Airborne fungal fragments and allergenicity.

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1: _Med Mycol._ (javascript:AL_get(this, 'jour', 'Med Mycol.') 2006

Sep;44 Suppl:245-55. _Related Articles,_

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Airborne fungal fragments and allergenicity.

_Green BJ_

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term= " Green+BJ " [Author]) , _Tovey ER_

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=

" Tovey+ER " [Author]) , _Sercombe JK_

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term= " Sercombe+JK " [Author]) ,

_Blachere FM_

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term= " Blachere+FM " [Author]) , _Beezhold DH_

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstr

act & term= " Beezhold+DH " [Author]) , _Schmechel D_

(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term= " Schmechel+D "

[Author]) .

Allergy and Clinical Immunology Branch, Health Effects Laboratory Division,

National Institute for Occupational Safety and Health, Centers for Disease

Control and Prevention, town, West Virginia, USA.

Exposure to fungi, particularly in water damaged indoor environments, has

been thought to exacerbate a number of adverse health effects, ranging from

subjective symptoms such as fatigue, cognitive difficulties or memory loss to

more definable diseases such as allergy, asthma and hypersensitivity

pneumonitis. Understanding the role of fungal exposure in these environments

has been

limited by methodological difficulties in enumerating and identifying various

fungal components in environmental samples. Consequently, data on personal

exposure and sensitization to fungal allergens are mainly based on the

assessment of a few select and easily identifiable species. The contribution of

other

airborne spores, hyphae and fungal fragments to exposure and allergic

sensitization are poorly characterized. There is increased interest in the role

of

aerosolized fungal fragments following reports that the combination of hyphal

fragments and spore counts improved the association with asthma severity.

These fragments are particles derived from any intracellular or extracellular

fungal structure and are categorized as either submicron particles or larger

fungal fragments. In vitro studies have shown that submicron particles of

several fungal species are aerosolized in much higher concentrations (300-500

times) than spores, and that respiratory deposition models suggest that such

fragments of Stachybotrys chartarum may be deposited in 230-250 fold higher

numbers than spores. The practical implications of these models are yet to be

clarified for human exposure assessments and clinical disease. We have developed

innovative immunodetection techniques to determine the extent to which larger

fungal fragments, including hyphae and fractured conidia, function as

aeroallergen sources. These techniques were based on the Halogen Immunoassay

(HIA), an immunostaining technique that detects antigens associated with

individual airborne particles >1 microm, with human serum immunoglobulin E

(IgE). Our

studies demonstrated that the numbers of total airborne hyphae were often

significantly higher in concentration than conidia of individual allergenic

genera. Approximately 25% of all hyphal fragments expressed detectable allergen

and the resultant localization of IgE immunostaining was heterogeneous among

the hyphae. Furthermore, conidia of ten genera that were previously

uncharacterized could be identified as sources of allergens. These findings

highlight

the contribution of larger fungal fragments as aeroallergen sources and

present a new paradigm of fungal exposure. Direct evidence of the associations

between fungal fragments and building-related disease is lacking and in order

to

gain a better understanding, it will be necessary to develop diagnostic

reagents and detection methods, particularly for submicron particles. Assays

using

monoclonal antibodies enable the measurement of individual antigens but

interpretation can be confounded by cross-reactivity between fungal species.

The

recent development of species-specific monoclonal antibodies, used in

combination with a fluorescent-confocal HIA technique should, for the first

time,

enable the speciation of morphologically indiscernible fungal fragments. The

application of this novel method will help to characterize the contribution of

fungal fragments to adverse health effects due to fungi and provide

patient-specific exposure and sensitization profiles.

PMID: 17050446 [PubMed - in process]