Impact of donor NKG2D and MICA gene polymorphism on clinical outcomes of adult and paediatric allogeneic cord blood transplantation for malignant diseases.

OBJECTIVES: NKG2D is an activating receptor expressed by natural killer (NK) and CD8+ T cells and activation intensity varies by NKG2D expression level or nature of its ligand. An NKG2D gene polymorphism determines high (HNK1) or low (LNK1) expression. MICA is the most polymorphic NKG2D ligand and stronger effector cell activation associates with methionine rather than valine at residue 129. We investigated correlation between cord blood (CB) NKG2D and MICA genotypes and haematopoietic stem cell (HSC) transplant outcome. METHODS: We retrospectively studied 267 CB HSC recipients (178 adult and 87 paediatric) who underwent transplant for malignant disease between 2007 and 2018, analysing CB graft DNA for NKG2D and MICA polymorphisms using Sanger sequencing. Multivariate analysis was used to correlate these results with transplant outcomes. RESULTS: In adult patients, LNK1 homozygous CB significantly improved 60-day neutrophil engraftment (hazard ratio (HR) 0.6; 95% confidence interval (CI) 0.4-0.9; p = .003). In paediatrics, HNK1 homozygous CB improved 60-day engraftment (HR 0.4; 95% CI 0.2-0.7; p = .003), as did MICA-129 methionine+ CB grafts (HR 1.7 95% CI 1.1-2.6; p = .02). CONCLUSION: CB NKG2D and MICA genotypes potentially improve CB HSC engraftment. However, results contrast between adult and paediatric recipients and may reflect transplant procedure disparities between cohorts.

Secondary Oral Squamous Cell Carcinoma following Haematopoietic Stem Cell Transplantation.

We report 10 cases of oral squamous cell carcinoma (SCC) post-haematopoietic stem cell transplant (HSCT).. Median latency from HSCT to oral SCC diagnosis was 10 years (range: 4-17 years) with 90% reporting a history of chronic graft-versus-host disease (cGVHD) and 40% exhibited active severe manifestations of oral GVHD. Clinical findings at diagnosis included induration, ulceration, tenderness, bleeding, hyperkeratosis, speckling and lymphadenopathy. The tongue and buccal mucosa were the commonest sites affected. Disease stage at presentation ranged from T1N0M0 to T4N2M0. Management included surgical resection in 90% of cases ± chemo/radiotherapy. Median follow-up for the cohort was l years with 50% mortality rate. SCC-specific mortality was 30%. Our data highlight the importance of regular, active oral and cutaneous surveillance of post-HSCT patients in specialised dermatology clinics, irrespective of GVHD severity and length of iatrogenic immunosuppression.

Impaired humoral and cellular response to primary COVID-19 vaccination in patients less than 2 years after allogeneic bone marrow transplant.

Allogeneic haematopoietic stem cell transplant (HSCT) recipients remain at high risk of adverse outcomes from coronavirus disease 2019 (COVID-19) and emerging variants. The optimal prophylactic vaccine strategy for this cohort is not defined. T cell-mediated immunity is a critical component of graft-versus-tumour effect and in determining vaccine immunogenicity. Using validated anti-spike (S) immunoglobulin G (IgG) and S-specific interferon-gamma enzyme-linked immunospot (IFNγ-ELIspot) assays we analysed response to a two-dose vaccination schedule (either BNT162b2 or ChAdOx1) in 33 HSCT recipients at ≤2 years from transplant, alongside vaccine-matched healthy controls (HCs). After two vaccines, infection-naïve HSCT recipients had a significantly lower rate of seroconversion compared to infection-naïve HCs (25/32 HSCT vs. 39/39 HCs no responders) and had lower S-specific T-cell responses. The HSCT recipients who received BNT162b2 had a higher rate of seroconversion compared to ChAdOx1 (89% vs. 74%) and significantly higher anti-S IgG titres (p = 0.022). S-specific T-cell responses were seen after one vaccine in HCs and HSCT recipients. However, two vaccines enhanced S-specific T-cell responses in HCs but not in the majority of HSCT recipients. These data demonstrate limited immunogenicity of two-dose vaccination strategies in HSCT recipients, bolstering evidence of the need for additional boosters and/or alternative prophylactic measures in this group.

Molecular MRD status and outcome after transplantation in NPM1-mutated AML.

