Implementation of Blockchain Technology Could Increase Equity and Transparency in Organ Transplantation: A Narrative Review of an Emergent Tool

In the last few years, innovative technology and health care digitalization played a major role in all medical fields and a great effort worldwide to manage this large amount of data, in terms of security and digital privacy has been made by different national health systems. Blockchain technology, a peer-to-peer distributed database without centralized authority, initially applied to Bitcoin protocol, soon gained popularity, thanks to its distributed immutable nature in several non-medical fields. Therefore, the aim of the present review (PROSPERO N° CRD42022316661) is to establish a putative future role of blockchain and distribution ledger technology (DLT) in the organ transplantation field and its role to overcome inequalities. Preoperative assessment of the deceased donor, supranational crossover programs with the international waitlist databases, and reduction of black-market donations and counterfeit drugs are some of the possible applications of DLT, thanks to its distributed, efficient, secure, trackable, and immutable nature to reduce inequalities and discrimination.

Improved growth with growth hormone treatment in children after hematopoietic stem cell transplantation

OBJECTIVE

Hematopoietic stem cell transplantation (HSCT) can be a curative treatment for malignant and nonmalignant diseases in children but is associated with significant late effects including growth failure. Growth hormone treatment (GHRx) is offered to improve growth, but limited data are available on its effect on adult height (AH). We aim to evaluate the effectiveness of GHRx.

DESIGN

Single-center retrospective study.

PATIENTS

Thirty-four patients who had received GHRx for ≥1 year were matched with two controls each, without GHRx, based on sex, indication for HSCT (malignancy, benign haematological disease or immunodeficiency), age at HSCT and conditioning with/without total body irradiation (TBI). All had reached AH.

MEASUREMENTS

The primary outcome measure was the difference between AH and predicted AH (PAH) at start of GHRx or the equivalent age in controls (AH-PAH), calculated according to Bailey and Pinneau.

RESULTS

GHRx was started at age 12.0 ± 2.6 years; median treatment duration was 3.8 years (range 1.7-9.2). AH-PAH standard deviation score (SDS) was significantly higher in growth hormone (GH) treated boys (-0.5 ± 0.7 SDS) than in controls (-1.5 ± 1.0 SDS, p < .001). Girls also had a higher AH-PAH after GHRx (+0.5 ± 0.6 SDS) compared to controls (-0.2 SDS ±0.7, p < .01). AH remained approximately 2 SDS below target height (TH) in treated and untreated individuals. Among GH-treated children, AH-PAH was higher in those who had received busulfan-based compared to TBI-based conditioning.

CONCLUSION

GHRx had a significant positive effect on AH compared to PAH, although AH remained far below TH. Higher AH-PAH was observed in girls and in those conditioned without TBI.

Evaluating the Efficacy, Toxicity and Pharmacokinetic Profile of Oral Busulfan in Allogeneic Stem Cell Transplant Patients

Background

Oral busulfan and intravenous cyclophosphamide (Bu/Cy) are common myeloablative preparations used in allogeneic hematopoietic stem cell transplantation (HSCT). Herein, we investigated the safety of (Bu/Cy) administration during HSCT.

Methods

Patients administered Bu/Cy for allogeneic HSCT at Royal Perth Hospital and Fiona Stanley Hospital between 2007 and 2017 were reviewed for inclusion in the study. We performed busulfan pharmacokinetic (PK) testing for a subset of patients and allometric scaling modeling to assess the best method of busulfan dosing in patients at extremes of weight.

Results

Sixty-nine patients were included in the clinical outcome analysis. The median follow-up period was 32 months (range, 9-114 months). The three-year overall survival rate was 62% (95% confidence interval (CI), 51%-75%), and transplant-related mortality was 4% at 6 months (95% CI, 1-7%), with a low rate of sinusoidal obstruction syndrome of the liver being observed. In addition, relapse was 38% (95% CI, 30%-44%) at 3 years. The PK information of 15 patients receiving busulfan was available after oral dosing. The average per-dose busulfan exposure was 1,350 μmol.min/L (range, 878-1,717 μmol.min/L), and the within target range was 1,000-1,500 μmol.min/L in 73% of patients. Of the size measures investigated, ideal and adjusted body weight (ABW40) provided the best fit. No association was observed between busulfan exposure, toxicity, and relapse.

