasion, 4 out of 13 noninvasive patients were IHC negative. Fluorescence in situ hybridization (FISH) study revealed negative results for HER-2 gene amplification in 8 IHC positive patients, including each 4 patients of both noninvasive and dermal invasive cases. Our results show that besides CK7, CK19 is another favorable marker of tumor cells of EMPD. Four patients with dermal invasion were strongly positive for HER-2, although negative results were obtained in the FISH study. Further investigations are required to confirm the results of the FISH study.

A novel lung injury animal model using KL-6-measurable human MUC1-expressing mice

KL-6, an epitope of MUC1 mucin expressed on type II pneumocytes and bronchiolar epithelia in humans, is a sensitive serum marker for interstitial pneumonia. However, an in vivo model for KL-6 has not been established because no KL-6 epitope is expressed in animals other than humans and apes. To investigate whether KL-6 is detectable in human MUC1-expressing (hMUC1-exp) mice and whether KL-6 level reflects the degree of lung injury, we examined serum and bronchoalveolar lavage fluid (BALF) levels of KL-6 and surfactant protein-D (SP-D) in either lipopolysaccharide (LPS)- or bleomycin (BLM)-induced lung injury models. KL-6 was expressed on type II pneumocytes and bronchiolar epithelial cells in naïve hMUC1-exp mice. Serum KL-6 levels in these mice were comparable to those in humans, and KL-6 levels in BALF were significantly higher than those in sera. In the LPS model, KL-6 levels in sera and BALF were slightly increased, although SP-D levels were markedly increased. During the inflammatory phase in the BLM model, KL-6 levels in sera were greatly increased, but those in BALF were decreased. Serum KL-6 levels were positively correlated with BALF albumin levels, a representative marker for increased the alveolar-capillary permeability. SP-D levels in sera and BALF were significantly increased compared to the corresponding levels in the LPS model. The increase in serum KL-6 levels appeared to be associated with the disruption of alveolar-capillary barrier after BLM-induced lung injury. This hMUC1-exp mouse can be used for assessment of KL-6 in vivo during lung injury.

Marked increase in serum KL-6 and surfactant protein D levels during the first 4 weeks after treatment predicts poor prognosis in patients with active interstitial pneumonia associated with polymyositis/dermatomyositis

OBJECTIVE

The aim of this study is to determine whether serum KL-6 and surfactant protein D (SP-D) levels predict the prognosis of patients with interstitial pneumonia (IP) in cases of polymyositis (PM) and dermatomyositis (DM).

PATIENTS AND METHODS

Fifty consecutive patients with PM (n = 17) or DM (n = 33) and active IP, 6 of whom died of respiratory failure, were enrolled in this study. Serum KL-6 and SP-D levels were measured every 2-4 weeks. Medical records were reviewed retrospectively. Univariate analyses and multivariate analyses with a logistic regression model were conducted.

RESULTS

Serum KL-6 and SP-D levels were elevated in patients with active IP. At the time of diagnosis of active IP, the serum KL-6 level was within the normal range in 28 % of patients and the SP-D level was within the normal range in 46 % of patients. Serum KL-6 level increased up to 3 months after starting treatment and then decreased gradually to baseline, whereas SP-D level peaked within the first 4 weeks after treatment and decreased rapidly to normal levels. Patients with poor prognosis showed increases in KL-6 and SP-D levels during the first 4 weeks after treatment, which was confirmed by uni- and multivariate analyses. Comparing the marker levels at 2-4 weeks after treatment with those at 0 weeks, an increase in the ratio over 1.70 for KL-6 and over 1.75 for SP-D, and an increase in KL-6 over 850 U/ml during the first 4 weeks after treatment, were poor prognostic factors.

CONCLUSIONS

Increases in serum KL-6 and SP-D levels during the first 4 weeks after starting therapy, but not their levels at any one time point, predict poor prognosis in patients with PM/DM. When marked increases of KL-6 and SP-D levels during the first 4 weeks are found or are predicted by serial measurement of the markers, patients have risks of poor prognosis and additional therapy should be considered.

