Proliferative alloresponse of T cytotoxic cells identifies rejection-prone children with small bowel transplantation.

Background: More than 60% children with small bowel transplantation (SBTx) experience acute cellular rejection.

Purpose/methods: To identify children at risk of rejection, donor- and third-party-induced proliferation of T-helper and T cytotoxic (Tc) cells, and their naïve and memory (M) subsets was evaluated simultaneously in single blood samples from 28 children who received SBTx after induction with rabbit anti-human thymocyte globulin. Proliferation was measured by dilution of the intravital dye carboxyfluorescein succinimidyl ester (CFSE) in 3- to 4-day mixed leukocyte reaction co-culture. The ratio of donor- and third-party-induced proliferation (CFSE(low)) of the T cells was reported as the immunoreactivity (IR) index for each subset. Rejectors were defined as those who experienced biopsy-proven acute cellular rejection within 60 days of the assay. IR more than 1 signified increased risk of rejection and IR less than 1 implied decreased risk.

Results: Rejectors (n=16) and Nonrejectors (n=12) were similar in general demographics. Significantly higher counts were observed for all proliferated CFSE(low) T-cell subsets among rejectors, compared with nonrejectors. Logistic regression, leave-one-out cross-validation, and receiver operating characteristic analyses showed that the IR of Tc associated best with biopsy-proven rejection (sensitivity >87.5%, specificity >83.3%). IR of CFSE(low) Tc correlated significantly with IR of proinflammatory, allospecific CD154(+)Tc-M (r=0.682, P=0.005) and inversely with IR of allospecific, antiinflammatory, CTLA4(+)Tc-M (r=-0.638, P=0.047).

Conclusions: Proliferative alloresponses of Tc cells can identify rejection-prone children receiving SBTx.