Identification of Phagocytosed Pneumocystis Carinii In Human Pulmonary Alveolar Macrophages

Examination of Papanicolaou-stained bronchoalveolar lavage samples from cases with Pneumocystis carinii pneumonitis under ultra-violet light reveals alveolar macrophages packed with fluorescent inclusions. Immunoenzymatic staining of the alveolar macrophages with a monoclonal antibody specific for P. carinii (3F6) showed that these inclusions contain intact pneumocysts or their degradation products. Fluorescence microscopy of Papanicolaou-stained smears is advocated as a sensitive and specific method of diagnosing P. carinii infection.     

尼古丁在诱导的肺泡巨噬细胞自噬及肺炎中的作用

目的:探讨尼古丁在诱导的小鼠肺泡巨噬细胞自噬及肺炎发生中的作用。方法:通过碘化丙啶(PI)/Hochest33258染色法检测尼古丁诱导巨噬细胞MH-S死亡;通过Western印迹和电子透射显微镜检测尼古丁诱导MH-S细胞自噬的发生;采用中性红摄取实验检测尼古丁处理后巨噬细胞的吞噬能力;通过攻毒实验检测尼古丁诱导的肺炎。结果:不同浓度尼古丁作用下PI染色的死细胞呈上升趋势;LC3BⅡ蛋白表达具有尼古丁剂量依赖性,并且1μmol/L的尼古丁能够增强LPS预刺激的MH-S细胞自噬发生。电子透射显微镜结果显示在1μmol/L尼古丁的作用下,细胞内自噬体数量增加;MH-S的中性红摄取能力与尼古丁浓度剂量呈负相关性;尼古丁能够诱导小鼠发生肺炎,并降低小鼠体重。结论:尼古丁能够增强肺泡巨噬细胞的自噬水平,并且可以诱导肺炎的发生,有助于进一步研究吸烟与肺炎的关系。     

Influence of Pneumocystis carinii on Nitrite Production by Rat Alveolar Macrophages1

ABSTRACT Nitrite production by rat alveolar macrophages was studied to determine the role of L-arginine oxidation in the interaction between these cells and Pneumocystis carinii. Alveolar macrophages from rats obtained from two different breeders were used: rats from Janvier breeder had latent P. carinii infection, while those from Charles River breeder were bred in a germ-free environment. Pneumocystis carinii increased in vitro nitrite generation by unstimulated alveolar macrophages from Janvier rats only, and this was blocked by N^G-monomethyl-L-arginine. Incubation of cells from Janvier and Charles River rats with lipopolysaccharide and/or interferon-gamma increased nitrite production to a similar extent. Pneumocystis carinii partially decreased nitrite release by activated alveolar macrophages, and this was still inhibited by N^G-monomethyl-L-arginine. In the presence of P. carinii, superoxide dismutase used as a superoxide anion scavenger had no effect on nitrite production by activated cells. These results show that prior exposure to P. carinii leads to nitric oxide production by rat alveolar macrophages. Although the magnitude of this production seems to be moderate, it is of biological significance since cells of P. curinii-naive rats do not generate nitrite whereas those of latently infected rats do.     

Pneumocystis Carinii Pneumonia in Children

From a retrospective study at the University of California, San Francisco, Medical Center, it is evident that pneumocystic carinii pneumonia is being seen more frequently as a secondary complication to the use of immunosuppressive drugs. This disease presents with nonspecific respiratory symptoms, therefore a high degree of suspicion and knowledge of the population at risk are necessary for an early diagnosis. Except for x-ray films of the chest, physical and laboratory studies are of minimal diagnostic value. In a patient with compromised immune defenses and respiratory distress, bilateral diffuse reticular infiltrates seen on a film of the chest are highly suggestive of pneumocystis carinii pneumonia. The diagnosis should be confirmed histologically because a variety of pathogens can cause these findings and each requires a specific treatment. At our institution, open thoracotomy is the method of choice for obtaining a lung biopsy specimen. Pentamidine isothionate is moderately effective against this usually fatal disease, but its effectiveness depends on beginning treatment early in the illness.