Relapse remains the most common cause of treatment failure for patients with acute myeloid leukemia (AML) who undergo allogeneic stem cell transplantation (alloSCT), and carries a grave prognosis. Multiple studies have identified the presence of measurable residual disease (MRD) assessed by flow cytometry before alloSCT as a strong predictor of relapse, but it is not clear how these findings apply to patients who test positive in molecular MRD assays, which have far greater sensitivity. We analyzed pretransplant blood and bone marrow samples by reverse-transcription polymerase chain reaction in 107 patients with NPM1-mutant AML enrolled in the UK National Cancer Research Institute AML17 study. After a median follow-up of 4.9 years, patients with negative, low (<200 copies per 105ABL in the peripheral blood and <1000 copies in the bone marrow aspirate), and high levels of MRD had an estimated 2-year overall survival (2y-OS) of 83%, 63%, and 13%, respectively (P < .0001). Focusing on patients with low-level MRD before alloSCT, those with FLT3 internal tandem duplications(ITDs) had significantly poorer outcome (hazard ratio [HR], 6.14; P = .01). Combining these variables was highly prognostic, dividing patients into 2 groups with 2y-OS of 17% and 82% (HR, 13.2; P < .0001). T-depletion was associated with significantly reduced survival both in the entire cohort (2y-OS, 56% vs 96%; HR, 3.24; P = .0005) and in MRD-positive patients (2y-OS, 34% vs 100%; HR, 3.78; P = .003), but there was no significant effect of either conditioning regimen or donor source on outcome. Registered at ISRCTN (http://www.isrctn.com/ISRCTN55675535).

Pruritic rash following haploidentical stem cell transplantation.

A woman who had undergone haematopoietic stem cell transplantation presented with cutaneous features suggestive of graft-versus-host disease. Histopathological examination revealed a diffuse dermal infiltration of atypical monomorphic cells with a high proliferative index. Immunohistochemistry revealed positivity for monocytic markers, but negativity for T-cell markers.

"Is this the GVHD?" A qualitative exploration of quality of life issues in individuals with graft-versus-host disease following allogeneic stem cell transplant and their experiences of a specialist multidisciplinary bone marrow transplant service.

BACKGROUND: Graft-versus-host disease (GVHD) is a significant cause of morbidity and mortality following allogeneic stem cell transplantation. These patients face unique challenges due to the complexity of GVHD which can affect multiple organ systems, and the toxicity of treatments. Despite the known impact on quality of life (QOL), qualitative data within the bone marrow transplantation (BMT) literature is rare, and there has been no qualitative work exploring patient experience of specialist healthcare provision for GVHD in the United Kingdom. METHODS: We conducted a primary explorative qualitative study of the experience of QOL issues and multidisciplinary care in patients with chronic GVHD following allogeneic stem cell transplantation. Eight patients were identified using convenience sampling from specialist BMT outpatient clinics. Following consent, patients were interviewed individually via telephone. Transcripts of interviews were analyzed using an inductive thematic approach. RESULTS: Mean participant age was 61-years-old (range 45-68), with a mean time post-transplant of 3 years at time of interview (range 3 months-15 years). Five key QOL themes were identified: (1) 'Restricted as to what I can do'; (2) Troubling symptoms-'you can sort of get GVHD anywhere'; (3) Confusion/uncertainty over GVHD symptoms-'Is this the GVHD?'; (4) Unpredictable course and uncertainty about the future; and (5) Adapting to the sick role. In addition, four themes related to experience of service provision were identified: (1) personal care and close relationship with BMT nurses; (2) efficiency versus long waits-'On the case straight away'; (3) information provision-'went into it with a bit of a rosy view'; and (4) the role of support groups. CONCLUSIONS: These qualitative data reflect the heterogeneity of experiences of the GVHD patient population, reflecting the need for a flexible and nuanced approach to patient care with emphasis on comprehensive information provision. We have identified the key role that BMT specialist nurses within the multidisciplinary team play in supporting patients. We advocate future research should focus on ways to meet the complex needs of this patient group and ensure that the personal care and close relationships are not lost in service redesigns embracing remote consultations.

Recipients Receiving Better HLA-Matched Hematopoietic Cell Transplantation Grafts, Uncovered by a Novel HLA Typing Method, Have Superior Survival: A Retrospective Study.