Utility of KL-6/MUC1 in the clinical management of interstitial lung diseases

Interstitial lung diseases (ILDs) are a diverse group of pulmonary disorders characterized by various patterns of inflammation and fibrosis in the interstitium of the lung. Because injury and/or regeneration of type II pneumocytes are prominent histological features of ILDs, substances derived from type II pneumocytes have been the focus of research investigating potential biomarkers for ILD. One important biomarker for ILD is the high-molecular-weight glycoprotein, Krebs von den Lungen-6 (KL-6). KL-6 is now classified as a human MUC1 mucin protein, and regenerating type II pneumocytes are the primary cellular source of KL-6/MUC1 in the affected lungs of patients with ILD. KL-6/MUC1 is detectable in the serum of patients with ILD, and extensive investigations performed primarily in Japan have revealed that serum KL-6/MUC1 is elevated in 70-100% of patients with various ILDs, including idiopathic interstitial pneumonias, collagen vascular disease-associated interstitial pneumonia, hypersensitivity pneumonia, radiation pneumonitis, drug-induced ILDs, acute respiratory distress syndrome, pulmonary sarcoidosis, and pulmonary alveolar proteinosis. The results from these various studies have supported the utility of KL-6/MUC1 as a serum biomarker for detecting these various ILDs. Moreover, KL-6/MUC1 serum levels have been demonstrated to be useful for evaluating disease activity and predicting the clinical outcomes of various ILD types. Based on these observations, we believe that KL-6/MUC1 is currently one of the best and most reliable serum biomarkers available for ILD management.

Pulmonary Collectins in Diagnosis and Prevention of Lung Diseases

Pulmonary surfactant is a complex mixture of lipids and proteins, and is synthesized and secreted by alveolar type II epithelial cells and bronchiolar Clara cells. It acts to keep alveoli from collapsing during the expiratory phase of the respiratory cycle. After its secretion, lung surfactant forms a lattice structure on the alveolar surface, known as tubular myelin. Surfactant proteins (SP)-A, B, C and D make up to 10% of the total surfactant. SP-B and SPC are relatively small hydrophobic proteins, and are involved in the reduction of surface-tension at the air-liquid interface. SP-A and SP-D, on the other hand, are large oligomeric, hydrophilic proteins that belong to the collagenous Ca²⁺-dependent C-type lectin family (known as “Collectins”), and play an important role in host defense and in the recycling and transport of lung surfactant (Awasthi 2010) (Fig. 43.1). In particular, there is increasing evidence that surfactant-associated proteins A and -D (SP-A and SP-D, respectively) contribute to the host defense against inhaled microorganisms (see 10.1007/978-3-7091-1065_24 and 10.1007/978-3-7091-1065_25). Based on their ability to recognize pathogens and to regulate the host defense, SP-A and SP-D have been recently categorized as “Secretory Pathogen Recognition Receptors”. While SP-A and SP-D were first identified in the lung; the expression of these proteins has also been observed at other mucosal surfaces, such as lacrimal glands, gastrointestinal mucosa, genitourinary epithelium and periodontal surfaces. SP-A is the most prominent among four proteins in the pulmonary surfactant-system. The expression of SP-A is complexly regulated on the transcriptional and the chromosomal level. SP-A is a major player in the pulmonary cytokine-network and moreover has been described to act in the pulmonary host defense. This chapter gives an overview on the understanding of role of SP-A and SP-D in for human pulmonary disorders and points out the importance for pathology-orientated research to further elucidate the role of these molecules in adult lung diseases. As an outlook, it will become an issue of pulmonary pathology which might provide promising perspectives for applications in research, diagnosis and therapy (Awasthi 2010).

Serum KL-6 level as an indicator of active or inactive interstitial pneumonitis associated with connective tissue diseases

OBJECTIVE

To elucidate the cut off levels of serum KL-6 indicating patients with interstitial pneumonitis (IP) and patients with active IP associated with connective tissue diseases (CTDs).

METHODS

CTD patients whose serum KL-6 level was measured were included. IP was diagnosed on the basis of medical records including XP/CT findings, and active IP was assumed in case that intervention for IP was newly added. The cut off levels were determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

Among 240 (174 females) patients, 67 (42) had IP and 15 (9) had active IP. The ages of patients with and without IP, and with active IP and with inactive IP were 70.3±9.5 and 62.8±15.3, and 72.8±8.1 and 69.6±9.8, respectively. IP was significantly more prevalent in males and the elderly. The KL-6 levels were 990±90 and 301±12 U/mL in patients with and without IP, and 1,905±236 and 726±54 U/mL in those with active IP and with inactive IP, respectively. ROC curve analysis showed a cut off level of 509 U/mL for indicating IP, and that of 1,051-1,060 U/mL for indicating active IP.

