Pulmonary aspergillus fumigatus Flashcards
what is the most important opportunistic mould pathogen of Immuno-compromised humans
aspergillus fumigatus
who are particularly vulnerable
people with haematological malignancy and allogeneic bone marrow transplant
how many cases of invasive pulmonary aspergillosis
> 200,000 cases worldwide per year
mortality rate of invasive pulmonary aspergillosis
30-95%
chronic pulmonary aspergillosis
3 million cases worldwide in patients with underlying lung diseases
allergic bronchopulmonary aspergillosis
4 million cases worldwide in patients with asthma and cystic fibrosis
aspergilloma
a clump of mold which exists in a body cavity such as a paranasal sinus or an organ such as the lung.
immunity against aspergilloma
- inactive candida are inhaled
- candida lodge in lower respiratory tract
- condida swell
MACROPHAGES (block the candida from germinating to hyphae)
NEUTROPHILS block hype from invading tissue and inviting blood vessels where they can disseminate
macrophages
block swelled candida from germinating to a hyphae
neutrophil
stop hyphae from invading tissue
if you are immunocompromised (have few macrophages and neutrophils)..
candida will be able to turn into hyphae, invade blood vessels and disseminate into the blood
diagnosing IPA
no single ‘gold standad’
what does diagnosis rely on
data from clinical, radiological, serological (GM and B-D gluten), molecular, histopathological and microbiological sources
diagnosis should conform to what writer for probable or proven detection of IPI
EORTC/MSG
what is important
that diagnosis is made without delay
serological detection of aspergillus fumigatus
serum shows elevated antibodies against A.fumigatus surface components
elevated antibody tigers shown to be due to the presence of abundnant
galactomannoprotein in the cell walls of the apthogen
which abundant galactomannoprotein is found in the cell walls of the A.fumigatus, that antibodies mount a response against
Afmp1p
Afmp1p can be detected using
western blotting
diagnosis using ELISA
recombinant Afmp1p protein used to coat wells of microsite plate
- sera taken from patients with aspergilloma, from patients with Invasive aspergillosis and patients with infections caused by other pathogenic fungi
- EISa highly specific for A.fumigatus
structure of the fungal cell wall
B-(1,6)- glucan on the outside and B-(1,3)- glucan makes up chitin (fungal cell wall)
- Phospholipid bilayer with ergosterol
- mannans and galactans
traditional immunological test for IPA centred around
detection of circulating fungal cell wall - galactomannan
what used to detect galactomannkn (GM)
rat mAb EB-A2 (DAS-ELISA)
specificity of GM assay
> 85%
negatives of GM assay
high false positives
reasons for GM assay false positive
cross-reactivity of EB-A2 with GM from other species
cross reactivity of mAb with galacotoxylomanna from cryptococcus neoformans
detection of GM in B-lactam antibiotics derived from penicillin species
GM found in food products e.g. baby formulas
cross-reactivity of mAb with anti-cancer drug cyclophosphamide
which other species have GM
Fusarium
anti cancer drug
cyclophosphamide
antibitoic
b-lactam
GM common in
baby milk formulas- crosses the gut into blood stream
another method of detection
pan-fungal detection
pan fungal diagnostic detects
(1-3)- B-D- glucans
(1-3)- B-D- glucans
glucose polymer
(1-3)- B-D- glucans is found in
most fungi, some bacteria, higher plants
(1-3)- B-D- glucans is up to
60% dry weight of fungal cell wall
(1-3)- B-D- gluons forms the basis of the commerical
Fungitell test
(1-3)- B-D- gluons - pan fungal diagnostics has a
high rate of false positives
Mouse mAb JF5 is what type of immunoglobulin
IgG3
Mouse mAb JF5 recognises
extracellular, constitutive, glycoprotein antigen
antigen detected by Mouse mAb JF5 is secreted during
active growth of hyphae and is not produce by dead or quiescent spores
Mouse mAb JF5 displays superior
specificity to mAb EB-A2 (Glucomannoproteins)
EB-A2 is used in
Bio-Rad Platelia GM-ELISA
Mouse mAb JF5 has been used to develop a
rapid, user-friendly, diagnostic test (lateral flow device) for detection of IPA
Immunofluorescence localises
JF5 antigens to actively growing hyphae
immunogold EM can be used to visualise
JF5 antigens released from growing hyphae (little dots around the structure)
Mouse mAb JF5 can differentiate between
A.fumigatus and S.apiospermum
