KIR specificity and avidity of standard and unusual C1, C2, Bw4, Bw6 and A3/11 amino acid motifs at entire HLA:KIR interface between NK and target cells, the functional and evolutionary classification of HLA class I molecules.

Natural killer (NK) cells make vital contributions to the immune system and the reproductive system. Notably, NK cells of donor origin can recognize and kill residual leukaemic cells and cure malignant patients in hematopoietic stem cell (HSC) transplant setting. NK cell function is regulated by KIRs that recognize cognate HLA class I molecules on target cells, depending on their amino acid residues. In review, we addressed the question of binding capacity and avidity of HLA class I molecules to different killer cell immunoglobulin-like receptors (KIRs) depending on all interacting amino acid residues both on HLA and KIR side. We searched PubMed database and analysed available HLA:KIR crystallographic data for amino acid residues in HLA molecules, those physically involved in binding KIRs (termed here the "entire KIR interface"). Within entire KIR interface, we selected five functional sequence motifs (14-19, 66-76, 77-84, 88-92 and 142-151) and classified them according to the conservation of their amino acid sequences among 8,942 HLA class I molecules. Although some conserved amino acid motifs were shared by different groups of KIR ligands, the HLA motif combinations were exclusive for the ligand groups. In 135 common HLA class I molecules with known HLA:KIR recognition, we found 54 combinations of five motifs in each of the KIR-binding interfaces (C1, C2, Bw4, A3/11) and conserved non-KIR-binding interfaces. Based on the entire KIR interface, this analysis allowed to classify 8,942 HLA class I molecules into KIR specificity groups. This functional and evolutionary classification of entire KIR interfaces provides a tool for unambiguously predicting HLA:KIR interactions for common and those HLA molecules that have not yet been functionally tested. Considering the entire KIR interface in HLA class I molecules, functional interactions of HLA and KIR can be predicted in immune responses, reproduction and allotransplantation. Further functional studies are needed on the HLA:KIR interaction variations caused by the repertoires of peptides presented by HLA molecules and KIR polymorphisms at allelic level.

Role of Donor Activating KIR-HLA Ligand-Mediated NK Cell Education Status in Control of Malignancy in Hematopoietic Cell Transplant Recipients.

Some cancers treated with allogeneic hematopoietic stem cell transplantation (HSCT) are sensitive to natural killer cell (NK) reactivity. NK function depends on activating and inhibitory receptors and is modified by NK education/licensing effect and mediated by coexpression of inhibitory killer-cell immunoglobulin-like receptor (KIR) and its corresponding HLA I ligand. We assessed activating KIR (aKIR)-based HLA I-dependent education capacity in donor NKs in 285 patients with hematological malignancies after HSCT from unrelated donors. We found significantly adverse progression-free survival (PFS) and time to progression (TTP) in patients who received transplant from donors with NKs educated by C1:KIR2DS2/3, C2:KIR2DS1, or Bw4:KIR3DS1 pairs (for PFS: hazard ratio [HR], 1.70; P = .0020, Pcorr = .0039; HR, 1.54; P = .020, Pcorr = .039; HR, 1.51; P = .020, Pcorr = .040; and for TTP: HR, 1.82; P = .049, Pcorr = .096; HR, 1.72; P = .096, Pcorr = .18; and HR, 1.65; P = .11, Pcorr = .20, respectively). Reduced PFS and TTP were significantly dependent on the number of aKIR-based education systems in donors (HR, 1.36; P = .00031, Pcorr = .00062; and HR, 1.43; P = .019, Pcorr = .038). Furthermore, the PFS and TTP were strongly adverse in patients with missing HLA ligand cognate with educating aKIR-HLA pair in donor (HR, 3.25; P = .00022, Pcorr = .00045; and HR, 3.82; P = .027, Pcorr = .054). Together, these data suggest important qualitative and quantitative role of donor NK education via aKIR-cognate HLA ligand pairs in the outcome of HSCT. Avoiding the selection of transplant donors with high numbers of aKIR-HLA-based education systems, especially for recipients with missing cognate ligand, is advisable.

Donor NK cell licensing in control of malignancy in hematopoietic stem cell transplant recipients.

Among cancers treated with allogeneic hematopoietic stem-cell transplantation (HSCT), some are sensitive to natural killer (NK) cell reactivity, described as the "missing self" recognition effect. However, this model disregarded the NK cell licensing effect, which highly increases the NK cell reactivity against tumor and is dependent on the coexpression of inhibitory killer cell immunoglobulin-like receptor (iKIR) and its corresponding HLA Class I ligand. We assessed clinical data, HLA and donor iKIR genotyping in 283 patients with myelo- and lymphoproliferative malignancies who underwent HSCT from unrelated donors. We found dramatically reduced overall survival (OS), progression free survival (PFS), and time to progression (TTP) among patients with malignant diseases with the lack of HLA ligand cognate with this iKIR involved in NK cell licensing in corresponding donor (events 83.3% vs. 39.8%, P = 0.0010; 91.6% vs. 47.7%, P = 0.00010; and 30.0% vs. 17.3%, P = 0.013, for OS, PFS, and TTP, respectively). The extremely adverse PFS have withstand the correction when patient group was restricted to HLA mismatched donor-recipient pairs. The incidence of aGvHD was comparable in two groups of patients. In malignant patients after HSCT the missing HLA ligand for iKIR involved in NK cell licensing in corresponding donor ("missing licensing proof") induced extremely adverse survival of the patients due to the progression of malignancy and not to the aGvHD. Avoiding the selection of HSCT donors with the "missing licensing proof" in the malignant patient is strongly advisable.

