Efficacy of subcutaneous immunotherapy achieved with a whole-body extract of Pseudomyrmex ant. A case reported in a young woman, in Argentina

The aim of this work is to report for the first time a patient case with anaphylaxis by Pseudomyrmex acanthobius /favidulus ant sting, prepare an extract with the wholeant-body, to study their biochemical and immunological properties and to validate the efficacy of the subcutaneous immunotherapy with this non-commercial extract. An argentine woman patient, 19 years old, with background of allergic rhinitis and bronchial asthma in the childhood, suffered repeated episodes of anaphylaxis by non-identified insect’s stings and previous immunotherapies treatment. The entomologic analysis revealed that the aggressor insect was an ant belonging to Pseudomyrmex genera and acanthobius or favidulus species. High serum total levels of IgE (202 UI/ml) were measured by ELISA and a positive 6-mm wheal and flare reaction (extract dilution 1/100000) was revealed by in vivo intradermal test. A sample of the extract proteins fraction was analysed by SDS-PAGE. The silver stained protein bands ranged since 20 to 220 kDa. The patient serum immune-recognized allergenic extract proteins at approximately 160, 90, and a double band at 42/46 kDa prior to desensitization treatment by electro-blotting. Interestingly, post-specific-subcutaneous-immunotherapy the mentioned double band almost disappeared. After a 6-years-treatment, the total IgE serum values strongly decreased and the specific intradermal test was negative up to 1/10 extract dilution. The tolerance to the treatment was good. Altogether, our findings revealed that the immunotherapy performed with the whole-body-Pseudomyrmex ant allergenic extract was highly effective and the IgE specific-double protein allergenic extract bands (42/46 kDa) that disappeared after immunotherapy were responsible for the anaphylactic shock.