[Candidates for virulence factors of Aspergillus fumigatus].

The number of patients with invasive fungal infection (IFI) has dramatically increased since the beginning of the 1980s. Aspergillus fumigatus, the most common species recovered from aspergillosis, is an important pathogen of IFI. Recently, new antifungal agents have become available in Japan, but mortality from aspergillosis is still high. Early initiation of therapy seems to improve the survival rate. Study of virulence factors of the fungus may lead to the development of novel diagnostic tools or advancements in therapy. Many candidates of the fungal virulence factors have been studied including proteases and mycotoxins. We previously discussed the influence of fungal secondary metabolites such as gliotoxin and other low molecular components on the virulence, and showed that A. fumigatus produces potent cytotoxic substances other than gliotoxin. Studies are in progress to clarify the significance of the unknown substances.

Gene expression profiling of polymorphonuclear leukocytes treated with the culture filtrate of Aspergillus fumigatus and gliotoxin.

Pathogens of the Aspergillus species are frequently seen in deep-seated mycoses. We previously demonstrated that the culture filtrate of Aspergillus fumigatus (CF) has immunosuppressive effects on polymorphonuclear leukocytes (PMNs), which act as the main phagocytes to hyphae of Aspergillus fumigatus (A. fumigatus). But little is known about the gene expression profiles involved in it. Therefore we investigated the changes in gene expression in human PMNs treated with CF or gliotoxin at two time points, using microarray analysis. CF and gliotoxin changed the expression of 548 and 381 genes, respectively. Only 51 genes showed the same expression patterns with the two stimulants, and CF-induced changes in gene expression occurred comparatively earlier than those induced by gliotoxin. Among 31 genes encoding apoptosis, which were up- or down-regulated in this assay, only 3 genes were similarly changed by both kinds of stimulation. Apoptosis was detected and quantified using two apoptosis assays. CF and gliotoxin changed the expessions of only 3 out of 19 regulated genes related to inflammatory mediators and receptors similarly. The up-regulation of the gene encoding annexin 1 (ANXA1), which is known to be involved in extravasation and apoptosis of neutrophils, may play a role in the immunosuppressive effect of A. fumigatus. The difference in expression changes between CF and gliotoxin is presumed to be caused by the interaction among the components of CF and therefore the interaction is an area of interest for further investigation.

Cytotoxic substances from Aspergillus fumigatus in oxygenated or poorly oxygenated environment.

Aspergillus fumigatus often causes serious health problems. The airway of the human body, the most common initial site of damage, is always exposed to an oxygenated condition, and the oxygen concentration may play a critical role in the virulence of A. fumigatus. In this study, oxygen content, fungal growth, the production of cytotoxic substance(s) in the fungal culture, and their relationship were investigated. Two clinical strains of A. fumigatus were cultured under certain oxygen contents (10, 14 and 20%), and cytotoxicity of their culture filtrates on murine macrophages and their fungal growth were evaluated. The components of these filtrates were analyzed by gas chromatography-mass spectrometry. All culture filtrates contained gliotoxin and showed potent cytotoxicity on macrophages at very low concentration. The amount of gliotoxin in the culture filtrate prepared at 10% oxygen was markedly less, but diminutions in fungal growth and cytotoxicity of this culture filtrate were negligible. These results suggest that a well-oxygenated condition is suitable for the production of gliotoxin by A. fumigatus. A significant role of cytotoxic substances(s) other than gliotoxin is also suggested.

[A case of perforative peritonitis complicated with lung and intestinal severe tuberculosis].

A 27-year-old man was admitted to our hospital in September 18, 2000, complaining of fever, cough, appetite loss and body weight loss. He was diagnosed as advanced lung tuberculosis, because of chest X-ray findings and positive acid-fast bacilli in his sputum. He was administrated rifampicin (RFP), isoniazid (INH) and ethambutol (EB). Two days after starting treatment he complained of abdominal pain and the signs of perforating peritonitis. Emergency laparotomy was performed and we observed multiple ulcers and a perforation of ileum. We resected a part of distal ileum and ascending colon and made ileostomy. Histopathologic examination of resected ileum and colon showed multiple ulcers and epithelioid cell granulomas with caseous necrosis. Many acid bacilli were identified from the lesion by specially stained tissue sections. He was administrated streptomycin and INH by injection post-operatively while oral administration was impossible. Six days after the first operation, we found the signs of perforation in another part of the ileum. So we were obliged to perform second laparotomy and resect the part involved. Five days after the second operation, he was able to take RFP, INH, and levofloxacin per oral route. On February 8, 2001 we performed ileocolonal reconstruction with side to side anastomosis and closed ileostomy at the third laparotomy. He had continued chemotherapy and went back to Korea in April 7, 2001. Although intestinal tuberculosis has sharply declined in Japan thanks to development of effective antituberculous drugs, we should keep in mind that it could be a possible cause of the acute abdomen.

[A study on low performance status cases of pulmonary tuberculosis in the elderly].

The subjects consisted of 42 patients aged over 60 years, whose performance status (PS) was grade 3 or 4, and who had been admitted for pulmonary tuberculosis at National Chiba-Higashi Hospital between 1997 and 1998. The average age (+/- SD) of the 34 men and 8 women was 77.6 (+/- 8.5) years (range, 60-91 years). The mean stay in the hospital of the improved patients was 166.6 days (range, 57-303 days), and the mean survival period from admission to death was 43.4 days (range, 2-179 days in died patients). On admission to our hospital, 26 cases were sputum smear positive, 8 cases were smear negative and culture positive, and 8 were negative both on smear and culture. The cavity was observed in 30 cases (71.4%) on the chest X-ray. The laboratory data on admission revealed low nutritional condition. The mean serum total protein, albumin, and cholesterol level on admission were 6.2 (+/- 0.82) g/dl, 2.7 (+/- 0.62) g/dl, and 143.0 (+/- 41.9) mg/dl. Most of the patients had a difficulty in taking foods, and 20 cases (47.6%) were performed parenteral nutrition by central venous catheter. 23 cases (54.8%) received oxygen therapy by facial mask or nasal tube. The most common cause of low PS on admission was pulmonary tuberculosis in 14 cases (33.3%), followed by cerebrovascular diseases in 11 cases, and orthopedic disease in 8 cases. The proportion of patients whose cause of low PS was not due to lung tuberculosis increased with age. Observing the mortality by the route of administration of antituberculosis medications on admission, 19 (55.9%) of 34 cases who could take drugs per oral route died. One (50.0%) of 2 cases who were administered drugs through gastric tube died, and all (100.0%) of 5 cases who could not take drugs per oral route and were injected isoniazid and streptomycin died. One case who could not administer any drug died. 16 cases improved and 26 cases died, of whom the most common cause of death was pulmonary tuberculosis in 11 cases (42.3%), followed by bacterial pneumonia in 5 cases, and cerebrovascular disease in 3 cases. The mortality by the PS on admission were as follows: 10 (47.6%) of 21 cases with PS 3 died. 16 (76.2%) of 21 cases with PS 4 died. 16 (6.4%) of 249 cases aged over 60 years with PS 0, 1 or 2, and were admitted for pulmonary tuberculosis at the same hospital during the same period died. This study confirms that the prognosis of low performance status patients of pulmonary tuberculosis in the elderly was significantly poor. We have to detect tuberculosis patients in the early stage, and give them antituberculosis medications per oral route as far as possible.