Conclusions

Overall, Bu/Cy administration appeared safe when dosed in relation to weight, showing a low early transplant-related mortality rate following adequate busulfan exposure in majority of the cases. Body size measures, such as ideal body weight or ABW40, are likely more suitable for use during busulfan dosing, particularly at high extremes of the body mass index classification.

Pregnancy post autologous stem cell transplant with BEAM conditioning for multiple sclerosis

BACKGROUND

Given the increasing numbers of multiple sclerosis (MS) patients undergoing autologous haematopoietic stem cell transplant (AHSCT) worldwide, and with women of childbearing age overrepresented in the target population, it is increasingly important to review fertility and pregnancy outcomes following AHSCT.

OBJECTIVE

To evaluate the rate of pregnancy and complications post-AHSCT for MS.

METHOD

Retrospective evaluation of the rate of pregnancy and associated complications in a cohort of patients post-AHSCT with BEAM conditioning for MS since 2010 in a tertiary referral centre.

RESULTS

In our ongoing Phase 2 trial of AHSCT for MS, 55 patients have undergone AHSCT with 30 females being of childbearing age at time of transplantation. Four pregnancies occurred following AHSCT. Two pregnancies were carried to term. No maternal or neonatal complications were reported in either case. Two pregnancies were not carried to term due to elective terminations. Both of these patients became pregnant unexpectedly 2 years following AHSCT. Of the 21 male patients, one patient has fathered three children since his AHSCT. There were no newborn complications.

CONCLUSIONS

This is the first report to our knowledge on fertility outcomes in both sexes post-AHSCT for MS. Patients of both sexes should be counselled prior to treatment on infertility and contraceptive use.

Reduced-Intensity Conditioning with Busulfan and Fludarabine for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Lymphoblastic Leukemia

PURPOSE

Allogeneic hematopoietic stem cell transplantation (HSCT) with optimal conditioning has helped better long-term survival in acute lymphoblastic leukemia (ALL). This study investigated the efficacy and safety of reduced-intensity conditioning (RIC) with busulfan and fludarabine in adult ALL patients unfit for myeloablation.

MATERIALS AND METHODS

Records of 78 patients who underwent HSCT with RIC consisting of 3.2 mg/kg/day of busulfan for 2 or 3 days and 30 mg/m²/day of fludarabine for 5 or 6 days were analyzed.

RESULTS

The median age at diagnosis was 49 years. Over a median follow-up of 22 months, 2-year estimates of relapse-free survival (RFS) and overall survival were 57.4% and 68.7%, respectively. Multivariate analysis showed a trend of improved RFS in patients with chronic graft-versus-host disease (GVHD) (hazard ratio, 0.53; 95% confidence interval, 0.26-1.08; p=0.080). The cumulative incidences of relapse and non-relapse mortality were 42.9% and 19.6%, respectively and one case of central nervous system relapse was noted. No hepatic veno-occlusive disease was reported. Grade II-IV acute GVHD and any grade chronic GVHD occurred in 21.1% and 41.7%, respectively.

CONCLUSION

RIC with busulfan and fludarabine is an effective and safe conditioning regimen for adult ALL patients unfit for myeloablation.

Lasting Gammaproteobacteria profile changes characterized hematological cancer patients who developed oral mucositis following conditioning therapy

Background: Oral mucositis (OM) is a common side effect of conditioning therapy implemented before hematopoietic stem cell transplantation (HSCT). The role of oral microbiome in OM is not fully elucidated. Objective: To determine oral microbiome profile changes post-conditioning in HSCT patients who developed moderate OM, or mild to no OM. Design: Patient groups were: Muc0-1 with OM-score = 0-1 (43 paired samples) and Muc2 with WHO OM-score = 2 (36 paired samples). Bacterial DNA was isolated from oral samples (saliva, swabs of buccal mucosa, tongue, and supragingival plaque) at pre-conditioning (T 0 ), post-conditioning mucositis onset (T Muc ), and one-year post-conditioning (T Year ). 16S-rRNA gene next-generation sequencing was used to determine the relative abundance (RA) of >700 oral species. Alpha-diversity, beta-diversity and linear discriminant analyses (LDA) were performed Muc2 versus Muc0-1. Results: Muc2 oral microbiome alpha- and beta-diversity differed between T 0 and T Muc . Muc2 alpha-diversity and Muc0-1 beta-diversity did not differ between T 0 and T Year . T 0 to T Muc LDA scores were significant in Muc2 for Gammaproteobacteria. For Muc2 patients, the average RA decreased for Haemophilus parainfluenza, a species known as mucosal surfaces protector, but increased for Escherichia-Shigella genera. Conclusions: Post-conditioning OM might contribute to long-term oral microbiome changes affecting Gammaproteobacteria, in HSCT patients.