HLA matching at an allelic-level resolution for volunteer unrelated donor (VUD) hematopoietic cell transplantation (HCT) results in improved survival and fewer post-transplant complications. Limitations in typing technologies used for the hyperpolymorphic HLA genes have meant that variations outside of the antigen recognition domain (ARD) have not been previously characterized in HCT. Our aim was to explore the extent of diversity outside of the ARD and determine the impact of this diversity on transplant outcome. Eight hundred ninety-one VUD-HCT donors and their recipients transplanted for a hematologic malignancy in the United Kingdom were retrospectively HLA typed at an ultra-high resolution (UHR) for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 using next-generation sequencing technology. Matching was determined at full gene level for HLA class I and at a coding DNA sequence level for HLA class II genes. The HLA matching status changed in 29.1% of pairs after UHR HLA typing. The 12/12 UHR HLA matched patients had significantly improved 5-year overall survival when compared with those believed to be 12/12 HLA matches based on their original HLA typing but were found to be mismatched after UHR HLA typing (54.8% versus 30.1%, P = .022). Survival was also significantly better in 12/12 UHR HLA-matched patients when compared with those with any degree of mismatch at this level of resolution (55.1% versus 40.1%, P = .005). This study shows that better HLA matching, found when typing is done at UHR that includes exons outside of the ARD, introns, and untranslated regions, can significantly improve outcomes for recipients of a VUD-HCT for a hematologic malignancy and should be prospectively performed at donor selection.

Impact of graft-versus-lymphoma effect on outcomes after reduced intensity conditioned-alemtuzumab allogeneic haematopoietic stem cell transplantation for patients with mature lymphoid malignancies.

Allogeneic haematopoietic stem cell transplant (allo-HSCT) offers potentially curative therapy for patients with relapsed/refractory lymphoid malignancies. Reduced-intensity conditioning (RIC) with Alemtuzumab reduces transplant-related mortality and graft-versus-host disease (GvHD), but may be associated with increased risk of relapse. With the aim of studying the effect of GVHD and donor lymphocyte infusions (DLI) on relapse, we performed a retrospective study of 288 patients (57% non-Hodgkin lymphoma, 24% Hodgkin lymphoma and 19% chronic lymphocytic leukaemia; 58% were relapsed/refractory) who underwent RIC-Alemtuzumab-HSCT between 2000 and 2012. Median follow-up time for survivors was 64 months. Five-year overall survival, relapse incidence, GvHD/relapse-free survival and non-relapse mortality were 47%, 33%, 37% and 28% respectively. Cumulative incidence of grade II-IV acute and extensive chronic GvHD was 22% and 21% at 100 days and 5 years respectively. On multivariate analysis, presence of GvHD (P = 0·03) and unrelated donor type (P = 0·03) were protective of relapse. 62/288 patients received DLI for either mixed donor chimerism (prophylactic DLI, n = 37) or clinical relapse (therapeutic DLI, n = 25). Prophylactic and therapeutic DLI successfully converted the patient to full or stable mixed donor chimerism in 78% and 56% of patients respectively. These data demonstrate good long-term outcomes and support the concept of the graft-vs-lymphoma effect as a key protective factor against relapse following RIC-Alemtuzumab allo-HSCT for patients with mature lymphoid malignancies.

Umbilical Cord Blood Cytomegalovirus Serostatus Does Not Have an Impact on Outcomes of Umbilical Cord Blood Transplantation for Acute Leukemia.

Several studies have reported an impact of adult hematopoietic stem cell donor cytomegalovirus (CMV) serostatus on allogeneic hematopoietic cell transplantation outcomes. Limited data, however, are available on the impact of cord blood unit (CBU) CMV serostatus on allogeneic umbilical cord blood transplantation (UCBT) outcomes. We analyzed, retrospectively, the impact of CBU CMV serostatus on relapse incidence (RI) and 2-year nonrelapse mortality (NRM) of single-unit CBU transplantation for acute leukemia. Data from 1177 de novo acute leukemia pediatric and adult patients transplanted within European Group for Blood and Marrow Transplantation centers between 2000 and 2012 were analyzed. CBUs were provided by the European Cord Blood Banks. The median follow-up time for live patients was 59.9 months. The recipients of CMV-seropositive and -seronegative CBUs showed a comparable RI (33% versus 35%, respectively, P = .6) and 2-year cumulative incidence of NRM (31% versus 32%, respectively, P = .5). We conclude that CBU CMV serostatus did not influence RI and NRM in de novo acute leukemia patients after allo-UCBT and should not be included as a criteria for cord blood choice.

Increased regulatory T cell graft content is associated with improved outcome in haematopoietic stem cell transplantation: a systematic review.

