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The biological activities of CD8+ that co-express CD57 remain poorly defined. It is unclear whether all CD8+ cells have the potential to become CD57+ or whether they represent a unique subset with distinct functions. Several studies have reported the association between elevated numbers of CD8+CD57+ and a wide range of clinical disorders such as viral reactivation of human cytomegalovirus (HCMV). In this study, we have investigated the relationship between viral reactivation and the effect of diminished interleukin (IL)-2 production. Using CD8+ cells isolated from patients at various times after allogeneic transplants and in vitro models of HCMV infection, we determined their combined effect on CD8+CD57+. Our results show that high numbers of CD8+CD57+ correlated with diminished killing of HCMV-infected targets. In addition, we showed a synergistic effect between IL-2 and HCMV in the expansion of CD8+CD57+ cells. Furthermore, these cells after anti-CD3 stimulation did not produce tumour necrosis factor (TNF)-α or interferon (IFN)-γ. Interestingly, IL-10 production was elevated in several patients which appeared to be associated with the time from transplant. [ABSTRACT FROM AUTHOR]

Patients with an ABL-class fusion have a high risk of relapse on standard chemotherapy but are sensitive to tyrosine kinase inhibitors (TKI). In UKALL2011, we screened patients with post-induction MRD ≥1% and positive patients (12%) received adjuvant TKI. As the intervention started during UKALL2011, not all eligible patients were screened prospectively. Retrospective screening of eligible patients allowed the outcome of equivalent ABL-class patients who did and did not receive a TKI in first remission to be compared. ABL-class patients who received a TKI in first remission had a reduced risk of relapse/refractory disease: 0% vs. 63% at four years (P = 0·009)., (© 2020 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Outcomes for teenage and young adult (TYA) patients with acute lymphoblastic leukaemia (ALL) who relapse on contemporary risk-adapted paediatric protocols are largely unknown and there is no consensus on optimal salvage strategies. We assessed the treatment and outcome of TYA patients (aged 16-24 years) recruited to the UKALL2003 trial, who relapsed following attainment of complete morphological remission. Forty-two of 223 patients (18·8%) relapsed, the majority (n = 26, 62%) on treatment. Thirty-eight (90%) patients received salvage treatment, with 22 (58%) achieving second remission (CR2) and 21 patients receiving an allogeneic haematopoietic cell transplant (alloHSCT). Post-relapse outcomes were poor with a 5-year overall survival (OS) of 23% (95% confidence interval; 11-37%). Outcomes for patients relapsing on active treatment were inferior to those relapsing after completing treatment (5-year OS 9% vs. 52%, log-rank P = 0·001). No patient with B cell ALL relapsing on treatment was alive at the end of the study period. TYA patients with ALL who relapse on the UK paediatric protocol, UKALL2003, are largely unsalvageable with conventional approaches aimed at achieving CR2 followed by alloHSCT. Future efforts should be aimed at identifying those patients who are destined to relapse and exploring novel treatment approaches for this high-risk group and for those who do relapse., (© 2018 John Wiley & Sons Ltd.)

Standard quality assurance (QA) of cryopreserved peripheral blood stem cells (PBSC) uses post-thaw viable CD34(+) cell counts. In 2013, concerns arose at Great Ormond Street Hospital (GOSH) about 8 patients with delayed engraftment following myeloablative chemotherapy with cryopreserved cell rescue, despite adequate post-thaw viable cell counts in all cases. Root cause analysis was undertaken; investigations suggested the freeze process itself was a contributing factor to suboptimal engraftment. Experiments were undertaken in which a single PBSC product was divided into three and cryopreserved in parallel using a control-rate freezer (CRF) or passive freezing method (-80°C freezer) at GOSH, or the same passive freezing at another laboratory. Viable CD34(+) counts were equivalent and adequate in each. Granulocyte-monocyte colony-forming unit assays demonstrated colonies from the products cryopreserved using passive freezing (both laboratories), but no colonies from products cryopreserved using the CRF. The CRF was shown to be operating within manufacturer's specifications with freeze-profile within acceptable limits. This experience has important implications for quality assurance for all transplant programmes, particularly those using cryopreserved products. The failure of post-thaw viable CD34(+) counts, the most widely used routine QA test available, to ensure PBSC function is of great concern and should prompt reassessment of protocols and QA procedures., (© 2016 John Wiley & Sons Ltd.)

