Published Online: January 21, 2015
Up to 500 million people worldwide suffer from allergic rhinoconjunctivitis, commonly known as hay fever. One therapy option is allergen-specific immunotherapy, also known as desensitization, either applied as “allergy shots” or in form of tablets. For a long time, allergists have hoped for a tool that could predict the success of the immunotherapy during the treatment phase, thus identifying in advance whether the therapy will improve the patient’s health and whether the patient will respond positively to the therapy. To date, however, the effectiveness of desensitization is predominantly judged by the severity of the symptoms during the pollen season. In clinical studies, the conjunctival provocation test (CPT) is another method physicians often use to assess the success of the immunotherapy. The patient, who has previously undergone allergen-specific immunotherapy, receives a single drop of a saline solution containing the patient’s individual symptom-causing allergen in the eye. If the patient’s eye turns extremely red and is accompanied by strong itching, the doctor may conclude that desensitization has not been successful and the patient will still suffer from allergy symptoms during the next pollen season.
In an article recently published in The Journal of Allergy and Clinical Immunology: In Practice, Kruse et al. sought to prove that the severity of allergic rhinoconjunctivitis symptoms during the pollen season could be predicted using conjunctival provocation.
The authors conducted two studies – one study with patients sensitized to grass pollen and one with patients sensitized to birch pollen – in which they used CPT to assess the effectiveness of a three-month course of sublingual tablet immunotherapy.
After completing the therapy, patients were divided into two groups: One group consisted of patients who did not show any reaction in the CPT at the end of the treatment, indicating that the desensitization had been successful. The other group consisted of patients who still reacted to the CPT, suggesting the desensitization had not been successful. During the following pollen season, the patients recorded their symptoms and their use of rescue medication on diary cards. The results confirmed the study hypothesis.
Patients in both studies who did not show a positive reaction in the last CPT had fewer symptoms, used significantly less rescue medication, such as antihistamines, and had more well-days (as opposed to sick days) during the following pollen season compared to those patients who still had a conjunctival reaction at the end of treatment.
Based on these results, the authors conclude that there is a correlation between conjunctival provocation before and the symptoms during the next pollen season. Consequently, the severity of allergic symptoms after sublingual tablet immunotherapy can be predicted using the CPT. This tool can become important in routine clinical practice because the effectiveness of desensitization therapy can be estimated prior to the pollen season and the therapy regimen for the approaching pollen season may be adapted accordingly. CPT is also appealing to patients and doctors because it is easy to apply and takes only a few minutes. Furthermore, using the CPT may possibly reveal the necessity for further immunotherapy, although further studies will be necessary to confirm this.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.