Overview of the progress on haploidentical hematopoietic transplantation

Adaptive NK cells undergo a dynamic modulation in response to human cytomegalovirus and recruit T cells in in vitro migration assays

Human cytomegalovirus (HCMV) reactivation remains a relevant complication after hematopoietic stem cell transplantation (HSCT) despite the great progress made in prophylaxis and treatment. Adaptive Natural Killer (NK) cells undergo a persistent reconfiguration in response to HCMV reactivation however, the exact role of adaptive NK cells in HCMV surveillance is currently unknown. We studied the relationship between HCMV reactivation and adaptive NK cells in 70 patients monitored weekly until day +100 after HSCT. Absolute cell counts of adaptive NK cells increased significantly after resolution of HCMV-reactivation compared to patients without reactivation. Patients with HCMV-reactivation had an early reconstitution of adaptive NK cells (“Responders”) and had mainly a single reactivation (75% Responders vs 48% Non-Responders). Adaptive NK cells eliminated HCMV-infected human foreskin fibroblasts (HFF) in vitro and recruited T cells in an in vitro transwell migration assay. An extensive cytokine/chemokine panel demonstrated strongly increased secretion of CXCL10/IP-10, IFN-α, IL-1α, IL-1β, IL-5, IL-7 and CCL4. Thus, adaptive NK cells may control viral spread and T cell expansion and survival during HCMV-reactivation. Taken together, we have demonstrated the potential of adaptive NK cells in the control of HCMV reactivation both by direct cytotoxicity and by recruitment of other immune cells.

Human cytomegalovirus (HCMV) is a β-herpes virus that causes life-long infection as a latent virus in its host. Its prevalence depends on socioeconomic geographical factors and can affect 50–90% of the population depending on these factors. HCMV infection is usually asymptomatic in healthy individuals. However, in patients lacking proper immune responses, such as following hematopoietic stem cell transplant (HSCT), HCMV can reactivate and increase the mortality and morbidity rates in these patients. We set to investigate the role of a population of innate cells, the adaptive Natural Killer (NK) cells, in the response to HCMV reactivation after HSCT. Our findings revealed that adaptive NK cells are modulated in response to HCMV reactivation after HSCT. Furthermore, in addition to their ability to eliminate HCMV-infected target cells after in vitro expansion, we have also shown that adaptive NK cells recruit T cells in response to co-culture with HCMV-infected target cells and identified secreted factors possibly involved in this recruitment.

Optimizing Blood Stem Cell Transplants Through Cellular Engineering

Haematopoietic stem cell transplants (HSCT) are used in the treatment of blood cancers, autoimmune diseases, and metabolic disorders. Over 1.5 million transplants have been performed around the world thus far. In an attempt to enhance the efficacy of the cells used for transplantation, efforts are underway to use cellular engineering to increase cell numbers through: (1) the expansion of hematopoietic stem and progenitor cells (HSPC); (2) cellular subset selection to remove cells that cause graft-versus-host disease (GvHD), while adding back cells, which can mediate anti-tumor and anti-viral immunity; (3) the use of immune regulatory cells, such as mesenchymal stromal cells (MSC) and regulatory T cells (Tregs) to control GvHD; (4) the use of immune effector cells to mount immunological control of tumor cells before, after, or independent of blood stem cell transplants.

Outpatient haploidentical hematopoietic stem cell transplant using post-transplant cyclophosphamide and incidence of hemorrhagic cystitis

Introduction

Hemorrhagic cystitis (HC) is a common complication of haploidentical hematopoietic stem cell transplantation (haplo-HSCT), characterized by irritative symptoms of the urinary tract and a higher morbidity and mortality rate. The worldwide incidence is reported between 10% and 70%. The use of alkylating agents and BK viral infection are the most frequent etiologies. The aim of this study was to report the HC incidence in an outpatient haplo-HCST program with a reduced intensity-conditioning (RIC) regimen, cataloguing risk factors, complications and final outcomes.

Methods

The medical database of patients who received a haplo-HSCT between January 2012 and November 2017 was retrospectively analyzed. Demographic variables, general characteristics and HC incidence were included.

Results

One hundred and eleven patients were included, 30 (27%) of whom developed HC, most of them (70%) being grade II, with a 30-day (7–149) median time of post-transplant HC onset. The BK virus was detected in 71% of the urine samples analyzed. All HC patients responded to treatment, except two (6.6%), who died due to HC complications.

Conclusions

There was no difference in the HC incidence or severity, compared to that reported when performing haplo-HSCT in hospitalized patients, although the donor-recipient sex mismatch did relate to a higher HC incidence.

