Gemtuzumab-Ozogamicin-Related Impaired Hemoglobin-Haptoglobin Scavenging as On-Target/Off-Tumor Toxicity of Anti-CD33 AML Therapy : A Report of Two Cases

Gemtuzumab-ozogamicin (GO) is a humanized anti-CD33 antibody, which is conjugated to a cytotoxic calicheamicin. It is used to treat acute myeloid leukemia (AML) in combination with chemotherapy. We describe here two GO-treated acute myeloid leukemia (AML) cases: both patients suffered from a toxic syndrome, which manifested as impaired hemoglobin-haptoglobin scavenging and accumulation of hemolysis-related products. Our observations and earlier reports indicated that the reaction was caused by GO-targeted destruction of CD33 + CD163+ monocytes/macrophages, which are responsible for the clearance of hemoglobin-haptoglobin complexes. The rise of plasma lactate dehydrogenase was an early sign of the reaction, and both patients had high levels of free plasma hemoglobin, but plasma haptoglobin and bilirubin levels were paradoxically normal. Symptoms included septic fever and abnormalities in cardiac tests and in the case of the first patient, severe neurological symptoms which required intensive care unit admittance. Therapeutic plasma exchanges supported the patients until the recovery of normal hematopoiesis. The symptoms may be easily confounded with infectious complications-related organ damage. Regarding the increasing use of gemtuzumab-ozogamicin and other emerging CD33-targeted cell therapies, we want to highlight this mostly unknown and probably underdiagnosed toxicity.Peer reviewe

A germline exome analysis reveals harmful POT1 variants in multiple myeloma patients and families

Peer reviewe

Enrichment of cancer-predisposing germline variants in adult and pediatric patients with acute lymphoblastic leukemia

Despite recent progress in acute lymphoblastic leukemia (ALL) therapies, a significant subset of adult and pediatric ALL patients has a dismal prognosis. Better understanding of leukemogenesis and recognition of germline genetic changes may provide new tools for treating patients. Given that hematopoietic stem cell transplantation, often from a family member, is a major form of treatment in ALL, acknowledging the possibility of hereditary predisposition is of special importance. Reports of comprehensive germline analyses performed in adult ALL patients are scarce. Aiming at fulfilling this gap of knowledge, we investigated variants in 93 genes predisposing to hematologic malignancies and 70 other cancer-predisposing genes from exome data obtained from 61 adult and 87 pediatric ALL patients. Our results show that pathogenic (P) or likely pathogenic (LP) germline variants in genes associated with predisposition to ALL or other cancers are prevalent in ALL patients: 8% of adults and 11% of children. Comparison of P/LP germline variants in patients to population-matched controls (gnomAD Finns) revealed a 2.6-fold enrichment in ALL cases (CI 95% 1.5-4.2, p = 0.00071). Acknowledging inherited factors is crucial, especially when considering hematopoietic stem cell transplantation and planning post-therapy follow-up. Harmful germline variants may also predispose patients to excessive toxicity potentially compromising the outcome. We propose integrating germline genetics into precise ALL patient care and providing families genetic counseling.Peer reviewe

CRISPR-Cas9 interrogation of a putative fetal globin repressor in human erythroid cells

Sickle Cell Disease and beta-thalassemia, which are caused by defective or deficient adult beta-globin (HBB) respectively, are the most common serious genetic blood diseases in the world. Persistent expression of the fetal beta-like globin, also known gamma-globin, can ameliorate both disorders by serving in place of the adult beta-globin as a part of the fetal hemoglobin tetramer (HbF). Here we use CRISPR-Cas9 gene editing to explore a potential gamma-globin silencer region upstream of the delta-globin gene identified by comparison of naturally-occurring deletion mutations associated with up-regulated gamma-globin. We find that deletion of a 1.7 kb consensus element or select 350 bp sub-regions from bulk populations of cells increases levels of HbF. Screening of individual sgRNAs in one sub-region revealed three single guides that caused increases gamma-globin expression. Deletion of the 1.7 kb region in HUDEP-2 clonal sublines, and in colonies derived from CD34+ hematopoietic stem/progenitor cells (HSPCs), does not cause significant up-regulation of gamma-globin. These data suggest that the 1.7 kb region is not an autonomous gamma-globin silencer, and thus by itself is not a suitable therapeutic target for gene editing treatment of beta-hemoglobinopathies.Peer reviewe

Truncating <em>NFKB1 </em>variants cause combined NLRP3 inflammasome activation and type I interferon signaling and predispose to necrotizing fasciitis

