Kenji Hibiya

Computed tomographic features of 23 sporadic cases with Legionella pneumophila pneumonia

OBJECTIVE To describe the chest computed tomographic (CT) findings of Legionella pneumophila pneumonia. METHODS CT scans obtained from 23 sporadic cases of L. pneumophila pneumonia were retrospectively reviewed. Chest CT findings were analyzed with regard to the patterns and distributions of pulmonary abnormalities. We also analyzed the histopathology of lungs from guinea pigs with experimentally induced L. pneumophila pneumonia. RESULTS Consolidation and ground-glass opacity (GGO) were the main findings of CT scans in L. pneumophila pneumonia. The distribution of opacities was categorized as non-segmental (n=20) and segmental (n=4). Non-segmental distribution may follow an onset of segmental distribution. Pleural effusion was observed in 14 (58.3%) patients, of which 13 were accompanied with non-segmental distribution. Abscess formation was observed in only one immunocompromised patient. In the animal pneumonia model, the lesions comprised of terminal bronchioles, alveolar spaces, and interstitia. Small bacilli were observed to be contained by many macrophages within the alveoli. CONCLUSION Non-segmental distribution was significantly more frequent than segmental distribution in L. pneumophila pneumonia. It is possible that L. pneumophila infection initially results in segmental pneumonia, which progresses to typical non-segmental distribution.

Legionella pneumophila infection induces programmed cell death, caspase activation, and release of high-mobility group box 1 protein in A549 alveolar epithelial cells: inhibition by methyl prednisolone

BackgroundLegionella pneumophila pneumonia often exacerbates acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Apoptosis of alveolar epithelial cells is considered to play an important role in the pathogenesis of ALI and ARDS. In this study, we investigated the precise mechanism by which A549 alveolar epithelial cells induced by L. pneumophila undergo apoptosis. We also studied the effect of methyl prednisolone on apoptosis in these cells.MethodsNuclear deoxyribonucleic acid (DNA) fragmentation and caspase activation in L. pneumophila-infected A549 alveolar epithelial cells were assessed using the terminal deoxyribonucleotidyl transferase-mediated triphosphate (dUTP)-biotin nick end labeling method (TUNEL method) and colorimetric caspase activity assays. The virulent L. pneumophila strain AA100jm and the avirulent dotO mutant were used and compared in this study. In addition, we investigated whether methyl prednisolone has any influence on nuclear DNA fragmentation and caspase activation in A549 alveolar epithelial cells infected with L. pneumophila.ResultsThe virulent strain of L. pneumophila grew within A549 alveolar epithelial cells and induced subsequent cell death in a dose-dependent manner. The avirulent strain dotO mutant showed no such effect. The virulent strains of L. pneumophila induced DNA fragmentation (shown by TUNEL staining) and activation of caspases 3, 8, 9, and 1 in A549 cells, while the avirulent strain did not. High-mobility group box 1 (HMGB1) protein was released from A549 cells infected with virulent Legionella. Methyl prednisolone (53.4 μM) did not influence the intracellular growth of L. pneumophila within alveolar epithelial cells, but affected DNA fragmentation and caspase activation of infected A549 cells.ConclusionInfection of A549 alveolar epithelial cells with L. pneumophila caused programmed cell death, activation of various caspases, and release of HMGB1. The dot/icm system, a major virulence factor of L. pneumophila, is involved in the effects we measured in alveolar epithelial cells. Methyl prednisolone may modulate the interaction of Legionella and these cells.

Diagnosis of intestinal tuberculosis using a monoclonal antibody to Mycobacterium tuberculosis

AIM To investigate the utility of immunohistochemical (IHC) staining with an antibody to Mycobacterium tuberculosis (M. tuberculosis) for the diagnosis of intestinal tuberculosis (TB). METHODS We retrospectively identified 10 patients (4 males and 6 females; mean age = 65.1 ± 13.6 years) with intestinal TB. Clinical characteristics, including age, gender, underlying disease, and symptoms were obtained. Chest radiograph and laboratory tests, including sputum Ziehl-Neelsen (ZN) staining, M. tuberculosis culture, and sputum polymerase chain reaction (PCR) for tubercle bacilli DNA, as well as Tuberculin skin test (TST) and QuantiFERON-TB gold test (QFT), were examined. Colonoscopic records recorded on the basis of Satos classification were also reviewed, in addition to data from intestinal biopsies examined for histopathological findings, including hematoxylin and eosin staining, and ZN staining, as well as M. tuberculosis culture, and PCR for tubercle bacilli DNA. For the present study, archived formalin-fixed paraffin-embedded (FFPE) intestinal tissue samples were immunohistochemically stained using a commercially available species-specific monoclonal antibody to the 38-kDa antigen of the M. tuberculosis complex. These sections were also stained with the pan-macrophage marker CD68 antibody. RESULTS From the clinical data, we found that no patients were immunocompromised, and that the main symptoms were diarrhea and weight loss. Three patients displayed active pulmonary TB, six patients (60%) had a positive TST, and 4 patients (40%) had a positive QFT. Colonoscopic findings revealed that all patients had type 1 findings (linear ulcers in a circumferential arrangement or linear ulcers arranged circumferentially with mucosa showing multiple nodules), all of which were located in the right hemicolon and/or terminal ileum. Seven patients (70%) had concomitant healed lesions in the ileocecal area. No acid-fast bacilli were detected with ZN staining of the intestinal tissue samples, and both M. tuberculosis culture and PCR for tubercle bacilli DNA were negative in all samples. The histopathological data revealed that tuberculous granulomas were present in 4 cases (40%). IHC staining in archived FFPE samples with anti-M. tuberculosis monoclonal antibody revealed positive findings in 4 patients (40%); the same patients in which granulomas were detected by hematoxylin and eosin staining. M. tuberculosis antigens were found to be mostly intracellular, granular in pattern, and primarily located in the CD68(+) macrophages of the granulomas. CONCLUSION IHC staining with a monoclonal antibody to M. tuberculosis may be an efficient and simple diagnostic tool in addition to classic examination methods for the diagnosis of intestinal TB.

