Background: Acute allograft rejection (AR) in solid organ transplantation i
s generally regarded to develop through cell-mediated immune response follo
wing activation of helper T cells. Since production of antibodies is also m
ediated by helper T cells, humoral immunity may play some roles in AR. Alth
ough flow cytometry crossmatch (FCXM) is reported as a useful method for th
e detection of antibodies against donor antigen, specific role of T- or B-c
ell FCXM and its sensitivity for AR is controversial.
Methods: T- and B-cell FCXM using fresh donor peripheral lymphocytes were p
erformed before and after blood-type compatible living donor liver transpla
ntation in 47 patients. IgM and IgG antidonor antibodies were analyzed in r
elation to clinical AR.
Results: Positive pre-transplant T-cell FCXM was associated with a high inc
idence of positive post-transplant T-cell FCXM (p = 0.017). Four of five ca
ses (80%) with positive pre-transplant T-cell FCXM experienced earlier AR (
day 8.0 +/- 4.4, mean +/- SID) than 16 of 42 cases (31%) with negative pre-
transplant T-cell FCXM (17.3 +/- 6.8; p = 0.016). In addition, higher dose
of steroids was given to treat AR episodes in cases with positive pre-trans
plant T-cell FCXM (79.9 +/- 10.3 mg/kg/month) than in those with negative p
re-transplant T-cell FCXM (47.1 +/- 26.6; p = 0.039). In the first month af
ter transplantation, 13 episodes of positive post-transplant T-cell FCXM we
re all concomitant with or preceded clinical AR compared with seven ARs in
T-cell FCXM-negative cases (p < 0.0001). T-cell FCXM between positive sera
and third parties revealed some crossreactions. In contrast, detection of a
ntibodies by B-cell FCXM in pre- and post-transplant phases was scarcely as
sociated with AR, and no correlation was found between T and B-cell FCXM be
fore and after transplantation.
Conclusions: Positive T-cell FCXM is closely related with AR and that befor
e transplantation is a predictor of early and refractory AR as well as post
-transplant FCXM. In contrast, not a few detections of antibodies irrelevan
t to AR are observed in B-cell FCXM, suggesting its low specificity.