Measurement of Defense Ability of Human Pulmonary Alveolar Macrophage Against Candida albicans

Abstract

Pulmonary alveolar macrophage (PAM) is thought to play an initial and major role in pulmonary fungal infection, but the researchers are still in the dark as to its precise mechanism. The purpose of this study was to establish a new method to assay the defense ability of PAM against Candida albicans. Bronchoalveolar lavage was performed in 27 patients (8 males and 19 females: normal control 14, sarcoidosis 4, aspergilloma 2, malignant neoplasm 6, immotile cilia syndrome 1) to harvest PAMs. These were then incubated with C. albicans (IFM 40009) and autologous serum. The PAM/C. albicans ratio, and concentration of serum were changed to determine the optimal incubating condition. After thirty minutes of incubation, the number of phagocytized C. albicans, phagocytizing PAM, etc. were counted under a microscope. Then, three hours later, PAMs were destroyed and C. albicans was implanted on Sabouraud medium. Colony forming units were counted twenty-four hours later to measure killing ability. The optimal condition was determined to be as follows: PAM 2.5×106 cells/ml, C. albicans 2.5×107 cells/ml, and serum concentration 10%. Under this condition, the phagocytosis was slightly increased in sarcoidosis patients and aspergilloma patients, while killing ability was decreased in malignant neoplasm patients (mainly lung cancer). We believe that the pulmonary defense ability of the host against fungi can be estimated by this method. This method may help to clarify the reason fungal infection so easily develops in some particular patients. © 1990, The Japanese Society for Medical Mycology. All rights reserved.