Quantitation of IgE binding to the chitinase and chitinase-like house dust mite allergens Der p 15 and Der p 18 compared to the major and mid-range allergens.
BACKGROUND
The prevalence of IgE binding to the group 15 and 18 house dust mite (HDM) allergens of the Dermatophagoides species is reported to be >50% and they are the major allergens of HDM-sensitised dogs. The objective was to quantitate the IgE titres to Der p 15 and Der p 18 and evaluate their importance in human HDM sensitisation compared to the known major and mid-tier allergens.


METHODS
Der p 15 and Der p 18 were produced in Pichia pastoris, and their structure validated by circular dichroism. IgE binding was measured in 37 Australian HDM-allergic adults using a quantitative DELFIA™ assay.


RESULTS
The prevalence of IgE titres to Der p 15 and Der p 18 >0.1 ng/ml was low (38%) and only one subject had a titre >10 ng/ml to either allergen. The mean anti-Der p 15 and Der p 18 titres were 1.2 and 2.6 ng/ml, respectively, i.e. approximately 10- to 20-fold lower than the response to the major Der p 1 and Der p 2 allergens (p < 0.001). The IgE responses to Der p 15 and Der p 18 were lower than the mid-tier allergens Der p 5 and Der p 7 and although they correlated with each other, they did not correlate with titres to either the major or mid-tier allergens.


CONCLUSIONS
Sensitisation to Der p 15 and Der p 18 makes a minor contribution to anti-HDM IgE titres, and the titres do not correlate with the size of the response to the major allergens.
Telethon Institute for Child Health Research and Centre for Child Health Research, University of Western Australia, Subiaco, W.A., Australia. belinda@ichr.uwa.edu.au
Belinda J
BJ
Hales
Claire E
CE
Elliot
Lee Ying
LY
Chai
Leigh J
LJ
Pearce
Thitinun
T
Tipayanon
Lee
L
Hazell
Shane
S
Stone
Surapon
S
Piboonpocanun
Wayne R
WR
Thomas
Wendy-Anne
WA
Smith
D000328:Adult; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology*; D060829:Arthropod Proteins / Q000276:immunology*; D001315:Australia; D002688:Chitinases / Q000276:immunology*; D004285:Dogs; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology* / Q000662:veterinary; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010843:Pichia / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D039981:Pyroglyphidae / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology*
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; C514374:Der p 15 allergen, Dermatophagoides pteronyssinus; C514375:Der p 18 allergen, Dermatophagoides pteronyssinus; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D002688:Chitinases