Allogeneic haematopoietic stem cell transplant (HSCT) recipients are at increased risk of morbidity and mortality, often due to the development of acute or chronic graft-versus-host disease (GVHD). Low numbers or proportions of regulatory T cells (Tregs) have been reported in patients who develop GVHD. We undertook a systematic review of studies that reported the Treg composition of HSCT grafts in patients with haematological malignancies. Fourteen eligible studies were identified, eight of which stratified patients by Tregs (absolute dose or ratio to CD3+ or CD4+ cells). Meta-analyses showed that high levels of Tregs in the grafts were associated with improved overall survival [hazard ratio (HR) 0·42, 95% confidence interval (CI) 0·23-0·74, P = 0·003, 2 studies], with a significant reduction in non-relapse mortality (HR 0·30, 95% CI 0·14-0·64, P = 0·002, 2 studies) and a reduced risk of acute GVHD (relative risk (RR) 0·59, 95% CI 0·40-0·89, P = 0·01, 6 studies). The consistency of these findings strongly suggests that the Treg composition of HSCT grafts has a powerful effect on the success of allogeneic HSCT. The major challenge is to translate these findings into better selection of allografts and future donors to provide a substantial improvement in allogeneic HSCT outcomes and practice.

Killer Cell Immunoglobulin-Like Receptor-Ligand Matching and Outcomes after Unrelated Cord Blood Transplantation in Acute Myeloid Leukemia.

The effect of killer cell immunoglobulin-like receptor (KIR)-ligand matching on outcomes after unrelated cord blood (CB) transplantation was studied in 461 patients with acute myeloid leukemia, categorizing KIR ligand for HLA-C groups C1 and C2 and Bw4. Donor-recipient HLA matching considered allele-level matching at HLA-A, -B, -C, and -DRB1. Separate analyses were conducted for 6-7/8 HLA-matched and 3-5/8 HLA-matched transplants because HLA matching confounded KIR-ligand matching (ie, KIR-ligand mismatching was less likely with better HLA matching). All patients received single CB unit and myeloablative conditioning. There were no significant differences in nonrelapse mortality (NRM), relapse, and overall mortality by KIR-ligand match status. However, among recipients of 3-5/8 HLA-matched transplants, NRM (HR, 2.26; P = .008) and overall mortality (HR, 1.78; P = .008) but not relapse were higher with KIR-ligand mismatched (host-versus-graft direction) compared with KIR-ligand matched transplants. These data do not support selecting CB units based on KIR-ligand match status for transplants mismatched at 1 or 2 HLA loci. Although transplants mismatched at 3 or more HLA loci are not recommended, avoiding KIR-ligand mismatching in this setting lowers mortality risks.

Recommendations for a standard UK approach to incorporating umbilical cord blood into clinical transplantation practice: an update on cord blood unit selection, donor selection algorithms and conditioning protocols.

Allogeneic haemopoietic stem cell transplantation offers a potentially curative treatment option for a wide range of life-threatening malignant and non-malignant disorders of the bone marrow and immune system in patients of all ages. With rapidly emerging advances in the use of alternative donors, such as mismatched unrelated, cord blood and haploidentical donors, it is now possible to find a potential donor for almost all patients in whom an allograft is indicated. Therefore, for any specific patient, the transplant physician may be faced with a myriad of potential choices, including decisions concerning which donor to prioritize where there is more than one, the optimal selection of specific umbilical cord blood units and which conditioning and graft-versus-host disease prophylactic schedule to use. Donor choice may be further complicated by other important factors, such as urgency of transplant, the presence of alloantibodies, the disease status (homozygosity or heterozygosity) of sibling donors affected by inherited disorders and the cytomegalovirus serostatus of patient and donor. We report UK consensus guidelines on the selection of umbilical cord blood units, the hierarchy of donor selection and the preferred conditioning regimens for umbilical cord blood transplantation, with a summary of rationale supporting these recommendations.

An innovative method to generate a Good Manufacturing Practice-ready regulatory T-cell product from non-mobilized leukapheresis donors.

