Search

Posttransplant leukemia detection before overt relapse is key to the success of immunotherapeutic interventions, as they are more efficient when leukemia burden is low. However, optimal schedule and monitoring methods are not well defined. We report the intensive bone marrow monitoring of minimal residual disease (MRD) using flow cytometry (FC) and nested reverse transcription polymerase chain reaction (RT-PCR) whenever a fusion transcript allowed it and chimerism by PCR at 11 timepoints in the first 2 years after transplant. Seventy-one transplants were performed in 59 consecutive children, for acute myeloid (n = 38), lymphoid (n = 31), or mixed-phenotype (n = 2) leukemia. MRD was monitored in 62 cases using FC (n = 58) and/or RT-PCR (n = 35). Sixty-seven percent of leukemia recurrences were detected before overt relapse, with a detection rate of 89% by RT-PCR and 40% by FC alone. Increased mixed chimerism was never the first evidence of recurrence. Two patients monitored by RT-PCR relapsed without previous MRD detection, one after missed scheduled evaluation and the other 4.7 years post transplant. Among the 22 cases with MRD detection without overt relapse, 19 received therapeutic interventions. Eight (42%) never relapsed. In conclusion, intensive marrow monitoring by RT-PCR effectively allows for early detection of posttransplant leukemia recurrence., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

The most frequent complication of allogeneic hematopoietic stem cell transplantation is acute Graft versus Host Disease (aGVHD). Proliferation and differentiation of donor T cells initiate inflammatory response affecting the skin, liver, and gastrointestinal tract. Besides recipient-donor HLA disparities, disease type, and the conditioning regimen, variability in the non-HLA genotype have an impact on aGVHD onset, and genetic variability of key cytokines and chemokines was associated with increased risk of aGVHD. To get further insight into the recipient genetic component of aGVHD grades 2-4 in pediatric patients, we performed an exome-wide association study in a discovery cohort (n = 87). Nine loci sustained correction for multiple testing and were analyzed in a validation group (n = 168). Significant associations were replicated for ERC1 rs1046473, PLEK rs3816281, NOP9 rs2332320 and SPRED1 rs11634702 variants through the interaction with non-genetic factors. The ERC1 variant was significant among patients that received the transplant from HLA-matched related individuals (p = 0.03), bone marrow stem cells recipients (p = 0.007), and serotherapy-negative patients (p = 0.004). NOP9, PLEK, and SPRED1 effects were modulated by stem cell source, and serotherapy (p < 0.05). Furthermore, ERC1 and PLEK SNPs correlated with aGVHD 3-4 independently of non-genetic covariates (p = 0.02 and p = 0.003). This study provides additional insight into the genetic component of moderate to severe aGVHD., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Umbilical cord blood transplantation (UCBT) has been used to treat malignant and non-malignant diseases. UCBT offers the advantages of easy procurement and acceptable partial HLA mismatches, but also shows delayed hematopoietic and immunological recoveries. We postulated that an intrabone (IB) infusion of cord blood could provide a faster short- and long-term engraftment in a pediatric population with malignant and non-malignant hematologic diseases. We conducted this phase I-II single arm, exploratory clinical trial (NCT01711788) from 2012 to 2016 in a single center. Fifteen patients aged from 1.9 to 16.4 years received an IB UCBT. Median time to neutrophils and platelet recoveries were 18 days (range: 13-36 days) and 42 days (range: 26-107 days), respectively. Rate of severe acute GVH grade was low, with only one patient with grade III aGVH. Relapse occurred in 5 patients (38.5%) and TRM occurred in 1 patient. This leads to 6 years EFS and OS of 66.7% and 80% respectively. In conclusion, IB UCBT is safe and well-tolerated in children and hematological recovery compared similarly to the results obtained with IV UCBT., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Hematopoietic stem-cell transplantation (HSCT) is currently the only curative therapeutic option for the treatment of thalassemia. In spite of the high cure rate, HSCT can lead to life-threatening adverse events in some patients. Busulfan (Bu) is a key component of the conditioning regimen prior to HSCT. Inter-individual differences in Bu pharmacokinetics (PK) are hypothesized to influence Bu efficacy and toxicity. Since Bu is mainly metabolized by glutathione S-transferase (GST), we investigated the relationship of GSTA1 and GSTM1 genotypes with first-dose PK and HSCT outcomes in 44 children with thalassemia intermedia and thalassemia major. All children received a myeloablative conditioning regimen with IV Bu. Association analysis revealed a relationship between GSTA169C>T (or haplotype *A/*B) and first Bu dose PK that was dependent on sex and Pesaro risk classification (PRC). Among female patients and patients with PRC I-II, homozygous individuals for the GSTA1T-69 allele defining haplotype *B, had higher Bu exposure and lower clearance (P⩽0.01). Association with HSCT outcomes showed that patients with the GSTM1 null genotypes had higher occurrence of regimen-related toxicity (P=0.01). These results suggest that GST genotypes could be useful to tailor the first Bu dose accordingly to improve HSCT outcome.

