Body odours as putative chemosignals in the father-child relationship: New insights on paternal olfactory kin recognition and preference from infancy to adolescence

Children's body odours are effective chemical cues in the parent-child relationship. Mothers can recognize the odour of their child and prefer this odour over that of unfamiliar children. This effect is mediated by genetic similarity and developmental stage and is therefore suited to promote parental care at pre-pubertal stage, while facilitating incest avoidance at (post-)pubertal stage. The present study tested whether similar mechanisms apply to fathers. Therefore n = 56 fathers evaluated body odour samples of their own and of unfamiliar children in varying genetic and developmental stages. Genetic status was determined by human leucocyte antigen (HLA) profiling, developmental status by standardized assessment of pubertal status and steroid hormone concentration (estradiol, testosterone). Similar to mothers, fathers identified their own child's body odour above chance and preferred that odour. The paternal preference did not relate to HLA similarity but decreased with increasing age of the child. The decline was associated with higher pubertal stages in daughters only, which supports the hypothesis of odour-mediated incest prevention in opposite-sex parent-child dyads.

Remission induction versus immediate allogeneic haematopoietic stem cell transplantation for patients with relapsed or poor responsive acute myeloid leukaemia (ASAP): a randomised, open-label, phase 3, non-inferiority trial

BACKGROUND

Whether high-dose cytarabine-based salvage chemotherapy, administered to induce complete remission in patients with poor responsive or relapsed acute myeloid leukaemia scheduled for allogeneic haematopoietic stem-cell transplantation (HSCT) after intensive conditioning confers a survival advantage, is unclear.

METHODS

To test salvage chemotherapy before allogeneic HSCT, patients aged between 18 and 75 years with non-favourable-risk acute myeloid leukaemia not in complete remission after first induction or untreated first relapse were randomly assigned 1:1 to remission induction with high-dose cytarabine (3 g/m2 intravenously, 1 g/m2 intravenously for patients >60 years or with a substantial comorbidity) twice daily on days 1-3 plus mitoxantrone (10 mg/m2 intravenously) on days 3-5 or immediate allogeneic HSCT for the disease control group. Block randomisation with variable block lengths was used and patients were stratified by age, acute myeloid leukaemia risk, and disease status. The study was open label. The primary endpoint was treatment success, defined as complete remission on day 56 after allogeneic HSCT, with the aim to show non-inferiority for disease control compared with remission induction with a non-inferiority-margin of 5% and one-sided type 1 error of 2·5%. The primary endpoint was analysed in both the intention-to-treat (ITT) population and in the per-protocol population. The trial is completed and was registered at ClinicalTrials.gov, NCT02461537.

FINDINGS

281 patients were enrolled between Sept 17, 2015, and Jan 12, 2022. Of 140 patients randomly assigned to disease control, 135 (96%) proceeded to allogeneic HSCT, 97 (69%) after watchful waiting only. Of 141 patients randomly assigned to remission induction, 134 (95%) received salvage chemotherapy and 128 (91%) patients subsequently proceeded to allogeneic HSCT. In the ITT population, treatment success was observed in 116 (83%) of 140 patients in the disease control group versus 112 (79%) of 141 patients with remission induction (test for non-inferiority, p=0·036). Among per-protocol treated patients, treatment success was observed in 116 (84%) of 138 patients with disease control versus 109 (81%) of 134 patients in the remission induction group (test for non-inferiority, p=0·047). The difference in treatment success between disease control and remission induction was estimated as 3·4% (95% CI -5·8 to 12·6) for the ITT population and 2·7% (-6·3 to 11·8) for the per-protocol population. Fewer patients with disease control compared with remission induction had non-haematological adverse events grade 3 or worse (30 [21%] of 140 patients vs 86 [61%] of 141 patients, χ2 test p<0·0001). Between randomisation and the start of conditioning, with disease control two patients died from progressive acute myeloid leukaemia and zero from treatment-related complications, and with remission induction two patients died from progressive acute myeloid leukaemia and two from treatment-related complications. Between randomisation and allogeneic HSCT, patients with disease control spent a median of 27 days less in hospital than those with remission induction, ie, the median time in hospital was 15 days (range 7-64) versus 42 days (27-121, U test p<0·0001), respectively.

INTERPRETATION

Non-inferiority of disease control could not be shown at the 2·5% significance level. The rate of treatment success was also not statistically better for patients with remission induction. Watchful waiting and immediate transplantation could be an alternative for fit patients with poor response or relapsed acute myeloid leukaemia who have a stem cell donor available. More randomised controlled intention-to-transplant trials are needed to define the optimal treatment before transplantation for patients with active acute myeloid leukaemia.

FUNDING

DKMS and the Gert and Susanna Mayer Stiftung Foundation.

Donor KIR genotype based outcome prediction after allogeneic stem cell transplantation: no land in sight

Optimizing natural killer (NK) cell alloreactivity could further improve outcome after allogeneic hematopoietic cell transplantation (alloHCT). The donor's Killer-cell Immunoglobulin-like Receptor (KIR) genotype may provide important information in this regard. In the past decade, different models have been proposed aiming at maximizing NK cell activation by activating KIR-ligand interactions or minimizing inhibitory KIR-ligand interactions. Alternative classifications intended predicting outcome after alloHCT by donor KIR-haplotypes. In the present study, we aimed at validating proposed models and exploring more classification approaches. To this end, we analyzed samples stored at the Collaborative Biobank from HLA-compatible unrelated stem cell donors who had donated for patients with acute myeloid leukemia (AML) or myelodysplastic neoplasm (MDS) and whose outcome data had been reported to EBMT or CIBMTR. The donor KIR genotype was determined by high resolution amplicon-based next generation sequencing. We analyzed data from 5,017 transplants. The median patient age at alloHCT was 56 years. Patients were transplanted for AML between 2013 and 2018. Donor-recipient pairs were matched for HLA-A, -B, -C, -DRB1, and -DQB1 (79%) or had single HLA mismatches. Myeloablative conditioning was given to 56% of patients. Fifty-two percent of patients received anti-thymocyte-globulin-based graft-versus-host disease prophylaxis, 32% calcineurin-inhibitor-based prophylaxis, and 7% post-transplant cyclophosphamide-based prophylaxis. We tested several previously reported classifications in multivariable regression analyses but could not confirm outcome associations. Exploratory analyses in 1,939 patients (39%) who were transplanted from donors with homozygous centromeric (cen) or telomeric (tel) A or B motifs, showed that the donor cen B/B-tel A/A diplotype was associated with a trend to better event-free survival (HR 0.84, p=.08) and reduced risk of non-relapse mortality (NRM) (HR 0.65, p=.01). When we further dissected the contribution of B subtypes, we found that only the cen B01/B01-telA/A diplotype was associated with a reduced risk of relapse (HR 0.40, p=.04) while all subtype combinations contributed to a reduced risk of NRM. This exploratory finding has to be validated in an independent data set. In summary, the existing body of evidence is not (yet) consistent enough to recommend use of donor KIR genotype information for donor selection in routine clinical practice.

