[Selective depletion of donor alloreactive T cells by using immuno-magnetic cell sorting]

This study was aimed to explore a new method of alleviating graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation through selective elimination of human alloreactive T cells expressing either CD25(+) or CD69(+) by immuno-magnetic cell sorting (MACS). Healthy donor peripheral blood mononuclear cells were cocultivated with bone marrow mononuclear cells from HLA-nonidentical leukemia recipient with remission in one-way mixed lymphocyte culture (OWMLC). After 3 days, both CD25(+) and CD69(+) lymphocytes were removed by MACS. The depleted donor fraction and untreated donor cells were then rechallenged in a secondary mixed lymphocyte culture (MLC) with the original stimulator cells or a third party to assess relative alloreactivity. The results showed that 50% inhibition of the secondary MLC was observed in the depleted donor fraction. Alloreactivity against unrelated third-party cells was largely preserved. It is concluded that this method reduces alloreactivity while retaining reactivity against a third party target in vitro.