Conditions: Allergic Rhinitis
Keywords: Basophils Mast Cells IgE IgE receptors omalizumab
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 18
Healthy volunteers: no

Brief summary:
This research is being done to study the effects of the drug omalizumab (Xolair) in people with cat allergies. The investigators will use omalizumab to study changes in the cells in the nose, skin and blood that cause allergies. The investigators predict that cells in the blood will be effected before cells in the nose or skin.

Detailed description:
Omalizumab is a monoclonal antibody directed against Immunoglobulin E (IgE) and is FDA-approved for use in allergic asthma, though its clinical role is not precisely defined. It binds IgE on the same site of the Fc domain as the high affinity IgE receptor (FcεRI), and therefore, blocks the interaction between IgE and mast cells or basophils. It, therefore, may be used as a mechanistic tool in the study of IgE. As IgE levels are reduced with omalizumab, FcεRI expression on human basophils is reduced. This reduction of basophil receptors and allergen induced activation is pronounced within 7 days of the initial administration and is reversible once omalizumab administration is discontinued. The omalizumab-induced reductions in mast cell FcεRI expression and function is unchanged at day 7 and significantly reduced by day 70. These changes were based upon intravenously administered omalizumab at a dose of 0.03 mg/kg/IU IgE/mL in a total of three subjects. We propose to exploit the kinetics of faster omalizumab effects on circulating basophils relative to tissue mast cells to elucidate the role of the basophil versus mast cell activation in nasal airway allergen challenge, which has not been studied to date.

Arms:
arm 1: This active are will receive treatment with omalizumab subcutaneously at the dose currently FDA-approved for the treatment of allergic asthma. There is a weight and IgE based dosing table in the and subjects receive therapy by subcutaneous injection every 2 or 4 weeks. The lower range of dosing is 150 mg q 4weeks ( one injection) with the upper range 375 mg every 2 weeks ( three injections).

The dosing is based on IgE levels and IGE and is given by subcutaneous injection every 2 to 4 weeks arm 2: This placebo arm will receive identical treatment with placebo injections subcutaneously at the dose currently FDA-approved for the treatment of allergic asthma. There is a weight and IgE based dosing table in the and subjects receive therapy by subcutaneous injection every 2 or 4 weeks. The lower range of dosing is 150 mg q 4weeks ( one injection) with the upper range 375 mg every 2 weeks ( three injections).

The dosing is based on IgE levels and IGE and is given by subcutaneous injection every 2 to 4 weeks.

Interventions: intervention 1: omalizumab intervention 2: placebo
Intervention descriptions: intervention 1: Dosing is based on IgE level and weight given every 2 or 4 weeks intervention 2: Dosing is based on IgE level and weight given every 2 or 4 weeks

Protocol document: