Aspergillosis

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Aspergillosis Other Filamentous Fungi
Shortcomings of the Old Solutions in the New
Edition! Thomas F. Patterson, MDProfessor
of MedicineDirector, San Antonio Center for
Medical Mycology The University of Texas Health
Science Centerat San Antonio
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Consensus Definitions (the Old set)
Aspergillosis Filamentous Fungi

• Combination of host factors, mycological findings
  clinical criteria
• Mycological criteria
• Definite histopathological evidence (with
  culture for genera claim) fungemia (not
  Aspergillus or Penicillium other than P.
  marneffei)
• Probable sputum culture or BAL samples positive
  for mould antigen testing (galactomannanoriginal
  higher cutoff, 2 serum samples, BAL or CSF)
• Possible new infiltrates with host criteria
  (fever)
• NB CT findings without mycology (Possible) not
  ?-D-glucan or PCR

Ascioglu et al Clin Infect Dis 2002377-14
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Consensus Definitions (the Old set)
Aspergillosis Filamentous Fungi

• Controversial features
• Mycology required for proven or probable
  diagnosiseven with specific radiological
  findings (halo, air-crescent sign, cavity)
• Host factor persistent fever included as a host
  factor rather than as a clinical criteria
• Included patients with non-specific ( likely
  non-fungal!) syndromes as possible invasive
  moulds
• Host factor risk groups with higher rates of
  invasive moulds required same clinical
  microbiological criteria as lower risk
• Clinical criteria includes non-specific
  radiographic signs non-specific symptoms
  signs
• Missed substantial cases
• Early diagnosis CT halo
• Autopsy series (Chamilos, ICAAC 2005, M-720)

MOULD spelled MOLD!! ?
Ascioglu et al Clin Infect Dis 2002377-14
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Voriconazole in Invasive Aspergillosis Global
Comparative Study

• Satisfactory (Complete/Partial Responses CR/PR)
  responses at week 12
• Difference 21.2
• Improved survival with voriconazole
• Importance of early therapy
• Limited role for rescue therapy
• Largest randomized trial of invasive
  aspergillosis
• Utilized modified EORTC/MSG criteria (published
  Nov 01)
• Study conducted July 97-Oct 01

Note OLATother licensed antifungal therapy
Herbrecht R et al NEJM 2002347408-15 Patterson
TF et al, Clin Infect Dis 2005411448-52.
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Global Comparative Aspergillosis Study
(307/602)Diagnostic Criteria Modifications from
Consensus Criteria
Did modifications make a difference?

• Host group positive BAL elevated case to proven
  in high risk (allogeneic HSCT/neutropenia)
• Allo HSCT/neutropenia Specific CT findings
  support probable diagnosis
• Lung transplant required tissue diagnosis
• Antigen tests (galactomannan, PCR, or ?-D-Glucan)
  not included in diagnostic criteria
• Diagnostic inclusion criteria reviewed by blinded
  Data Review Committee with specified criteria

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Global Comparative Aspergillosis Study (307/602)
Patient Disposition
392Entered
Voriconazole
Amphotericin B
3
8
No Treatment
196
185
SAFETY ITT MITT Per Protocol
IncorrectRandomization
2
0
194
185
No DEF/PROBper Blinded DRC
50
52
144
133
DRC assessedother exclusions
13
22
131
111
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Patients with Satisfactory Treatment
ResponseCategorized by Baseline CT Findings
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23
21
21
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Herbrecht R et al NEJM 2002347408-15 Patterson
TF et al, Clin Infect Dis 2005411448-52 Greene
R et al. ECCMID 2003
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Detection of GM in the Diagnosis Management of
Invasive Aspergillosis

• Utility of GM at baseline
• Patients with EORTC/MSG confirmed IA
• 60/144 (41.7) positive (O.D. 0.5)
• Limited number of samples
• Utility of GM in serial samples
• Poor correlation between baseline level
  response
• Trend to decreased response and higher antigen
  titers after 5 days

Herbrecht R et al, Advances Against
Aspergillosis, 2004
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Diagnosis of Invasive Aspergillosis Filamentous
Moulds
Have We Made Progress??
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Consensus Definitions Aspergillus Filamentous
Fungi

• Criteria must be
• Reproducible
• Feasible to perform
• Controversial criteria
• Consensus opinion regarding utility
• Data from prior definitions still useful

de Pauw Patterson Clin Infect Dis
200541S377-80
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Non-Culture Based Diagnosis of Invasive
Aspergillosis

