Nasal IL-13 production identifies patients with late-phase allergic responses.

BACKGROUND: There is limited knowledge on how local cytokine secretion patterns after nasal allergen challenge correlate with clinical symptoms especially with regard to the "late allergic response," which occurs in approximately 40% to 50% of patients with allergy. OBJECTIVE: We sought to characterize the immunologic and clinical nasal responses to birch pollen allergen challenge with a special focus on the late allergic response. METHODS: In this randomized, double-blind, placebo-controlled trial, birch pollen-allergic participants were challenged with birch pollen extract (n = 20) or placebo (n = 10) on 3 consecutive days. On days 1 and 3, nasal secretions were collected at selected time points over a 24-hour time course for the measurement of 33 inflammatory mediators. Clinical responses were determined through subjective symptom scores and objective nasal airflow measurements. RESULTS: Provoked participants had significantly greater clinical responses and showed significant increases in tryptase and the soluble IL-33 receptor serum stimulation 2 (sST2) in nasal secretions within minutes compared with the placebo group. Eight of 20 provoked participants displayed high IL-13 levels 2 to 8 hours after allergen provocation. This group also showed significant changes in clinical parameters, with a secondary drop in nasal airflow measured by peak nasal inspiratory flow and increased symptoms of nasal obstruction, which significantly differed from IL-13 nonresponders after 6 hours. CONCLUSIONS: IL-13 response status correlates with clinical responses and type 2 cytokine responses in the late phase after allergen provocation.

Optimisation of grass pollen nasal allergen challenge for assessment of clinical and immunological outcomes.

Nasal allergen challenge can be used to assess the clinical and immunological aspects of rhinitis due to inhalant allergens. We aimed to develop a reproducible technique for grass pollen nasal allergen challenge and to study biomarkers within nasal secretions. 20 Grass pollen allergic individuals underwent nasal challenges with purified Timothy grass allergen. An initial dose-titration challenge was used to determine dose-response characteristics. Subsequently, volunteers underwent 3 further challenges using individualised threshold doses. Symptom scores, visual analogue scores, and peak nasal inspiratory flow (PNIF) were recorded at baseline and up to 6h after challenge. Nasal secretions were collected at each time point using synthetic filter papers or absorptive polyurethane sponges and analysed for IL-4, -5, -10, -13, IFN-γ, Tryptase and Eosinophil Cationic Protein (ECP). Challenges gave reproducible symptom scores and decreased PNIF. Tryptase levels in nasal fluid peaked at 5 min after challenge and returned to baseline levels at 1h. ECP, IL-5, IL-13 and IL-4 levels were increased from 2-3 h and showed progressive increases to 5-6 h. Sponges proved the superior nasal fluid sampling technique. We have developed a reproducible nasal allergen challenge technique. This may be used as a surrogate clinical endpoint in trials assessing the efficacy of treatments for allergic rhinitis. Tryptase in local nasal secretions is a potential biomarker of the early phase response; ECP and the Th2 cytokines IL-5, -13 and -4 markers of late phase allergic responses. Our model allows correlation between clinical responses and local biomarkers following nasal allergen challenge.

The safety and side effects of monoclonal antibodies.

Monoclonal antibodies (mAbs) are now established as targeted therapies for malignancies, transplant rejection, autoimmune and infectious diseases, as well as a range of new indications. However, administration of mAbs carries the risk of immune reactions such as acute anaphylaxis, serum sickness and the generation of antibodies. In addition, there are numerous adverse effects of mAbs that are related to their specific targets, including infections and cancer, autoimmune disease, and organ-specific adverse events such as cardiotoxicity. In March 2006, a life-threatening cytokine release syndrome occurred during a first-in-human study with TGN1412 (a CD28-specific superagonist mAb), resulting in a range of recommendations to improve the safety of initial human clinical studies with mAbs. Here, we review some of the adverse effects encountered with mAb therapies, and discuss advances in preclinical testing and antibody technology aimed at minimizing the risk of these events.