Diagnosis of Alternaria alternata sensitization with natural and recombinant Alt a 1 allergens

J Allergy Clin Immunol. 2005 Jun;115(6):1210-7. doi: 10.1016/j.jaci.2005.02.012.


Background: Diagnosis of Alternaria alternata sensitization is hampered by the variability and complexity of fungal extracts, and thus simplification of the diagnostic procedures with purified allergens should be pursued.

Objective: We sought to compare A alternata extract and purified natural Alt a 1 (nAlt a 1) and recombinant Alt a 1 (rAlt a 1) allergens for their diagnostic value.

Methods: Forty-two patients allergic to A alternata , 10 atopic patients with negative skin prick test responses to A alternata extract, and 10 healthy subjects were investigated. Skin prick tests and determination of specific IgE levels were performed with nAlt a 1 and 2 different types of rAlt a 1: rbAlt a 1, expressed in Escherichia coli , and ryAlt a 1, expressed in the yeast Yarrowia lipolytica .

Results: Prevalence for Alt a 1, Alt a 2, and Alt a 11 by IgE dot-blot testing was 98%, 0%, and 15%, respectively, and therefore Alt a 1 was used as a marker for A alternata sensitization. Immunoblotting and inhibition analysis showed no IgE-binding differences between nAlt a 1 and rAlt a 1. The whole group of patients with allergy to A alternata had positive skin test reactions to purified allergens at 100 microg/mL, whereas no false-positive reactions were detected. Natural or ryAlt a 1 elicited a similar response in skin tests compared with A alternata extract, although a reduced reactivity was observed with rbAlt a 1. Specific IgE levels to nAlt a 1 or rAlt a 1 showed significant correlation and similar sensitivity and specificity.

Conclusions: Alt a 1, either in its natural or recombinant form, is sufficient for a reliable diagnosis of A alternata sensitization and induces skin prick reactivity comparable with that produced by A alternata extract.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Allergens / biosynthesis
  • Allergens / immunology*
  • Alternaria / immunology*
  • Antibodies, Fungal / blood
  • Antibody Specificity
  • Antigens, Plant
  • Child
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Female
  • Fungal Proteins / biosynthesis
  • Fungal Proteins / immunology*
  • Humans
  • Hypersensitivity / diagnosis*
  • Hypersensitivity / etiology*
  • Hypersensitivity / immunology
  • Immunization
  • Immunoglobulin E / blood
  • Male
  • Recombinant Proteins / biosynthesis
  • Skin Tests
  • Yarrowia / metabolism


  • ALTA1 protein, Alternaria alternata
  • Allergens
  • Antibodies, Fungal
  • Antigens, Plant
  • Fungal Proteins
  • Recombinant Proteins
  • Immunoglobulin E