Central Unrelated Potential Bone Marrow and Cord Blood Registry in Poland: Structure and Numbers.

Poland's Central Unrelated Potential Bone Marrow Donor and Cord Blood Registry (CBMDR Poltransplant) was established in 2011. Affiliated with the World Marrow Donor Association (WMDA) as PL5, the CBMDR is an internationally recognized hematopoietic stem cell donor registry with a large, high-quality donor database. Overall, Polish resources in this domain are the second largest in Europe and the fourth largest in the world, accounting for 4.8% of the WMDA Register of over 33.5 million records. In the last 10 years, the number of potential hematopoietic stem cell donors registered in Poland has increased more than 10-fold, from about 146,000 to 1,579,809 at the end of 2018. Such a growing number of donors in the CBMDR is contributing to an increase in overall numbers of donor searches in Polish databases, as well as in donations from Polish donors.

High-resolution allele frequencies for NGS based HLA-A, B, C, DQB1 and DRB1 typing of 23,595 bone marrow donors recruited for the Polish central potential unrelated bone marrow donor registry.

Next-generation sequencing (NGS)-based typings of HLA-A, B, C, DQB1 and DRB1 loci were performed from 2018 to 2019 in 23 595 newly recruited or re-typed adult potential bone marrow donors registered in Poltransplant Registry to characterize allele and haplotype frequencies of HLA system for loci important for hematopoietic stem cell transplantation. The donors were recruited for registry and not for any other purpose including controls in a disease association study. The population sample was collected in various regions of Poland including all voivodships. The data regarding the degree of relatedness among individuals in the sample were not collected. Typings were supported by public funds as a part of the Polish National Program for Transplant Medicine Development. HLA frequency data are available in the Allele Frequencies Net Database.

CD44 is expressed in non-myelinating Schwann cells of the adult rat, and may play a role in neurodegeneration-induced glial plasticity at the neuromuscular junction.

CD44 is a multifunctional cell surface glycoprotein which regulates cell-cell and cell-matrix interactions in a variety of tissues. In particular, the protein was found to be expressed in glial cells of developing, but not adult, peripheral nerves, where it takes part in signaling mediated by ErbB class of receptors for neuregulins. Here, we demonstrate, using high resolution morphological methods, tissue fractionation and RT-PCR, that CD44 is strongly expressed in terminal Schwann cell (TSC) at the neuromuscular junction (NMJ) of the adult rat skeletal muscle. As CD44 is also expressed by Schwann cells of the non-myelinated Remak bundles of the proximal peripheral nerves, it appears to be a marker of non-myelinating Schwann cell subpopulation. The analysis of transgenic rats bearing a mutated superoxide-dismutase gene (SOD1(G93A)) causing familial amyotrophic lateral sclerosis (ALS) revealed that TSC activation and morphological plasticity at the NMJ, caused by ongoing denervation-reinnervation is associated with a strong increase in CD44 expression therein. Notably, CD44 immunoreactivity is present in fine axon-escheating processes of the glial cells that guide reinnervation. In addition, we found that both in normal and SOD1(G93A) muscle, CD44 expressed in TSC partially colocalizes with immunoreactivities of neuregulin receptors ErbB2 and ErbB3. The colocalization appears to reflect a physical interaction, as evidenced by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) analysis between CD44 and ErbB3. Importantly, TSC activation upon ALS-like neurodegeneration results in significant increase in molecular proximity of CD44 and ErbB3, which may have an impact on glial plasticity at the NMJ.

Epstein-Barr virus infections are strongly dependent on activating and inhibitory KIR-HLA pairs after T-cell replate unrelated hematopoietic stem cell transplantation, the principles, and method of pairing analysis.

Viral infections are the main cause of increased morbidity and mortality among recipients in allogeneic hematopoietic stem cell transplantation (HSCT). Natural killer (NK) cells fight virally infected cells provided directional activation of cytotoxicity. In this study, we analyzed the role of receptor-ligand pairs that include inhibitory or activating killer cell immunoglobulin-like receptors (KIRs) with their HLA class I ligands in the course of viral infections. The paper also presents an algorithm that allows performing automated inhibitory (i) KIR:HLA pairing and rechecking in the clinical setting. The obtained results indicate a significant adverse roles of reduced number of iKIR:HLA pairs (40% vs 9%; odds ratio [OR] = 6.67; P = .0057; 95% confidence interval [CI] 1.74-25.62) and the presence of activating KIR:HLA pairs (15% vs 5%, OR = 3.58, P = .028, 95% CI 1.19-10.73) in EBV infections post HSCT.

