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Update on Antigen Detection Paul E. Verweij, MD Nijmegen University Center for Infectious Diseases s Eukaryotic cell 2005;4:1308-16.

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Presentation on theme: "Update on Antigen Detection Paul E. Verweij, MD Nijmegen University Center for Infectious Diseases s Eukaryotic cell 2005;4:1308-16."— Presentation transcript:

1 Update on Antigen Detection Paul E. Verweij, MD Nijmegen University Center for Infectious Diseases s Eukaryotic cell 2005;4:

2 Background Sandwich ELISA Detects galactofuranosyl antigen Detection limit 1 ng/ml Early marker of invasive aspergillosis Variable performance reported

3 Factors affecting performance Combining surrogate markers Clinical evaluation 1 2 3

4 Bifidobacteria Cross reacting lipoglycans in Gram positive cell wall Lipoglycans containing a -1,5- galactofuranosyl chain JCM 2005;43:

5 Bifidobacteria: reactivity with GM-ELISA JCM 2005;43:

6 Measured in faeces neonates 200 – 36,320 Reactivity in faeces JCM 2005;43:

7 GM and –lactam agents (31 batches analysed) JCM 2005;43: May 2003 – November

8 GM and –lactam agents: impact on patient management No IA 24 Possible IA 11 probable IA 0 before after No IA 0 Possible IA 24 probable IA 11 Antifungal therapy AMX based therapy 5/13 PTZ18/22 JCM 2005;43:

9 J Infect Dis 2004;190:641-9 AML, MDS Receiving antifungal prophylaxis Effect of exposure to mould- active antifungals 1

10 Comparative release of surrogate markers in vitro PCR Mennink et al, submitted 2

11 GM and BG ITZVCZ

12 JCM 2005;43: GM and PCR Gm positive samples

13 Clinical evaluation of diagnostic procedures: CT vs GM Patients: allo HSCT (65), autol HSCT (30), chemotherapy (66) Prophylaxis: fluconazole 161 episodes in 107 patients Weekly CT scan, twice weekly GM CT: major sign (halo, cresent, cavity) minor sign (all other infiltrates) GM: 0.5 in 2 consecutive samples CID 2005;41:

14 No infiltrates minormajorGM+ No IA (109) Possible (32) Probl/prov (20) CT scan CID 2005;41: PTZ

15 Factors associated with positive GM CID 2005;41: …the decision to administer mould-active treatment should be based on detection of new pulmonary infiltrates on CT performed early during infection, rather than on results of EIA for detection of GM….

16 CID 2005;41: CT+CT- IA+812 IA-0109 GM+GM- IA+164 IA-2089 CT GM Sensitivity: 40% Specificity:100% Sensitivity: 80% Specificity:81% Performance

17 CID 2005;41:

18 Pre-emptive strategy 88 hematology patients (136 episodes, 4170 samples) Febrile neutropenia group (117 episodes) -> 9 were treated with AmBisome 41 episodes qualified for empiric therapy reduction in use antifungals: 35% to 7.7% 10 non-febrile episodes of febrile episodes with alternative explanation received antifungal therapy CID 2005;41:

19 Pre-emptive strategy Breakthrough fungal infections: C. glabrata fungemias (blood culture) – 2 cases Disseminated zygomycoses – 1 case CID 2005;41:

20 Conclusions Increased insight in factors that are important for the performance of GM detection Studies should focus on comparison of markers and on management strategies that incorporate surrogate markers Differences in performance remains an important problem


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