HLA matching is a critical determinant of outcomes for patients who have undergone umbilical cord blood transplantation (UCBT). Data have been published on the importance of donor/recipient HLA mismatch direction on UCBT outcomes. HLA mismatch in the graft-versus-host (GVH) direction is defined as a donor homozygous at an HLA locus, while the recipient shares one HLA Ag with the donor. HLA mismatch in the host-versus-graft (HVG) direction is defined as a recipient homozygous with the donor sharing one HLA Ag. In our study we focused on confirming, using an independent population, whether transplantation outcomes would be different when HLA mismatch direction was considered. We analyzed 1565 patients who received a single-unit UCBT for malignant disease. Median age was 15 years and 72% of patients were transplanted for leukemia. In multivariate analysis, using the 5/6 HLA-matched population as reference, one or two HLA mismatches in the GVH or HVG direction were not associated with non-relapse related mortality and survival. On the basis of our results, there is no evidence to support a change in the current practice for cord blood unit selection.

BU is a key compound of conditioning regimens in children undergoing hematopoietic SCT (HSCT). Inter-individual differences in BU pharmacokinetics (PKs) might affect BU efficacy and toxicity. As BU is mainly metabolized by glutathione S-transferase (GST), we investigated the relationship between GSTA1, GSTM1 and GSTP1 genotypes with first-dose BU PKs, and the relationship with HSCT outcomes in 69 children receiving myeloablative conditioning regimen. GSTM1 null genotype correlated with higher BU exposure and lower clearance in patients older than 4 years (P ≤ 0.04). In accordance with the suggested functional role, GSTA1*A2 haplotype was associated with lower drug levels and higher drug clearance (P ≤ 0.03). Gene-dosage effect was also observed (P ≤ 0.007). GSTA1 haplotypes were associated with HSCT outcomes. Patients with two copies of haplotype *A2 had better event free survival (P=0.03). In contrast, homozygous individuals for haplotypes *B and *B1 had higher occurrence of veno-occlusive disease (P=0.009). GSTM1 null individuals older than 4 years had more frequently graft versus host disease (P=0.03). In conclusion, we showed that GST gene variants influence BU PK and outcomes of HSCT in children. A model for the dosage adjustment with the inclusion of genetic and non-genetic factors should be evaluated in a future prospective validation cohort.

The aim of the present study was to assess the influence of socioeconomic status (SeS) on the outcome of allo-SCT at a Brazilian SCT center. In total, 201 patients receiving HLA-identical related allo-SCTs were studied. The median age was 30 years. Overall, 163 patients had malignancies (CML 68, ALL/AML 63, myelodysplastic syndrome 12 and others 20). SeS was defined according to the Brazilian Association of Market Research Agencies classification, where people are clustered in groups A-E (richest to poorest). In total, 146 patients (72%) were classified as richest (A+B+C) and 55 (28%) as poorest (D+E). The D+E SeS group was associated with a higher incidence of chronic GVHD and acute GVHD (hazard ratio (HR)=2.61; P=0.001 and HR=2.62; P=0.001, respectively), better platelet and neutrophil engraftment (HR=1.94; P=<0.001 and HR=2.12; P=0.001) and with a higher TRM in multivariate analysis (HR=1.92; P=0.039). Estimated overall survival at 5 years was 55.2%. A D+E SeS (HR=2.13; P=0.001) was associated with a worse survival on multivariate analysis. In conclusion, a lower SeS is a strong prognostic factor in patients undergoing allo-SCT in Brazil, influencing engraftment, TRM and overall survival.

