<prompt> Bronchiectasis with predominantly upper lobe involvement isKaegeners syndromeHypogammaglobinemiaCystic fibrosisAlpha 1 antitrypsin deficiency  <response>: More pronounced involvement of the upper lung fields is most common in cystic fibrosisCF and is also observed in post radiation fibrosis,corresponding to the lung region encompassed by the radiation po.Bronchiectasis with predominant involvement of the lower lung fields is seen in fibrotic lung diseases or hypogammaglobulinemia.Congenital causes of bronchiectasis with predominant midlung field involvement include the dyskineticimmotile cilia syndrome or Kaageners syndrome.Finally,predominant involvement of the central airways is repoed in association with allergic bronchopulmonary aspergillosis. Ref:Harrisons medicine-18th edition,page no:2142. 