1-cell subsets in autologous and allogeneic peripheral blood stem cell concentrates

Background and Objectives Regulatory T cells (Tregs) and other T-cell subsets are of importance in the setting of autologous and allogeneic stem cell transplantations. We conducted a study to assess the content of peripheral blood stem cell concentrates and related apheresis parameters in the autologous and allogeneic setting. Material and Methods We characterized 53 donors, patients and peripheral blood stem cell concentrates (PBSC) regarding the content of CD45(+) cells, lymphocytes, CDr cells, CD3(+) CD4* T cells, CDr CD4(+) CD25(+) T cells, CDT CD4- CD25* CDI271' /negative -bregs and CD34(+) cells and calculated cell yields, recruitment factors and collection efficiency for all cell types. We compared allogeneic data with autologous data. Results Autologous PBSC show significantly lower concentrations of T-cell subsets compared to allogeneic PBSC (17 11241.1CD4-, 14 858/ill CD4 CD25+ and 1579/mu l CD3(+) CD4(+) CD25+ CDI27(low/negative) Tregs in autologous compared to 65 539/mu l CD4-, 44 208-/p1 CD4* CD25* and 5040/01 CD3- CD4- CD25* CD1271'/negative Tregs in allogeneic PBSC, respectively), in contrast to CD34* concentrations (5342/CD34(+) in autologous compared to 2367/1.11 CD34* in allogeneic PBSC, respectively). Accordantly, all T-cell yields are lower in the autologous setting compared to allogieneic PBSC. However, recruitment factor and collection efficiency of all cell types are higher in autologous compared to allogeneic PBSC, but not all parameters differ significantly when groups are compared. Conclusion T-cell subsets and especially Trcgs are a substantial part of PBSC transplantation, as considerable recruitment during apheresis occurs. In large volume apheresis, the collection efficiency of Treg is comparable to that of CD34(+) cells, while recruitment factors are even higher,