Bone marrow transplant conditioning intensified with liposomal clodronate to eliminate residual host antigen presenting cells fails to ameliorate GVHD and increases peri-BMT mortality
La. Everse et al., Bone marrow transplant conditioning intensified with liposomal clodronate to eliminate residual host antigen presenting cells fails to ameliorate GVHD and increases peri-BMT mortality, TRANSPLANT, 71(5), 2001, pp. 611-618
Background Graft versus host disease (GVHD) mediated by allogeneic donor T
cells may be initiated and/or exacerbated by residual host antigen presenti
ng cells (APC) which survive the transplant conditioning regimen, We examin
ed whether the depletion of hepatic and splenic APC could reduce the severi
ty of hepatic GVHD after bone marrow transplantation (BMT).
Methods. Recipient mice were depleted for hepatic and splenic phagocytic AP
Cs by i,v, injection of clodronate- (dichloromethylene diphosphonate) conta
ining liposomes before fully allogeneic or MHC-matched, minor Ag-mismatched
BMT, Severity of hepatic GVHD was scored on histological sections 2, 3, 4,
or 9 weeks after BMT,
Results, No differences in the severity of GVHD were observed between APC-d
epleted mice and control mice. APC-depleted mice had increased peritranspla
nt mortality due to sepsis, Bacterial clearance assays showed that APC-depl
eted mice were unable to efficiently clear bacteria, although nondepleted,
transplanted mice were able to clear bacteria as quickly as naive control m
ice.
Conclusions. Residual host phagocytic APC do not appear to play a role in t
he induction of GVHD after BMT. They are, however, essential for prevention
of sepsis in the transplant host.