Providing hematopoietic stem cell products from unrelated donors to the world: DKMS donor centers and DKMS Registry

Allogeneic hematopoietic stem cell (HSC) transplantation is a curative therapy for many severe blood diseases. As many patients have no suitable family donor, large unrelated donor registries and donor centers have been established in many countries, along with an international system for the provision of unrelated donor HSC products. As an essential part of this system, DKMS operates donor centers in 7 countries with a total of 12.2 million donors and over 114,000 donations so far, and a multinational donor registry. In 2022, DKMS donors contributed 57.5% of all cross-border donations worldwide. In this review, we describe the international system for the provision of unrelated donor HSC products as well as tasks and responsibilities of donor registries and donor centers. We also discuss relevant aspects of DKMS donor centers, namely donor file composition, matching and donation probabilities and actual donations, and the unique multinational approach of the DKMS Registry.

ICH Q14-inspired novel approach to establish an SFC-based purity method for carbamazepine

The proposed ICH Q14 guideline "Analytical procedure development" describes science and risk-based approaches for development and maintenance of analytical procedures suitable for the assessment of the quality of drug substances and drug products. As a case study, the systematic development and validation of a supercritical fluid chromatography (SFC)-based purity method for carbamazepine is presented. Systematic analytical quality by design (AQbD) principles were applied using the software package Fusion QbD to the method development approach. The relationship between chromatographic parameters and the responses of interest were examined to improve the reliability of the method by understanding, reducing, and controlling sources of variability. Method performance qualification in terms of method robustness was finally carried out with the parameters that were classified as critical after method development and a validation study met previously set acceptance criteria. The developed SFC purity method for carbamazepine demonstrated readiness as a viable alternative to the official HPLC method published in the Ph.Eur. with improved peak resolution, improved peak symmetry, and faster analysis times (3 min vs. 80 min for the official method). Its inherent reliability illustrates the superiority of AQbD in method development and application for drug quality assurance.

High population frequencies of MICA copy number variations originate from independent recombination events

MICA is a stress-induced ligand of the NKG2D receptor that stimulates NK and T cell responses and was identified as a key determinant of anti-tumor immunity. The MICA gene is located inside the MHC complex and is in strong linkage disequilibrium with HLA-B. While an HLA-B*48-linked MICA deletion-haplotype was previously described in Asian populations, little is known about other MICA copy number variations. Here, we report the genotyping of more than two million individuals revealing high frequencies of MICA duplications (1%) and MICA deletions (0.4%). Their prevalence differs between ethnic groups and can rise to 2.8% (Croatia) and 9.2% (Mexico), respectively. Targeted sequencing of more than 70 samples indicates that these copy number variations originate from independent nonallelic homologous recombination events between segmental duplications upstream of MICA and MICB. Overall, our data warrant further investigation of disease associations and consideration of MICA copy number data in oncological study protocols.

Controlling the elution order of insulin and its analogs in sub-/supercritical fluid chromatography using methanesulfonic acid and 18-crown-6 as mobile phase additives

The purity analysis of therapeutic peptides can often be challenging, demanding the application of more than a single analytical technique. Supercritical fluid chromatography nowadays is a promising alternative to reversed-phase liquid chromatography, providing orthogonal and complementary information. This study investigated its applicability for the separation of human insulin, its analogs and degradation products. A previously published method development protocol for peptides up to 2000 Da was successfully applied to the higher molecular weight insulins (6 kDa). A single gradient method was optimized for all insulins using a Torus DEA column (100 × 3.0 mm, 1.7 μm), carbon dioxide and a modifier consisting of methanol/acetonitrile/water/methanesulfonic acid (65:35:2:0.1, v/v/v/v). Consecutively, the crown ether 18-crown-6, which is well known to complex charged lysine sidechains and other amino functionalities, was added to the modifier to evaluate its impact on selectivity. A decreased retention and a shift in the elution order for the insulins were observed. An inverse effect on retention was found when combined with a neutral stationary phase chemistry (Viridis BEH).

5 years DKMS Chile: approach, results and impact of the first unrelated stem cell donor center in Chile

Introduction

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is performed worldwide to treat blood cancer and other life-threatening blood disorders. As successful transplantation requires an HLA-compatible donor, unrelated donor centers and registries have been established worldwide to identify donors for patients without a family match. Ethnic minorities are underrepresented in large donor registries. Matching probabilities are higher when donors and patients share the same ethnic background, making it desirable to increase the diversity of the global donor pool by recruiting donors in new regions. Here, we report the establishment and the first 5 years of operation of the first unrelated stem cell donor center in Chile, a high-income country in South America with a population of over 19 million.

Methods

We used online and in-person donor recruitment practices through patient appeals and donor drives in companies, universities, the armed forces, and public services. After confirmatory typing donors were subjected to medical work-up and cleared for donation.

Results

We recruited almost 170,000 donors in 5 years. There were 1,488 requests received for confirmatory typing and donor availability checks, of which 333 resulted in medical work-up, leading to 194 stem cell collections. Products were shipped to Chile (48.5%) and abroad. Even when the COVID-19 pandemic challenged our activities, the number of donors recruited and shipped stem cell products remained steady. In Chile there was an almost 8-fold increase in unrelated donor transplantation activity from 16 procedures in 2016-2018 to 124 procedures in 2019-2021, mainly for pediatric patients following the center's establishment. We estimate that 49.6% of Chilean patients would find at least one matched unrelated donor in the global DKMS donor pool.

Discussion

Establishing a DKMS donor center in Chile has significantly increased donor availability for Chilean patients and contributed to an increase of unrelated donor stem cell transplant activity.

HLA-DP on Epithelial Cells Enables Tissue Damage by NKp44+ Natural Killer Cells in Ulcerative Colitis

BACKGROUND & AIMS

Ulcerative colitis (UC) is characterized by severe inflammation and destruction of the intestinal epithelium, and is associated with specific risk single nucleotide polymorphisms in HLA class II. Given the recently discovered interactions between subsets of HLA-DP molecules and the activating natural killer (NK) cell receptor NKp44, genetic associations of UC and HLA-DP haplotypes and their functional implications were investigated.

