title: Characterization of human breast milk leukocytes and their potential role in cytomegalovirus transmission to newborns.
abstract: BACKGROUND
  Breast milk is the primary source of cytomegalovirus (CMV) transmission to newborns and premature infants. The role of cell-free milk whey in virus transmission is well understood, yet the knowledge about the role of milk cells in this process is scarce.
  
  
  OBJECTIVE
  To preliminarily characterize different breast milk cell types during various stages of lactation to evaluate their potential role in the transmission of CMV.
  
  
  METHODS
  Breast milk cells of 18 lactating and 3 CMV-seropositive mothers of preterm infants were isolated and characterized for expression of myeloid markers by flow cytometry. In parallel, cytospin preparations were stained with α-naphthyl acetate esterase to identify milk macrophages and describe the dynamic changes of the macrophage-granulocyte population during lactation. The influence of different time points of lactation was analyzed by FACS analysis of double-stained (CD15/CD66b) milk cells. To characterize CMV target cells in breast milk, we enriched CD14+ cells by MACS (Miltenyi) and monitored cell fractions using CMV IEEx4 nested PCR and pp67 CMV RNA by NASBA.
  
  
  RESULTS
  Virolactia, viral DNAlactia, and viral pp67 late mRNA could be detected in breast milk cells only in defined time periods. Granulocytes and macrophages demonstrated an inverse dynamic with neutrophils predominating in the early stages (<30 days postpartum) and macrophages in later stages (>60 days postpartum) of lactation. Enrichment of CD14-positive cells resulted in viral DNA and pp67 late mRNA detection.
  
  
  CONCLUSIONS
  Granulocytes and monocytes/macrophages are the predominating cell populations in breast milk with changing frequencies during early lactation. These results demonstrate that CD14-positive breast milk cells seem to be one of the target cells for CMV in breast milk.
authors: Department of Neonatology, University Hospital Tübingen, Tübingen, Germany.
authors: Jens
authors: J
authors: Maschmann
authors: Rangmar
authors: R
authors: Goelz
authors: Simone
authors: S
authors: Witzel
authors: Ute
authors: U
authors: Strittmatter
authors: Max
authors: M
authors: Steinmassl
authors: Gerhard
authors: G
authors: Jahn
authors: Klaus
authors: K
authors: Hamprecht
mesh_terms: D015415:Biomarkers; D001942:Breast Feeding; D003587:Cytomegalovirus / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000635:transmission*; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D018445:Infectious Disease Transmission, Vertical; D007774:Lactation; D007962:Leukocytes / Q000821:virology*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008895:Milk, Human / Q000166:cytology* / Q000821:virology; D012333:RNA, Messenger / Q000032:analysis; D000067796:Whey / Q000821:virology
chemical_list: D015415:Biomarkers; D004279:DNA, Viral; D018950:Lipopolysaccharide Receptors; D012333:RNA, Messenger