Trial With Allergic Rhinitis Patients Taking GSK256066 Versus Placebo In A Pollen Challenge Chamber

Inclusion Criteria: * The subject is healthy. * They are aged 18 to 50 years inclusive. * Body mass index less than 29.0 kg/m² with weight range of 55.0kg (females 50kg) to 95.0kg inclusive. * They have a history of seasonal allergic rhinitis * They exhibit a moderate response to 1500 grass pollen grains/m3 after 2h in the Vienna Challenge Chamber, * They have a positive skin prick test for grass pollen at or within the 12 months preceding the screening visit. * They have a positive RAST for grass pollen at or within the 12 months preceding the screening visit. * They are current non-smokers who have not used any tobacco products in the 6 months preceding the screening visit * They must have a baseline FEV1\>80% predicted and a baseline FEV1 (maximum recorded value)/ FVC (associated value)\>70% predicted. Exclusion Criteria: * Pregnant or nursing females. * Women of childbearing potential who are unwilling or unable to use an appropriate method of contraception. * any structural nasal abnormalities or nasal polyposis, a history of frequent nosebleeds, recent nasal surgery or recent (within 2 weeks) or ongoing upper respiratory tract infection. * The subject is likely to be unable to abstain from salbutamol use for 8 hours before a challenge * The subject has a history of drug or other allergy * The subject is concurrently participating in another clinical study in the past 3 months * A supine blood pressure that is persistently higher than 140/90 millimetres of mercury (mmHg) at screening * A supine mean heart rate outside the range 40-90 beats per minute (bpm) at screening. * The subject has donated a unit of blood within the previous 3 months.