METHODS

HLA-DP haplotype and UC risk association analyses were performed (UC: n = 13,927; control: n = 26,764). Expression levels of HLA-DP on intestinal epithelial cells (IECs) in individuals with and without UC were quantified. Human intestinal 3-dimensional (3D) organoid cocultures with human NK cells were used to determine functional consequences of interactions between HLA-DP and NKp44.

RESULTS

These studies identified HLA-DPA1∗01:03-DPB1∗04:01 (HLA-DP401) as a risk haplotype and HLA-DPA1∗01:03-DPB1∗03:01 (HLA-DP301) as a protective haplotype for UC in European populations. HLA-DP expression was significantly higher on IECs of individuals with UC compared with controls. IECs in human intestinal 3D organoids derived from HLA-DP401pos individuals showed significantly stronger binding of NKp44 compared with HLA-DP301pos IECs. HLA-DP401pos IECs in organoids triggered increased degranulation and tumor necrosis factor production by NKp44+ NK cells in cocultures, resulting in enhanced epithelial cell death compared with HLA-DP301pos organoids. Blocking of HLA-DP401-NKp44 interactions (anti-NKp44) abrogated NK cell activity in cocultures.

CONCLUSIONS

We identified an UC risk HLA-DP haplotype that engages NKp44 and activates NKp44+ NK cells, mediating damage to intestinal epithelial cells in an HLA-DP haplotype-dependent manner. The molecular interaction between NKp44 and HLA-DP401 in UC can be targeted by therapeutic interventions to reduce NKp44+ NK cell-mediated destruction of the intestinal epithelium in UC.

Small volume bone marrow aspirates with high progenitor cell concentrations maximize cell therapy dose manufacture and substantially reduce donor hemoglobin loss

BACKGROUND

Bone marrow (BM) transplantation is a life-saving therapy for hematological diseases, and the BM harbors also highly useful (progenitor) cell types for novel cell therapies manufacture. Yet, the BM collection technique is not standardized.

METHODS

Benchmarking our collection efficiency to BM collections worldwide (N = 1248), we noted a great variability of total nucleated cell (TNC) yields in BM products (HPC-M) with superior performance of our center, where we have implemented a small volume aspirate policy. Thus, we next prospectively aimed to assess the impact of BM collection technique on HPC-M quality. For each BM collection (N = 20 donors), small volume (3 mL) and large volume (10 mL) BM aspirates were sampled at 3 time points and analyzed for cell composition.

RESULTS

Compared to large volume aspirates, small volume aspirates concentrated more TNCs, immune cells, platelets, hematopoietic stem/progenitor cells, mesenchymal stromal cells (MSCs), and endothelial progenitors. Inversely, the hemoglobin concentration was higher in large volume aspirates indicating more hemoglobin loss. Manufacturing and dosing scenarios showed that small volume aspirates save up to 42% BM volume and 44% hemoglobin for HPC-M donors. Moreover, MSC production efficiency can be increased by more than 150%.

CONCLUSIONS

We propose to consider small volume BM aspiration as standard technique for BM collection.

Genotype List String 1.1: Extending the Genotype List String grammar for describing HLA and Killer-cell Immunoglobulin-like Receptor genotypes

The Genotype List (GL) String grammar for reporting HLA and Killer-cell Immunoglobulin-like Receptor (KIR) genotypes in a text string was described in 2013. Since this initial description, GL Strings have been used to describe HLA and KIR genotypes for more than 40 million subjects, allowing these data to be recorded, stored and transmitted in an easily parsed, text-based format. After a decade of working with HLA and KIR data in GL String format, with advances in HLA and KIR genotyping technologies that have fostered the generation of full-gene sequence data, the need for an extension of the GL String system has become clear. Here, we introduce the new GL String delimiter "?," which addresses the need to describe ambiguity in assigning a gene sequence to gene paralogs. GL Strings that do not include a "?" delimiter continue to be interpreted as originally described. This extension represents version 1.1 of the GL String grammar.

HLA allele and haplotype frequencies of registered stem cell donors in Chile

Patients in need of hematopoietic stem cell transplantation often rely on unrelated stem cell donors matched in certain human leukocyte antigen (HLA) genes. Donor search is complicated by the extensive allelic variability of the HLA system. Therefore, large registries of potential donors are maintained in many countries worldwide. Population-specific HLA characteristics determine the registry benefits for patients and also the need for further regional donor recruitment. In this work, we analyzed HLA allele and haplotype frequencies of donors of DKMS Chile, the first Chilean donor registry, with self-assessed "non-Indigenous" (n=92,788) and "Mapuche" (n=1,993) ancestry. We identified HLA alleles that were distinctly more abundant in the Chilean subpopulations than in worldwide reference populations, four of them particularly characteristic for the Mapuche subpopulation, namely B*39:09g, B*35:09, DRB1*04:07g, and DRB1*16:02g. Both population subsamples carried haplotypes of both Native American and European origin at high frequencies, reflecting Chile's complex history of admixture and immigration. Matching probability analysis revealed limited benefits for Chilean patients (both non-Indigenous and Mapuche) from donor registries of non-Chilean donors, thus indicating a need for ongoing significant donor recruitment efforts in Chile.

World Marrow Donor Association guidelines for the reporting of novel HLA alleles

The guidelines for the implementation and reporting of HLA nomenclature for the World Marrow Donor Association have served as a reliable standard for communication of HLA data in the hematopoietic cell transplantation process. Wider use of next-generation sequencing made a special provision of the guidelines increasingly pertinent: how to communicate novel HLA alleles. Novel alleles need to be recognized by the WHO Nomenclature Committee for Factors of the HLA system to obtain official allele designations. Until then they have to be handled according to the specific rules. Leaving the actual rules basically unchanged we give some advice on how to communicate novel alleles to best facilitate the search process for cases where novel alleles are identified on donor or patient side.

Ternary eluent compositions in supercritical fluid chromatography improved fingerprinting of therapeutic peptides

Currently, little information has been published on the application of ternary eluent compositions in supercritical fluid chromatography for separating peptides. This work investigates the benefits of adding acetonitrile to methanol as the modifier. Three cyclic antibiotic peptides (bacitracin, colistin, and daptomycin) ranging between 1000 and 2000 Da were chosen as model substances. The ternary mixture of carbon dioxide, methanol, and acetonitrile is optimized to increase the resolution of the peptide's fingerprint. In addition, varying compositions of methanol and acetonitrile were found to change the elution order of the analytes, which is a valuable tool during method development. An individual gradient method using two Torus 2-PIC columns (each 100 × 3.0 mm, 1.7 μm), carbon dioxide, and a modifier consisting of acetonitrile/methanol/water/methanesulfonic acid (60:40:2:0.1, v:v:v:v) was optimized for each of the peptides. Subsequently, a generic method development protocol applicable to polypeptides is proposed.

