Natural killer (NK) cell immunotherapy has gained attention as a promising strategy for treatment of various malignancies. In this study, we used a genome-wide CRISPR screen to identify genes that provide protection or susceptibility to NK cell cytotoxicity. The screen confirmed the role of several genes in NK cell regulation, such as genes involved in interferon-γ signaling and antigen presentation, as well as genes encoding the NK cell receptor ligands B7-H6 and CD58. Notably, the gene TMEM30A , encoding CDC50A–beta-subunit of the flippase shuttling phospholipids in the plasma membrane, emerged as crucial for NK cell killing. Accordingly, a broad range of TMEM30A knock-out (KO) leukemia and lymphoma cells displayed increased surface levels of phosphatidylserine (PtdSer). TMEM30A KO cells triggered less NK cell degranulation, cytokine production and displayed lower susceptibility to NK cell cytotoxicity. Blockade of PtdSer or the inhibitory receptor TIM-3, restored the NK cell ability to eliminate TMEM30A -mutated cells. The key role of the TIM-3 – PtdSer interaction for NK cell regulation was further substantiated by disruption of the receptor gene in primary NK cells, which significantly reduced the impact of elevated PtdSer in TMEM30A KO leukemic cells. Our study underscores the potential significance of agents targeting the interaction between PtdSer and TIM-3 in the realm of cancer immunotherapy.

Due to a mutation in the phosphatidylinositol glycan class A (PIGA) gene, hemolytic anemia, thrombosis, and bone marrow failure are the hallmarks of the uncommon hematologic illness known as paroxysmal nocturnal hemoglobinuria (PNH). Although by different processes, hemoglobinopathies, such as thalassemia, can manifest with hemolytic anemia. The 40-year-old female patient in this case study had a complicated clinical presentation with both hemoglobinopathy - more precisely, a form of thalassemia - and PNH. Abdominal pain, fatigability, and dark urine episodes were the patient's initial complaints. PNH was confirmed by laboratory testing, which showed low hemoglobin, increased lactate dehydrogenase, and hemosiderinuria. Thalassemia was discovered by a further hematologic workup. It is quite uncommon for hemoglobinopathy and PNH to coexist. This case emphasizes how crucial it is to perform a thorough hematologic examination on patients who have hemolytic anemia to customize treatment plans and enhance patient outcomes. We will discuss therapeutic hurdles, possible treatment choices, and the clinical journey of the patient with a classical type of PNH with access only to steroids, blood transfusions, and supplements.

HLA-B alleles are associated with outcomes in various pathologies, including autoimmune diseases and malignancies. The encoded HLA-B proteins are pivotal in antigen presentation to cytotoxic T cells, and some variants containing a Bw4 motif also serve as ligands to the killer immunoglobulin-like receptors (KIR) 3DL1/S1 of NK cells. We investigated the potential impact of HLA-B genotypes on the efficacy of immunotherapy for relapse prevention in acute myeloid leukemia (AML). Seventy-eight non-transplanted AML patients receiving HDC/IL-2 in the post-consolidation phase were genotyped for HLA-B and KIR genes. HLA-B*44 heralded impaired LFS (leukemia-free survival) and overall survival (OS), but the negative association with outcome was not shared across alleles of the HLA-B44 supertype. Notably, HLA-B*44 is one of few HLA-B44 supertype alleles containing a Bw4 motif with a threonine at position 80, which typically results in weak binding to the inhibitory NK receptor, KIR3DL1. Accordingly, a strong interaction between KIR3DL1 and Bw4 was associated with superior LFS and OS ( p = 0.014 and p = 0.027, respectively). KIR3DL1 + NK cells from 80 T-Bw4 donors showed significantly lower degranulation responses and cytokine responses than NK cells from 80I-Bw4 donors, suggesting impaired KIR3DL1-mediated education in 80 T-Bw4 subjects. We propose that presence of a strong KIR3DL1 + –Bw4 interaction improves NK cell education and thus is advantageous in AML patients receiving HDC/IL-2 immunotherapy for relapse prevention.

Practically, all major organ systems can be impacted by an immune-mediated fibro-inflammatory condition known as immunoglobulin G4-related disease (IgG4-RD). Even though it is not unusual, the level of orbital involvement in IgG4-RD can change depending on where the lymphoplasmacytic infiltrate is located. We address a case of IgG4-RD in this study who presented with large bilateral upper and lower eyelids swelling, mediastinal lymphadenopathy, and elevated serum IgG4. It was necessary to do a histopathology examination to confirm the diagnosis of the IgG4-RD and rule out any possible mimicking hematological conditions. In conclusion, this case report emphasizes the value of clinical symptoms and imaging in reducing the number of potential diagnoses, although biopsy remains a gold standard to confirm the diagnosis of IgG4-RD.