Imatinib mesylate (IM) is now first-line treatment for CML. To study the results of treatment with IM after IFN failure/intolerance versus allogeneic BMT (allo-BMT), we retrospectively analyzed 264 patients treated for CML in first chronic phase in three different institutions. Over a 6-year period (2001-2006), 174 patients received IM after failure of or intolerance to IFN. During the same period of time, 90 patients received an allo-BMT from an HLA-matched sibling (n=83) or an unrelated donor (n=7). The IM group was older (41 versus 33 years, P<0.001). Five-year EFS was 62% among patients receiving IM and 52% among patients undergoing allo-BMT (P=0.0002). OS at 5 years was 93% for IM-treated patients and 59% for patients undergoing allo-BMT (P<0.0001). Allo-BMT cannot be considered as first-line treatment for CML patients in first chronic phase.

Fifty-three patients with hematological malignancies who underwent Allo-SCT from HLA-identical siblings were randomly assigned to receive glutamine-enriched parenteral nutrition-PN (GlPN, n=27) or standard PN (PN, n=26), in isonitrogenous solutions. Deaths (D+100 and D+180), infections, acute GVHD, length of stay, time of neutropenia and intestinal permeability (IP) were studied. Ages, gender, diagnosis, disease status and treatment variables were equally distributed between groups. Survival on D+180 was increased in GlPN (74%) vs PN (46%), P=0.03 (log-rank), as on D+100 (P=0.05). Most deaths occurred before D+100, especially in PN (10/26, 39%) vs GlPN (4/27, 15%). GVHD was the most frequent cause of death (8/21, 38%), especially in PN (n=6, five before D+100). Other outcomes were not affected. IP was affected on admission, was not affected by glutamine enrichment, but consistently worsened throughout the study. Results showed that GlPN was efficacious in increasing short-term survival after Allo-SCT. Benefits of glutamine seem to be independent of mucosal protection, as IP was not affected by its use. A trend to a lower incidence of GVHD deaths may suggest an immunomodulatory role of glutamine.

Poor graft function (PGF) is a frequent cause of morbidity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). To study the value of granulocyte colony-stimulating factor (G-CSF) in PGF, we retrospectively analyzed 81 episodes of PGF in 66 patients transplanted from 01/94 to 01/99 from an HLA-identical sibling (n = 45) or an unrelated (n = 21) donor. Median age was 29 years, 55 patients had malignancies. A total of 11 patients received a CD34+ selected graft. Viral infections (25%), myelotoxic drug (33%), fungal/bacterial infections (14%), and GVHD (31%) were present before PGF diagnosis. Median time from allo-HSCT to PGF was 75 (25-474) days. All patients were treated with G-CSF. In 77/81 episodes, there was a response that was sustained in 57. A total of 27 patients presented an increase of white cell count (WBC) >0.1 x 10(9)/l after 3 days of G-CSF. The 5-year survival was 37% and was significantly better in patients with increased WBC > 0.1 x 10(9)/l after 3 days of G-CSF (65 vs 18%, P < 0.0001). In multivariate analysis, increased WBC > 0.1 x 10(9)/l after 3 days of G-CSF (P = 0.002) was associated with better survival, while BuCy-based conditioning (P = 0.02) and GVHD (P = 0.005) were associated with higher risk of death. In conclusion, hematological response after 3 days with G-CSF predicted a better survival for patients with PGF after allo-SCT.

In order to study the influence of bone marrow CD34(+) cell dose on the outcome of allogeneic bone marrow transplantation (BMT), we analysed the results of BMT from HLA-identical siblings donors in 50 patients with chronic myeloid leukaemia (CML). The median numbers of nucleated cells (NC) and CD34(+) cells infused were 2.18 x 10(8)/kg (0.05-4.14 x 10(8)/kg) and 3.12 x 10(6)/kg (0.35-8.52 x 10(6)/kg), respectively. All patients engrafted. In univariate analysis, there was no correlation between the number of CD34(+) cells infused and the time to neutrophil recovery (P = 0.17). The Kaplan-Meier estimate of grade II-IV acute graft-versus-host disease (GVHD) at day 100 was 53 +/- 14% and 2-year survival was 46 +/- 15%. A number of CD34(+) cells infused greater than the median was the main factor increasing survival (P = 0.0006) and decreasing 100 day transplant-related mortality (P = 0.009). Patient-, disease- and transplant-related characteristics were not statistically different among patients receiving more or less than the median number of CD34(+) cells. The rate of infectious deaths was significantly higher in patients receiving less than 3.12 x 10(6) CD34/kg (48% vs 16%, P = 0.01). In a multivariable analysis, two factors associated with increased risk of death were advanced disease status at transplant (HR: 2.5 (95% CI: 1.09-5.75), P = 0.03) and a lower number of marrow CD34(+) cells infused/kg (HR: 4.55 (95% CI: 1.87-10.90), P = 0.0008).