Acute Kidney Injury and CKD Associated with Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is a life-saving therapy for many patients with cancer, as well as patients with some nonmalignant hematologic disorders, such as aplastic anemia, sickle cell disease, and certain congenital immune deficiencies. Kidney injury directly associated with stem cell transplantation includes a wide range of structural and functional abnormalities, which may be vascular (hypertension, thrombotic microangiopathy), glomerular (albuminuria, nephrotic glomerulopathies), and/or tubulointerstitial. AKI occurs commonly after stem cell transplant, affecting 10%-73% of patients. The cause is often multifactorial and can include sepsis, nephrotoxic medications, marrow infusion syndrome, hepatic sinusoidal obstruction syndrome, thrombotic microangiopathy, infections, and graft versus host disease. The risk of post-transplant kidney injury varies depending on patient characteristics, type of transplant (allogeneic versus autologous), and choice of chemotherapeutic conditioning regimen (myeloablative versus nonmyeloablative). Importantly, AKI is associated with substantial morbidity, including the need for KRT in approximately 5% of patients and the development of CKD in up to 60% of transplant recipients. AKI has been associated universally with higher all-cause and nonrelapse mortality regardless of transplant type, and studies have consistently shown extremely high (>80%) mortality rates in those patients requiring acute dialysis. Accordingly, prevention, early recognition, and prompt treatment of kidney injury are essential to improving kidney and patient outcomes after hematopoietic stem cell transplantation, and for realizing the full potential of this therapy.

Decitabine-Containing Conditioning Regimen for Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Intermediate- and High-Risk Myelodysplastic Syndrome/Acute Myeloid Leukemia: Potential Decrease in the Incidence of Acute Graft versus Host Disease

Purpose

To evaluate the role of Decitabine in the allo-HSCT conditioning regimen for intermediate- and high-risk patients with MDS or AML.

Patients and methods

Retrospective analysis of data pertaining to 76 intermediate- and high-risk patients with MDS or AML who underwent allo-HSCT between December 2005 and June 2018 at the Peking University First Hospital. Forty patients received Decitabine-containing conditioning regimen before transplantation, while thirty-six patients received regimen without Decitabine.

Results

Over a median follow-up of 40 months (range, 1 to 155), the cumulative incidence of grade II to IV acute graft versus host disease was 12.4% [95% confidence interval (CI) 4.9–30.9%] in the Decitabine group and 41.5% (95% CI 28.1–61.2%) in the non-Decitabine group (P=0.005). On multivariate analysis, Decitabine-containing conditioning regimen was found to protect against grade II to IV aGVHD (HR=0.279, 95% CI 0.102–0.765, P=0.013). Incidence of respiratory infection in the Decitabine and non-Decitabine groups was 22.5% and 52.78%, respectively (P=0.012). No significant between-group difference was observed with respect to 3-year OS, DFS, or RR (P=0.980, 0.959, and 0.573, respectively), while the median relapse time was longer in the Decitabine group [7 months (range, 2–12) versus 3 months (range, 2–4), P=0.171]. Decitabine-containing conditioning showed a tendency for lower relapse rate among higher risk patients, as assessed by IPSS R; however, the between-group difference was not statistically significant (P=0.085).

Conclusion

Inclusion of Decitabine in the conditioning regimen for allo-HSCT in intermediate- and high-risk patients may lower the incidence of aGVHD and respiratory infections, and contribute to longer median relapse time.

Clinical outcomes in allogeneic haematopoietic stem cell transplantation: A comparison between young and elderly patients. Observational study

OBJECTIVES

To analyse clinical outcomes comparing two age groups of patients undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT), and to identify risk factors associated with older patients' mortality.

