Automated isolation of primary antigen-specific T cells from donor lymphocyte concentrates: results of a feasibility exercise.

BACKGROUND: The safety and clinical efficacy of adoptive transfer of prospectively isolated antigen-specific T cells are well established. Several competing selection methods are available, one of which is based on immunomagnetic enrichment of T cells secreting IFNγ after incubation with the relevant antigen. The proprietary, GMP-conforming selection technology, called 'cytokine capture system' (CCS) is established in many laboratories for the CliniMACS Plus system. It is robust and efficient, but labour-intensive and incompatible with a single-shift working schedule. An automatic immunomagnetic cell processing system, CliniMACS Prodigy ('Prodigy'), including a protocol for fully automatic CCS execution was recently released. MATERIAL AND METHODS: Feasibility of clinical-scale CMV-specific T-cell selection using Prodigy was evaluated using leukoapheresis products from five healthy CMV sero-positive volunteers. Clinical reagents and consumables were used throughout. RESULTS: The process required no operator input beyond set-up and QC-sample collection, that is, feasibility was given. An IFNγ-secreting target T-cell population was detectable after stimulation, and >2 log-scale relative depletion of not CMV-reactive T cells in the target population was achieved. Purity, that is the frequency of CMV-reactive T cells among all CD3(+) cells ranged between 64 and 93%. CONCLUSION: The CCS protocol on Prodigy is unrestrictedly functional. It runs fully automatically beyond set-up and thus markedly reduces labour. The quality of the products generated is similar to products generated with CliniMACS Plus. The automatic system is thus suitable for routine clinical application.

Treatment of relapse after allogeneic stem cell transplantation in children and adolescents with ALL: the Frankfurt experience.

Therapy for post-transplant relapse of paediatric ALL is limited. Standardised curative approaches are not available. We hereby describe our local procedure in this life-threatening situation. A total of 101 ALL patients received their first allogeneic stem cell transplantation (SCT) in our institution. After relapse, our primary therapeutic goal was to cure the patient with high-dose chemotherapy or specific immunotherapy (HDCHT/SIT) followed by a second SCT from a haploidentical donor (transplant approach). If this was not feasible, low-dose chemotherapy and donor lymphocyte infusions (LDCHT+DLI) were offered (non-transplant approach). A total of 23 patients suffered a post-transplant relapse. Eight patients received HDCHT/SIT, followed by haploidentical SCT in 7/8. Ten received LDCHT+DLI. The eight patients treated with a second transplant and the ten treated with the non-transplant approach had a 4-year overall survival of 56% and 40%, respectively (P=0.232). Prerequisites for successful treatment of post-transplant relapse by either a second transplant or experimental non-transplant approaches are good clinical condition and the capacity to achieve haematological remission by the induction treatment element.