Despite the substantial outcome improvements achieved in paediatric acute lymphoblastic leukaemia (ALL), survival in teenage and young adult (TYA) patients has remained inferior. We report the treatment outcomes and toxicity profiles observed in TYA patients treated on the UK paediatric ALL trial, UKALL2003. UKALL2003 was a multi-centre, prospective, randomized phase III trial, investigating treatment intensification or de-escalation according to minimal residual disease (MRD) kinetics at the end of induction. Of 3126 patients recruited to UKALL2003, 229 (7·3%) were aged 16-24 years. These patients were significantly more likely to have high risk MRD compared to 10-15 year olds (47·9% vs. 36·6%, P = 0·004). Nonetheless, 5-year event-free survival for the TYA cohort (aged 16-24 years) was 72·3% [95% confidence interval (CI): 66·2-78·4] overall and 92·6% (95% CI: 85·5-99·7) for MRD low risk patients. The risk of serious adverse events was higher in patients aged ≥10 years compared to those aged 9 or younger (P < 0·0001) and novel age-specific patterns of treatment-related toxicity were observed. TYA patients obtain excellent outcomes with a risk- and response-adapted paediatric chemotherapy protocol. Whilst those aged 10 years and older have excess toxicity compared with younger patients, the age association is specific to individual toxicities., (© 2015 John Wiley & Sons Ltd.)

We investigated the outcome for children and young people with Early T-precursor acute lymphoblastic leukaemia (ETP-ALL), a recently described poor prognosis sub-group of T-ALL, treated on a contemporary protocol, UKALL 2003. After a median follow-up of 4 years and 10 months, the ETP sub-group, representing 16% of T-ALL patients, had non-significantly inferior 5-year event-free survival (76·7% vs. 84·6%, P = 0·2) and overall survival (82·4% vs. 90·9%, P = 0·1), and a higher relapse rate (18·6% vs. 9·6%, P = 0·1) compared to typical T-ALL. ETP-ALL has an intermediate risk outcome, which does not warrant experimental treatment or first remission allogeneic transplant for the group universally., (© 2014 John Wiley & Sons Ltd.)

We report the outcome for children and young people with Down syndrome-associated acute lymphoblastic leukaemia (DS-ALL) treated on a contemporary protocol. Compared with non-DS ALL, patients with DS-ALL had an inferior event-free survival (65·6% vs. 87·7% at 5 years; P < 0·00005) and overall survival (70·0% vs. 92·2%; P < 0·00005). Excess treatment-related mortality - was primarily responsible for the worse outcomes for DS-ALL (21·6% at 5 years, vs. 3·3%, P < 0·00005). Minimal residual disease (MRD) risk status was highly discriminant for relapse in DS patients with 0/28 relapses in the MRD low risk group., (© 2014 John Wiley & Sons Ltd.)

We retrospectively analysed the outcome of consecutive children with idiopathic severe aplastic anaemia in the United Kingdom who received immunosuppressive therapy (IST) or matched unrelated donor (MUD) haematopoietic stem cell transplantation (HSCT). The 6-month cumulative response rate following rabbit antithymocyte globulin (ATG)/ciclosporin (IST) was 32·5% (95% CI 19·3-46·6) (n = 43). The 5-year estimated failure-free survival (FFS) following IST was 13·3% (95% confidence interval [CI] 4·0-27·8). In contrast, in 44 successive children who received a 10-antigen (HLA-A, -B, -C, -DRB1, -DQB1) MUD HSCT there was an excellent estimated 5-year FFS of 95·01% (95% CI 81·38-98·74). Forty of these children had failed IST previously. HSCT conditioning was a fludarabine, cyclophosphamide and alemtuzumab (FCC) regimen and did not include radiotherapy. There were no cases of graft failure. Median donor chimerism was 100% (range 88-100%). A conditioning regimen, such as FCC that avoids total body irradiation is ideally suited in children. Our data suggest that MUD HSCT following IST failure offers an excellent outcome and furthermore, if a suitable MUD can be found quickly, MUD HSCT may be a reasonable alternative to IST., (© 2012 Blackwell Publishing Ltd.)

