ABSTRACT
BACKGROUND: Although the relationship between allergic inflammation and lung carcinogenesis is not clearly defined, several reports suggest an increased incidence of lung cancer in patients with asthma. We aimed at determining the functional impact of allergic inflammation on chemical carcinogenesis in the lungs of mice. METHODS: Balb/c mice received single-dose urethane (1 g/kg at day 0) and two-stage ovalbumin during tumor initiation (sensitization: days -14 and 0; challenge: daily at days 6-12), tumor progression (sensitization: days 70 and 84; challenge: daily at days 90-96), or chronically (sensitization: days -14 and 0; challenge: daily at days 6-12 and thrice weekly thereafter). In addition, interleukin (IL)-5 deficient and wild-type C57BL/6 mice received ten weekly urethane injections. All mice were sacrificed after four months. Primary end-points were number, size, and histology of lung tumors. Secondary end-points were inflammatory cells and mediators in the airspace compartment. RESULTS: Ovalbumin provoked acute allergic inflammation and chronic remodeling of murine airways, evident by airspace eosinophilia, IL-5 up-regulation, and airspace enlargement. Urethane resulted in formation of atypical alveolar hyperplasias, adenomas, and adenocarcinomas in mouse lungs. Ovalbumin-induced allergic inflammation during tumor initiation, progression, or continuously did not impact the number, size, or histologic distribution of urethane-induced pulmonary neoplastic lesions. In addition, genetic deficiency in IL-5 had no effect on urethane-induced lung tumorigenesis. CONCLUSIONS: Allergic inflammation does not impact chemical-induced carcinogenesis of the airways. These findings suggest that not all types of airway inflammation influence lung carcinogenesis and cast doubt on the idea of a mechanistic link between asthma and lung cancer.
Subject(s)
Disease Models, Animal , Lung Neoplasms/chemically induced , Lung Neoplasms/immunology , Lung/immunology , Lung/pathology , Respiratory Hypersensitivity/immunology , Respiratory Hypersensitivity/pathology , Animals , Bronchoalveolar Lavage Fluid/cytology , Bronchoalveolar Lavage Fluid/immunology , Carcinogenicity Tests/methods , Lung/drug effects , Lung Neoplasms/pathology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Random Allocation , Urethane/toxicityABSTRACT
BACKGROUND: Rates of invasive group B Streptococcus (GBS; Streptococcus agalactiae) disease in adults are on the rise. Invasive GBS disease can be community- or healthcare-associated. We report an outbreak of GBS catheter-related bacteremia in a hemodialysis (HD) unit. MATERIALS AND METHODS: Two patients undergoing HD at the same outpatient HD unit were admitted on the same day (within a few hours of each other) with catheter-related GBS bacteremia. A retrospective study was undertaken at the HD unit to address risk factors for febrile illness on the last HD session day. A detailed questionnaire was completed by all HD patients treated on the same day as the two GBS patients and by all members of the nursing and medical staff. Medical and nursing records of the HD unit were reviewed, as well as infection control and catheter care practices. Patients and staff members submitted swabs for culture. RESULTS: No rectal or vaginal culture of any HD patient or staff member was positive for GBS. The development of recent febrile disease was significantly associated with the presence of a hemodialysis catheter (p=0.028) and care for more than 30min by a specific nurse during the last two HD sessions (p=0.007). CONCLUSIONS: We speculate that the GBS strain was transmitted from one patient to the other through the hands of medical personnel. No such outbreak has ever been reported in HD patients. The importance of strict infection control practices in HD units and the avoidance of catheters for long-term HD should be emphasized.
