HLA-haploidentical hematopoietic stem cells transplantation with regulatory and conventional T-cell adoptive immunotherapy in pediatric patients with very high-risk acute leukemia.

Allogeneic hematopoietic stem cell transplantation (HSCT) is still needed for many children with very high-risk acute leukemia. An HLA-haploidentical family donor is a suitable option for those without an HLA-matched donor. Here we present outcomes of a novel HLA-haploidentical HSCT (haplo-HSCT) strategy with adoptive immunotherapy with thymic-derived CD4+CD25+ FoxP3+ regulatory T cells (Tregs) and conventional T cells (Tcons) performed between January 2017 and July 2021 in 20 children with high-risk leukemia. Median age was 14.5 years (range, 4-21), 15 had acute lymphoblastic leukemia, 5 acute myeloid leukemia. The conditioning regimen included total body irradiation (TBI), thiotepa, fludarabine, cyclophosphamide. Grafts contained a megadose of CD34+ cells (mean 12.4 × 106/Kg), Tregs (2 × 106/Kg) and Tcons (0.5-1 × 106/Kg). All patients achieved primary, sustained full-donor engraftment. Only one patient relapsed (5%). The incidence of non-relapse mortality was 15% (3/20 patients). Five/20 patients developed ≥ grade 2 acute Graft versus Host Disease (aGvHD). It resolved in 4 who are alive and disease-free; 1 patient developed chronic GvHD (cGvHD). The probability of GRFS was 60 ± 0.5% (95% CI: 2.1-4.2) (Fig. 6), CRFS was 79 ± 0.9% (95% CI: 3.2-4.9) as 16/20 patients are alive and leukemia-free. The median follow-up was 2.1 years (range 0.5 months-5.1 years). This innovative approach was associated with very promising outcomes of HSCT strategy in pediatric patients.

Immunomagnetic isolation of CD4+CD25+FoxP3+ natural T regulatory lymphocytes for clinical applications.

Although CD4(+)/CD25(+) T regulatory cells (T(regs)) are a potentially powerful tool in bone marrow transplantation, a prerequisite for clinical use is a cell-separation strategy complying with good manufacturing practice guidelines. We isolated T(regs) from standard leukapheresis products using double-negative selection (anti-CD8 and anti-CD19 monoclonal antibodies) followed by positive selection (anti-CD25 monoclonal antibody). The final cell fraction (CD4(+)/CD25(+)) showed a mean purity of 93.6% +/- 1.1. Recovery efficiency was 81.52% +/- 7.4. The CD4(+)/CD25(+bright) cells were 28.4% +/- 6.8. The CD4(+)/CD25(+) fraction contained a mean of 51.9% +/- 15.1 FoxP3 cells and a mean of 18.9% +/- 11.5 CD127 cells. Increased FoxP3 and depleted CD127 mRNAs in CD4(+)CD25(+)FoxP3(+) cells were in line with flow cytometric results. In Vbeta spectratyping the complexity scores of CD4(+)/CD25(+) cells and CD4(+)/CD25(-) cells were not significantly different, indicating that T(regs) had a broad T cell receptor repertoire. The inhibition assay showed that CD4(+)/CD25(+) cells inhibited CD4(+)/CD25(-) cells in a dose-dependent manner (mean inhibition percentages: 72.4 +/- 8.9 [ratio of T responder (T(resp)) to T(regs), 1:2]; 60.8% +/- 20.5 (ratio of T(resp) to T(regs), 1:1); 25.6 +/- 19.6 (ratio of T(resp) to T(regs), 1:0.1)). Our study shows that negative/positive T(reg) selection, performed using the CliniMACS device and reagents, enriches significantly CD4(+)CD25(+)FoxP3(+) cells endowed with immunosuppressive capacities. The CD4(+)CD25(+)FoxP3(+) population is a source of natural T(reg) cells that are depleted of CD8(+) and CD4(+)/CD25(-) reacting clones which are potentially responsible for triggering graft-versus-host disease (GvHD). Cells isolated by means of this approach might be used in allogeneic haematopoietic cell transplantation to facilitate engraftment and reduce the incidence and severity of GvHD without abrogating the potential graft-versus-tumour effect.

Why is the use of clopidogrel increasing rapidly in Australia? An exploration of geographical location, age, sex and cardiac stenting rates as possible influences on clopidogrel use.

PURPOSE: To explore clopidogrel use within Australia, investigating geography, age, sex and cardiac stenting rates. METHODS: Data for clopidogrel supply (Pharmaceutical Benefits Scheme (PBS) and Repatriation Pharmaceutical Benefits Scheme (RPBS)) and cardiac stenting procedures (State Health Departments) were obtained for four different geographic regions (very remote/remote and major city in two Australian states). General linear modelling and correlation analyses were used to test for associations and chi2 analyses for proportions. RESULTS: Clopidogrel supply increased rapidly in Australia since introduction, from 1.2 to 9.0 Defined Daily Doses (DDD)/1000 population/day. Among concessional and veteran populations use was much higher. Analysis of geographical area data confirmed an association between clopidogrel supply rates and cardiac stenting rates (r = 0.8-0.9 Spearman's rho, p < 0.01). Sex, age and geographical location were associated with both rates when considered together and when considered independently. Further modelling indicated that between 30 and 73% of clopidogrel supply could be accounted for by people receiving cardiac stents. CONCLUSIONS: The supply of clopidogrel increases with age, male sex and living in a major city. These same demographic variables were important for cardiac stenting, an indication which is currently not approved for subsidy by the Australian government, but which modelling indicated could account for between one-third and three quarters of clopidogrel use. A review may be required to ensure subsidised indications reflect current evidence and cost-effective use.

Using ambulance service records to examine nonfatal heroin overdoses.

Overdoses are a preventable health hazard associated with heroin use. In the first study of its kind, we examined the records on nonfatal overdoses of the Australian Capital Territory (ACT) Ambulance Service from August 1990 to July 1993. There was a dramatic increase in the number of overdoses in the second half of 1992 and the first half of 1993, but the reasons for the increase are not clear. Most overdoses occurred in men aged under 30, indoors, and many cases were taken to hospital. Often there was no information on why the overdose occurred; when information was available, about half the cases were attributed to taking heroin in combination with other drugs. Suggestions for improving the quality of the data collected are made. These include more systematic recording by ambulance officers of the drug involved in the overdose and whether the drug was used alone or in combination with others, and linkage of ambulance service records with survey data and information from analysis of heroin purity.

Controlled heroin availability in Australia? How and to what end?

The general public, police, service providers, and users/ex-users were asked their views about options for trial design and trial outcomes with regard to a proposal for experimental controlled heroin availability. There was substantial agreement between the samples on issues concerning trial design. In general, the samples from the community, service providers and users/ex-users were more likely to report that a trial would result in positive outcomes, whereas the police sample was more likely to report that a trial would result in negative outcomes. This study illustrates the value of systematic consultation of key groups in exploring the options for change, raising potential difficulties, and highlighting different interests.

The ethics of experimental heroin maintenance.

In response to widespread concern about illegal drug use and the associated risk of the spread of HIV/AIDS, a study was undertaken to examine whether it was, in principle, feasible to conduct a trial providing heroin to dependent users in a controlled manner. Such a trial involves real ethical issues which are examined in this paper. The general issues examined are: should a trial be an experiment or an exercise in public policy?; acts and omissions; countermobilization; termination of a trial, and payment for drugs and for a trial. The specific issues examined are: selection of trial participants; privacy; issues for staff working on a trial; coupling the trial with other treatment, and issues for researchers. A number of alternative approaches to the various ethical issues are presented and discussed.