Post-COVID-19 condition in the German working population: A cross-sectional study of 200,000 registered stem cell donors

BACKGROUND

The SARS-CoV-2 pandemic has strained health systems worldwide, and infection numbers continue to rise. While previous data have already shown that many patients suffer from symptoms for months after an acute infection, data on risk factors and long-term outcomes are incomplete, particularly for the working population.

OBJECTIVES

We aimed to provide information on the prevalence of post-COVID-19 conditions in a subset of the German working-age population (18-61 years old) and to analyze risk factors.

METHODS

We conducted an online survey with a health questionnaire among registered potential stem cell donors with or without a self-reported history of polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection. Logistic regression models were used to examine the risks of severity of acute infection, sex, age, body mass index, diabetes mellitus, and arterial hypertension medication on post-COVID-19 symptoms.

RESULTS

A total of 199,377 donors reported evaluable survey questionnaires-12,609 cases had a history of SARS-CoV-2 infection and 186,768 controls had none. Overall, cases reported physical, cognitive, and psychological complaints more frequently compared to controls. Increased rates of complaints persisted throughout 15 months postinfection, for example, 28.4%/19.3% of cases/controls reported fatigue (p <0.0001) and 9.5%/3.6% of cases/controls reported loss of concentration (p <0.0001). No significant differences were observed in the frequency of reported symptoms between 3 and 15 months postinfection. Multivariate analysis revealed a strong influence of the severity of the acute SARS-CoV-2 infection episode and age on the risk for post-COVID-19 conditions.

CONCLUSION

We report the prevalence of post-COVID-19 conditions in mainly unvaccinated individuals with SARS-CoV-2 infections between February 2020 and August 2021. The severity of the acute course and age were major risk factors. Vaccinations may reduce the risk of post-COVID-19 conditions by reducing the risk of severe infections.

Prevalence of nitrosamine contaminants in drug samples: Has the crisis been overcome?

Various drug samples (N = 249; drug substances, tablets, capsules, solutions, crèmes, and more) from the European pharmaceutical market were collected since 2019 and analyzed for 16 nitrosamines (NAs). In 2.0% of the cases, NAs were detected. These findings included four active pharmaceutical ingredients already known for potential NA contamination: losartan (N-nitrosodimethylamine [NDMA] and N-nitrosodiethylamine, simultaneously), valsartan (NDMA), metformin (NDMA) and ranitidine (NDMA). The fifth new finding, which has not been reported yet, discovered contamination of a molsidomine tablet sample with N-nitrosomorpholine (NMor). The tablet contained 144% of the toxicological allowable intake for NMor. NMor was included in our screening from the beginning and is currently the focus of regulatory authorities, but was added to the guidelines only last year. Thus, it may not have been the focus of regulatory investigations for too long. Our results indicate that the majority of drug products in the market are nonhazardous in terms of patient safety and drug purity. Unfortunately, the list of individual affected products keeps growing constantly and new NA cases, such as molsidomine or nitrosated drug substances (nitrosamine drug substance-related impurities [NDSRI]), continue to emerge. We therefore expect nitrosamine screenings to remain a high priority.

Engagement of TRAIL triggers degranulation and IFNγ production in human natural killer cells

NK cells utilize a large array of receptors to screen their surroundings for aberrant or virus‐infected cells. Given the vast diversity of receptors expressed on NK cells we seek to identify receptors involved in the recognition of HIV‐1‐infected cells. By combining an unbiased large‐scale screening approach with a functional assay, we identify TRAIL to be associated with NK cell degranulation against HIV‐1‐infected target cells. Further investigating the underlying mechanisms, we demonstrate that TRAIL is able to elicit multiple effector functions in human NK cells independent of receptor‐mediated induction of apoptosis. Direct engagement of TRAIL not only results in degranulation but also IFNγ production. Moreover, TRAIL‐mediated NK cell activation is not limited to its cognate death receptors but also decoy receptor I, adding a new perspective to the perceived regulatory role of decoy receptors in TRAIL‐mediated cytotoxicity. Based on these findings, we propose that TRAIL not only contributes to the anti‐HIV‐1 activity of NK cells but also possesses a multifunctional role beyond receptor‐mediated induction of apoptosis, acting as a regulator for the induction of different effector functions.

Host KIR/HLA-C Genotypes Determine HIV-Mediated Changes of the NK Cell Repertoire and Are Associated With Vpu Sequence Variations Impacting Downmodulation of HLA-C

NK cells play a pivotal role in viral immunity, utilizing a large array of activating and inhibitory receptors to identify and eliminate virus-infected cells. Killer-cell immunoglobulin-like receptors (KIRs) represent a highly polymorphic receptor family, regulating NK cell activity and determining the ability to recognize target cells. Human leukocyte antigen (HLA) class I molecules serve as the primary ligand for KIRs. Herein, HLA-C stands out as being the dominant ligand for the majority of KIRs. Accumulating evidence indicated that interactions between HLA-C and its inhibitory KIR2DL receptors (KIR2DL1/L2/L3) can drive HIV-1-mediated immune evasion and thus may contribute to the intrinsic control of HIV-1 infection. Of particular interest in this context is the recent observation that HIV-1 is able to adapt to host HLA-C genotypes through Vpu-mediated downmodulation of HLA-C. However, our understanding of the complex interplay between KIR/HLA immunogenetics, NK cell-mediated immune pressure and HIV-1 immune escape is still limited. Therefore, we investigated the impact of specific KIR/HLA-C combinations on the NK cell receptor repertoire and HIV-1 Vpu protein sequence variations of 122 viremic, untreated HIV-1⁺ individuals. Compared to 60 HIV-1^- controls, HIV-1 infection was associated with significant changes within the NK cell receptor repertoire, including reduced percentages of NK cells expressing NKG2A, CD8, and KIR2DS4. In contrast, the NKG2C⁺ and KIR3DL2⁺ NK cell sub-populations from HIV-1⁺ individuals was enlarged compared to HIV-1^- controls. Stratification along KIR/HLA-C genotypes revealed a genotype-dependent expansion of KIR2DL1⁺ NK cells that was ultimately associated with increased binding affinities between KIR2DL1 and HLA-C allotypes. Lastly, our data hinted to a preferential selection of Vpu sequence variants that were associated with HLA-C downmodulation in individuals with high KIR2DL/HLA-C binding affinities. Altogether, our study provides evidence that HIV-1-associated changes in the KIR repertoire of NK cells are to some extent predetermined by host KIR2DL/HLA-C genotypes. Furthermore, analysis of Vpu sequence polymorphisms indicates that differential KIR2DL/HLA-C binding affinities may serve as an additional mechanism how host genetics impact immune evasion by HIV-1.