METHODS

In this retrospective study, the medical charts of all consecutive patients admitted in one hospital for allo-HSCT were reviewed. Overall survival (OS) and other outcomes were compared between patients aged up to 55 years (YG) and older than 55 (EG).

RESULTS

From January 2007 to August 2014, 111 adult patients were admitted for allo-HSCT and were included 75 in the YG and 36 in the EG group. The OS rate at D+ 100 was 84% for YG individuals in contrast to 75% in the EG (p = 0.01), and 71% vs. 50% at one year after HSCT (p = 0.01) respectively. Therapy-related mortality (TRM) rates for the YG and EG were, respectively, 14% vs. 17% (p = 0.04) at D+ 100 and 17% vs. 32% (p = 0.04) at one year. Haploidentical donor type and active disease status significantly increased mortality risk in the EG (hazard ratio 2.42; p = 0.018; and 2.04; p = 0.033).

CONCLUSION

YG and EG have similar TRM rates early after allo-HSCT, but the elderly had higher TRM during the critical period from 100 days to one year.

Successful immune reconstitution by means of hematopoietic stem cell transplantation in a Colombian patient with chronic granulomatous disease

INTRODUCTION

Chronic granulomatous disease is a primary immunodeficiency that results from mutations in proteins of the NADPH oxidase system that affect the microbicidal activity of phagocytes. Immune reconstitution by hematopoietic stem cell transplantation is currently the only curative therapy for this disease. 

OBJECTIVE

To describe the clinical and molecular characterization of a patient with X-linked chronic granulomatous disease and the successful immune reconstitution by means of a hematopoietic stem cell transplantation. 

METHODS

The respiratory burst was measured by flow cytometry using the dihydrorodamine 123 (DHR) oxidation test in neutrophils of peripheral blood. Mutational analysis of CYBB was performed by PCR amplification in complementary DNA, as well as sequencing and comparative genomic hybridization in genomic DNA. HLA-identical stem cells from the patient's younger brother were used for the transplantation and reduced intensity pre-transplantation conditioning was administered. Post-transplantation immune reconstitution was evaluated periodically by serial complete blood counts and DHR 123 in peripheral blood neutrophils. 

RESULTS

The diagnosis of X-linked chronic granulomatous disease resulted from a hemizygous deletion affecting Xp21.1 that included the entire CYBB. Post-transplantation engraftment was documented in platelets and peripheral blood neutrophils at days 10 and 11, respectively. Total hematological reconstitution was achieved by day 30 post-transplantation and no complications or infections have been observed in the three years since the transplantation. 

CONCLUSION

Hemopoietic stem cell transplantation allows for total reconstitution of the immune function related to microbicidal activity of phagocytic cells from patients with X-linked chronic granulomatous disease.

An analysis of the therapeutic benefits of genotyping in pediatric hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation is a high-risk procedure that is offered, with curative intent, to patients with malignant and nonmalignant disease. The clinical benefits of personalization of therapy by genotyping have been demonstrated by the reduction in transplant related mortality from donor-recipient HLA matching. However, defining the relationship between genotype and transplant conditioning agents is yet to be translated into clinical practice. A number of the therapeutic agents used in stem cell transplant preparative regimens have pharmacokinetic parameters that predict benefit of incorporating pharmacogenomic data into dosing strategies. Busulfan, cyclophosphamide, thio-TEPA and etoposide have well-described drug metabolism pathways, however candidate gene studies have identified there is a gap in the identification of pharmacogenomic data that can be used to improve transplant outcomes. Incorporating pharmacogenomics into pharmacokinetic modeling may demonstrate the therapeutic benefits of genotyping in transplant preparative regimen agents.

Normothermic machine perfusion of the kidney: better conditioning and repair?

Kidney transplantation is limited by hypothermic preservation techniques. Prolonged periods of cold ischaemia increase the risk of early graft dysfunction and reduce long-term survival. To extend the boundaries of transplantation and utilize kidneys from more marginal donors, improved methods of preservation are required. Normothermic perfusion restores energy levels in the kidney allowing renal function to be restored ex vivo. This has several advantages: cold ischaemic injury can be avoided or minimized, the kidney can be maintained in a stable state allowing close observation and assessment of viability and lastly, it provides the ideal opportunity to add therapies to directly manipulate and improve the condition of the kidney. This review explores the experimental and clinical evidence for ex vivo normothermic perfusion in kidney transplantation and its role in conditioning and repair.

