Cladosporium Spores May Protect Against Allergies in Children

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Cladosporium Spores May Protect Against Allergies in Children

MedPage Today - Little Falls,NJ

By Jeff Minerd, MedPage Today Staff Writer

Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University

of Pennsylvania School of Medicine.

June 16, 2006

http://www.medpagetoday.com/AllergyImmunology/Allergy/tb/3562

Be aware that this study suggests the type of mold found in the home

may be a more important factor than absolute spore counts in why

some children develop allergies.

Review

CINCINNATI, June 16 — When it comes to inducing allergies in young

children, not all types of airborne fungal spores are created equal,

researchers here have found.

Some types of fungi, such as Apergillus, appear to sensitize

children to a wide variety of allergens, while another type,

Cladosporium, seemed to protect against allergic sensitization, said

Tiina Reponen, Ph.D., of the University of Cincinnati.

In some children, exposure to Cladosporium spores was associated

with a 40% reduction in the odds for testing positive to any

allergen on a skin prick test, Dr. Reponen and colleagues said

online in Pediatric Allergy and Immunology.

The researchers collected fungal spores from the homes of 144

infants enrolled in the Cincinnati Childhood Allergy and Air

Pollution Study (CCAAPS) during 2003 and 2004. Children in this

study had at least one parent with a positive skin prick test. The

researchers identified and counted the spores via microscopy. The

children, all between the ages of one and three, received a clinical

exam and a skin prick test for 17 allergens.

Analysis of the relationship between fungi types found in the home

and rhinitis symptoms or a positive skin prick test in the children

yielded the following results:

Basidiospores were significantly associated with rhinitis symptoms,

regardless of skin prick test results (odds ratio not given; P<.01).

Ganoderma was also associated with rhinitis symptoms, although the

trend was not statistically significant (OR not given; P<.10).

Penecillium, Aspergillus, and Alternaria spores were significantly

associated with a positive skin prick test for any allergen (ORs not

given; P<.01 for all).

Cladosporium, however, was inversely associated with a positive skin

prick test for any allergen (OR not given; P<.05). Further analysis

showed that if the mother was sensitized to Cladosporium, exposure

to this fungus reduced the odds of a positive skin prick test for

any allergen in her children (OR=0.6; 95% CI=0.4 to 0.9).

That last finding was surprising, especially since Cladosporium has

been linked to allergic sensitization in adults, the researchers

said. However, this fungus could have an entirely different effect

on a child's developing immune system, they added. Cladosporium

exposure might inhibit a developing immune system's Th2 cell

response, thereby decreasing the likelihood of allergic reactions,

they speculated.

" To our knowledge, this study is the first one to report an inverse

association between fungal exposure and health outcome (rhinitis and

allergic sensitization) in infants, " the researchers said.

The study found no association between total concentration of fungal

spores in the home and rhinitis or positive skin prick test.

" We believe that contrasting relationships among the various fungal

genera to the health outcomes investigated in this study might

actually cancel the effect that total concentration may have on

these outcomes, " the researchers said. " This finding would help to

explain some of the lack of association in the reporting of health

effects and total fungal spore concentrations observed in previous

studies. "

However, the indoor environment is a complicated one where

allergens, pollutants, and toxins mix and have the potential for

synergistic relationships, which were not examined in the current

study, the investigators noted.

" Based on the data presented in this paper, it appears that

clinicians and researchers should be attentive to the composition of

the fungal spore profile and the respective concentrations of the

fungal genera present rather than total or culturable spore count

alone, " the researchers concluded.

They pointed out that as the study was conducted in an infant

population the health outcomes may or may not be transient.

" Long-term follow-up of this cohort will show how early fungal

exposure affects the development of allergy and asthma in children

later in life, " they wrote