Risk assessment for nitrosated pharmaceuticals: A future perspective in drug development

Since June 2018, thousands of drug products from around the world had to be recalled due to the unexpected presence of nitrosamines (NAs). Starting with the pharmaceutical group of sartans, antidiabetic drugs, antihistamines, and antibiotics also became the subject of investigation. The occurrence of NAs has shown that pharmaceutical companies and regulatory agencies did not focus on these substances in the past during drug development. In this study, we incorporated a nitrosation assay procedure into high-resolution supercritical fluid chromatography (SFC)-mass spectrometry screening to test the potential of direct nitrosation of active pharmaceutical ingredients (APIs). The forced degradation study was performed with a four-fold molar excess of sodium nitrite, relative to the drug substance, at pH 3-4 for 4 h at 37°C. Chromatographic separation was performed on a porous graphitic carbon column by SFC. The mass analysis then focused on direct N-nitrosation or N-nitroso compounds (NOCs) formed after dealkylation. Substances (n = 67) from various pharmaceutical classes were evaluated and 49.3% of them formed NOCs, of which 21.2% have not yet been reported in the literature. In addition, for two APIs, which are known to form an unidentified NOC, the structure could be identified. A few substances also showed multiple NOCs and even N,N'-dinitroso-species. As NAs are carcinogens, they have to be eliminated or at least limited to prevent cancer in patients, who rely on these drugs. This study contributes a procedure that can be implemented in preapproval drug development and postapproval risk assessment to prevent unexpected findings in the future.

Graphical user interface for the haplotype frequency estimation software Hapl-o-Mat

Population-specific human leukocyte antigen (HLA) haplotype frequencies are an essential basis of advanced algorithms for donor selection in unrelated hematopoietic stem cell transplantation. In 2016, we introduced Hapl-o-Mat, a versatile tool for haplotype frequency estimation based on an expectation-maximization algorithm (https://github.com/DKMS/hapl-o-Mat). Hapl-o-Mat is specifically tailored to the analysis of HLA genes and able to cope with the heterogeneous genotyping data usually found in donor registries. To make Hapl-o-Mat accessible to a wider range of users, we designed a graphical user interface module that considerably facilitates the interaction with the application (https://github.com/DKMS/hapl-o-Mat_GUI). We further provide a precompiled version of Hapl-o-Mat that can be used on Windows personal computers without dependency on additional software libraries (https://github.com/DKMS/hapl-o-Mat_WinBin). We are confident that these new, user-oriented features will encourage more researchers to apply Hapl-o-Mat to their data, thereby increasing knowledge and public availability of population-specific HLA haplotype frequencies.

Noninvasive Determination of CMV Serostatus From Dried Buccal Swab Samples: Assay Development, Validation, and Application to 1.2 Million Samples

BACKGROUND

Buccal swab sampling constitutes an attractive noninvasive alternative to blood drawings for antibody serostatus assays. Here we describe a method to determine the cytomegalovirus immunoglobulin G (CMV IgG) serostatus from dried buccal swab samples.

METHODS

Upon solubilization, CMV IgG is determined by an ELISA assay specifically adapted to cope with low IgG concentrations. The derived CMV titer is normalized against the total protein concentration to adjust for incorrectly or less efficiently sampled buccal swabs. Assay parameters were optimized on a set of 713 samples.

RESULTS

Validation with 1784 samples revealed distinct results for > 80% of samples with 98.6% specificity and 99.1% sensitivity. Based on the analysis of 1.2 million samples we derived age- and sex-stratified CMV prevalence statistics for Germany, Poland, United Kingdom, and Chile. To confirm accuracy of the assay in routine operation, the CMV status of 6518 donors was reassessed by independent laboratories based on conventional blood samples revealing 96.9% specificity and 97.4% sensitivity.

CONCLUSIONS

The assay accurately delivers the CMV IgG serostatus from dried buccal swab samples for > 80% of the participants. Thereby it provides a noninvasive alternative to plasma-based CMV monitoring for nondiagnostic purposes such as hematopoietic stem cell transplantation donor screening or population studies.

Estimating HLA haplotype frequencies from homozygous individuals - A Technical Report

We estimated HLA haplotype frequencies based on individuals homozygous for 4, 5 or 6 loci. Validation of our approach using a sample of over 3.4 million German individuals was successful. Compared to an expectation‐maximization algorithm, the errors were larger. However, our approach allows the unequivocal detection of rare haplotypes.

Individual HLA-A, -B, -C, and -DRB1 Genotypes Are No Major Factors Which Determine COVID-19 Severity

HLA molecules are key restrictive elements to present intracellular antigens at the crossroads of an effective T-cell response against SARS-CoV-2. To determine the impact of the HLA genotype on the severity of SARS-CoV-2 courses, we investigated data from 6,919 infected individuals. HLA-A, -B, and -DRB1 allotypes grouped into HLA supertypes by functional or predicted structural similarities of the peptide-binding grooves did not predict COVID-19 severity. Further, we did not observe a heterozygote advantage or a benefit from HLA diplotypes with more divergent physicochemical peptide-binding properties. Finally, numbers of in silico predicted viral T-cell epitopes did not correlate with the severity of SARS-CoV-2 infections. These findings suggest that the HLA genotype is no major factor determining COVID-19 severity. Moreover, our data suggest that the spike glycoprotein alone may allow for abundant T-cell epitopes to mount robust T-cell responses not limited by the HLA genotype.

HLA-E typing of more than 2.5 million potential hematopoietic stem cell donors: Methods and population-specific allele frequencies

We developed a cost-efficient workflow for genotyping HLA-E by NGS and applied it for genotyping more than 2.5 million potential stem cell donors. The data obtained were used to determine HLA-E allele frequency distributions for 104 populations. Our results confirm the known dominance of the alleles E*01:01 and E*01:03, which have a combined frequency of more than 0.99 in 97 of the 104 populations. E*01:01 is more frequent in Africa and the western part of South America, E*01:03 in Southeast and East Asia. E*01:03 shows a pronounced regional substructure at the high-resolution level with E*01:03:01G being particularly common in a large connected region extending from Turkey to China, E*01:03:02G in Northwestern Europe and E*01:03:03 in Central and Eastern Europe as well as Central Asia. The presented results are relevant both as a basis for further population genetics studies and for optimizing stem cell donor searches.

