First report of pediatric hematopoietic stem cell transplantation activities in the eastern mediterranean region from 1984 to 2011: on behalf of the pediatric cancer working committee of the eastern mediterranean blood and marrow transplantation group

To describe the hematopoietic stem cell transplantation (HSCT) activities for children in the Eastern Mediterranean (EM) region, data on transplants performed for children less than 18 years of age between 1984 and 2011 in eight EM countries (Egypt, Iran, Jordan, Lebanon, Oman, Pakistan, Saudi Arabia and Tunisia) were collected. A total of 5187 transplants were performed, of which 4513 (87%) were allogeneic and 674 (13%) were autologous. Overall, the indications for transplantation were malignant diseases in 1736 (38.5%) and non-malignant in 2777 (61.5%) patients. A myeloablative conditioning regimen was used in 88% of the allografts. Bone marrow (BM) was the most frequent source of stem cells (56.2%), although an increasing use of PBSC was observed in the last decade. The stem cell source of autologous HSCT has shifted over time from BM to PBSC, and 80.9% of autologous HSCTs were from PBSCs. The donors for allogeneic transplants were matched-related in 94.5% of the cases, and unrelated transplants, mainly cord blood (99%) in 239 (5.5%) cases. This is the first report to describe the pediatric HSCT activities in EM countries. Non-malignant disorders are the main indication for allogeneic transplantation. Frequency of alternate donor transplantation is low.

Reduced intensity conditioning is effective for hematopoietic SCT in dyskeratosis congenita-related BM failure

BM failure (BMF) is a major and frequent complication of dyskeratosis congenita (DKC). Allogeneic hematopoietic SCT (allo-HSCT) represents the only curative treatment for BMF associated with this condition. Transplant-related morbidity/mortality is common especially after myeloablative conditioning regimens. Herein, we report nine cases of patients with DKC who received an allo-SCT at five different member centers within the Eastern Mediterranean Blood and Marrow Transplantation Registry. Between October 1992 and February 2011, nine DKC patients (male, 7 and female, 2), with a median age at transplantation of 19.1 (4.9-31.1) years, underwent an allo-HSCT from HLA-matched, morphologically normal-related donors (100%). Preparative regimens varied according to different centers, but was reduced intensity conditioning (RIC) in eight patients. Graft source was unstimulated BM in five cases (56%) and G-CSF-mobilized PBSCs in four (44%) cases. The median stem cell dose was 6.79 (2.06-12.4) × 10(6) cells/kg body weight. GVHD prophylaxis consisted of CsA in all nine cases; MTX or mycophenolate mofetil were added in five (56%) and two (22%) cases, respectively. Anti-thymocyte globulin was administered at various doses and scheduled in four (44%) cases. Median time-to-neutrophil engraftment was 21 (17-27) days. In one case, late graft failure was noted at 10.4 months post allo-HSCT. Only one patient developed grade II acute GVHD (11%). Extensive chronic GVHD was reported in one case, whereas limited chronic GVHD occurred in another four cases. At a median follow-up of 61 (0.8-212) months, seven (78%) patients were still alive and transfusion independent. One patient died of metastatic gastric adenocarcinoma and graft failure was the cause of death in another patient. This study suggests that RIC preparative regimens are successful in inducing hematopoietic cell engraftment in patients with BMF from DKC. Owing to the limited sample size, the use of registry data and heterogeneity of preparative as well as GVHD prophylaxis regimens reported in this series, we are unable to recommend a particular regimen to be considered as the standard for patients with this disease.

Expansion of CD4+CD7- T cells, a memory subset with preferential interleukin-4 production, after bone marrow transplantation

BACKGROUND

Inadequate reconstitution of CD4+ lymphocyte and interleukin (IL)-2 production defect are observed after bone marrow or peripheral blood stem cell transplantation (SCT).

METHODS

We studied immune reconstitution after SCT in 33 consecutive patients who received allogeneic SCT (17 patients) or autologous SCT (16 patients). The aims were to assess the regeneration of the CD4+ T-cell subset with regard to helper cell differentiation. CD4+ T-cell subset regeneration and expansion of the CD4+CD7- subset were studied by immunofluorescence analysis. CD4+CD7- cell cytokine secretion was analyzed after cell sorting and costimulation of the CD3 and CD28 pathways, in enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction assays.

RESULTS

We report a relative expansion of the CD4+CD7- subset within CD4+ T cells, detected as early as 1 month after bone marrow transplantation and decreasing after day 60. CD4+CD7- T cells preferentially expressed CD45RO and activation markers such as CD57, CD25, and HLA-DR. No relationship was observed between the CD4+CD7- expansion and transplant-related complications. We observed no significant IL-2 production in supernatants from sorted CD4+CD7- T cells, whereas IL-4 levels were comparable to those produced by cells from normal individuals. Autologous CD4+CD7+ cells showed little, if any, IL-4 production, and IL-2 production was lower than that by normal CD4+CD7+ T cells. Reverse transcription-polymerase chain reaction assays showed similar amounts of interferon-gamma transcripts in the two subsets; tumor necrosis factor-alpha, IL-4, and IL-10 transcripts were detected in CD4+CD7- T cells but not in their CD4+CD7+ counterparts.

CONCLUSIONS

These data confirm the IL-2 production defect after bone marrow transplantation and suggest that the CD4+CD7- T-cell subset might be preferentially involved in the enhanced production of IL-4 and low production of IL-2. These data show that the early immune reconstitution in CD4+ T cells after SCT preferentially involves memory T cells with a Th0/Th2 differentiation that might participate in the T-helper cell defect.