I am particularly indebted to Drs Graça Loureiro, Beatriz Tavares, Daniel Machado and Prof A Segorbe Luís, from Immunoallergy Departement of Coimbra University Hospital Center who willingly assisted me in the review and in the scientific discussion of some fundamental aspects that have benefited the final version. The preparation of this edition for publication depends heavily on the excellent professional secretarial work of Ms Molly Kaliman, Publishing Process Manager. Of course a special thanks to the Intech-Open Access Publisher who had honored me with that feat challenge. I am exceedingly grateful to my family and all those who are close to me for successfully enduring this ordeal yet.
