title: Critical role of sensitized serum in rejection of allogeneic bone marrow cells.
abstract: OBJECTIVE
  Humoral immunity has been clearly implicated in solid organ transplantation, but little is known about the relationship between humoral immunity and hematopoietic stem cell transplantation. This study was designed to investigate that relationship.
  
  
  METHODS
  Sensitized serum was obtained from a sensitized murine model established by allogeneic splenocyte transfusion. Sensitized serum was incubated with allogeneic bone marrow cells (BMCs) in vitro and the cytotoxicity was evaluated by the complement-dependent cytotoxicity method. Mice were transplanted with allogeneic BMCs incubated with sensitized serum after lethal irradiation. The engraftment was assayed by hematopoietic recovery and chimera analysis. Moreover, mice received passive transfer of sensitized serum 1 day prior to transplantation. Mortality was scored daily after bone marrow transplantation.
  
  
  RESULTS
  The in vitro experiments showed that sensitized serum was capable of impairing allogeneic BMCs through the complement-dependent cytotoxicity pathway. The animal studies showed that BMCs incubated with sensitized serum failed to rescue mice from lethal irradiation. The engraftment assay showed that the allogeneic BMCs incubated with sensitized serum were rejected with time in the recipients. Furthermore, the mice died of marrow graft rejection by transfer of sensitized serum prior to transplantation.
  
  
  CONCLUSIONS
  Taken together, our results indicated that sensitized serum played a critical role in graft rejection during hematopoietic stem cell transplantation.
authors.affiliation: Sun Yat-sen University, Sun Yat-sen Memorial Hospital, Department of Pediatrics, Guangzhou, China. E-ma-il: xulvhong@126.com.
authors.forename: Lu-Hong
authors.initials: LH
authors.lastname: Xu
authors.forename: Jian-Pei
authors.initials: JP
authors.lastname: Fang
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Weng
authors.forename: Hong-Gui
authors.initials: HG
authors.lastname: Xu