Immunopathological characteristics of immune reconstitution inflammatory syndrome caused by Mycobacterium parascrofulaceum infection in a patient with AIDS.

Immune reconstitution inflammatory syndrome (IRIS) caused by mycobacterium in patients with AIDS is often experienced in clinical practice. There is, however, a paucity of data documenting the histopathological findings and the pathogenesis. We determined the immunopathological characteristics of IRIS associated with Mycobacterium parascrofulaceum infection in an AIDS patient. A patient presented with pulmonary lymphadenitis and involvement of the pulmonary lingular segment. Portions of the involved lymph nodes and lung were excised, and the immunological properties were analyzed by immunohistochemical assays. The histological characteristics of lymph nodes showed a caseous necrosis. Histopathologically, the pulmonary lesion was composed of exudative and proliferative lesions. CD4(+), CD8(+), CD57(+), and CD25(+)/FoxP3(+) cells were observed in both types of lesions. Clusters of CD20(+) cells and GATA3(+) cells were predominantly observed in exudative lesions, while T-bet(+) cells were dominant in proliferative lesions. ROR-γ(+) cells were also observed in exudative lesions. These results indicate that the cellular immunity to mycobacteria was recovering in the lung tissue. In M. parascrofulaceum pulmonary infection, the exudative lesion had characteristics of Th2 and Th17-type immunities. In contrast, the proliferative lesion had characteristics of Th-1 type immunity. Our data provide the first evidence to reveal the status of the axis of distinctive immunity in the process of granuloma formation caused by a mycobacterium-related infection.

Pigs as an experimental model for systemic Mycobacterium avium infectious disease

Mycobacterium avium complex (MAC) is an opportunistic pathogen in AIDS patients and pigs, and causes dissemination through primary intestinal lesions. However, its pathogenesis is not well understood. In this article, we hypothesize that pigs can provide a suitable experimental model of disseminated MAC disease. We compared the initial route of infection, the characteristics of the pathogenic strains, the immunological status of the hosts, and the histological characteristics. The route of infection and infective strains are similar in AIDS patients and pigs. Pigs can respond to infection by the formation of systemic epithelioid granuloma with sufficient cell-mediated immunity. However, there are differences in immunological status and histological features between AIDS patients and pigs. Therefore, pigs might be used as an appropriate animal model because of their good cell mediated immunity triggered by systemic mycobacterial infection. In conclusion, MAC infections in AIDS patients and pigs show similarities in terms of the initial route of infection and the genetic characteristics of the pathogenic strains.

A Case of Pulmonary and Hepatic Cystic Echinococcosis of CE1 Stage in a Healthy Japanese Female that Was Suspected to Have Been Acquired During Her Stay in the United Kingdom

We herein report a case of a young Japanese female who was confirmed to have cystic echinococcosis (CE) 1 stage based on the World Health Organization Informal Working Group on Echinococcosis pathological classification of CE, and she was also suspected to be infected with eggs of the G1 Echinococcus granulosus sensu stricto during her stay in the United Kingdom and therefore, suffered from synchronous pulmonary and hepatic CE. Oral albendazole was administered initially, but rupture of a lung hydatid cyst was observed. To avoid additional rupture, we performed two surgeries. CE is very rare in Japan; all CE cases in Japan during the past two decades have been confirmed to be imported, and almost all cases are hepatic CE. This case is the first case report of a Japanese patient who had concomitant giant lung and liver CE with early-stage CE1 and was successfully treated by surgery and pharmacotherapy with a serological follow-up.