• Galactomannan
• Sandwich ELISA (Platelia)
• PCR
• TaqMan, LightCycler PCR
• 18s ribosomal DNA
• Multi-copy or single target genes
• b-D-glucan
• Amebocyte Limulus lysate
• Chromogenic (Fungitell)
• Kinetic (Wako)

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Screening for Invasive Aspergillosis using
Aspergillus Platelia EIA

• Maertens et al (2001)
• Sensitivity 89 Specificity 98
• Serial testing needed for optimal results
• Herbrecht et al (2002) Marr et al (2004)
• Limited sensitivity (43-70) Better specificity
  (70-93)
• Lower cut-off on empirical antifungals or
  prophylaxis
• Original criteria Pos (Index 1.0-1.5) on 2
  consecutive samples
• US Pos (0.5) on repeat testing (same sample)
• EU Pos (0.5-0.7) dynamic endpoint (Maertens,
  2005)
• False-positive results (Verweij, 1998)
• Weakly positive samples Cross-reactivity
• Laboratory contamination Dietary
• Piperazillin/Tazobactam (Viscoli, 2003 Sulahian,
  2003)

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Impact of modified ELISA cutoff values in adult
non-allogeneic transplants
Herbrecht et al. J Clin Oncol 2002201998
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Utility of Galactomannan Detection in BAL Samples
GM detection in CT-based BAL fluid has a high
PPV for diagnosing invasive pulmonary
aspergillosis early in untreated patients
Becker et al. Br J Haematol 2003 121 448
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Factors Affecting Galactomannan Performance
Positive galactomannan in Serum/BAL/CSF Accepted
Mycological Criteria

• Presence of antibodies
• Storage / preparation
• Epidemiological factors
• Patient population
• Prevalence of infection/disease
• Sampling strategy
• Definitions (positive result cut-off, positive
  patient)

• Biological factors
• Site of infection
• Aspergillus species
• Microenvironment (nutrients, pH, etc)
• Molecule structure of released antigen
• Underlying condition / immune suppression
• Exposure to antifungals
• Renal clearance, hepatic metabolism

Mennink-Kersten MA, et al, Lancet Infect Dis
20044349-57
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Utility of ?-Glucan Detection in Invasive Fungal
Infection

• 30 candidemic pts/30 controls
• Cut-off gt60 pg/ml
• 283 pts AML/MDS (twice weekly samples)
• Sensitivity 20/20 IFI pts at least one positive
• Specificity 90
• Organisms detected Candida, Aspergillus,
  Trichosporon, Fusarium
• 163 pt IFI/170 controls (single samples)
• Sensitivity 70
• Specificity 87

Obadasi Z et al. Clin Infect Dis 200439199-205
Ostrosky-Zeichner L et al. Clin Infect Dis
200541654-9
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Which test most useful?
Positive ?-D-glucan in Serum Accepted Mycological
Criteria

• Kawazu (2004)
• 96 pts (11 proven/prob IA) GM vs PCR vs
  ?-glucan
• GM more sensitive than PCR (100 vs 55)
• Earlier detection with GM at 0.6 cutoff (median
  10 days sooner)
• Pazos (2005)
• 40 pts (9 proven/prob IA) GM vs ?-glucan
• Identical sensitivity (87.5), specificity
  (89.6)
• ?-glucan positive earlier
• Combination improved specificity (100)

Kawazu et al, J Clin Micro 2004422733-41 Pazos
et al, J Clin Micro 200543299-305
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PCR for Invasive Moulds
PCR not (yet) accepted for mycological criteria

• Variable sensitivity / specificity
• Limited per test positivity
• Technical false positives/negatives
• Lack of standardized targets/reagents
• Not externally validated

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Consensus Definitions (New set) Aspergillus
Filamentous Fungi

• Proven invasive mould
• Histopathology culture (for genera level
  confirmation)
• Probable invasive mould
• 1 host 1 microbiological 1 clinical
• Positive galactomannan or ?-D-glucan
• Positive sputum or BAL culture
• Possible
• 1 host 1 microbiological OR 1 clinical
• Higher level of confirmation in new set
• More specific signs / symptoms
• CT halo, air-crescent, cavity
• New infiltrate specific pulmonary
• Pleural rub pleural pain hemoptysis

de Pauw Patterson Clin Infect Dis
200541S377-80
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Consensus Definitions Aspergillus Filamentous
Fungi

• Consideration for modification of criteria to
  include possible cases of invasive moulds to
  meet study case criteria
• Not majority of cases
• Results biologically plausible and consistent
  with microbiologically defined cases
• Validation of criteria
• Detection of invasive moulds
• Limit inclusion of patients without invasive
  moulds

de Pauw Patterson Clin Infect Dis
200541S377-80
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