Progeria caused by a rare LMNA mutation p.S143F associated with mild myopathy and atrial fibrillation.

We present a 6-year-old girl with premature aging associated with mild myopathy, displaying muscle weakness, joint contractures and hyporeflexia. Genetic analysis revealed rare heterozygous point mutation in lamin A/C gene, g.428C>T. Cardiological evaluation showed atrial fibrillation, but we did not find signs of coronary heart disease, which is life-threatening cardiovascular complication in progeria. Electron microscopy of the muscle revealed abnormalities in nuclear architecture, i.e. blebbing, thick lamina and peripheral distribution of heterochromatin. As some diagnostic criteria characteristic for classic progeria are not fulfilled, this case could be regarded as atypical progeria associated with myopathy and atrial fibrillation. To our knowledge, this is the second case of such association described in the literature.

Role of donor HLA class I mismatch, KIR-ligand mismatch and HLA:KIR pairings in hematological malignancy relapse after unrelated hematopoietic stem cell transplantation.

HLA are functional in cancer immunosurveillance in adaptive and innate immunity pathways. In unrelated hematopoietic stem cell transplantation (HSCT) in 688 patients with hematological malignancies we compared antitumor efficacy of transplant in three models including the level of: (a) donor-recipient HLA class I mismatch, (b) KIR-ligand mismatch, (c) post-transplant cognate HLA:KIR pairing. The effects were directly compared in multivariate models with backward elimination including all three effects in initial model. In final multivariate model HLA mismatch and KIR-ligand mismatch levels were eliminated and HLA:KIR-dependent NK cell licensing effect remained independent prognostic factor for DFS, relapse/progression incidence, and overall survival (OS). These results suggested that NK cell licensing via cognate HLA:KIR pairs is primarily functional in cancer immunosurveillance in HSCT.

HLA-inferred extended haplotype disparity level is more relevant than the level of HLA mismatch alone for the patients survival and GvHD in T cell-replate hematopoietic stem cell transplantation from unrelated donor.

Serious risks in unrelated hematopoietic stem cell transplantation (HSCT) including graft versus host disease (GvHD) and mortality are associated with HLA disparity between donor and recipient. The increased risks might be dependent on disparity in not-routinely-tested multiple polymorphisms in genetically dense MHC region, being organized in combinations of two extended MHC haplotypes (Ehp). We assessed the clinical role of donor-recipient Ehp disparity levels in N = 889 patients by the population-based detection of HLA allele phase mismatch. We found increased GvHD incidences and mortality rates with increasing Ehp mismatch level even with the same HLA mismatch level. In multivariate analysis HLA mismatch levels were excluded from models and Ehp disparity level remained independent prognostic factor for high grade acute GvHD (p = 0.000037, HR = 10.68, 95%CI 5.50-32.5) and extended chronic GvHD (p < 0.000001, HR = 15.51, CI95% 5.36-44.8). In group with single HLA mismatch, patients with double Ehp disparity had worse 5-year overall survival (45% vs. 56%, p = 0.00065, HR = 4.05, CI95% 1.69-9.71) and non-relapse mortality (40% vs. 31%, p = 0.00037, HR = 5.63, CI95% 2.04-15.5) than patients with single Ehp disparity. We conclude that Ehp-linked factors contribute to the high morbidity and mortality in recipients given HLA-mismatched unrelated transplant and Ehp matching should be considered in clinical HSCT.

Prediction of NK Cell Licensing Level in Selection of Hematopoietic Stem Cell Donor, Initial Results.

Natural killer (NK) cell licensing status depends on clonal expression of inhibitory killer cell immunoglobulin-like receptors (iKIR) and short term HLA environment. Licensed NK cells are more efficient in tumor killing than unlicensed NK cells. Cognate KIR-HLA pairs in hematopoietic stem cell transplant (HSCT) donor and recipient are decisive for the possible change in the NK cell licensing status after HSCT. We assessed clinical outcomes in 297 patients with lymphoproliferative or myeloproliferative malignancies, or myelodysplastic syndrome in a model with upward licensing, downward resetting, and unchanged licensing genetics status after T cell replate HSCT from unrelated donors. We found extremely low (0%) relapse/progression incidence (RI), and better (59%) event-free survival (EFS) in recipients with upward licensing status and highly increased RI (37.5%), and reduced EFS (8%) among patients with the downward resetting status of repopulated donor NK cells after HSCT, as compared with unchanged NK cell licensing (RI 23%, EFS 47%). These trends were confirmed in adjusted multivariable models (for RI p = 6.66E-09, OR = 1.47, 95% CI 1.29-1.66 and for EFS p = 3.79E-13, OR = 1.67, 95% CI 1.50-1.84). Differences in the incidence of acute graft versus host disease (GvHD 62, 69, and 47%) and chronic GvHD (24, 44, and 15%, respectively) in three groups were insignificant. It would be rationale the preferential selection of the donors with upward licensing over downward resetting inhibitory KIR:HLA constellation and inclusion of the KIR genotyping in the donor selection algorithm for malignant patients. Further studies using enlarged cohorts of patients with more homogenous diagnosis are essential to reliably verify these preliminary data.