Analysis of genomic DNA from medieval plague victims suggests long-term effect of Yersinia pestis on human immunity genes

Pathogens and associated outbreaks of infectious disease exert selective pressure on human populations, and any changes in allele frequencies that result may be especially evident for genes involved in immunity. In this regard, the 1346-1353 Yersinia pestis-caused Black Death pandemic, with continued plague outbreaks spanning several hundred years, is one of the most devastating recorded in human history. To investigate the potential impact of Y. pestis on human immunity genes we extracted DNA from 36 plague victims buried in a mass grave in Ellwangen, Germany in the 16th century. We targeted 488 immune-related genes, including HLA, using a novel in-solution hybridization capture approach. In comparison with 50 modern native inhabitants of Ellwangen, we find differences in allele frequencies for variants of the innate immunity proteins Ficolin-2 and NLRP14 at sites involved in determining specificity. We also observed that HLA-DRB1*13 is more than twice as frequent in the modern population, whereas HLA-B alleles encoding an isoleucine at position 80 (I-80+), HLA C*06:02 and HLA-DPB1 alleles encoding histidine at position 9 are half as frequent in the modern population. Simulations show that natural selection has likely driven these allele frequency changes. Thus, our data suggests that allele frequencies of HLA genes involved in innate and adaptive immunity responsible for extracellular and intracellular responses to pathogenic bacteria, such as Y. pestis, could have been affected by the historical epidemics that occurred in Europe.

DR2S: an integrated algorithm providing reference-grade haplotype sequences from heterozygous samples

Background

High resolution HLA genotyping of donors and recipients is a crucially important prerequisite for haematopoetic stem-cell transplantation and relies heavily on the quality and completeness of immunogenetic reference sequence databases of allelic variation.

Results

Here, we report on DR2S, an R package that leverages the strengths of two sequencing technologies—the accuracy of next-generation sequencing with the read length of third-generation sequencing technologies like PacBio’s SMRT sequencing or ONT’s nanopore sequencing—to reconstruct fully-phased high-quality full-length haplotype sequences. Although optimised for HLA and KIR genes, DR2S is applicable to all loci with known reference sequences provided that full-length sequencing data is available for analysis. In addition, DR2S integrates supporting tools for easy visualisation and quality control of the reconstructed haplotype to ensure suitability for submission to public allele databases.

Conclusions

DR2S is a largely automated workflow designed to create high-quality fully-phased reference allele sequences for highly polymorphic gene regions such as HLA or KIR. It has been used by biologists to successfully characterise and submit more than 500 HLA alleles and more than 500 KIR alleles to the IPD-IMGT/HLA and IPD-KIR databases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-021-04153-0.

CCR5Δ32 mutations do not determine COVID-19 disease course

OBJECTIVES

To determine the impact of the 32 bp deletion (CCR5Δ32) in the coding region of the C-C chemokine receptor 5 (CCR5) on the risk of contracting SARS-CoV-2 and severe COVID-19.

METHODS

Cross-sectional study among stem cell donors registered with DKMS in Germany. Genetic information was linked to self-reported COVID-19 outcome data. Multivariable regression models were fitted to determine the risk of contracting SARS-CoV-2, severe respiratory tract infection (RTI) and respiratory hospitalization.

RESULTS

CCR5 information was available for 110 544 donors who were tested at least once for SARS-CoV-2; 5536 reported SARS-CoV-2 infection. For 4758 donors, the COVID-19 disease course was fully evaluable; 498 reported no symptoms, 1227 described symptoms of severe respiratory tract infection, of whom 164 required respiratory hospitalization. The distribution of CCR5Δ32 genotypes (homozygous wild-type vs CCR5Δ32 present) did not differ significantly between individuals with or without SARS-CoV-2 infection (odds ratio (OR) 0.96, 95% CI 0.89-1.03, P = 0.21) nor between individuals with or without symptomatic infection (OR 1.13, 95% CI 0.88-1.45, P = 0.32), severe RTI (OR 1.03, 95% CI 0.88-1.22, P = 0.68) or respiratory hospitalization (OR 1.16, 95% CI 0.79-1.69, P = 0.45).

CONCLUSIONS

Our data implicate that CCR5Δ32 mutations do not determine the risk of SARS-CoV-2 infections nor the disease course.

TRIAL REGISTRATION

We registered the study with the German Center for Infection Research (https://dzif.clinicalsite.org/de/cat/2099/trial/4361).

The clinical implications of clonal hematopoiesis in hematopoietic cell transplantation

Clonal hematopoiesis (CH) describes somatic mutations in hematopoietic stem and progenitor cells resulting in clonal expansion in individuals with no overt hematologic disease. Since CH increases in an age-related manner, understanding its role in hematopoietic cell transplantation (HCT) has become increasingly relevant to an aging transplant population. Multiple factors distinguish post-transplant hematopoiesis from unperturbed, steady-state hematopoiesis, including the influence of immunosuppressants, cytotoxic reagents, and marked proliferative stress, all of which may enhance or diminish the opportunity for clonal expansion. We reviewed the available clinical evidence on the consequences of CH at time of transplant in patients undergoing autologous HCT, and the impact of donor and recipient CH on allogeneic HCT outcomes. In the absence of evidence-based guidelines, we share our suggestions for managing donors and recipients found to have CH. Large-scale studies are needed to guide an evidence-based, uniform approach for the management of CH in the setting of HCT.

HLA-E diversity unfolded: Identification and characterization of 170 novel HLA-E alleles

HLA-E is a member of the nonclassical HLA class Ib genes. Even though it is structurally highly similar to the classical HLA class Ia genes, it is less diverse and only 45 alleles and 12 proteins were known in December 2019 (IPD-IMGT/HLA, release 3.38.0). Since 2017, we have genotyped over 3 million voluntary stem cell donors for HLA-E by sequencing the most relevant allele-determining bases of exons 2 and 3. As expected, most donors harbor the two predominant alleles HLA-E*01:01 and/or HLA-E*01:03. However, in 1666 (0.05%) of our samples we detected 345 distinct novel HLA-E sequences. The most frequent one was identified in 162 samples and has by now been named HLA-E*01:114. To characterize these novel alleles in full-length, we used both short-read Illumina and long-read PacBio sequencing to obtain fully phased and highly accurate sequences. This resulted in 234 submissions to IPD-IMGT/HLA comprising 170 novel HLA-E alleles, which encode for 93 novel HLA-E proteins, as well as 64 confirmations or sequence extensions. Consequently, the number of HLA-E alleles in the database (release 3.42.0) has now increased to 256 HLA-E alleles and 110 HLA-E proteins.