Protective effect of HLA-DPB1 mismatch remains valid in reduced-intensity conditioning unrelated donor hematopoietic cell transplantation

A mismatch at HLA-DPB1 locus is associated with higher acute GVHD and lower relapse rate after myeloablative (MAC) allogeneic hematopoietic cell transplantation (alloHCT). Also, in MAC setting, mismatch permissiveness and expression level impact alloHCT outcomes. However, in reduced intensity (RIC), DP mismatch effect on transplant outcomes is unknown. We retrospectively evaluated DP mismatch influence (number, permissiveness, and expression) on HCT outcomes in 310 patients with high-resolution typing (HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1), who underwent RIC-HCT. By multivariable analysis, 11/12 had better overall survival (OS) and relapse vs. 12/12 (HR=1.61 and 2.02; p=0.04 and 0.01, respectively) and better OS vs. 10/12 (HR=1.68; p=0.02). Within the 11/12, non-permissive mismatch (NoPR) was associated with higher risk of grade II-IV acute GVHD (HR=1.97; p=0.005) and non-relapse mortality (HR=2.13; p=0.02) vs. permissive (PR). Grouping 11/12 based on the DP expression conferred higher mortality (HR=3.78; p= 0.003) when low expressers received a graft from high expressers (AG) vs. low expressers (AA). Better OS was achieved in PR 11/12, when expression was low in patient and donor (AA) vs. all other combinations. Therefore, in RIC HCT, a single DP mismatch has a protective role, especially in permissive setting, when donor and recipient are low expressers.

Low incidence of hemorrhagic cystitis following ex vivo T-cell depleted haploidentical hematopoietic cell transplantation in children

Hemorrhagic cystitis (HC) is a debilitating complication following allogenic hematopoietic cell transplantation (HCT). HLA disparity and T-cell depletion have been implicated as risk factors for HC. However, reports on the incidence and risk factors for HC in ex vivo T-cell depleted haploidentical HCT (haploHCT) in children are lacking. We studied 96 haploHCT procedures performed in 83 children between 2002 and 2017. Sixty-three patients were diagnosed with a malignant disease and 20 with nonmalignant disease. All but three patients with SCID underwent myelotoxic and/or lymphotoxic conditioning therapy. Grafts were CD3+ (36.5%) or TcRαβ+ (63.5%) depleted to prevent graft versus host disease (GvHD). Fourteen patients (14.6%) were diagnosed with HC; 12 (12.5%) had clinically significant stage II-IV HC. All patients with HC had BK viruria and/or viremia. Increasing age and chemotherapeutic treatment prior to conditioning were identified as risk factors for HC. Immune recovery did not significantly differ between patients with and without HC. Thus, we report a low incidence of HC in pediatric haploHCT using ex vivo T-cell depletion. The combination of a reduced toxicity conditioning regimen, and typically absent pharmaceutical post-HCT GvHD prophylaxis in our patients might have contributed to the decreased the risk of HC, despite HLA disparity.

Allogeneic Hematopoietic Cell Transplantation in Patients with Primary Immunodeficiencies in Korea: Eleven-Year Experience in a Single Center

PURPOSE

We aimed to report our single-center experience of allogeneic hematopoietic cell transplantation (HCT), which has been the only curative option for certain patients with lethal primary immunodeficiencies (PIDs).

METHODS

We summarized the results of HCT performed for patients with PIDs for 11 consecutive years from 2006 to 2016 at Samsung Medical Center, Seoul, Korea. Twenty-six patients with PIDs received HCT. Most had chronic granulomatous disease (42.3%), Wiskott Aldrich syndrome (15.4%), or severe combined immunodeficiency (11.5%).

RESULTS

Nine patients (34.6%) received HCT during the former half period and 17 patients (65.4%) during the latter half period. Donor types were categorized as: matched sibling donor (n = 5), unrelated donor (n = 17), and familial mismatched donor (FMMD) (n = 4). Unrelated HCT and FMMD transplantation were increasingly performed in the latter half period compared to the first (5 vs. 16, P = 0.034). Five patients experienced initial engraftment failure, but all of them were eventually engrafted after additional HCTs. The 3-year probability of overall survival was 72.0%. Seven patients (26.9%) died, and the causes of death were bacterial sepsis (n = 4), pneumonia (n = 1), chronic graft-versus-host disease (GVHD) (n = 1), and diffuse alveolar hemorrhage (n = 1). Two patients with bacterial sepsis and a patient with pneumonia also had chronic GVHD. Unrelated HCT and use of methotrexate were associated with poor outcome. Complete chimerism was attained in 85.0% at 1 year after HCT.

CONCLUSION

PID candidates have been increasingly identified for allogeneic HCT in Korea, and the majority of them could be cured by HCT. Establishment of a systematic registry of PID patients for HCT is needed.

[Hot topics in 2017 in oncology and hematology. A selection by the editorial board of Bulletin du Cancer]

Actuality was dense in 2017 for oncology and hematology. The editorial board of the Bulletin du Cancer proposes a selection of key data distinguishing four trends: precision medicine, immunotherapy, focus on early stages and global management of metastatic disease. A summary of results which have been published or presented in congresses is proposed and the impact on daily practices is discussed.