Distribution of mycobacterial antigen based on differences of histological characteristics in pulmonary Mycobacterium avium infectious diseases—Consideration of the extent of surgical resection from the pathological standpoint

Quantitative assessment of mycobacterial antigens is very important to determine the surgical indication, as well as the area of resection for pulmonary Mycobacterium avium complex (MAC) infectious disease. However, at present, pathological assessment is only possible as a postoperative examination. We performed quantitative evaluation of mycobacterial antigens using lung tissues with MAC pulmonary infection obtained from surgical resection. The distribution of mycobacterial antigens was evaluated by immunohistochemical staining with monoclonal antibody for mycobacteria. In exudative reactions, many monocyte-lineage cells containing mycobacterial antigens were observed in alveoli, whereas the quantity of mycobacterial antigens was extremely decreased in proliferative reactions. Epithelioid cells or multinucleated giant cells contained mycobacterial antigens in necrotic granulomas. In solitary nodules with central necrosis, mycobacterial antigens were frequently observed, whereas they were rarely observed in solitary nodules without caseous necrosis. Mycobacterial antigens were not observed in the epithelial layer of bronchioles in any cases, although proliferative granulomas were notably observed in the developed lymphoid follicles in subepithelial lesions of bronchiole. Thus, exudative reactions or nodules with caseous necrosis indicate the possibility of numerous mycobacteria remaining in the pulmonary focus. Therefore, intraoperative histological assessment may help in the determination of the area of surgical resection. This is the first study to quantitatively evaluate mycobacterial antigens according to histological characteristics in MAC pulmonary disease.

Descriptive analysis of the prevalence and the molecular epidemiology of Mycobacterium avium complex-infected pigs that were slaughtered on the main island of Okinawa.

Recent genetic studies have revealed that several epidemiological factors affect Mycobacterium avium complex (MAC) infection in pig populations. However, mechanisms underlying the spread of MAC infection among hog farms have not been clarified. In consideration of this situation, we cross-sectionally investigated the mechanisms underlying the spread of MAC on the island of Okinawa. Pigs slaughtered (n=706,763) and 331 hog farms on Okinawa were surveyed during the years 2002-2004. Two outbreaks of MAC infection were occurred in several farms during survey period. Bacteria were isolated from randomly selected pigs and genotype of isolates was determined by using genetic finger printing methods with the insertion sequence (IS) 1245 restriction fragment length polymorphism (RFLP). Most isolates had large numbers of IS1245 copies, while strains with low copy numbers of IS1245 and isolates without IS1245 were seen in few farms. MACs strains were repeatedly isolated from pigs of the affected farms during the survey period. Those farms with an identical pig rearing systems showed synchronic changes in the prevalence of MAC infection. An industrial farm without an outbreak had an independent pig flow, but maintained distinct MAC strains. Multivariate analysis did not reveal independent factors for the prevalence of the MAC infection. These findings suggest that there were three clusters distinguished genetically in the main island of Okinawa, which were potentially spread by common pig flow. However, the outbreaks occurred because of unspecified conditions on each farm environment.

Hepatocyte growth factor levels in Legionella pneumonia: a retrospective study.

BackgroundHepatocyte growth factor (HGF) is known to be involved in the resolution of pulmonary inflammation and repair of acute lung injury. Legionella pneumonia is sometimes complicated by acute lung injury. Our study aimed to determine the role of serum HGF levels in Legionella pneumonia.MethodsSera from patients with Legionella pneumonia (42 cases), other bacterial pneumonia (33 cases), pulmonary tuberculosis (19 cases), and normal controls (29 cases) were collected. The serum HGF levels for each serum sample were determined by sandwich ELISA. Clinical and laboratory data were collected by reviewing the medical charts.ResultsSerum HGF levels were higher in patients with Legionella pneumonia than in those with other bacterial pneumonia, pulmonary tuberculosis, and controls. The HGF levels were compared with white blood cell counts, C-reactive protein, Alanine amino- transferase, and lactate dehydrogenase (LDH). The HGF levels were correlated to serum LDH levels. Moreover, serum HGF levels were significantly higher in non-survivors than in survivors.ConclusionsHGF levels increased in severer pneumonia caused by Legionella, suggesting that HGF might play a significant role in the Legionella pneumonia.

Nonspecific interstitial pneumonia pattern as pulmonary involvement in human T-cell lymphotropic virus type 1 carriers.

It is well established that diffuse interstitial shadows are observed in human T-cell lymphotropic virus type 1 (HTLV-1) carriers. However, the pathological pattern of nonspecific interstitial pneumonia (NSIP) has rarely been reported. Here, we describe the clinical features of four patients with histologically proven NSIP and HTLV-1 infection. The patients, one woman and three men, had a median age of 59.5 years. High-resolution computed tomography of the lungs was performed in all patients, and no apparent honeycomb formations were detected. The present study demonstrates that the NSIP pattern is a significant pathological classification of interstitial pneumonia associated with HTLV-1 carriers.