CONCLUSION

A serum KL-6 level of higher than 500 U/mL is a marker of the presence of IP, and a level of higher than 1,000 U/mL is a marker of the presence of active IP associated with CTDs.

Immunohistochemical and ultrastructural characterization of the signet-ring cell carcinoma component in a case of urothelial carcinoma of the urinary bladder

Characterization of the signet-ring cell carcinoma (sig) component of a urothelial carcinoma (UC) in the urinary bladder of a 64-year-old man, obtained by transurethral resection of bladder tumor (TUR-BT), is reported. In the present case, a characteristic sig component was detected in approximately 20% of UC, G2 tissues. The sig cells were morphologically similar to those found in gastric cancers and were positively stained with periodic acid-Schiff reaction and Alcian blue and mucicarmine stains. Immunohistochemically, the sig cells were selectively positive for carcinoembryonic antigen (CEA), MUC2, and MUC5AC. These immunohistochemical characteristics were similar to those of sig cells in the stomach, except for the positivity with MUC2. It is interesting to note that CAM5.2-positive sig cells were surrounded by CAM5.2-positive UC cells in a solid nest with no apparent associated adenocarcinoma element. In addition, the ultrastructure of sig cells showed multivacuolar cytoplasmic mucin, which proved to be similar to the ultrastructure of gastric cancers. In the present case of UC, G2 was associated with a sig component. Regarding the origin of the sig component in the bladder, it has been suggested that MUC2-positive sig cells in the bladder might be derived directly from metaplasia of UC, without an associated adenocarcinoma component. From this perspective, it may be noteworthy that sig cells in the bladder were selectively positive for MUC2, exhibiting common antigenicity with mucous cells of the gastric intestinal metaplasia. Because UC associated with a sig component carries a worse prognosis than ordinary UC, the presence of the sig component in any UC should be evaluated even within TUR-BT tissues, as in the present case.

Immunohistochemical and electron microscopy studies of a case of hyalinizing trabecular tumor of the thyroid gland, with special consideration of the hyalinizing mass associated with it

Hyalinizing trabecular tumor (HTT) of the thyroid gland is rare and benign, and it neither recurs nor metastasizes. In this lesion, tumor cells are arranged in trabeculae, in association with hyalinizing mass in the stroma. The origin and nature of the hyalinizing mass are still controversial. We report here a case of HTT with cytological, immunohistochemical, and ultrastructural findings, focused in particular on the hyalinizing mass. Cytologically, tumor cells exhibiting many intranuclear cytoplasmic inclusions and nuclear grooves were found in association with light green-positive, irregular, fluffy membranous structures on touch smear. Staining with antibody to collagen type IV was positive in these membranous structures. Histopathologically, tumor cells exhibited many intranuclear cytoplasmic inclusions, and were positive for staining with antibodies to S100 protein, neuron-specific enolase, thyroglobulin, and vimentin. The hyalinizing eosinophilic mass, which was positive for PAS reaction, and for staining by antibody to collagen type IV, gradually increased in the areas surrounding tumor cells. This mass then appeared to replace the tumor cells, and exhibited a peculiar filiform pattern. We demonstrated ultrastructurally that this pattern was composed of long, irregular, fine cytoplasmic processes of tumor cells and basal lamina-like substance in the hyalinizing mass. In fact, the homogeneous hyalinizing mass, similar to basal lamina-like substance, contained many degenerated cytoplasmic processes at the ultrastructural level. These results suggested that the key cytological finding in differentiating HTT from papillary carcinoma is the fluffy membranous structure, although nuclear pseudoinclusions are important as well. The filiform pattern noted at light microscopic level consisted of long cytoplasmic processes of tumor cells and hyalinized mass at the ultrastructural level.