BACKGROUND AIMS: There is real and sustained interest in preparing T-regulatory cells from leukapheresis collections for cellular therapy through the use of simple, effective and reliable methods conforming to Good Manufacturing Practice (GMP). We describe a GMP-ready isolation procedure for CD25(+) products with the use of a sterile docking device, pigtail sampling, a laminar flow hood and the CliniMACS system that uses leukapheresis collections made by two apheresis machines. METHODS: We used CD8/CD19 depletion followed by CD25-positive selection. The median number of CD4(+) cells recovered was 72.5 ± 32.6 × 10(6), of which 60.5% ± 17.8% were CD25(+)FOXP3(+) cells. Suppression of autologous CD25(-) cell proliferation by the cryopreserved CD25(+) products was 51.3% ± 4.4%, 49.0% ± 3.7% and 39.0% ± 3.6% at CD25(+):CD25(-) ratios of 1:1, 1:2 and 1:4 (n = 6), respectively, comparable to suppression by fresh CD25(+) products (53% ± 6.2%, 51% ± 3.3% and 39% ± 7.1%). RESULTS: We found Leukapheresis collections by Cobe Spectra contained more lymphocytes and platelets than collections by Spectra Optia apheresis machine (median, 9.2 × 10(9) versus 6.7 × 10(9); P = 0.04) and platelets (median, 610 × 10(9) versus 170 × 10(9); P = 0.04). The frequency of CD4(+)CD25(+)FOXP3(+) was significantly higher in the leukapheresis (4.85%; 95% confidence interval, 1.95% to 5.38%) than in peripheral blood (3.9%; 95% confidence interval, 2.63% to 6.45%) (P = 0.02). The CD8- and CD19-negative depletion step was associated with significant loss of total CD4(+) T cells (P = 0.001). CONCLUSIONS: Results suggest that functional CD25(+) products can be isolated with a GMP-ready method, and good recovery can be obtained with the use of an optimized cryopreservation protocol. These data and methods show the potential, possibilities and future work needed to isolate target cell populations in a reproducible, time-efficient and cost-efficient manner for clinical applications.

Characterisation of RAET1E/ULBP4 exon 4 and 3' untranslated region genetic architecture reveals further diversity and allelic polymorphism.

NKG2D is a natural killer cell activating receptor recognising ligands on infected or tumorigenic cells, leading to their cytolysis. There are eight known genes encoding NKG2D ligands: MICA, MICB and ULBP1-6. MICA and MICB are highly polymorphic and well characterised, whilst ULBP ligands are less polymorphic and the functional implication of their diversity is not well understood. Using International HLA and Immunogenetics Workshop (IHIW) cell line DNA, we previously characterised alleles of the RAET1E gene (encoding ULBP4 proteins), including the 5' UTR promoter region and exons 1-3. We found 11 promoter haplotypes associating with alleles based on exons 1-3, revealing 19 alleles overall. The current study extends this analysis using 87 individual DNA samples from IHIW cell lines or cord blood to include RAET1E exon 4 and the 3' UTR, as polymorphism in these regions have not been previously investigated. We found two novel exon 4 polymorphisms encoding amino acid substitutions altering the transmembrane domain. An amino acid substitution at residue 233 was unique to the RAET1E*008 allele whereas the substitution at residue 237 was shared between groups of alleles. Additionally, four haplotypes were found based on 3' UTR sequences, which were unique to certain alleles or shared with allele groups based on exons 1-4 polymorphisms. Furthermore, putative microRNAs were identified that may interact with these polymorphic sites, repressing transcription and potentially affecting expression levels.

Selective depletion of FOXP3(high) cells by Fas-Fas-L-induced apoptosis occurs in CD4(+)CD25(+)-enriched populations during repeated expansion.

BACKGROUND AIMS: Expansion of anti-CD25 bead-isolated human Tregs culture has paradoxically resulted in reduced suppressive activity, but the mechanism(s) responsible for these observations are poorly defined. METHODS: Magnetic-bead isolated human CD25(+) cells were expanded with anti-CD3/CD28 beads and high doses of rhIL-2. Detection of Fas and Fas ligand (Fas-L) expression, activation of Caspase 8, cell proliferation and cytokine production was evaluated by multi-color fluorescence-activated cell sorting analysis. The role of Fas-Fas-L-mediated cell death was dissected through the use of agonist or antagonist monoclonal antibodies directed at Fas and Fas-L. RESULTS: Repeated expansion of bead-enriched CD4(+)CD25(+) cells generated a cellular product with markedly reduced suppressive activity and with significantly increased CD8(+) T cells and CD4(+) T cells producing interferon-γ and/or interleukin-2. We showed that Fas-Fas-L-mediated apoptosis of CD4(+)FOXP3(high) cells and rapid cell-cycling of CD8(+) T cells were collectively responsible for the reduced proportion of CD4(+)FOXP3(high) cells in expanded cultures. The depletion of CD4(+)FOXP3(high) cells and activation of Caspase 8 in CD4(+)FOXP3(high) cells was attenuated by Fas antagonist antibody, ZB4, in short-term culture. However, the loss of CD4(+)FOXP3(high) cells during expansion was not prevented by either Fas or Fas-L antagonist antibodies. CONCLUSIONS: Taken together, the data show that Fas-Fas-L-mediated apoptosis may limit the expansion of anti-CD25 bead-isolated cells in vitro.