Abstract HLA-B proteins interact with key immune receptors on both T and NK cells, and variants of the encoding gene are associated with outcomes in various pathologies, including autoimmune diseases and malignancies. HLA-B is pivotal in antigen presentation to cytotoxic T cells, and some variants containing a Bw4 motif also serve as ligands to the killer immunoglobulin-like receptors (KIR) 3DL1/S1 of NK cells. We investigated the potential impact of HLA-B genotypes on the efficiency of immunotherapy for relapse prevention in acute myeloid leukemia (AML). Seventy-nine non-transplanted AML patients receiving HDC/IL-2 in the post-consolidation phase were genotyped for HLA-B and KIRs genes. HLA-B*07 associated with improved leukemia-free survival (LFS), while HLA-B*44 heralded impaired LFS and overall survival (OS). The negative association with outcome was not shared across alleles of the HLA-B44 supertype. Notably, HLA-B*44 is one of few HLA-B44 supertype alleles containing a Bw4 motif with a threonine at position 80, which typically results in weak binding to the inhibitory NK receptor, KIR3DL1. Accordingly, a strong interaction between KIR3DL1 and Bw4 was associated with superior LFS and OS (p = 0.014 and p = 0.027, respectively). KIR3DL1 + NK cells from 80T-Bw4 donors showed significantly lower degranulation responses and cytokine responses than NK cells from 80I-Bw4 donors, suggesting impaired KIR3DL1-mediated education in 80T-Bw4 subjects. We propose that presence of a strong KIR3DL1 + - Bw4 interaction is advantageous in AML patients receiving immunotherapy for relapse prevention. This is likely achieved by improved NK cell education and a reduced expression of HLA-Bw4 on malignant leukemic cells.

BACKGROUND:The natural killer (NK) complex (NKC) harbors multiple genes such as KLRC1 (encoding NKG2A) and KLRK1 (encoding NKG2D) that are central to regulation of NK cell function. We aimed at determining to what extent NKC haplotypes impact on NK cell repertoire and function, and whether such gene variants impact on outcome of IL-2-based immunotherapy in acute myeloid leukemia (AML).METHODS:Genotype status of NKG2D rs1049174 and NKG2A rs1983526 was determined using the TaqMan-Allelic discrimination approach. To dissect the impact of single nucloetide polymorphim (SNP) on NK cell function, we engineered the K562 cell line with CRISPR to be killed in a highly NKG2D-dependent fashion. NK cells were assayed for degranulation, intracellular cytokine production and cytotoxicity using flow cytometry.RESULTS:In AML patients receiving immunotherapy, the NKG2A gene variant, rs1983526, was associated with superior leukemia-free survival and overall survival. We observed that superior NK degranulation from individuals with the high-cytotoxicity NKG2D variant was explained by presence of a larger, highly responsive NKG2A+ subset. Notably, NK cells from donors homozygous for a favorable allele encoding NKG2A mounted stronger cytokine responses when challenged with leukemic cells, and NK cells from AML patients with this genotype displayed higher accumulation of granzyme B during histamine dihydrochloride/IL-2 immunotherapy. Additionally, among AML patients, the NKG2A SNP defined a subset of patients with HLA-B-21 TT with a strikingly favorable outcome.CONCLUSIONS:The study results imply that a dimorphism in the NKG2A gene is associated with enhanced NK cell effector function and improved outcome of IL-2-based immunotherapy in AML.

Natural killer cells are important effector cells in the immune response against myeloid malignancies. Previous studies show that the expression of activating NK cell receptors is pivotal for efficient recognition of blasts from patients with acute myeloid leukemia (AML) and that high expression levels impact favorably on patient survival. This study investigated the potential impact of activating receptor gene variants on NK cell receptor expression and survival in a cohort of AML patients receiving relapse-preventive immunotherapy with histamine dihydrochloride and low-dose IL-2 (HDC/IL-2). Patients harboring the G allele of rs1049174 in the KLRK1 gene encoding NKG2D showed high expression of NKG2D by CD56 bright NK cells and a favorable clinical outcome in terms of overall survival. For DNAM-1, high therapy-induced receptor expression entailed improved survival, while patients with high DNAM-1 expression before immunotherapy associated with unfavorable clinical outcome. The previously reported SNPs in NCR3 encoding NKp30, which purportedly influence mRNA splicing into isoforms with discrete functions, did not affect outcome in this study. Our results imply that variations in genes encoding activating NK cell receptors determine receptor expression and clinical outcome in AML immunotherapy.

