IL-18 plays a key role in the pathogenesis of pulmonary inflammatory diseases including pulmonary infection, pulmonary fibrosis, lung injury and chronic obstructive pulmonary disease (COPD). However, it is unknown whether IL-18 plays any role in the pathogenesis of asthma. We hypothesized that overexpression of mature IL-18 protein in the lungs may exacerbate disease activities of asthma. We established lung-specific IL-18 transgenic mice on a Balb/c genetic background. Female mice sensitized– and challenged– with antigen (ovalbumin) were used as a mouse asthma model. Pulmonary inflammation and emphysema were not observed in the lungs of naïve transgenic mice. However, airway hyperresponsiveness and airway inflammatory cells accompanied with CD4+ T cells, CD8+ T cells, eosinophils, neutrophils, and macrophages were significantly increased in ovalbumin-sensitized and challenged transgenic mice, as compared to wild type Balb/c mice. We also demonstrate that IL-18 induces IFN-γ, IL-13, and eotaxin in the lungs of ovalbumin-sensitized and challenged transgenic mice along with an increase in IL-13 producing CD4+ T cells. Treatment with anti-CD4 monoclonal antibody or deletion of the IL-13 gene improves ovalbumin-induced airway hyperresponsiveness and reduces airway inflammatory cells in transgenic mice. Overexpressing the IL-18 protein in the lungs induces type 1 and type 2 cytokines and airway inflammation, and results in increasing airway hyperresponsiveness via CD4+ T cells and IL-13 in asthma.

Introduction

A necrotic lung ball is a rare radiological feature that is sometimes seen in cases of pulmonary aspergillosis. This paper reports a rare occurrence of a necrotic lung ball in a young male caused by Candida and Streptococcus pneumoniae.

Case report

A 28-year-old male with pulmonary candidiasis was found to have a lung ball on computed tomography (CT) of the chest. The patient was treated with β-lactams and itraconazole and then fluconazole, which improved his condition (as found on a following chest CT scan) and serum β-D-glucan level. The necrotic lung ball was suspected to have been caused by coinfection with Candida and S. pneumoniae.

Conclusion

A necrotic lung ball can result from infection by Candida and/or S. pneumoniae, indicating that physicians should be aware that patients may still have a fungal infection of the lungs that could result in a lung ball, even when they do not have either Aspergillus antibodies or antigens.