Artikel
Serum (1→3)-β-D-Glucan measurement for the diagnosis of Pneumocystis jirovecii pneumonia and its usefulness for monitoring treatment efficiency
Serum (1→3)-β-D-Glucan Bestimmung zur Diagnose der Pneumocystis jirovecii Pneumonie und ihre Eignung zur Therapiekontrolle
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Autoren
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J. Held
- University of Freiburg, Institute of Medical Microbiology and Hygiene, Freiburg, Germany
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M.-S. Koch
- University of Freiburg, Institute of Medical Microbiology and Hygiene, Freiburg, Germany
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D. Wagner
- University of Freiburg, Center for Infectious Diseases and Travel Medicine, Freiburg, Germany
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A. Serr
- University of Freiburg, Institute of Medical Microbiology and Hygiene, Freiburg, Germany
| Veröffentlicht: | 2. Juni 2010 |
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Gliederung
Text
Pneumocystis jirovecii pneumonia (PJP) is a major cause of illness and death in immunocompromised individuals. Therefore early detection and therapy is vital in reducing mortality. After initiation of treatment the patient's condition should start to improve after at least 7 days. Otherwise resistance has to be assumed and therapy should be changed to second line drugs. Until now, reliable serological parameters for diagnosis and monitoring of treatment efficiency have been lacking.
(1→3)-β-D-Glucan (BG) is a cell wall component of P. jirovecii. During the course of an infection, BG is released into the serum. Emerging data from the past few years have pointed to serum BG measurement as a promising new tool for the diagnosis of PJP. We therefore conducted a retrospective study on 50 patients with PJP and 50 control patients to address the question of the diagnostic performance of serum BG measurement with a special emphasis on the capabilities of the BG assay to follow the patient's clinical course and identify treatment failure.
Results: 49 out of 50 patients in the PJP-group tested positive for BG at the time of diagnosis using a cut-off value of 80 pg/ml. Median BG concentration in the PJP-group was 823 pg/ml. Altogether, the sensitivity of the BG-assay in the diagnosis of PJP was 98%, specificity was 91.5%, NPV was 99.8% and PPV was 54.4%. Interestingly, 94% of patients already had elevated BG levels at an average of 5 days before diagnosis was confirmed by detection of P. jirovecii in BAL fluid.
From 10 patients, consecutive sera were available to compare BG levels and the clinical course of the disease. In 4 out of 5 patients with mild PJP, good response to treatment was reflected by a prompt and steady decrease in BG levels. Correlation in severe or fatal cases was not as satisfactory, probably due to confounding factors such as comorbidities or medical complications. In one patient with initially good response to treatment and decreasing BG levels, Pneumocystis therapy had to be changed because of adverse effects. The change was followed by a radiological and microbiological relapse and at the same time BG levels increased more than 7 fold indicating treatment failure.
In summary, serum BG measurement is a reliable indicator for PJP and could be used as an early diagnostic test for patients at risk. Furthermore our results suggest that BG levels reflect the clinical course of the disease and might be capable of identifying treatment failures.
