Addition of exogenous cytokines in mixed lymphocyte culture for selecting related donors for bone marrow transplantation

Abstract

CONTEXT: Mixed lymphocyte culturing has led to conflicting opinions regarding the selection of donors for bone marrow transplantation. The association between a positive mixed lymphocyte culture and the development of graft-versus-host disease (GVHD) is unclear. The use of exogenous cytokines in mixed lymphocyte cultures could be an alternative for increasing the sensitivity of culture tests. OBJECTIVE: To increase the sensitivity of mixed lymphocyte cultures between donor and recipient human leukocyte antigen (HLA) identical siblings, using exogenous cytokines, in order to predict post-transplantation GVHD and/or rejection. TYPE OF STUDY: Prospective study. SETTING: Bone Marrow Transplantation Unit, Universidade Estadual de Campinas. PARTICIPANTS: Seventeen patients with hematological malignancies and their respective donors selected for bone marrow transplantation procedures. PROCEDURES: Standard and modified mixed lymphocyte culturing by cytokine supplementation was carried out using donor and recipient cells typed for HLA. MAIN MEASUREMENTS: Autologous and allogenic responses in mixed lymphocyte cultures after the addition of IL-4 or IL-2. RESULTS: In comparison with the standard method, average responses in the modified mixed lymphocyte cultures increased by a factor of 2.0 using IL-4 (p < 0.001) and 6.4 using IL-2 (p < 0.001), for autologous donor culture responses. For donor-versus-recipient culture responses, the increase was by a factor of 1.9 using IL-4 (p < 0.001) and 4.1 using IL-2 (p < 0.001). For donor-versus-unrelated culture responses, no significant increase was observed using IL-4, and a mean response inhibition of 20% was observed using IL-2 (p < 0.001). Neither of the cytokines produced a significant difference in the unrelated control versus recipient cell responses. CONCLUSION: IL-4 supplementation was the best for increasing the mixed lymphocyte culture sensitivity. However, IL-4 also increased autologous responses, albeit less intensively than IL-2. Thus, with this loss of specificity we believe that it is not worth modifying the traditional mixed lymphocyte culture method, even with IL-4 addition.