KL-6 is another useful marker in assessing a micropapillary pattern in carcinomas of the breast and urinary bladder, but not the colon

To evaluate the peculiar "inside-out" pattern in micropapillary (MP) carcinoma, we investigated the usefulness of KL-6 antibody in the assessment of the MP pattern of cancers, in comparison with antibodies to epithelial membrane antigen (EMA), MUC1 (CD227), and CD 10. Immunohistochemical investigation was performed on specimens exhibiting an MP pattern obtained from 12 persons with cancer: 4 with breast carcinoma, 3 with carcinoma of the urinary bladder, and 5 with colonic carcinoma. Immunohistochemical study with KL-6, EMA, and MUC1 antibodies revealed similar continuous linear positive patterns restricted to the surface of the MP pattern in both breast and urinary bladder cancers, revealing the peculiar "inside-out" morphology. However, EMA also gave cytoplasmic positivity in most of the cases tested, and MUC1 was also present in the cytoplasm of some cases. In sharp contrast, immune reactions of colon carcinomas with these antibodies were negative, except for focal positivity for KL-6 and MUC1 antibodies in some cases. CD10 was only focally positive in an MP pattern in 4 of the 5 cases of colon carcinoma and in 1 case with carcinoma of the urinary bladder. These findings suggest that KL-6 is a useful marker to assess the MP character of breast and urinary bladder carcinomas; that MUC1 was similarly positive, with the addition of cytoplasmic positivity in some cases; and that the MP pattern of colon cancer, positive for CD 10, was different in character from both breast and urinary bladder carcinomas, although all these cancers seemingly exhibit similar MP patterns on histopathology. This heterogeneity of the MP pattern in various cancers needs to be investigated when more cases have been accumulated.

Clinical utility of serum beta-D-glucan and KL-6 levels in Pneumocystis jirovecii pneumonia

OBJECTIVE

New serum markers (1-->3) beta-D-glucan (beta-D-glucan) and KL-6 are reported to be useful for the clinical diagnosis of Pneumocystis jirovecii pneumonia (PCP). However, the utility of these markers in PCP with HIV infection (HIV PCP) and without HIV (non-HIV PCP) is unknown. This study was aimed to evaluate the utility of beta-D-glucan and KL-6 for the diagnosis of PCP in patients with HIV infection (HIV PCP) and non-HIV PCP.

METHODS

Retrospective study.

PATIENTS

We reviewed the medical records of consecutive 35 patients. The serum levels of beta-D-glucan and KL-6 in HIV PCP and non-HIV PCP were comparatively evaluated. We evaluated these markers in survivors and non survivors.

RESULTS

The detection rates of serum beta-D-glucan and KL-6 levels in non-HIV PCP were lower than those in HIV PCP (88% vs. 100%, 66% vs. 88%, respectively). The false positive rates of these markers in both groups were similar (12%, 37%, respectively). Oxygenation index, serum albumin, and mechanical ventilation were the variables which were significantly associated with poor outcome in the univariate analysis.

CONCLUSION

In conclusion, beta-D-glucan was a reliable diagnostic marker for PCP. However, the detection rate of beta-D-glucan and KL-6 in non-HIV PCP was lower than in HIV PCP. Neither beta-D-glucan nor KL-6 was associated with the outcome of PCP.

A rare case of coexistence of pulmonary adenocarcinoma with Langerhans' cell histiocytosis

We report a rare case of coexisting pulmonary adenocarcinoma and Langerhans' cell histiocytosis (LCH) in a 78-year-old woman who did not smoke. During follow-up of diabetes mellitus, she had complained of chest pain and was found to have a nodular lesion in S9 of the left lower lobe, which was resected surgically. No abnormal laboratory findings were obtained. Before surgical resection, needle biopsy specimens confirmed the existence of adenocarcinoma. The resected tumor in the left lower lobe was 3.0 x 1.8 x 3.0 cm, and histologically both acinar and bronchioloalveolar cell subtypes of adenocarcinoma were found in cancer foci. In addition to pulmonary adenocarcinoma, Langerhans' cell proliferation associated with marked eosinophil infiltration was incidentally found in a small nodule, approximately 3 x 2 mm in size in the subpleural region. The Langerhans' cells contained interdigitated nuclei, exhibiting rather clear nucleoplasm and cytoplasm; they were positive for S-100 protein, CD1a, and also CD4. Massive eosinophil infiltration was found around the focus of Langerhans' cell proliferation. This nodule appeared to be LCH. The adenocarcinoma and LCH were adjacent, and cancer cells were infiltrated only in the peripheral parts of LCH. The coexistence of adenocarcinoma and LCH appeared to be incidental. The association of adenocarcinoma and LCH is rare, and only several reports of it can be found in the English literature.

