Does contegra xenograft implantation evoke cellular immunity in children?

The aim of the study was to search for changes in subpopulations of peripheral blood lymphocytes and in their activation as the manifestation of cellular immunity against xenograft in recipients of bovine valved conduit used for right ventricle outflow tract reconstruction. Between 24-06-1999 and 19-10-2000 35 children were operated in ECC, 19 had a xenograft implanted, the rest entered the control group. Immunophenotype of lymphoid cells and T cells activation was evaluated with use of flow cytometer: preoperatively and 3, 6 and 12 months after the operation in both groups. There were no differences in numbers of CD3+, CD4+, CD8+ and natural killer cells between groups. A significant rise of B-cells percentages (from 15.5% to 23%) between 3rd and 6th month was noted. The T-lymphocyte activation study revealed higher numbers of CD69+ (0.17 vs. 0.09 G/l) and CD71+ (0.23 vs. 0.11 G/l) cells one year after the implantation in xenograft recipients. Difference between groups in number of CD69+ and CD71+ cells in 12th month may suggest mild activation (<10%) of these subgroups in xenograft recipients. This data may hint the presence of cellular reactivity. Changes in numbers of B-cells may evidence humoral immunity activation. Influence of these phenomena on graft survival remains to be established.