Molecular diagnosis of Pneumocystis jirovecii in patients with malignancy: Clinical significance of quantitative polymerase chain reaction

摘要

Pneumocystis jirovecii pneumonia (PJP) is increasingly seen in association with the use of new and potent immunosuppressive therapies in populations not infected with human immunodeficiency virus. Today, molecularmethods are widely used to improve diagnostic yield; however, the relationship between clinical findings and quantitative polymerase chain reaction (qPCR) results is undefined. Our objective was to describe characteristics of PJP in patients with malignancies and determine if qPCR results were correlated with clinical findings. From 2007 to 2012, all patients at the Peter MacCallum Cancer Centre with positive Pneumocystis PCR were identified from a microbiology database. Clinical, radiological, and microbiological records were reviewed. PJP was defined as the presence of positive PCR for Pneumocystis on a respiratory specimen, radiological abnormalities consistent with a pneumonic process, and receipt of targeted PJP treatment. qPCR was performed on all diagnostic specimens, and values were reported according to clinical findings. Forty-five patients fulfilled inclusion criteria: 44.4% had underlying solid organ tumors and 55.6% had hematological malignancies. Nonsmall cell lung carcinoma and lymphoma were the most frequent predispositions. Shortness of breath, cough, and fever were reported in 64.4%, 48.9%, and 42.2% of the patients, respectively. Admission to the intensive care unit and mortality rates were lower than in previous reports. Overall, a relationship between other clinical features and qPCR results was not identified. In the era of routine molecular diagnostics, patients with malignancy and PJP have improved outcomes. However, there was no demonstrable relationship between qPCR results and clinical features or PCR data and outcomes.