S. Sarnacki et al., Blockade of the integrin alpha L beta 2 but not of integrins alpha 4 and/or beta 7 significantly prolongs intestinal allograft survival in mice, GUT, 47(1), 2000, pp. 97-104
Background-Small bowel transplantation remains a difficult therapeutic opti
on endangered by a high rate of rejection and infectious complications. To
improve these clinical results, it is mandatory to set up animal models to
test alternative immunosuppressive regimens which may lead to immunotoleran
ce.
Aims-To determine the value of blockade of alpha L beta 2 (LFA-1) and alpha
3 and beta 7 integrins (alpha 4 beta 1, alpha 4 beta 7, and alpha E beta 7
) in the prevention of rejection of fetal small bowel grafts in mice and th
e effect of the association of calcineurin dependent drugs in anti-LFA-1 tr
eated mice.
Methods-Adult recipient mice engrafted with allogeneic fetal small bowel re
ceived a short course of anti-alpha 4 and/or anti-LFA-1 monoclonal antibodi
es (mAb) with or without FK506 or cyclosporin A. In addition, in a set of e
xperiment, beta 7(-/-) mice were used as recipients. Graft biopsies were pe
rformed and processed for standard histology.
Results-Blockade of the pathways of the integrins alpha 4 and beta 7 had a
modest or no effect on intestinal graft survival. In contrast, transitory,
short administration of anti-LFA-1 monoclonal antibody alone, when started
before engraftment (day-1), allowed long term survival of intestinal grafts
, even when associated with calcineurin dependent drugs. However, early wit
hdrawal of FK506 reversed the immunosuppressive effect of anti-LFA-1 treatm
ent.
Conclusions-These results suggest that firstly, anti-LFA-1, but not anti-al
pha 4 mAb treatment, may be useful in improving the results of intestinal t
ransplantation, and secondly, that this treatment is not incompatible with
long term administration of tacrolimus currently used in the prevention of
small bowel graft rejection in humans.