Sensitization to the storage mite Tyrophagus putrescentiae in urban population of Upper Silesia (Poland)

Abstract

Exposure to indoor allergens, especially dust mites has been recognized as a risk factor for sensitization and allergy symptoms that in extreme conditions could develop into asthma. To determine specific antigens responsible for allergy in patients positive for mite allergy skin tests whole protein extracts from the cultured mite species Tyrophagus putrescentiae [TP], and from their excrements were obtained. The proteins were fractionated by SDS PAGE and identified by Western blot. The patient antibodies against particular antigens were identified in serum IgE fraction using anti-human anti-IgE monoclonal antibody. Western blot analysis revealed differences in reactivity of sera from patients positive for standard mite allergy skin tests with fractionated mite antigens. A total of 17 of 30 sera (56.7%) from patients positive to skin tests showed specific cross reactivity with antigens isolated from extracts of TP. The results revealed that 12 out of 30 tested sera (40.0%) reacted specifically with new antigens identified as protein fractions of extracts from excrements of TP. When assessing mite allergen reaction using mixture of mite proteins the results of the test are not satisfactory for determining the antigen causing patient allergy. The results obtained from studies reported here indicate significant discrepancy between the so called standard allergy skin test and what the patient is actually sensitive to. Also, a new class of immunizing protein of about 25 kDa has been identified in excrements from TP reacting with IgE from patients showing allergy to other mite extracts. A total of 4 of 30 sera (approx. 13.3%) from patients positive to skin tests showed specific cross reactivity with antigens isolated from mite excrements rather than from mite whole extracts.