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Exaggerated reaction

An innovative diagnostic kit monitors the evolution of respiratory allergy

NegreirosThe very tiny dust mites present in domestic dust are responsible for more than 80% of the cases of patients who possess a respiratory allergy, mainly asthma and allergic rhinitis. Two proteins, the Der p 1 and the Der p 2, present in these arachnoids called Dermatophagoides pteronyssinus, related to spiders and to ticks, are points to by specialists as the main culprits responsible for the action of the organism’s defense cells and that bring about inflammation of the nose, throat and lungs. One of the treatments in use to combat respiratory allergy is immunotherapy with allergens, substances that bring about an allergy reaction in some people and are used in growing concentrations until they reach the maintenance dose in vaccines. “Currently the specialists who treat their patients with this type of immunotherapy follow as a parameter an improvement in their patients’ clinical symptoms” says professor Ernesto Akio Taketomi, from the Allergy and Clinical Immunology Laboratory of the Federal University of Uberlandia (UFU), in the state of Minas Gerais, the coordinator of the research that resulted in the development of a series of innovative tests for the diagnosing of an allergy and the monitoring of patients under treatment. This means that all of the stages of the allergy’s manifestation can be minutely followed up  via laboratory evaluation.

Through this new technique, with a simple blood exam it is possible to detect if specific antibodies induced by the proteins of the same species of dust mite belong mainly to group 1, the Der p 1, or to group 2, the Der p 2. Treatment carried out today does not take into consideration whether or not the patient is allergic to the protein of group 1 or 2 of this dust mite. “We’re treating different patients equally” says the researcher.

The method is also capable of pointing out the phase at which the illness finds itself, by way of the detection of the level of three antibodies, specific to these proteins, the IgE, a class of antibodies that indicate the manifestation of the allergy, the IgG1 and the IgG4, two other classes of antibodies brought about in defense and that are produced by the organism naturally or induced during the treatment period. At the start of the illness, when the allergy symptoms manifest themselves intensely, elevated IgE antibodies and low IgG1 and IgG4 exist. During treatment, if the patient clinically responds well, this relationship should be inverted. Evaluations using kits allow the doctor, by way of blood examinations, to accompany, in detail, the patient’s response to treatment.

Sensitive and specific
The system used to detect the antibodies produced by the organism, specific to the dust mite proteins, is the reverse reverse immunoenzymatic   assay, or reverse Elisa,  a methodology that makes use of monoclonal antibodies, molecules produced in the laboratory  and that react specifically to the protein of the dust mite. “In comparison with the conventional methodology, it’s more sensitive and specific” says  Taketomi.

The research that resulted in the diagnostic kit began back in 1999. During June of 2001, the research the State of Minas Gerais Research Foundation (Fapemig), which funded the project, registered a patent referring to the IgE antibody detection technique. Afterwards two studies were done to evaluate the efficiency of the proposed method. In one of them 47 patients selected from the Clinical Allergy Sector of the Hospital das Clinicas of the Federal University of Uberlandia participated.

The results pointed out that 27 individuals, corresponding to 57.5% of the patients, presented antibodies for the proteins of Groups 1 and 2. While the 42.5% remaining, only 3 patients (6.4%) responded to the Group 1 protein and 4 patients (8.5%) to Group2 protein and 13 patients (27.5%) didn’t respond to either of the proteins. The study was published in the Spanish  Journal of Investigational Allergology and Clinical Immunology, in April of this year. The other study was carried out with 73 patients from the town of Itumbiara, in the state of Goiás, by the pediatrician Meimei Queirós during her master’s degree dissertation defended in 2005, supervised by professor Taketomi. The results were similar to those found in Uberlandia.

The expectation is that the diagnostic kit will be distributed to clinical analysis laboratories starting from next year. The initial estimate is of 20 units of each one of the nine different kits for the evaluation of the type of specific antibodies for the dust mite proteins, totaling a monthly production of 180 groups of kits. As each unit can be used to carry out 40 tests, with the monthly production forecast it will be possible to realize 7,200 exams. The production and sale of the kits will be done through the company named Laboratório de Investigação em Alergia (Alergolab), founded by Taketomi and installed at the Entrepreneurial Activities Incubation Center of the Mineira university.