[This corrects the article DOI: 10.3389/fimmu.2021.796072.].

BACKGROUND:Hermansky-Pudlak syndrome (HPS) is a rare autosomal-recessive disorder with clinical manifestations of bleeding diathesis, multi-organ disease and variable oculocutaneous albinism (OCA). In women, it can cause life-threatening obstetric and gynecological (OB/GYN) bleeding. OBJECTIVE:To summarize OB/GYN presentations, outcomes, and management strategies in women with HPS. SEARCH STRATEGY:Main databases (MEDLINE, EMBASE, Cochrane, PubMed, Web of Science Core Collection and Google Scholar) were searched from inception until June 30, 2020. SELECTION CRITERIA:Case reports/series of women with confirmed HPS. DATA COLLECTION AND ANALYSIS:A systematic review using PRISMA guidelines. Methodological quality assessment performed using adapted Newcastle Ottawa scale. MAIN RESULTS:A total 29 pregnancies in 15 women and 2 gynecological patients were identified. Heavy menstrual bleeding (HMB), the most common bleeding symptom, was reported in 8/15 (53%) of women. HMB and post-partum hemorrhage (PPH) led to diagnosis of HPS in 5/17 (29%) women. Primary PPH was reported in 12/27 (44%) of viable pregnancies; half were major PPH. In 17 pregnancies with known HPS diagnosis, 9 had hemostatic cover with desmopressin and 8 with platelet transfusion. Major PPH occurred in 3/9 (33%) pregnancies covered with desmopressin compared with none in the platelet group. CONCLUSION:Diagnosis of HPS should be considered in women with OCA presenting with HMB or PPH. Hemostatic management options include desmopressin and platelet transfusion. Management should be multidisciplinary with close collaboration between OB/GYN and hematology teams.

Natural killer (NK) cell function is regulated by inhibitory receptors, such as the family of killer immunoglobulin-like receptors (KIRs) and the NKG2A/CD94 heterodimer. These receptors recognize cognate HLA class I molecules on potential target cells, and recent studies imply that an HLA-B dimorphism at position -21 in the gene segment encoding the leader peptide dictates whether NK cell regulation primarily relies on the KIRs or the NKG2A/CD94 receptor. The impact of this HLA-B dimorphism on NK cell-mediated destruction of leukemic cells or on the course of leukemia is largely unknown. In a first part of this study, we compared functions of NK cells in subjects carrying HLA-B -21Mor 21T using interleukin-2 (IL-2)-activated NK cells and leukemic cells from patients with acute myeloid leukemia (AML). Subjects carrying HLA-B -21M harbored better-educated NKG2A1 NK cells and displayed superior capacity to degranulate lytic granules against KIR ligandmatched primary leukemic blasts. Second, we aimed to define the potential impact of HLA-B -21 variation on the course of AML in a phase 4 trial in which patients received IL-2based immunotherapy. In keeping with the hypothesis that 21M may be associated with improved NK cell functionality, we observed superior leukemia-free survival and overall survival in -21M patients than in -21T patients during IL-2based immunotherapy. We propose that genetic variation at HLA-B -21 may determine the antileukemic efficacy of activated NK cells and the clinical benefit of NK cell-activating immunotherapy.

NK cells are negatively regulated by inhibitory receptors, such as the family of Killer Immunoglobulin-like Receptors (KIR) and the NKG2A/CD94 heterodimer. These receptors recognize cognate HLA class I molecules, and recent studies suggest that an HLA-B dimorphism in the leader peptide at position -21 dictates whether NK cell regulation mainly relies on the KIRs or the NKG2A/CD94 receptor. Thus, haplotypes with -21M delivers functional peptides to HLA-E, but will rarely harbor genes encoding the KIR ligand HLA-C2. However, little is known regarding the clinical implications of this dimorphism. For this study, we performed HLA typing and an extensive flow cytometry analysis of the NK cell repertoire in 80 AML patients who received immunotherapy with histamine dihydrochloride (HDC) and IL-2 for the prevention of relapse in the post-consolidation phase. Below median levels of HLA class I expression, reflecting low-grade NK cell inhibition, were found to correlate with significantly better outcome in HDC/IL-2-treated patients, indicating that the efficacy of the immunotherapy is NK cell-dependent. In contrast to healthy controls, the majority of NK cells in AML patients in complete remission displayed expression of NKG2A, which was even more prominent in patients after 3 weeks of HDC/IL-2 treatment, or after in vitro culture of NK cells with IL-2. Thirty-eight patients (47.5 %) carried the M/x genotype in HLA B -21 (predicting NKG2A dependence) and 42 patients (52.5 %) carried the T/T genotype (KIR dependence). Despite the high percentage of NKG2A+ NK cells, M/x patients showed significantly improved leukemia-free survival (p=0.04) and overall survival (p=0.007) compared with T/T patients. Only patients with M/x genotype benefited from low expression of HLA class I. The IL-2-induced NKG2A expression was associated with enhanced NKG2A-mediated inhibition as pure populations of NKG2A-expressing NK cells were inhibited by a leukemic cell line transfected to express the NKG2A ligand HLA E, which was reverted by antibody blockade of NKG2A. Our results suggest that the outcome of AML immunotherapy is affected by (i) expression levels of HLA class I, and (ii) the HLA B-21 dimorphism and, hence, whether the KIR or NKG2A-CD94 are the dominant inhibitory pathway for NK cells. Furthermore, the pronounced expression of NKG2A in HDC/IL-2-treated patients suggests that combination strategies, including checkpoint inhibitors targeting NKG2A together with HDC/IL-2, may be feasible for relapse prevention in AML.

