Stefano Ceccarelli

Selective Depletion of αβ T Cells and B Cells for Human Leukocyte Antigen–Haploidentical Hematopoietic Stem Cell Transplantation. A Three-Year Follow-Up of Procedure Efficiency

HLA-haploidentical family donors represent a valuable option for children requiring allogeneic hematopoietic stem cell transplantation (HSCT). Because graft-versus-host diseases (GVHD) is a major complication of HLA-haploidentical HSCT because of alloreactive T cells in the graft, different methods have been used for ex vivo T cell depletion. Removal of donor αβ T cells, the subset responsible for GVHD, and of B cells, responsible for post-transplantation lymphoproliferative disorders, have been recently developed for HLA-haploidentical HSCT. This manipulation preserves, in addition to CD34+ progenitors, natural killer, γδ T, and monocytes/dendritic cells, contributing to anti-leukemia activity and protection against infections. We analyzed depletion efficiency and cell yield in 200 procedures performed in the last 3 years at our center. Donors underwent CD34+  hematopoietic stem cell (HSC) peripheral blood mobilization with granulocyte colony-stimulating factor (G-CSF). Poor CD34+ cell mobilizers (48 of 189, 25%) received plerixafor in addition to G-CSF. Aphereses containing a median of 52.5 × 109 nucleated cells and 494 × 106 CD34+ HSC were manipulated using the CliniMACS device. In comparison to the initial product, αβ T cell depletion produced a median 4.1-log reduction (range, 3.1 to 5.5) and B cell depletion led to a median 3.4-log reduction (range, 2.0 to 4.7). Graft products contained a median of 18.5 × 106 CD34+ HSC/kg recipient body weight, with median values of residual αβ T cells and B cells of 29 × 103/kg and 33 × 103/kg, respectively. Depletion efficiency monitored at 6-month intervals demonstrated steady performance, while improved recovery of CD34+ cells was observed after the first year (P = .0005). These data indicate that αβ T cell and B cell depletion of HSC grafts from HLA-haploidentical donors was efficient and reproducible.

Mobilization of healthy donors with plerixafor affects the cellular composition of T-cell receptor (TCR)-αβ/CD19-depleted haploidentical stem cell grafts

BackgroundHLA-haploidentical hematopoietic stem cell transplantation (HSCT) is suitable for patients lacking related or unrelated HLA-matched donors. Herein, we investigated whether plerixafor (MZ), as an adjunct to G-CSF, facilitated the collection of mega-doses of hematopoietic stem cells (HSC) for TCR-αβ/CD19-depleted haploidentical HSCT, and how this agent affects the cellular graft composition.MethodsNinety healthy donors were evaluated. Single-dose MZ was given to 30 ‘poor mobilizers’ (PM) failing to attain ≥40 CD34+ HSCs/μL after 4 daily G-CSF doses and/or with predicted apheresis yields ≤12.0x106 CD34+ cells/kg recipient’s body weight.ResultsMZ significantly increased CD34+ counts in PM. Naïve/memory T and B cells, as well as natural killer (NK) cells, myeloid/plasmacytoid dendritic cells (DCs), were unchanged compared with baseline. MZ did not further promote the G-CSF-induced mobilization of CD16+ monocytes and the down-regulation of IFN-γ production by T cells. HSC grafts harvested after G-CSF + MZ were enriched in myeloid and plasmacytoid DCs, but contained low numbers of pro-inflammatory 6-sulfo-LacNAc+ (Slan)-DCs. Finally, children transplanted with G-CSF + MZ-mobilized grafts received greater numbers of monocytes, myeloid and plasmacytoid DCs, but lower numbers of NK cells, NK-like T cells and Slan-DCs.ConclusionsMZ facilitates the collection of mega-doses of CD34+ HSCs for haploidentical HSCT, while affecting graft composition.

Adoptive immunotherapy with antigen-specific T cells during extracorporeal membrane oxygenation (ECMO) for adenovirus-related respiratory failure in a child given haploidentical stem cell transplantation.

We report on the successful infusion of human adenovirus (HAdV)‐specific T cells in a child with congenital amegakaryocytic thrombocytopenia, given T‐cell‐depleted hematopoietic stem cell transplantation (HSCT) from the HLA‐haploidentical mother during extracorporeal membrane oxygenation (ECMO) for severe HAdV‐related respiratory failure. Donor‐derived, interferon (IFN)‐γ‐secreting HAdV‐specific T cells were enriched using the cytokine capture assay, after in vitro stimulation with overlapping peptides from the immunodominant HAdV5 hexon protein. Two weeks after T‐cell transfer, viral load decreased and ECMO was discontinued. T‐cell responses to HAdV antigens were documented after four weeks and were associated with viral clearance, immune reconstitution and clinical amelioration. Pediatr Blood Cancer 2014;61:376–379.

Extracorporeal photopheresis for paediatric patients experiencing graft-versus-host disease (GVHD).

Extracorporeal photopheresis (ECP) is broadly used in adults with cutaneous T-cell lymphoma, acute or chronic graft-versus-host disease (GVHD), rejection of solid organ transplants, and a variety of autoimmune, cell-mediated diseases. The predominant use of ECP in children and adolescents is for treating GVHD. Children pose specific challenges to ECP, due to their unique physiology and to patients size. Herein, we will focus on current clinical trials with ECP in children with GVHD, with an emphasis on technical and clinical issues that are peculiar to the paediatric setting.

Anastomotic ulcers in short bowel syndrome: New suggestions from a multidisciplinary approach

BACKGROUND AND AIMS Anastomotic ulceration (AU) is a rare potential life-threatening complication that may occur after intestinal resection. The diagnosis is often delayed after a long-lasting history of refractory anemia. The pathogenesis remains unknown and there are no established therapies. The aim of the study was to analyze the medical history of children with short bowel syndrome (SBS) who were experiencing AU. METHODS Records of SBS children were retrospectively reviewed. Demographics, baseline characteristics, presentation, diagnosis and treatment of AU cases were analyzed. RESULTS Eight out of 114 children with SBS were identified as having AU. Mean gestational age was 32.5weeks. Underlying diseases were: 5 necrotising enterocolitis, 2 gastroschisis and 1 multiple intestinal atresia. The mean age at AU diagnosis was 6.5years (diagnosis delay of 35months). All but 2 patients had AU persistency after medical treatment. Endoscopic treatment (2 argon plasma coagulation; 1 platelet-rich fibrin instillation; 2 endoscopic hydrostatic dilations) was effective in 3 out of 5 children. Surgery was required in 3 patients. CONCLUSIONS Severe bowel ischemic injury, especially in preterm infant, could predispose to AU development. Medical treatment showed discouraging results. We firstly described that different endoscopic treatment could be attempted before resorting to further surgery. LEVEL OF EVIDENCE IV.