A method to detect opioid allergies
Cristina G. Pedraz/ DICYT Allergens and antigens are substances that produce allergies or any hypersensitivity reaction in people who have previously been in contact and are susceptible to them. Patients with allergies to plant products like pollen, nuts and fruits are very common; but, until recently, nobody had thought of hypersensitivity to other biological products: drugs such as cannabis, cocaine and heroin. This issue was set out in 2008 by a research team in the Hospital Río Hortega in Valladolid, Spain, which has delved into this new line of work for the last five years obtaining significant results.
As we were reported by allergist Alicia Armentia, who, in 2012, presented this breakthrough in a scientific session in the Palacio de los Vivero (Real Academia de Medicina y Cirugía de Valladolid). As DiCYT was told, before this study started in 2008, drugs have been considered a product triggering various toxic effects, “nothing related to immune-based hypersensivity”.
Working hand in hand with researchers from the Department of Toxicology of the Hospital Río Hortega, the Asociación Ciudadana de Ayuda a la Drogodependencia (Aclad), an association for aid to drug dependence, the Universidad de País Vasco and the Department for Allergies, the team has develop a project sponsored by the Junta de Castilla y León, a local governance body, in order to determine whether drug abusers “have antibodies to drugs, that is, if they have toxic problems and also produce measurable antibodies”.
The research team designed a series of experiments and worked with two groups of patients: (a) people with allergies presenting at the Hospital, “because this group is the most likely to be sensitive to animal, vegetable or any kind of product; and (b) drug-dependent patients who volunteered for the study.
“We found samples of the drugs that could be affecting the patients; cannabis is the most consumed, but cocaine and heroin are also used. Authorization was granted to us in order to research on cannabis and cocaine; regarding heroin, we are handling its source: opium seeds, since allergenic proteins are most important over toxic elements; seeds contain the entire proteome, that is, every protein producing the plant”, Dr. Armentia states.
A Simple and Inexpensive Method
Thanks to the trials using the samples on the two groups, researchers have been able to design and patent “a simple and inexpensive method to discover antibodies to opioids”. This is of major importance since opioids are very used in medicine as anesthetics in surgeries and as analgesics. “In some cases, they are not widely used because of the severe allergic reactions they produce. With the method we have designed, based on simple technology: an immunoassay, we are able to detect antibodies to opioids, cannabis and cocaine.”
This means we are overcoming limitations in current techniques, that only allow to measure these drugs when recently consumed, “whereas if a person gets sensitized to drugs, antibodies can be measured for many years, and we would be able to know if that patient has been in contact with those drugs, which has legal and forensic consequences, as well as being useful to alert patients at risk who are to undergo surgery in order to change the anesthetic, an application we are currently using”, she underlines.
At the present times, the project is progressing and researchers have improved a new technique based on proteomics, “an allergen molecular analysis technique used to determine not only the source of the allergy, but the specific epitope, the smallest portion of an allergen that may trigger the immune reaction”. Furthermore, researchers have applied for the European patent and they expect it to be exportable to the United States.
The main goal is to consider drugs, other than toxic agents, “substances able to produce immune reactions as, for example, wasp venom, a toxic substance able to kill an allergic person”. Thanks to this technique, “we will be able to prevent such severe adverse reactions”. There is a Spanish patent; a month ago, they applied for the European patent that can be used in all EU countries and, possibly, in the United States.
A Problem on the Increase
Even when the Encuesta Nacional de Drogas (Domestic Drug Survey) shows a drop in consumption levels, the number of related-emergency patients increases. Regarding cannabis, “these admissions have multiplied ten-fold for the last years”; whereas in cocaine, “they have increased from 20 to 70%”. “We realized these figures cannot be justified by a mere toxic reaction, there had to be a more severe response increasing the number of patients”, as we were told by Dr. Armentia. She also stated that urban and smoker younger people are increasingly suffering from allergies, because “they get more sensitized to allergens, and drugs are considered allergens”.