Demand for Continuous and Long-Term Care in Transplant Recipients: Data From the Organ Transplantation Registry-Poltransplant Activity.

BACKGROUND: This study aimed to determine the number of recipients with active transplants under the care of transplant centers in 2022 and the current volume and needs for continuous and long-term care in this group of transplant recipients. Data came from the organ transplant registry, one of the registries maintained by the Polish Transplant Coordinating Center Poltransplant. We included recipients of individual organs who, on January 1, 2022, were living with an active transplant performed in previous years and recipients who received a transplant in 2022. The number of recipients under the care of transplant centers in 2022 was 20,994 (55% of all transplants performed in Poland since the beginning of activity in 1966).

Molecular relapse monitoring reveals the domination of impaired NK cell education over impaired inhibition in missing KIR-ligand recognition in patients after unrelated hematopoietic stem cell transplantation for malignant diseases.

Transplantation of HLA and/or KIR mismatched allogeneic hematopoietic stem cells can lead NK cells to different states of activation/inhibition or education/resetting and change anti-tumor immunosurveillance. In this study, we used molecular relapse monitoring to investigate a correlation between either missing ligand recognition or variation of the cognate iKIR-HLA pairs with clinical outcomes in patients with hematological malignancies requiring allogeneic hematopoietic stem cell transplantation (allo-HSCT). Patients (N = 418) with acute myeloid leukemia (AML), chronic myeloid leukemia (CML), acute lymphoblastic leukemia (ALL), myelodysplastic syndrome (MDS), or lymphoma receiving T-cell repleted graft from HLA-matched or partly mismatched unrelated donors between 2012 and 2020 in our center were included in this study. Missing-ligand recognition was assessed through the presence or absence of recipients' HLA ligand for a particular inhibitory KIR (iKIR) exhibited by the donor. Inhibitory KIR-HLA pair number variation was defined by loss or gain of a new cognate pair of HLA-KIR within the new HLA environment of the recipient, compared with the donor's one. Considering the results of our research, we drew the following conclusions: (i) loss of iKIR-HLA cognate pair for C1, C2, and/or Bw4 groups led to significant deterioration of disease-free survival (DFS), molecular relapse, overall survival (OS) and non-relapse mortality (NRM) for patients undergoing allo-HSCT in the standard phase of the disease. This phenomenon was not observed in patients who underwent transplantation in advanced hematological cancer. (ii) The missing ligand recognition had no impact if the proportion of HLA mismatches was not considered; however, adjustments of HLA mismatch level in the compared groups highlighted the adverse effect of the missing ligand constellation. (iii) The adverse effect of adjusted missing ligand suggests a predominance of lost NK cell education over lost NK cell inhibition in posttransplant recipients' new HLA environment. Our results suggested that donors with the loss of an iKIR-HLA cognate pair after transplantation should be avoided, and donors who provided an additional iKIR-HLA cognate pair should be preferred in the allo-HSCT donor selection process.

Hematopoietic Stem-Cell Transplant Registry in Poland: 2020 Summaries.

In the pandemic year 2020, 634 allogeneic hematopoietic stem-cell (HSC) transplants were performed in Poland, including fully matched and haploidentical family donors (n = 248) as well as unrelated donors transplantation (n = 386). In 48 recipients (7.6%) for allogeneic transplantation, hematopoietic bone marrow cells were transplanted, and in 586 recipients (92.4%), peripheral blood hematopoietic cells. The effect of the pandemic was noticeable but not disastrous-the number of HSC transplants from unrelated donors was lower by 9% compared to 2019 and the use of haploidentical donors slightly increased compared to 2019. Out of all 386 unrelated HSC transplants, the material for 143 transplants (37%) came from international donors, whereas for 243 transplants (63%) material collected from domestic donors was used. Along with the increase in the number of potential bone marrow donors in the national resources, the share of transplants from Polish donors in the total number of transplants increased noticeably from 2006 to 2020. The total number of allogeneic transplants performed in 18 Polish transplant centers between 2006 and 2020 is 7426. Total transplant rates (cumulative number of all allogeneic HSC transplants performed from 2006 to 2020 per 1 million inhabitants) differs between regions and for regions with nonzero number of transplants varies from 520 in Mazowieckie Voivodship to 14 in Lodzkie Voivodship.