Micropapillary component of urothelial carcinoma detected in transurethral resection of bladder tumor (TUR-BT) tissues: a case report

A case of urothelial carcinoma (UC) containing a micropapillary carcinoma (MPC) component in the urinary bladder of an 83-year-old man is reported. The MPC component of UC has been reported to be a variant featuring poor prognosis and rapid progression. In the present case, a characteristic MPC component with micropapillary growth, in association with a fine meshwork-like stroma, was observed in less than 10% of fragmented cancer tissues of UC, G3, obtained by transurethral resection of a bladder tumor (TUR-BT). Lymphatic invasion was also detected. UC cancer cells had invaded the prostatic glands and replaced the original epithelial cells. The unique "insideout" feature of the MPC component was immunohistochemically obvious on staining with antibody to epithelial membrane antigen (EMA). On immunohistochemical study, cancer cells of both UC and MPC components were positive for pancytokeratin AE1/AE3 and cytokeratins 7 and 20. Carcinoembryonic antigen (CEA) and CAM5.2 were only focally positive in UC cells. MIB-1(Ki-67) labeling index was high, at 80%-90%, in cancer cells of UC. This was a case of UC, G3 with invasion to the muscularis propria layer of the urinary bladder and also to the prostate. MPC and MPC components in cancers should be recognized as a marker of poor prognosis, even when detected in less than 10% of UC within TUR-BT tissues, as in the present case.

Multiple minute nests of incidentally detected paraganglionic cells associated with urothelial carcinoma of the urinary bladder in a 73-year-old woman

A 73-year-old woman who had undergone resection of urothelial carcinoma (UC) (G3 > G2) of the ureter was also found to have UC (G3) in the urinary bladder, spread throughout the urinary bladder with multiple foci of carcinoma in situ and small papillary cancers. Total cystectomy was therefore performed. On detailed microscopic examination of the extirpated urinary bladder, multiple minute cell nests, 14 in number and less than 2 mm in diameter each, consisting of cells harboring small nuclei and clear cytoplasm, were incidentally detected within the sub-mucosal layer and the proper muscle layer, mainly in the posterior wall of the urinary bladder. Some cell nests were clearly associated with ganglion cells. The cells in minute nests were positive on Grimelius staining and also strongly positive on staining with antibodies to chromogranin A, neuron-specific enolase (NSE), synaptophysin, and vimentin on immunohistochemical staining. In addition, sustentacular cells in the minute cell nests were positive for S100 protein. Staining with antibodies to pancytokeratin AE1/AE3, glial fibrillary acidic protein, and p53 was negative in the cell nests. Based on these findings, the multiple minute foci were diagnosed as paraganglionic cells (PGCs) incidentally detected in the urinary bladder of an elderly woman, in association with UC. Although PGCs are rarely detected in adult human urinary bladder on routine histopathological examination, the possibility of their existence should be kept in mind by pathologists, especially in coexistence with UC. This is the first case of PGCs associated with UC in the human urinary bladder in the English literature.

Immunohistochemical and electron microscopic studies of Langerhans cells in a case of multiple eccrine spiradenomas

Multiple eccrine spiradenomas are rare. In the present study, a detailed investigation of eccrine spiradenoma was performed, focusing in particular on the presence of Langerhans cells (LCs) in the tumor, and their immunohistochemical and ultrastructural characterization. The patient was a woman in her mid-forties who underwent resection of two tumors of the head that were 2.0 and 0.7 cm in size. They were diagnosed as eccrine spiradenoma and were composed of small and large tumor cells with a dense fibrous capsule in the dermis. Immunohistochemically, staining by antibodies to cytokeratins (AE1/AE3, CAM5.2) and CK 5/6 was diffusely positive in all tumor cells, although not in intermingled LCs, which harbored interdigitated nuclei. The cytoplasm of LCs was positive for S-100 protein and CD1a, and their nuclei were also occasionally positive for S-100 protein. Antibody to epithelial membrane antigen was positive for the surface of both intracytoplasmic and true glandular lumina. Fine structural examination revealed the presence of LCs among the tumor cells, extending fine irregular processes among the tumor cells. Birbeck granules were clearly demonstrated in the cytoplasm of LCs. Other fine structural findings included intracytoplasmic lumina with microvilli on their surfaces in some tumor cells. In these examinations of eccrine spiradenoma, LCs, approximately 15/HPF in the tumor, were distinctly detected even at light microscopic level as negative for various types of cytokeratin stains, although they were positive for S-100 protein and CD1a, whereas on ultrastructural examination Birbeck granules were demonstrated in their cytoplasm. Determination of the significance of these LCs in eccrine spiradenoma requires further investigation of a larger number of cases.