What is the role for Immunotherapy in Asthma According to the National Heart, Lung, Blood Institute's 2007 Guidelines for Asthma?

We have discussed what immunotherapy is earlier.  When should immunotherapy be considered?  The National Heart, Lung and Blood Institute published the third edition of guidelines for the Diagnosis and Management of Asthma in 2007.  The summary describes the role of immunotherapy on pages 15, 17, 18, 37, 45, and 57.  

From page 14: "Consideration of subcutaneous immunotherapy for patients who have allergies at steps 2–4 of care (mild or moderate persistent asthma) when there is a clear relationship between symptoms and exposure to an allergen to which the patient is sensitive."

From page 18: "Refer to an asthma specialist for consultation or comanagement if there are difficulties achieving or maintaining control; step 4 care or higher is required (step 3 care or higher for children 0–4 years of age); immunotherapy or omalizumab is considered; or additional testing is indicated; or if the patient required 2 bursts of oral systemic corticosticosteroids in the past year or a hospitalization."
Step 2 and greater means any inhaled corticosteroid inhaler is used. I try to follow the Guidelines, which on the other hand, do not recommend immunotherapy for every person with asthma.  Immunotherapy is a simply a recognized option. 
The Allergy Dude has shared his philosophy on immunotherapy.  More later.