Umbilical cord blood transplant (UCBT) is associated with impaired early immune reconstitution. This might be explained by a lower T-cell dose infused, the naivety of cord blood T-cells and the use of in vivo T-cell depletion. We studied the pattern of early immune reconstitution and the clinical outcome of children undergoing unrelated UCBT when in vivo T-cell depletion was omitted. Thirty children affected by malignancies (46%) or immunodeficiencies (54%) underwent an unrelated UCBT. Prospective assessment of immune reconstitution and clinical outcome was performed. We observed an unprecedented CD4(+) T-cell reconstitution, with a median cell count at 30 and 60 d post UCBT of 0.3 × 10(9) /l and 0.56 × 10(9) /l, respectively. Early T-cell expansion was thymic-independent, with a rapid shift from naïve to central memory phenotype and early regulatory T-cell recovery. Viral infections were frequent (63%) but resolved rapidly in most cases and virus-specific T-lymphocytes were detected within 2 months post-UCBT. Acute graft-versus-host disease (GvHD) was frequent (grade II = 34%, grade III-IV = 16%) but steroid responsive, and the incidence of chronic GvHD was low (14%). The omission of in vivo T-cell depletion promotes a unique thymic-independent CD4(+) T-cell reconstitution after unrelated UCBT in children. We postulate that this relates to the specific immunological and ontological qualities of fetal-derived lymphocytes., (© 2012 Blackwell Publishing Ltd.)

This study investigated the efficacy of a pre-emptive strategy based on the combination of Epstein-Barr virus (EBV) viraemia and poor T cell reconstitution in preventing post-transplant lymphoproliferative disease (PTLD) following T cell depleted stem cell transplant (SCT). EBV viral load and immune reconstitution were prospectively monitored in 70 consecutive children undergoing SCT following reduced intensity conditioning with alemtuzumab. Patients who developed significant EBV viraemia (> 40 000 copies/ml blood) were treated pre-emptively with rituximab if they were within 3 months of SCT or their CD3 count was <0·3 × 10⁹ /l. Of 20/70 patients who developed significant EBV viraemia, 13 received pre-emptive rituximab. The incidence of PTLD was significantly reduced in the pre-emptive cohort compared to historical controls (1·4% vs. 21·7%, P = 0·003). This difference was more marked among viraemic patients (2·7% vs. 62·5%P < 0·0001). Patients treated with rituximab demonstrated significantly delayed B cell reconstitution at 1 year post-SCT but this was not associated with an increase in infectious mortality. In 6/6 patients >3 months post-SCT who had a CD3 count >0·3 × 10⁹ /l, reduced immunosuppression only resulted in successful resolution of EBV viraemia without PTLD. This strategy is safe and highly effective in preventing PTLD following T cell depleted SCT, and directs rituximab therapy to patients at highest risk of this complication., (2011 Blackwell Publishing Ltd.)

We report the incidence and outcome of venous thrombosis (VT) in the UK acute lymphoblastic leukaemia (ALL) 2003 trial. VT occurred in 59/1824 (3.2%) patients recruited over 5 years with 90% occurring during a period of Asparagine depletion. Pegylated Escherichia Coli Asparaginase (Peg-ASP) 1000 units/m(2) was used throughout. Thirty-four children received further Peg-ASP, most with concurrent heparin prophylaxis. There were no episodes of bleeding or recurrent thrombosis. Optimal Asparagine depletion is central to success of modern regimes for treatment of ALL. This report confirms a significant risk of thrombosis with such therapy, but demonstrates that re-exposure to Asparaginase is feasible and safe.

Treosulfan is an immuno-suppressive and myeloablative alkylating agent that has been introduced as a conditioning agent in stem cell transplantation (SCT). Most studies have been performed in adult patients with malignancy where a low incidence of regimen-related toxicity has been reported. We report the use of treosulfan in 32 consecutive children undergoing SCT for non-malignant disease. Patients received a total treosulfan dose of 36 or 42 g/m(2)/patient given in three daily, divided doses. A range of other conditioning agents and serotherapy was administered to patients who underwent family donor SCT (n = 11), or unrelated donor SCT (n = 21). One patient (3%) died early. Transplant morbidity was limited and mucositis was only mild. Dermatological toxicity was frequent but mild. Twenty-eight patients (87.5%) established donor cell engraftment. In 25 patients (78%) there was adequate, stable donor engraftment. Four patients have required additional transplant procedures to maintain adequate donor-derived haemopoiesis. Twenty-seven patients (84%) survive with a median follow up of 417 d. There were four late deaths due to progression of the underlying disease, graft-versus-host disease or infection. Treosulfan-based conditioning regimens achieve excellent engraftment with reduced regimen-related toxicity in children with non-malignant disease at high risk for both regimen-related toxicity and graft failure.

The continued improvement in the prognosis of childhood acute myeloid leukaemia (AML) has been paralleled by the use of increasingly intensive therapy. This has led to attempts to develop risk-directed strategies in which the most intensive treatment is reserved for those at highest risk of relapse. Unfortunately, current approaches, which rely on cytogenetic sub-grouping and morphological assessment of response to therapy, are inaccurate. New prognostic factors are needed. This annotation proposes that the introduction of protocols based on the measurement of minimal residual disease (MRD) holds the key to progression from an era of 'cure at all costs' to a more individualised approach. However, the full potential of MRD technologies will only be realised through properly designed studies with scrupulous attention to logistics and quality assurance. The article illustrates which children may benefit most from MRD analysis in AML and explores practical issues that should be addressed in the design of clinical trials.