\ua9 2024 The AuthorsIn monogenic autoinflammatory diseases, mutations in genes regulating innate immune responses often lead to uncontrolled activation of inflammasome pathways or the type I interferon (IFN-I) response. We describe a mechanism of autoinflammation potentially predisposing patients to life-threatening necrotizing soft tissue inflammation. Six unrelated families are identified in which affected members present with necrotizing fasciitis or severe soft tissue inflammations. Exome sequencing reveals truncating monoallelic loss-of-function variants of nuclear factor κ light-chain enhancer of activated B cells (NFKB1) in affected patients. In patients’ macrophages and in NFKB1-variant-bearing THP-1 cells, activation increases both interleukin (IL)-1β secretion and IFN-I signaling. Truncation of NF-κB1 impairs autophagy, accompanied by the accumulation of reactive oxygen species and reduced degradation of inflammasome receptor nucleotide-binding oligomerization domain, leucine-rich repeat-containing protein 3 (NLRP3), and Toll/IL-1 receptor domain-containing adaptor protein inducing IFN-β (TRIF), thus leading to combined excessive inflammasome and IFN-I activity. Many of the patients respond to anti-inflammatory treatment, and targeting IL-1β and/or IFN-I signaling could represent a therapeutic approach for these patients

Long-term follow up of families with pathogenic NFKB1 variants reveals incomplete penetrance and frequent inflammatory sequelae

Publisher Copyright: © 2022 The AuthorsNuclear factor κ light-chain enhancer of activated B cells (NF-κB) family of evolutionarily conserved transcription factors are involved in key cellular signaling pathways. Previously, hypogammaglobulinemia and common variable immunodeficiency (CVID)-like phenotypes have been associated with NFKB1 variants and loss-of-function NFKB1 variants have been reported as the most common monogenic cause for CVID among Europeans. Here, we describe a Finnish cohort of NFKB1 carriers consisting of 31 living subjects in six different families carrying five distinct heterozygous variants. In contrast to previous reports, the clinical penetrance was not complete even with advancing age and the prevalence of CVID/hypogammaglobulinemia was significantly lower, whereas (auto)inflammatory manifestations were more common (42% of the total cohort). At current stage of knowledge, routine genetic screening of asymptomatic individuals is not recommended, but counseling of potential adult carriers seems necessary.Peer reviewe

An Activating STAT3 Mutation Causes Neonatal Diabetes through Premature Induction of Pancreatic Differentiation

Activating germline mutations in STAT3 were recently identified as a cause of neonatal diabetes mellitus associated with beta-cell autoimmunity. We have investigated the effect of an activating mutation, STAT3(K392R,) on pancreatic development using induced pluripotent stem cells (iPSCs) derived from a patient with neonatal diabetes and pancreatic hypoplasia. Early pancreatic endoderm differentiated similarly from STAT3(K392R) and healthy-control cells, but in later stages, NEUROG3 expressionwas upregulated prematurely in STAT3(K392R) cells together with insulin (INS) and glucagon (GCG). RNA sequencing (RNA-seq) showed robust NEUROG3 downstream targets upregulation. STAT3 mutation correction with CRISPR/Cas9 reversed completely the disease phenotype. STAT3(K392R) -activating properties were not explained fully by altered DNA-binding affinity or increased phosphorylation. Instead, reporter assays demonstrated NEUROG3 promoter activation by STAT3 in pancreatic cells. Furthermore, proteomic and immunocytochemical analyses revealed increased nuclear translocation of STAT3(K392R). Collectively, our results demonstrate that the STAT3(K392R) mutation causes premature endocrine differentiation through direct induction of NEUROG3 expression.Peer reviewe

Biallelic hexokinase 1 (HK1) variants causative of non-spherocytic haemolytic anaemia: A case series with emphasis on the HK1 promoter variant and literature review

The hexokinase (HK) enzyme plays a key role in red blood cell energy production. Hereditary non-spherocytic haemolytic anaemia (HNSHA) caused by HK deficiency is a rare disorder with only 12 different disease-associated variants identified. Here, we describe the clinical features and genotypes of four previously unreported patients with hexokinase 1 (HK1)-related HNSHA, yielding two novel truncating HK1 variants. The patients' phenotypes varied from mild chronic haemolytic anaemia to severe infantile-onset transfusion-dependent anaemia. Three of the patients had mild haemolytic disease caused by the common HK1 promoter c.-193A>G variant combined with an intragenic HK1 variant, emphasizing the importance of including this promoter variant in the haemolytic disease gene panels. HK activity was normal in a severely affected patient with a homozygous HK1 c.2599C>T, p.(His867Tyr) variant, but the affinity for ATP was reduced, hampering the HK function. In cases of HNSHA, kinetic studies should be considered in the functional studies of HK. We reviewed the literature of previously published patients to provide better insight into this rare disease and add to the understanding of genotype-phenotype correlation