title: Osteoclastogenesis during infective exacerbations in patients with cystic fibrosis.
abstract: BACKGROUND
  Adults with cystic fibrosis (CF) are at increased risk of developing osteoporosis. During infective exacerbations, increased production of proinflammatory cytokines and markers of bone resorption have been reported.
  
  
  OBJECTIVE
  The aim of this study is to investigate the growth and proliferation of potential osteoclast precursor cells before, during, and after intravenous antibiotic treatment of infective exacerbations in patients with CF.
  
  
  METHODS
  Hematopoietic precursor cell growth was examined using colony formation assays using Methocult culture medium. Circulating potential osteoclast precursors were identified using four-color flow cytometry by CD14, CD33, CD34, and CD45 expression.
  
  
  RESULTS
  At the start of an infective exacerbation increases in hematopoietic precursor colony formation (15.42 colonies/10(5) cells plated, p = 0.025), proliferation (28.5%, p < 0.001), and the numbers of circulating potential osteoclast precursors (6.5%, p < 0.001) were seen in comparison with baseline levels. These increases declined after treatment with intravenous antibiotics to a level close to baseline.
  
  
  CONCLUSIONS
  The results demonstrate an increase in the production of potential osteoclast precursors in the peripheral blood during CF infective exacerbations. This may result in increased bone resorption and contribute to bone loss in patients with CF.
authors: Department of Haematology, NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom. lizzshead@hotmail.com
authors: Elizabeth F
authors: EF
authors: Shead
authors: Charles S
authors: CS
authors: Haworth
authors: Elaine
authors: E
authors: Gunn
authors: Diana
authors: D
authors: Bilton
authors: Mike A
authors: MA
authors: Scott
authors: Juliet E
authors: JE
authors: Compston