Respiratory allergy to the indoor ant (Monomorium pharaonis) not related to sting allergy.
BACKGROUND
Many studies are available on systemic reactions to ant sting, but few have described the direct role of ants in respiratory allergy. The nonstinging house ant, Monomorium pharaonis (pharaoh ant), is a highly infesting species in indoor environments.


OBJECTIVE
To determine whether the pharaoh ant is an indoor source of aeroallergens.


METHODS
Two patients with asthma who lived in homes with ant infestation were enrolled. Pharaoh ants were collected at the patients' homes, and crude extracts were prepared. Skin prick tests with ant extracts were performed. Specific IgE to pharaoh ant was measured by enzyme-linked immunosorbent assay (ELISA), and the allergenic components were determined by using immunoblot analysis. Cross-reactivity among pharaoh ant, imported fire ant, Pachycondyla chinensis ant, and other indoor allergens was evaluated by ELISA inhibition tests. Specific bronchial challenge testing was performed using pharaoh ant extracts.


RESULTS
Both patients had positive skin test reactions to pharaoh ant extract and high levels of specific IgE antibodies to pharaoh ant. The ELISA inhibition test results demonstrated significant inhibition by pharaoh ant; however, P. chinensis, cockroach, and house dust mite showed no inhibition of the IgE binding to pharaoh ant. Two important IgE-binding components, 9.4 and 34 kDa, were identified by using immunoblot analysis. Pharaoh ant bronchial challenge test results showed typical early asthmatic reactions in 1 patient and dual asthmatic reactions in the other patient.


CONCLUSIONS
Ants can induce IgE-mediated bronchoconstriction regardless of sting in sensitized patients. Ants should be taken into consideration as a cause of respiratory allergy in patients living in homes with visual evidence of infestation.
Kim
Cheol-Woo
CW
Department of Internal Medicine, Inha University College of Medicine, Incheon, Korea.
Choi
Soo-Young
SY
Park
Jung-Won
JW
Hong
Chein-Soo
CS
D016902:Air Pollution, Indoor; D000485:Allergens / Q000276:immunology; D000818:Animals; D001000:Ants / Q000276:immunology*; D001985:Bronchial Provocation Tests; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood; D007299:Insect Bites and Stings; D008875:Middle Aged; D012130:Respiratory Hypersensitivity / Q000097:blood / Q000209:etiology* / Q000276:immunology; D012882:Skin Tests
D000485:Allergens; D007073:Immunoglobulin E