Some children with relapsed or high-risk acute leukaemia have an improved outcome if they have an allogeneic stem cell transplant, preferably from a sibling or well-matched unrelated donor. However, some children do not have these options or there is an urgent need to proceed to transplant because of disease status. We have investigated the role of haploidentical family members as donors in 34 patients with acute leukaemia (median age 11 years, range 1-16 years). Patients were conditioned with cyclophosphamide and total body irradiation (14.4 Gy in eight fractions) and received T-cell depleted peripheral blood stem cell grafts with a median CD34 cell dose of 13.8 x 10(6)/kg (range 4.2-35.1) and 0.7 x 10(4) CD3-positive cells/kg. The actuarial survival at 2 years was 26% (13-41%, 95% CI). Eight patients have survived disease-free with a median follow up of 62 months. They have good performance status and a median lymphocyte count of 1.8 x 10(9)/l. Relapse (14 patients) and adenoviral (six patients) or fungal infections (four patients) were the major causes of death. Haploidentical stem cell transplantation can produce medium term disease-free survival in a proportion of children with high-risk or relapsed acute leukaemia. None of the nine patients with acute myeloid leukaemia not in remission have survived.

Allogeneic stem cell transplantation (SCT) is a highly effective therapy for childhood acute lymphoblastic leukaemia (ALL). Concerns about unnecessary toxicity and expense mean that SCT is currently largely reserved for children who cannot be cured with chemotherapy. Not surprisingly, many such children also fail SCT. Retrospective studies have shown that a single analysis of minimal residual disease (MRD) pre-SCT identified those at highest risk of relapse. It is now appropriate to call for the universal incorporation of standardized MRD testing into SCT protocols as the next step to maximize the clinical impact of this technology in ALL.

The impact of transfusion of leucodepleted platelet concentrates (PCs) on cytomegalovirus (CMV) disease was assessed in 215 allogeneic (145 unrelated and 70 related donor) transplants over 3 years. In 43%, both donor and patient were CMV seronegative (CMV-/-). All received CMV-seronegative red cells and random leucodepleted PCs. No CMV disease occurred in any CMV-/- (low risk) transplant. CMV infection occurred in 31 seropositive patients (26%); 13 died and five deaths were attributable to CMV disease. When compared with historical controls, who received CMV-seronegative PCs, we found no difference in transfusion-acquired CMV in the current cohort.

In this study, we retrospectively analysed the clinical features, risk factors and outcome of 22 patients with thrombotic thrombocytopenic purpura (TTP) occurring after allogeneic stem cell transplantation. All but two of these patients received stem cells from unrelated donors (UDs), two-thirds were female, three-quarters were adults and leukaemia was the major reason for transplant. The incidence of TTP was 20 out of 332 patients (6%) with UD transplants and two out of 104 recipients (2%) of matched sibling allografts (P = 0.16). In order to ascertain basic demographic risk factors for the development of TTP, we compared the 22 patients with 434 patients who did not develop TTP. Compared with patients who did not develop TTP, patients with TTP were nearly three times older (P < 0.001) and were more than twice as likely to be female (P = 0.001). Because > 90% of patients were recipients of UD marrow, we then compared the 20 UD-bone marrow transplantation (BMT) patients with 60 randomly selected UD-BMT patients who did not develop TTP. On univariate analysis, age and female gender were again significant risk factors, as was grade II-IV acute graft-versus-host disease (GvHD) (P = 0.002), and there was a trend towards an association with chronic GvHD (P = 0.083). However, after logistic regression analysis, only age and sex remained significant (P < 0.001 and 0.009 respectively). We report an 86% mortality with only three survivors out of 22 patients, and one of these remains thrombocytopenic and red cell transfusion dependent, possibly in part because of graft hypoplasia. Six out of 17 patients responded to plasmapheresis, but the majority of them ultimately succumbed because of TTP, often in association with GvHD or fungal infection.