Analytical lifecycle management for comprehensive and universal nitrosamine analysis in various pharmaceutical formulations by supercritical fluid chromatography

Since the detection of nitrosamines (NA) in valsartan pharmaceuticals, over two years have passed. At present, the occurrence of NAs can be limited to a few drug substances and drug products, but it is already becoming apparent that the issue appears to be much bigger than initially thought. The impact on the global pharmaceutical market has been tremendous and the problem can be attributed mainly to uncritically adopted approval changes and the lack of suitable, modern analytical methods to detect those impurities in time. We hereby demonstrate how lifecycle management (LCM) can be used to develop and improve suitable and universal analytical methods within short time. The resulting SFC-MS/MS method is intended for a universal nitrosamine investigation in drug substances and drug products. Successful NA analysis was demonstrated for seven sartans, metformin, pioglitazone and ranitidine. Additionally, combination drug products, containing also amlodipine, hydrochlorothiazide, vildagliptin and sitagliptin, were analyzed successfully. The method achieved separation of 16 NAs in 4 min with a total run time of 11.5 min, utilizing a Supel Carbon porous graphitic carbon (PGC) column. Carbon dioxide together with 0.1% TFA in methanol as modifier were used as eluents and 0.35% formic acid in methanol as make-up solvent for mass spectrometric NA detection. By implementing LCM in this case study, development time was reduced and knowledge was implemented fast. At the same time, a high adaptability of this "vital" method was achieved, which makes it possible to implement the constantly changing regulatory requirements within the shortest possible time. Supplemental development data, according to the ICH guidelines Q8, Q12 and the proposed Q14 are disclosed, demonstrating the scientific Quality-by-Design (QbD) development approach, the "fitness for use" and the robustness of the analytical procedure. This method contributes to the still ongoing risk assessment process of the pharmaceutical industry and the regulatory agencies, in order to understand root causes of NA formation, maintain the drug supply and prevent drug shortage.

Haplotype Motif-Based Models for KIR-Genotype Informed Selection of Hematopoietic Cell Donors Fail to Predict Outcome of Patients With Myelodysplastic Syndromes or Secondary Acute Myeloid Leukemia

Results from registry studies suggest that harnessing Natural Killer (NK) cell reactivity mediated through Killer cell Immunoglobulin-like Receptors (KIR) could reduce the risk of relapse after allogeneic Hematopoietic Cell Transplantation (HCT). Several competing models have been developed to classify donors as KIR-advantageous or disadvantageous. Basically, these models differ by grouping donors based on distinct KIR–KIR–ligand combinations or by haplotype motif assignment. This study aimed to validate different models for unrelated donor selection for patients with Myelodysplatic Syndromes (MDS) or secondary Acute Myeloid Leukemia (sAML). In a joint retrospective study of the European Society for Blood and Marrow Transplantation (EBMT) and the Center for International Blood and Marrow Transplant Research (CIBMTR) registry data from 1704 patients with secondary AML or MDS were analysed. The cohort consisted mainly of older patients (median age 61 years) with high risk disease who had received chemotherapy-based reduced intensity conditioning and anti-thymocyte globulin prior to allogeneic HCT from well-matched unrelated stem cell donors. The impact of the predictors on Overall Survival (OS) and relapse incidence was tested in Cox regression models adjusted for patient age, a modified disease risk index, performance status, donor age, HLA-match, sex-match, CMV-match, conditioning intensity, type of T-cell depletion and graft type. KIR genes were typed using high-resolution amplicon-based next generation sequencing. In univariable and multivariable analyses none of the models predicted OS and the risk of relapse consistently. Our results do not support the hypothesis that optimizing NK-mediated alloreactivity is possible by KIR-genotype informed selection of HLA-matched unrelated donors. However, in the context of allogeneic transplantation, NK-cell biology is complex and only partly understood. KIR-genes are highly diverse and current assignment of haplotype motifs based on the presence or absence of selected KIR genes is over-simplistic. As a consequence, further research is highly warranted and should integrate cutting edge knowledge on KIR genetics, and NK-cell biology into future studies focused on homogeneous groups of patients and treatment modalities.

High-resolution HLA allele and haplotype frequencies of the Saudi Arabian population based on 45,457 individuals and corresponding stem cell donor matching probabilities

We estimated HLA allele and haplotype frequencies of the Saudi Arabian population from a sample of 45,457 registered stem cell donors. The most frequent HLA alleles were A*02:01g (18.5%), C*06:02g (16.1%), B*51:01g (14.1%), DRB1*07:01g (16.2%), DQB1*02:01g (30.5%), and DPB1*04:01g (33.6%). The most frequent 5-locus haplotypes were A*02:05g~C*06:02g~B*50:01g~DRB1*07:01g~DQB1*02:01g (1.73%), A*02:01g~C*06:02g~B*50:01g~DRB1*07:01g~DQB1*02:01g (1.66%), and A*26:01g~C*07:02g~B*08:01g~DRB1*03:01g~DQB1*02:01g (1.38%). Furthermore, we used the calculated haplotype frequencies to estimate stem cell donor matching probabilities for Saudi Arabian donor and patient populations under various matching requirements. These results are relevant for strategic donor registry planning in the Kingdom of Saudi Arabia.

Distinct Signatures in the Receptor Repertoire Discriminate CD56bright and CD56dim Natural Killer Cells

NK cells are phenotypically and functionally diverse lymphocytes due to variegated expression of a large array of receptors. NK-cell activity is tightly regulated through integration of receptor-derived inhibitory and activating signals. Thus, the receptor profile of each NK cell ultimately determines its ability to sense aberrant cells and subsequently mediate anti-viral or anti-tumor responses. However, an in-depth understanding of how different receptor repertoires enable distinct immune functions of NK cells is lacking. Therefore, we investigated the phenotypic diversity of primary human NK cells by performing extensive phenotypic characterization of 338 surface molecules using flow cytometry (n = 18). Our results showed that NK cells express at least 146 receptors on their surface. Of those, 136 (>90%) exhibited considerable inter-donor variability. Moreover, comparative analysis of CD56bright and CD56dim NK cells identified 70 molecules with differential expression between the two major NK-cell subsets and allowed discrimination of these subsets via unsupervised hierarchical clustering. These receptors were associated with a broad range of NK-cell functions and multiple molecules were not previously associated with predominant expression on either subset (e.g. CD82 and CD147). Altogether, our study contributes to an improved understanding of the phenotypic diversity of NK cells and its potential functional implications on a cellular and population level. While the identified distinct signatures in the receptor repertoires provide a molecular basis for the differential immune functions exerted by CD56bright and CD56dim NK cells, the observed inter-individual differences in the receptor repertoire of NK cells may contribute to a diverging ability to control certain diseases.

