Published: February 28, 2007
Reviewed by Robert Jasmer, MD; Associate Clinical
Professor of Medicine, University of California, San Francisco
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SAN DIEGO, Feb. 28 -- Allergic fungal sinusitis deserves a
place of its own at the table of nasty chronic rhinosinusitis infections,
researchers asserted here.
It may account for up to 10% of chronic rhinosinusitis, said Patricia S.
Hutcheson, of Saint Louis University Medical School, at a briefing during the
American Academy of Allergy, Asthma, & Immunology meeting here.
Action Points
· Explain to patients who ask that some researchers suspect
fungi as the source of a large proportion of chronic sinus infections. This study
suggests that allergic fungal sinusitis may be an entity distinct from chronic
rhinosinusitis.
· This study was published as an abstract and presented as a
poster and orally in a briefing at a conference. These data and conclusions
should be considered to be preliminary as they have not yet been reviewed and
published in a peer-reviewed publication.
"Allergic
fungal sinusitis appears to be a separate and distinct form of chronic
rhinosinusitis," she said.
Clinically,
patients with allergic fungal sinusitis look pretty much the same as those with
chronic rhinosinusitis of non-fungal origin, but the serology tells a different
story, said Raymond G. Slavin, M.D., director of the division of allergy &
immunology, at Saint Louis University, who headed the research team.
The question
is, however, what can be done about it?
"With
allergic fungal sinusitis, certainly the most successful treatment has been
long term prednisone," Dr. Slavin said. "There is great controversy
about antifungal treatment of chronic rhinosinusitis, and as a matter of fact
there is now an ongoing multicenter double-blind placebo study on intranasal
amphotericin B, and there's also one in the offing on oral itraconazole
[Sporanox] for chronic rhinosinusitis, following the Mayo Clinic proposition
that the vast majority are due to fungi."
In a study of
84 patients with chronic rhinosinusitis and nasal polyps who underwent
nasosinus surgery, the authors found that the patients with fungal infection
had total immunglobulin E (IgE), specific immunoglobulin G (IgG) anti-
Alternaria
mold antibody, and specific IgE against seven different fungi were
significantly elevated compared with patients with chronic rhinosinusitis. Also
IgE appears to play an important role in the pathogenesis of the fungal
infections.
The
investigators came to their conclusions after recovering exudates from the
patients, culturing them and examining them by histology for the presence of
eosinophils, Charcot-Leyden crystals (breakdown products of eosinophils), and
for fungal elements, such as hyphae.
They also
looked for serum total IgE and IgG anti-
Alternaria antibodies, and
looked for evidence of six additional fungal species including
Aspergillus,
Bipolaris, Curvularia, Epicoccum, Fusarium and
Phoma.
They found
that the exudates from 66 patients had high numbers of eosinophils, visible
fungal hyphae, or were culture positive, and these patients were designated as
having allergic fungal sinustitis. An additional 18 patients were labeled as
having standard (non-fungal) chronic rhinosinusitis.
Both the serum
total IgE and specific IgG anti-
Alternaria were statistically
significantly elevated in the allergic fungal compared to the chronic
rhinosinusitis group. The total mean IgE was 1,080 IU/ml (range, 28-12,230
IU/ml) for patients with fungal infections, compared with 324 IU/ml (range
8.8-1081 IU/ml) for those without evidence of fungal infection.
The mean
specific IgG-anti-
Alternaria 40.6 mg/l (range 0-182 mg/l) for those with
allergic fungal sinusitis, and 8.2 mg/l (range 2-37.7 mg/l) for those with
chronic sinusitis.
Among the 15
patients who were tested for the presence of all seven fungi, immunoblotting
tests for IgE anti-fungi showed multiple bands to all fungi in nine of 10
patients with allergic fungal infections, compared with none of five patients
with chronic rhinosinusitis. The number of positive bands for each fungus was
significantly higher among patients with allergic fungal sinusitis compared
with those with chronic rhinosinusitis.
"A
significant and distinct immune response was observed in allergic fungal
sinusitis subjects that was different from that seen in chronic rhinosinusitis
subjects," Hutcheson said. "The antibody responses reflect our view
that IgE antibodies do indeed play an important role in the differences seen in
allergic fungal sinusitis subjects, and this distinguishes them from chronic
rhinosinusitis subjects."
"IgG is
also increased in these subjects, probably due to a heightened general
inflammatory resposnse," she continued. "Interestingly, the one
chronic rhinosinusitis patient in whom IgE reactivity was seen against all
seven fungi had twice the specific IgG-anti-
Alternatira level of any
other chronic rhinosinusitis subject."
http://www.medpagetoday.com/MeetingCoverage/AAAAIMeeting/tb/5135
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