Detection of residual disease after completion of therapy or following bone marrow transplantation (BMT) in patients with acute promyelocytic leukaemia (APL) predicts relapse and is associated with a poor prognosis. Here we describe the successful treatment of residual disease post-transplant in APL using prolonged all-trans retinoic acid (ATRA) therapy in two children in whom autologous BMT (ABMT) had been performed in second complete remission (CR). ATRA treatment was well tolerated and found to be beneficial despite its prior use as a component of the initial induction protocol. ATRA therapy post-transplant led to molecular remission as determined by fluorescence in situ hybridization (FISH) as well as reverse transcriptase-polymerase chain reaction (RT-PCR) analyses and remission now exceeds 3.5 years in both patients. Overall, this study not only demonstrates that ATRA may successfully salvage APL patients with residual disease post-transplant, but also suggests a potential role for retinoids post-consolidation as a means of eliminating residual disease which could be beneficial even in patients previously exposed to ATRA as a component of the induction protocol.

We have analysed the behaviour of minimal residual disease (MRD) after allogeneic bone marrow transplantation (allo-BMT) in 71 children with acute lymphoblastic leukaemia (ALL). The method relied on PCR of IgH, TCRdelta and/or TCRgamma gene rearrangements followed by electrophoretic size resolution and allele-specific oligoprobing. Patients were similarly conditioned; 55 received marrow from unrelated donors and 16 from related donors. MRD was assessed at various time-points up to 24 months after BMT. Three children were not evaluable due to transplant-related mortality. MRD was detected in 28/32 patients (88%) who relapsed post-BMT; 16 were positive at all times and 12 were initially negative but became positive at a median of 3 months (range 1.5-11) prior to relapse. In contrast, only eight of 36 (22%) patients who remained in continuing complete remission (CCR) (median follow-up 43 months, range 20-94) showed MRD at any time after BMT (P<0.0001). In these eight patients MRD was found up to 9 months after transplant and at low levels (0.01-0.001%). All eight (median follow-up 39 months, range 24-87) had at least two MRD-negative samples tested subsequently and five of the eight had evidence of grade I-II acute graft-versus-host disease (GvHD), raising the possibility of a graft-versus-leukaemia effect. In general, any evidence of MRD after allo-BMT is a poor prognostic sign. However, if immunotherapy were to be targeted towards patients with evidence of persisting MRD after BMT, the method described would expose only a small proportion of patients to unnecessary additional toxicity.

We report a largely retrospective analysis of minimal residual disease (MRD) in a cohort of 66 children suffering from acute lymphoblastic leukaemia (ALL). All patients lacked high-risk features at diagnosis, i.e. the presenting white cell count was <50 x 10(9)/l, age 1-16 years and translocations t(9;22) and t(4;11) were not present. All were treated according to either the MRC protocols UKALL X or XI. PCR of IgH, TCRdelta and TCRgamma gene rearrangements and allele-specific oligoprobing were employed for the detection of MRD. Sensitivity was at least 10(-4) in 78/82 (93%) probes examined. A total of 33 patients relapsed (seven on therapy and 26 off) and 33 remain in continuing complete remission (CCR) (median follow-up 69 months from diagnosis). Of those who remain in CCR, MRD was present in the bone marrow in 32%, 10% and 0% at 1, 3 and 5 months into therapy respectively. This is in marked contrast to the presence of MRD at these times in 82%, 60% and 41% of patients who relapsed (P<0.001, P<0.005 and P<0.005). These results provide further evidence of a strong correlation between clearance of MRD early in therapy and clinical outcome in childhood ALL.

Approximately one-third of first relapses of childhood ALL occur at an extramedullary site without morphological evidence of bone marrow disease. However, the high incidence of subsequent medullary relapse in these cases strongly suggests that leukaemia is present at submicroscopic levels at the time of 'isolated' relapse. PCR analysis of immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements now allows detection of leukaemia at levels as low as 0.001%. We have therefore used this technique to reassess bone marrow status at morphologically isolated relapse in 13 children with B-lineage ALL (11 with off-treatment relapses, two on treatment). In 12 of these 13 patients marrow disease was detectable by PCR at the time of this relapse--in all cases at levels below the threshold of light microscopy. Where relapse occurred off-therapy this indicated re-emergence of disease. since MRD has never been detected by PCR at this stage in patients remaining in long-term remission. In both patients who relapsed on-therapy the level of MRD at the time of relapse represented an increase on that seen in their previous marrow sample. We conclude that re-emerging bone marrow disease can be detected in most cases of 'isolated' relapse when investigated by this highly sensitive technique. Our findings at a molecular level confirm a long-held clinical suspicion and indicate that full systemic re-induction as well as local therapy is obligatory for these children.

A 16-year-old youth with life-threatening virus-associated haemophagocytic syndrome (VAHS) responded remarkably to treatment with cyclosporin A during two periods of active disease, the second of which was due to noncompliance with treatment. Our clinical observations support the hypothesis that VAHS is cytokine driven as a result of an aberrant T-cell response to infection.