654. Diagnostic Yield of S-Adenosylmethionine and 1-->3 β-D-Glucan Serum Levels and Correlation with Clinical Parameters in Non-HIV+ Immunocompromised Patients with Pneumocystis Pneumonia
Session: Abstracts: Mycology
Friday, October 22, 2010
Background: Measurement of serum S-adenosylmethionine (S-AdoMet) and (1→3) β-D-glucan (β-D-glucan) were recently (re-)introduced as highly sensitive diagnostic tests for Pneumocystis jirovecii pneumonia (PcP) in patients with HIV. This study aimed to assess the clinical utility of these markers for the diagnosis of PcP and their correlation with clinical parameters in immunocompromised patients without HIV infection.

Methods: Measurement of serum β-D-glucan and S-Adomet was performed in a prospective study. HIV-negative, immunocompromised patients suspected of having PcP - on the basis of clinical signs, symptoms and chest imaging - were included. The diagnosis was confirmed or rejected by results of direct microscopy and/or real time PCR on broncho-alveolar lavage (BAL) fluid. Serum samples were collected at the time of enrollment and at 2 or more time points during follow-up. Both β-D-glucan and S-Adomet were assessed for diagnostic accuracy and correlation with other parameters (arterial pO2, LDH, PCR cycle treshhold value, chest imaging characteristics and outcome).

Results: In thirty-one patients enrolled (20 were PcP positive, 11 were PcP negative), S-AdoMet serum levels did not discriminate between patients with- and without PcP at various cut-offs. Serum levels of β-D-glucan were significantly higher in PcP-positive patients (p=0.001). Receiver operating curves showed that β-D-glucan was a reliable indicator (AUC 0.897 SE 0.07, p=0.001) with a sensitivity and specitivity of 0.91 and 0.89 respectively at the cut-off level of 60 pg/mL. In patients with PcP, β-D-glucan serum levels decreased after start of treatment (p=0.028). S-AdoMet levels were not linked with the studied clinical characteristics but β-D-glucan serum levels inversely correlated with the PCR cycle treshhold value in BAL fluid in PcP-positive patients.

Conclusion: The β-D-glucan serum test - despite its panfungal nature – within the clinical context was diagnostic for PcP. In addition it may serve as marker for pulmonary PcP load and treatment monitoring. In contrast, serum S-AdoMet levels yielded insufficient accuracy for the diagnosis of PcP in non-HIV+ immunocompromised patients at risk for PcP.


Subject Category: M. Mycology including clinical and basic studies of fungal infections

Speakers:
Mark G.J. de Boer, M.D. , Dept. of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
Luc B.S. Gelinck, M.D., PhD , Dept. of Infectious Diseases and Medical Microbiology, Erasmus University Medical Center, Rotterdam, Netherlands
Bertrand D. van Zelst , Dept. of Pharmacy and Medical Toxicology, Erasmus University Medical Center, Rotterdam, Netherlands
Wendy W.J. van de Sande, PhD , Dept. of Infectious Diseases and Medical Microbiology, Erasmus University Medical Center, Rotterdam, Netherlands
Robert de Jonge, PhD , Dept. of Pharmacy and Medical Toxicology, Erasmus University Medical Center, Rotterdam, Netherlands
Frank P. Kroon, M.D., PhD , Dept. of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands

Disclosures:

M. G. J. de Boer, None

L. B. S. Gelinck, None

B. D. van Zelst, None

W. W. J. van de Sande, None

R. de Jonge, None

F. P. Kroon, None

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