De Castro N, Pavie J, Lagrange-Xélot M, Molina J M
Service de Maladies Infectieuses et Tropicales, AP-HP, Hôpital Saint-Louis, Paris, France.
Rev Mal Respir. 2007 Jun;24(6):741-50. doi: 10.1016/s0761-8425(07)91148-1.
Although the use of prophylactic medication has reduced the incidence of Pneumocystis jiroveci pneumonia (PCP), it still occurs in cancer patients and is associated with a high morbidity and mortality.
Patients with haematological malignancies are at high risk for PCP because of chemotherapy and steroid-induced immunosuppression. Despite highly active prophylactic regimens, most cases occur in patients who are not receiving any prophylactic treatment even though the risk factors are well described. PCR techniques have been used for PCP diagnosis but these highly sensitive methods may not be able to discriminate between airway colonisation and infection.
Prophylaxis should be widely recommended for patients receiving prolonged steroid therapy or other immunosuppressive drugs. A low CD4+-T cell count (less than 200/microl) may be a useful marker to identify high risk patients who should not discontinue prophylaxis.
Because PCP is very severe in cancer patients, higher risk patients must be identified and long-term prophylaxis should be maintained as long as immunosuppression persists.
尽管预防性用药已降低了耶氏肺孢子菌肺炎（PCP）的发病率，但在癌症患者中仍有发生，且与高发病率和死亡率相关。
血液系统恶性肿瘤患者因化疗和类固醇诱导的免疫抑制而处于PCP的高风险中。尽管有高度有效的预防方案，但大多数病例发生在未接受任何预防性治疗的患者中，即使风险因素已被充分描述。聚合酶链反应（PCR）技术已用于PCP诊断，但这些高灵敏度方法可能无法区分气道定植和感染。
对于接受长期类固醇治疗或其他免疫抑制药物的患者，应广泛推荐预防措施。低CD4 + T细胞计数（低于200/微升）可能是识别不应停止预防的高风险患者的有用标志物。
由于PCP在癌症患者中非常严重，必须识别出高风险患者，并在免疫抑制持续存在期间维持长期预防。