Stem cell donor registry activities during the COVID-19 pandemic: a field report by DKMS

The COVID-19 pandemic has serious implications also for patients with other diseases. Here, we describe the effects of the pandemic on unrelated hematopoietic stem cell donation and transplantation from the perspective of DKMS, a large international donor registry. Especially, we cover the development of PBSC and bone marrow collection figures, donor management including Health and Availability Check (HAC), transport and cryopreservation of stem cell products, donor recruitment and business continuity measures. The total number of stem cell products provided declined by around 15% during the crisis with a particularly strong decrease in bone marrow products. We modified donor management processes to ensure donor and product safety. HAC instead of confirmatory typing was helpful especially in countries with strict lockdowns. New transport modes were developed so that stem cell products could be safely delivered despite COVID-19-related travel restrictions. Cryopreservation of stem cell products became the new temporary standard during the pandemic to minimize risks related to transport logistics and donor availability. However, many products from unrelated donors will never be transfused. DKMS discontinued public offline donor recruitment, leading to a 40% decline in new donors during the crisis. Most DKMS employees worked from home to ensure business continuity during the crisis.

Salvage treatment with plerixafor in poor mobilizing allogeneic stem cell donors: results of a prospective phase II-trial

We conducted a prospective clinical trial to investigate the safety and efficacy of plerixafor (P) in allogeneic peripheral blood stem cells (PBSC) donors with poor mobilization response to standard-dose granulocyte colony-stimulating factor (G-CSF), defined by <2 × 10⁶ CD34 + cells/kg recipient body-weight (CD34+/kg RBW) after 1st apheresis. A single dose of 240 µg/kg P was injected subcutaneously at 10 p.m. on the day of the 1st apheresis. Thirty-seven allogeneic PBSC donors underwent study treatment. The median CD34+ count in peripheral blood was 15/µl on Day 1 after G-CSF alone, versus 44/µl on Day 2 after G-CSF plus P (p < 0.001). The median yield of CD34+ cells was 1.1 × 10⁸ on Day 1 and 2.8 × 10⁸ on Day 2. In contrast to a median yield of only 1.31 × 10⁶ CD CD34+/kg RBW on Day 1, triggering study inclusion, a median of 3.74 × 10⁶ CD CD34+/kg RBW were collected with G-CSF plus P on Day 2. Of 37 donors, 21 reached the target cell count of >4.5 × 10⁶ CD34+/kg RBW (57%, 95%CI 40-73%). No donor experienced a severe adverse event requiring treatment. In conclusion, P might be considered on a case-by-case basis for healthy allogeneic donors with very poor stem cell mobilization success after G-CSF.

Marriage does not relate to major histocompatibility complex: a genetic analysis based on 3691 couples

Optimization of chances for healthy offspring is thought to be one of the factors driving mate choice and compatibility of the major histocompatibility complex (MHC) is assumed to determine the offspring's fitness. While humans have been claimed to be able to perceive information of MHC compatibility via the olfactory channel, it remains unknown whether humans use such information for mate choice. By investigation of 3691 married couples, we observed that the high polymorphism of MHC leads to a low chance for homozygous offspring. MHC similarity between couples did not differ from chance, we hence observed no MHC effect in married couples. Hormonal contraception at the time of relationship initiation had no significant effect towards enhanced similarity. A low variety of alleles within a postcode area led to a higher likelihood of homozygous offspring. Based on this data, we conclude that there is no pattern of MHC dis-assortative mating in a genetically diverse Western society. We discuss the question of olfactory mate preference, in-group mating bias and the high polymorphism as potential explanations.

High Metabolic Function and Resilience of NKG2A-Educated NK Cells

Natural killer (NK) cells are an important component of the innate immune system for the control of intracellular pathogens and cancer cells. NK cells demonstrate heterogeneous expression of inhibitory surface receptors. Signaling through these various receptors during NK cell development promotes functionality, referred to as NK cell education. Here we investigated the impact of education on NK cell metabolism through functional assessment of critical metabolic pathways and calcium signaling. Educated NK cells had an increased uptake of the metabolic substrates 2-NBDG, a fluorescent glucose analog, and BODIPY FL C₁₆, a fluorescent palmitate, compared to uneducated NK cells. Comparison of NK cells educated via KIRs or NKG2A showed that NKG2A-educated NK cells were the main contributor to these differences in uptake of metabolites, and that NKG2A-educated NK cells were functionally more resilient in response to metabolic blockade of oxidative phosphorylation. Furthermore, NKG2A-educated NK cells exhibited higher peak calcium concentration following stimulation, indicating stronger signaling events taking place in these educated NK cells. These results demonstrate that cellular metabolism plays an important role in the functional differences observed between educated and uneducated NK cells, and show that NKG2A-educated NK cells remain more functionally competent than KIR-educated NK cells when oxidative phosphorylation is restricted. Understanding metabolic programming during NK cell education may unveil future targets to manipulate NK cell function for use in clinical settings, such as cancer therapies.

Introduction of principles of blood management to healthy donor bone marrow harvesting

BACKGROUND AND OBJECTIVES

Patient blood (more accurately: haemoglobin, Hb) management (PBM) aims to optimize endogenous Hb production and to minimize iatrogenic Hb loss while maintaining patient safety and optimal effectiveness of medical interventions. PBM was adopted as policy for patients by the World Health Organization (WHO), and, all the more, should be applied to healthy donors.

MATERIALS AND METHODS

Observational data from 489 bone marrow (BM) donors were retrospectively analysed, and principles of patient blood management were applied to healthy volunteer BM donations.

RESULTS AND CONCLUSION

We managed to render BM aspiration safe for donors, notably completely avoiding the collection of autologous blood units and blood transfusions through iron management, establishment and curation of high-yield aspiration technique, limitation of collection volume to 1·5% of donor body weight and development of volume prediction algorithms for the requested cell dose.

Body odours as a chemosignal in the mother-child relationship: new insights based on an human leucocyte antigen-genotyped family cohort

Mothers are able to identify the body odour (BO) of their own child and prefer this smell above other BOs. It has hence been assumed that the infantile BO functions as a chemosignal promoting targeted parental care. We tested this hypothesis and examined whether children's BOs signal genetic similarity and developmental status to mothers. In addition, we assessed whether BOs facilitate inbreeding avoidance (Westermarck effect). In a cross-sectional design, N = 164 mothers participated with their biological children (N = 226 children, aged 0-18 years) and evaluated BO probes of their own and four other, sex-matched children. Those varied in age and in genetic similarity, which was assessed by human leucocyte antigen profiling. The study showed not only that mothers identified and preferred their own child's BO, but also that genetic similarity and developmental status are transcribed in BOs. Accordingly, maternal preference of their own child's odour changes throughout development. Our data partly supported the Westermarck effect: mothers' preference of pubertal boys' BOs was negatively related to testosterone for the own son, but not for unfamiliar children. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.