The primary objective is to assess the concentration of Blomia tropicalis allergenic extract that induces a wheal of size equivalent to that produced by a 10 mg/mL histamine dihydrochloride solution, in order to be used as in-house reference preparation (IHRP).
The trial will consist of a single visit, in which the following procedures will be carried out: * Demographic data (age, race, and gender). * Clinical history. * Inclusion/exclusion criteria. * Physical examination (cardiovascular, pulmonary, neurobiological, gastrointestinal, dermatological, other body systems and height, weight). * Pregnancy test. * Performance of prick-tests (3 concentrations of of Blomia tropicalis extract, positive control, and negative control). * Collection of blood sample (10 mL) from the patient to create a pool of sera for in vitro standardization of the allergen extract. Each serum sample will be labeled with the subject's number and frozen. These serum samples will remain in the freezer until the study concludes. Once the study is complete, they will be transported to the sponsor's facilities, where all sera will be pooled. This serum pool will be used for additional in vitro tests necessary to standardize and characterize the extract and produce its corresponding In-House Reference Product (IHRP), as indicated by the Spanish Pharmacopeia and the European Pharmacopeia. Additionally, it will be used in the necessary in vitro analyses for the standardization of new batches of the allergenic extract. After the serum pool is formed, the tubes containing the original serum samples are destroyed. \- Assessment of adverse events during the 72 hours following skin testing.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
30
In each subject, a drop of each of the 3 concentrations of the allergenic extract, in addition to the positive control (histamine) and the negative control, will be applied. The application will be duplicated on the subject's anterior forearm, with a distance of approximately 4 cm between each application to avoid overlapping reactions and false-positives results.
Hospital Universitario de Canarias
San Cristóbal de La Laguna, Santa Cruz De Tenerife, Spain
Size of the induced papule on the skin
Size of the induced papule on the skin when applying each of the concentrations of the allergenic extracts and the positive (histamine) and negative controls, using the prick test.
Time frame: 15 minutes
Adverse reactions
The secondary outcome is to assess the safety and tolerability of Blomia tropicalis extract. Mild side reactions such as pruritus, erythema, local oedema may occur during the diagnostic skin test by prick test. There is a risk, albeit rare and exceptional, of systemic reactions, sometimes severe (urticaria, asthma, anaphylactic shock) (28) (urticaria, asthma, anaphylactic shock, etc.).
Time frame: 30 minutes
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