Transplantation tolerance: from theory to clinic

Tolerance induction and alloreactivity can be applied to the clinic for the transplantation of solid organs and in the treatment of human cancers respectively. Hematopoietic chimerism, the stable coexistence of host and donor blood cells, guarantees that a solid organ from the same donor will be tolerated without a requirement for maintenance immunosuppression, and it also serves as a platform for the adoptive immunotherapy of hematologic malignancies using donor lymphocyte infusions. This review focuses on clinically relevant methods for inducing hematopoietic chimerism and transplantation tolerance, with a special emphasis on reduced intensity transplantation conditioning and high dose, post-transplantation cyclophosphamide to prevent graft rejection and graft-versus-host disease (GVHD). Reduced intensity transplantation regimens permit a transient cooperation between donor and host immune systems to eradicate malignancy without producing GVHD. Their favorable toxicity profile also enables the application of allogeneic stem cell transplantation to treat non-malignant disorders of hematopoiesis and to induce tolerance for solid organ transplantation.

Role of hematopoietic stem cell transplant in the management of follicular lymphoma

Despite decades of published data regarding the application of autologous and allogeneic stem cell transplant in patients with follicular lymphoma, there remain no uniform indications for its use in this disease. Autologous transplant has been shown to lead to longer progression-free survival times in randomized trials when compared with postremission interferon-based chemoimmunotherapy. However, the development of rituximab and its use in frontline, salvage, and maintenance therapy complicates the decision to pursue autologous transplant, a modality developed prior to the advent of anti-CD20 monoclonal antibodies. Allogeneic transplant offers the advantages of lymphoma-free grafts and the immunologic graft-versus-lymphoma effect. These factors may confer the possibility of long-term remission, though historically they have been accompanied by high rates of upfront morbidity and mortality, especially in heavily pretreated patients with a poor performance status or chemotherapy-refractory disease. Advances in patient selection, human leukocyte antigen (HLA) matching, conditioning regimens, and supportive care have reduced transplant-related mortality and the incidence of graft-versus-host disease. Recently published data focus on the incorporation of rituximab and radioimmunoconjugates prior to, during, and following autologous transplant. Furthermore, reduced-intensity allogeneic stem cell transplantation has increasingly been used for relapsed follicular lymphoma patients with comorbidities or advanced age. Several recent reports suggest that reduced-intensity regimens may provide a high likelihood of long-term disease-free survival for patients up to 70 years of age with a good performance status, chemotherapy-sensitive disease, and HLA-matched sibling donors. Such patients with relapsed disease should be referred to a transplant center that can enroll them in one of the forthcoming clinical trials that aim to confirm these outcomes.

Successful long-term outcome of the first combined heart and kidney transplant in a patient with systemic Al amyloidosis

Simultaneous cardiac and renal involvement is associated with a particularly poor prognosis in patients with AL amyloidosis (AL-A). We report the first case of a successful long-term outcome of combined heart and kidney transplantation not followed by autologous stem cell transplantation in a patient with systemic AL-A. The recipient was a 46-year-old man with end-stage renal failure associated with serious cardiac involvement in the context of AL-A. Before transplantation, two courses of oral melphalan plus prednisone induced partial hematologic remission, as shown by the decrease in circulating free light chain with no improvement of renal or heart function. The patient underwent combined heart and kidney transplantation as a rescue treatment. During the follow-up period (36 months), plasma cell dyscrasia remains in complete remission, with normal free lambda light chain levels and no recurrence of amyloid deposition on heart and kidney grafts. This case report demonstrates that combined heart and kidney transplantation not systematically associated with stem cell transplantation may be considered an additional therapeutic option in AL-A patients with severe organ dysfunction and partial hematologic remission.

[Allograft "acceptance" and tolerance: a new concept]

Discovery of microchimerism in kidney and liver transplantation provided an important framework for a better understanding of allograft acceptance, for analysis of management problems and for therapeutically oriented transplanted research. In these new concept correlations with infectious diseases caused by non cytopathic microorganisms, previous enigmas, immunologic reaction, counter argument and general immunologic implications are discussed.