Pulmonary nocardiosis in an immunocompetent patient with COPD: The role of defective innate response

Objectives Pulmonary nocardiosis is an uncommon opportunistic infection affecting mainly immunocompromised patients. We herein present a case of nocardiosis without profound underlying immunodeficiency. Background A female, 84-years' old patient with stage IV chronic obstructive pulmonary disease (COPD) is presented. No profound causes of immunodeficiency existed, such as HIV infection, diabetes mellitus, malignancy, alcoholism, chemotherapy or previous corticosteroid intake. The patient recovered after treatment with trimethoprim/sulfamethoxazole for 6 months. Results One year after infection resolution, stimulation of the patient's blood monocytes with Nocardia antigens revealed defective production of tumor necrosis factor-alpha, interleukin (IL)-6 and IL-17. Conclusion We provide preliminary evidence for a link between defective innate immune responses and predisposition for Nocardia infections. Further studies must be conducted in order to fully investigate this mechanism of infection acquisition.