Phelps D S, Rose R M
Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Am Rev Respir Dis. 1991 May;143(5 Pt 1):1072-5. doi: 10.1164/ajrccm/143.5_Pt_1.1072.
Respiratory infection with Pneumocystis carinii (PC) is the most frequent serious opportunistic infection in the clinical setting of acquired immunodeficiency syndrome (AIDS). The factors responsible for the predisposition of human immunodeficiency virus (HIV)-infected patients for PC infection are not fully understood. We postulated that changes in the alveolar lining material (ALM) could play a role in the pathogenesis of PC infection in AIDS. We have compared constituents of ALM in bronchoalveolar lavage fluid from normal, nonsmoking volunteers with that of HIV-infected patients with pneumonia. Using an ELISA, we found that surfactant protein A (SP-A) was markedly elevated in the pneumonia patients. Mean SP-A values for the normal nonsmoking individuals (n = 21) were 1.50 +/- 0.25 micrograms/ml (mean +/- SEM). SP-A levels in the HIV-infected patients (n = 22) were significantly elevated (p less than 0.01) with a mean of 5.23 +/- 0.54 micrograms/ml. This increase was greatest in the patients with more clinically severe pneumonia. The increase in SP-A did not appear to be pathogen-specific as it was also observed in cases of non-PC pneumonia. We also found that total protein levels were nearly five times higher in the HIV-infected pneumonia patients. These studies indicate that the protein component of the ALM is markedly different from normal in cases of HIV-associated PC and non-PC infection. Further investigation is needed to determine the mechanism of these alterations and their role, if any, in AIDS-related pneumonia.
卡氏肺孢子虫（PC）引起的呼吸道感染是获得性免疫缺陷综合征（AIDS）临床环境中最常见的严重机会性感染。人类免疫缺陷病毒（HIV）感染患者易发生PC感染的因素尚未完全明确。我们推测肺泡内衬物质（ALM）的变化可能在AIDS患者PC感染的发病机制中起作用。我们比较了正常、不吸烟志愿者支气管肺泡灌洗 fluid中ALM的成分与HIV感染肺炎患者的成分。使用酶联免疫吸附测定（ELISA），我们发现肺炎患者中表面活性蛋白A（SP-A）明显升高。正常不吸烟个体（n = 21）的平均SP-A值为1.50 +/- 0.25微克/毫升（平均值 +/- 标准误）。HIV感染患者（n = 22）的SP-A水平显著升高（p < 0.01），平均为5.23 +/- 0.54微克/毫升。这种升高在临床症状更严重的肺炎患者中最为明显。SP-A的升高似乎不是病原体特异性的，因为在非PC肺炎病例中也观察到了这种情况。我们还发现HIV感染的肺炎患者总蛋白水平几乎高出五倍。这些研究表明，在HIV相关的PC感染和非PC感染病例中，ALM的蛋白质成分与正常情况明显不同。需要进一步研究以确定这些改变的机制及其在AIDS相关肺炎中的作用（如果有的话）。
