Early Adaptive Natural Killer Cell Expansion Is Associated with Decreased Relapse After Autologous Transplantation for Multiple Myeloma.

Adaptive natural killer (NK) cells are long-lived and exhibit properties of immunologic memory against cytomegalovirus (CMV). We previously reported that expansion of adaptive NK cells after CMV reactivation in recipients of allogeneic hematopoietic cell transplantation (HCT) was associated with a lower rate of relapse of acute myelogenous leukemia. In the present study, we examined the impact of adaptive NK cell expansion in a cohort of 110 individuals who underwent autologous HCT (AHCT) for a lymphoid malignancy (lymphoma or multiple myeloma [MM]). In this cohort, higher absolute numbers of adaptive NK cells (>1.58/µL) at day 28 post-AHCT were associated with significantly decreased risk of relapse in patients with MM. No significant association was seen in patients with lymphoma. Further stratification of MM patients by CMV serostatus found a strong protective effect of adaptive NK cells only in CMV-seropositive individuals. These findings suggest that strategies to increase adaptive NK cells after AHCT may be a therapeutic option in patients with MM.

Unraveling exhaustion in adaptive and conventional NK cells.

Immune exhaustion in T cells significantly impacts their ability to control malignancies and infections, and its discovery has led to revolutionary therapies for cancer in the form of checkpoint blockade. NK cells, like T cells, are lymphocytes that recognize virally infected and malignantly transformed cells. However, it remains unclear if NK cells are similarly susceptible to exhaustion. In this review, the aims are to summarize what is currently known and to identify key areas of variability that skew the scientific literature on NK cell exhaustion. A lack of consensus on the defining features of NK cell dysfunctional states such as senescence, suppression, and exhaustion has made a comparison between studies difficult. There are also significant differences in the biology of NK cell subsets with long-lived, adaptive NK cells sharing an epigenetic signature closer to memory CD8+  T cells than to conventional NK cells. Very different checkpoint receptor expression and effector functions have been shown in adaptive versus conventional NK cells chronically exposed to activating signals. Adaptive NK cells develop in individuals with cytomegalovirus (CMV) infection and well over half of the human population worldwide is CMV seropositive by adulthood. Despite this high prevalence, most studies do not account or control for this population. This may contribute to some of the variability reported in the literature on checkpoint receptor expression on NK cells. In this review, the protective role that exhaustion plays in T cells will also be discussed and the evidence for a similar phenomenon in NK cells will be examined.

A Randomized Controlled Trial of a CPR Decision Support Video for Patients Admitted to the General Medicine Service.

BACKGROUND: Patient preferences regarding cardiopulmonary resuscitation (CPR) are important, especially during hospitalization when a patient's health is changing. Yet many patients are not adequately informed or involved in the decision-making process. OBJECTIVE: We examined the effect of an informational video about CPR on hospitalized patients' code status choices. DESIGN: This was a prospective, randomized trial conducted at the Minneapolis Veterans Affairs Health Care System in Minnesota. PARTICIPANTS: We enrolled 119 patients, hospitalized on the general medicine service, and at least 65 years old. The majority were men (97%) with a mean age of 75. INTERVENTION: A video described code status choices: full code (CPR and intubation if required), do not resuscitate (DNR), and do not resuscitate/do not intubate (DNR/DNI). Participants were randomized to watch the video (n = 59) or usual care (n = 60). MEASUREMENTS: The primary outcome was participants' code status preferences. Secondary outcomes included a questionnaire designed to evaluate participants' trust in their healthcare team and knowledge and perceptions about CPR. RESULTS: Participants who viewed the video were less likely to choose full code (37%) compared to participants in the usual care group (71%) and more likely to choose DNR/DNI (56% in the video group vs. 17% in the control group) (𝑃 < 0.00001). We did not see a difference in trust in their healthcare team or knowledge and perceptions about CPR as assessed by our questionnaire. CONCLUSIONS: Hospitalized patients who watched a video about CPR and code status choices were less likely to choose full code and more likely to choose DNR/DNI.

KIR2DS4 promotes HIV-1 pathogenesis: new evidence from analyses of immunogenetic data and natural killer cell function.

BACKGROUND: KIR2DS4 gene variants encode full-length and truncated protein products, with only the former serving as membrane-bound receptors to activate natural killer (NK) cells. We have previously shown that full-length KIR2DS4 was associated with relatively high viral load and accelerated heterosexual HIV-1 transmission. Our objective here was to provide confirmatory data and to offer new insights about the potential mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Mixed models for repeated (longitudinal) outcome measurements on 207 HIV-1 seropositive American youth revealed an association of full-length KIR2DS4 with relatively high viral load and low CD4+ T-cell count (p<0.01 for both). Depending on KIR2DS4 expression (presence or absence) on cell surface, NK cells from 43 individuals with untreated, chronic HIV-1 infection often differed in functional properties, including degranulation and secretion of IFN-γ and MIP-1ß. In particular, polyfunctional NK cells were enriched in the KIR2DS4-positive subset. CONCLUSIONS/SIGNIFICANCE: Full-length KIR2DS4 promotes HIV-1 pathogenesis during chronic infection, probably through the maintenance of an excessively pro-inflammatory state.

Structure of tumor necrosis factor-alpha haploblocks in European populations.

DNA variants in the tumor necrosis factor-α (TNF) and linked lymphotoxin-α genes, and specific alleles of the highly polymorphic human leukocyte antigen B (HLA-B) gene have been implicated in a plethora of immune and infectious diseases. However, the tight linkage disequilibrium characterizing the central region of the human major histocompatibility complex (MHC) containing these gene loci has made difficult the unequivocal interpretation of genetic association data. To alleviate these difficulties and facilitate the design of more focused follow-up studies, we investigated the structure and distribution of HLA-B-specific MHC haplotypes reconstructed in a European population from unphased genotypes at a set of 25 single nucleotide polymorphism sites spanning a 66-kilobase long region across TNF. Consistent with the published data, we found limited genetic diversity across the so-called TNF block, with the emergence of seven common MHC haplotypes, termed TNF block super-haplotypes. We also found that the ancestral haplotype 8.1 shares a TNF block haplotype with HLA-B*4402. HLA-B*5701, a known protective allele in HIV-1 pathogenesis, occurred in a unique TNF block haplotype.

HLA-B signal peptide polymorphism influences the rate of HIV-1 acquisition but not viral load.

Human leukocyte antigen alleles influence the immune response to HIV-1. Signal peptides cleaved from those alleles bind to HLA-E and mediate natural killer cell function. Signal peptides of HLA-A and HLA-C proteins carry methionine (Met) at anchor position 2 (P2); those of HLA-B carry Met or threonine (Thr). Different P2 residues alter HLA-E binding to its cognate receptors and may impact HIV-1 acquisition. Among Zambian couples (N = 566) serodiscordant for HIV-1, P2-Met accelerated acquisition in the HIV-1-negative partner (relative hazard [RH], 1.79). Among seroconverting Zambian (n = 240) and Rwandan (n = 64) partners, P2-Met also accelerated acquisition (RH, 1.47 and RH, 1.83 respectively). HLA-B alleles displaying the reportedly protective Bw4 epitope carry P2-Thr. Bw4/P2-Thr and Bw6/P2-Thr showed similar protective effects compared with Bw6/P2-Met. Neither motif was associated with viral load. The influence of HLA-B alleles on HIV/AIDS may derive from multiple motifs in and beyond the mature proteins.