Evidence of an increased prevalence of rhinitis in patients with asthma, and asthma in patients with rhinitis, supports the 1 airway concept. However, there are basic differences between the upper and lower airways, such as the virtual absence of remodeling in the nose compared with the bronchi, despite the presence of similar inflammation. Etiologic factors in chronic rhinosinusitis (CRS) attract increasing interest. Peripheral blood monocytes from patients with CRS release IL-4, IL-13, and IFN-γ on stimulation with fungal antigens, especially those from Alternaria. This is not seen with cells from normal controls. However, a double-blind trial of intranasal amphotericin in CRS was negative. Evidence continues to accumulate of the pivotal role of regulatory T-lymphocytes secretion of IL-10 in the response to allergen immunotherapy. In patients with asthma and house dust mite allergy who are receiving appropriate pharmacotherapy and have instituted environmental controls, house dust mite immunotherapy provides marginal additional benefits in asthma control. Immunotherapy with cat dander extract at a maintenance dose containing 15 μg Fel d 1 produces a more consistent immunologic response than with maintenance doses containing 3.0 μg, whereas doses containing only 0.6 μg are no more effective than placebo. Sublingual immunotherapy for seasonal grass allergy can be safely administered by general practitioners, but symptom relief begins only in the second season of therapy. Sublingual immunotherapy for seasonal grass allergy in children reduced symptoms and onset of new asthma symptoms but, again, beginning only in the second year of treatment. A course of 6 weekly injections of ragweed Amb a 1 bound to cytosine phosphorothionate guanosine containing DNA produced a shift from T_H2 to T_H1 cytokine release both in peripheral blood cells and in the nose after allergen challenge. No symptom improvement was seen the first year, but symptoms were reduced the second year without further treatment.