May–Hegglin anomaly (MHA) is an autosomal dominant disorder, characterized by a variable degree of thrombocytopaenia, large platelets and inclusion bodies in white blood cells. Bleeding manifestations are generally mild, but severe bleeding episodes have been reported. This is a systematic review of literature for MHA during pregnancy. The review revealed 26 articles (25 case reports and one case series) including 75 pregnancies (five twin pregnancies) in 40 women. In 11 women, first presentation was incidental thrombocytopaenia during routine antenatal blood test. Of these, five women were misdiagnosed as idiopathic thrombocytopenic purpura (ITP), including three who underwent splenectomy for resistant ITP. Postpartum haemorrhage (PPH) and bleeding after miscarriage were presenting symptoms in two women. Antiplatelet antibody was found in three pregnancies. Only one of them required intervention with intravenous immunoglobulin (IVIG) to prevent neonatal alloimmune thrombocytopaenia. PPH was reported in four pregnancies; three were primary PPH, of which one had blood transfusion, one had platelet and cryoprecipitate transfusion and the third was managed conservatively. There was one secondary PPH that was treated conservatively. Neonatal outcome included 78 live neonates and two intrauterine fetal deaths. Thirty-four neonates had thrombocytopaenia and subsequently were diagnosed with MHA, three of them required platelet transfusion prophylactically as they developed very low platelet counts and one neonate with platelet count of 29 × 109 cells/l and received IVIG, as the mother had a positive antiplatelet antibody during pregnancy. No obvious bleeding complications were reported among the neonates. MHA can present challenges during pregnancy and be associated with adverse maternal and neonatal outcome because of bleeding complications. Joint management by obstetrician and haematologists is required to minimize these risks.

May–Hegglin anomaly (MHA) is an autosomal dominant disorder, characterized by a variable degree of thrombocytopaenia, large platelets and inclusion bodies in white blood cells. Bleeding manifestations are generally mild, but severe bleeding episodes have been reported. This is a systematic review of literature for MHA during pregnancy. The review revealed 26 articles (25 case reports and one case series) including 75 pregnancies (five twin pregnancies) in 40 women. In 11 women, first presentation was incidental thrombocytopaenia during routine antenatal blood test. Of these, five women were misdiagnosed as idiopathic thrombocytopenic purpura (ITP), including three who underwent splenectomy for resistant ITP. Postpartum haemorrhage (PPH) and bleeding after miscarriage were presenting symptoms in two women. Antiplatelet antibody was found in three pregnancies. Only one of them required intervention with intravenous immunoglobulin (IVIG) to prevent neonatal alloimmune thrombocytopaenia. PPH was reported in four pregnancies; three were primary PPH, of which one had blood transfusion, one had platelet and cryoprecipitate transfusion and the third was managed conservatively. There was one secondary PPH that was treated conservatively. Neonatal outcome included 78 live neonates and two intrauterine fetal deaths. Thirty-four neonates had thrombocytopaenia and subsequently were diagnosed with MHA, three of them required platelet transfusion prophylactically as they developed very low platelet counts and one neonate with platelet count of 29 × 109 cells/l and received IVIG, as the mother had a positive antiplatelet antibody during pregnancy. No obvious bleeding complications were reported among the neonates. MHA can present challenges during pregnancy and be associated with adverse maternal and neonatal outcome because of bleeding complications. Joint management by obstetrician and haematologists is required to minimize these risks.