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The interleukin-3 receptor [alpha] subunit, CD123, is expressed in many hematologic malignancies including acute myeloid leukemia (AML) and blastic plasmacytoid dendritic cell neoplasm (BPDCN). Tagraxofusp (SL-401) is a CD123-targeted therapy consisting of interleukin-3 fused to a truncated diphtheria toxin payload. Factors influencing response to tagraxofusp other than CD123 expression are largely unknown. We interrogated tagraxofusp resistance in patients and experimental models and found that it was not associated with CD123 loss. Rather, resistant AML and BPDCN cells frequently acquired deficiencies in the diphthamide synthesis pathway, impairing tagraxofusp's ability to ADP- ribosylate cellular targets. Expression of DPH1, encoding a diphthamide pathway enzyme, was reduced by DNA CpG methylation in resistant cells. Treatment with the DNA methyltransferase inhibitor azacitidine restored DPH1 expression and tagraxofusp sensitivity. We also developed a drug-dependent ADP-ribosylation assay in primary cells that correlated with tagraxofusp activity and may represent an additional novel biomarker. As predicted by these results and our observation that resistance also increased mitochondrial apoptotic priming, we found that the combination of tagraxofusp and azacitidine was effective in patient-derived xenografts treated in vivo. These data have important implications for clinical use of tagraxofusp and led to a phase 1 study combining tagraxofusp and azacitidine in myeloid malignancies., Introduction CD123, or the interleukin-3 (IL-3) receptor (IL-3R) [alpha] chain, is a cell-surface marker associated with a variety of hematologic malignancies and is often enriched on tumor cells compared with [...]

We report on outcomes of 111 patients with treatment naïve Waldenström macroglobulinemia (TN WM) treated with frontline bendamustine–rituximab (BR) (n = 57) or rituximab–cyclophosphamide–vincristine–prednisone (RCVP) (n = 54). Median follow-up was 60.7 months (range 1.9–231.6). Median progression-free survival (PFS) was 60.5 months (95% CI 47.6–73.4) for BR and 79.0 months (95% CI 31.3–126.8) for RCVP (p =.96). Median overall survival (OS) was not reached for BR and 153.4 months (95% CI 114.5–192.4) for RCVP (p =.37). While overall and major response rates did not differ between treatment groups, BR had numerically higher rate of very good partial response or better response (51% vs. 37%, p =.30) and complete response (26% vs. 13%, p =.13). RCVP confers comparable outcomes to BR in a real-world population of TN WM patients and remains an effective regimen, particularly when tolerance or frailty is an issue, or in resource-limited settings. [ABSTRACT FROM AUTHOR]

Objectives Multiple case reports describe Kikuchi-Fujimoto disease (KFD) following COVID-19 vaccination, but the true nature of this phenomenon is unknown. The purpose of this study was to further assess the relationship between KFD and COVID-19 vaccination at the population level. Methods Confirmed KFD cases from January 2018 to April 2022 were identified from provincial pathology archives and analyzed in the context of vaccination statistics from public health resources. Results Our statistical models provide evidence of a temporal association between KFD and both antecedent COVID-19 vaccine administration as well as age-stratified vaccination rates. Eight new cases of plausible COVID-19 vaccine-associated KFD are presented, collectively exhibiting clinical and pathologic features that overlap substantially with those of idiopathic KFD. Conclusions Our findings indicate that KFD is observed in association with COVID-19 vaccination and suggest that mechanistic studies are warranted. [ABSTRACT FROM AUTHOR]

This article is a reply to a previous report on the association between Kikuchi-Fujimoto disease (KFD) and COVID-19 vaccine administration in British Columbia. The authors discuss the prevalence of axillary lymphadenopathy in KFD cases and how it relates to COVID-19 vaccine-associated KFD. They also acknowledge the complexities of comparing studies across diverse populations and highlight the potential influence of biological and other factors on vaccine-induced KFD risk elevation. The authors mention the need for further research and appreciate the opportunity for scientific discourse on this topic. [Extracted from the article]

Secondary amenorrhea is not uncommon in the adolescent female population. There are multiple etiologies to consider, and a comprehensive evaluation is often pursued. Sometimes, however, despite a thorough workup, the diagnosis remains unclear. Here, we report an unusual cause of secondary amenorrhea in a 15-year-old girl. Our patient presented with secondary amenorrhea after a 4-year history of regular menstrual cycles. Her evaluation was notable for very low FSH and low estradiol but normal LH; pregnancy, adrenal, thyroid, prolactin studies, and brain magnetic resonance imaging scan did not reveal a cause of her amenorrhea. Her transabdominal ultrasound showed an enlarged right ovary, initially suggestive of a hemorrhagic cyst. Inhibin A and B were measured because of the persistently low FSH; these were found to be very elevated, concerning for an inhibin-producing tumor. The patient had surgical removal of her right ovary; pathology revealed a juvenile granulosa-cell tumor. Postoperatively, the patient had normalization of serum inhibin A and B and resumption of normal menstrual cycles. This report illustrates that careful consideration of laboratory findings and other studies is essential for correctly identifying the underlying cause of secondary amenorrhea, particularly when the results are not consistent with common causes of this condition. [ABSTRACT FROM AUTHOR]

A detailed bioinformatics analysis of six glycopeptide biosynthetic gene clusters isolated from soil environmental DNA (eDNA) megalibraries is performed to gain insight into a subset of these gene cluster that contains collections of tailoring enzymes that are predicted to result in the production of new glycopeptide congeners. The derivatization of known natural products with eDNA-derived tailoring enzymes could find possible use as applicable strategy for generating libraries of new natural product variants.

The phenotypic screening of broad-host-range environmental DNA libraries in six different proteobacteria, Agrobacterium tumefaciens, Burkholderia graminis, Caulobacter vibrioides, Escherichia coli, Pseudomonas putida, and Ralstonia metallidurans are reported. The findings for the host strains used provide access to unique sets of clones showing minimal overlap and also demonstrate the potential advantage conferred on functional metagenomics through the use of multiple diverse host species.

Studies supporting a model in which Bcl-[x.sub.L] activity is controlled by reversible insertion of its N-terminal domain into the mitochondrial outer membrane are presented. The N-terminal domain of Bcl-[x.sub.L] in the absence of its transmembrane domain reversibly inserts into the membrane upon binging approximately two protons.

"Double-hit" and "double-expressor" lymphomas represent distinct but overlapping subsets of aggressive B-cell non-Hodgkin lymphoma. The high rates of bone marrow involvement by these lymphomas pose a major therapeutic challenge due to the chemotherapy-resistant nature of the bone marrow microenvironment and the limited utility of rituximab-based salvage regimens in patients with relapsed/refractory disease. Preclinical studies utilizing high-dose cyclophosphamide in combination with the anti-CD52 monoclonal antibody alemtuzumab have recently shown promise in the treatment of intramedullary disease, and a Phase I human trial is now underway. In support of such efforts, here we perform CD52 target validation on a series of double-hit (n = 40) and double-expressor (n = 58) lymphomas using immunohistochemistry. CD52 expression levels varied considerably across samples, however positive staining was observed in 75% of both double-hit and double-expressor lymphomas. Similarly, high levels of CD52 expression were seen in patients whose disease was associated with high-risk clinical features, including primary refractory status (73%), higher IPI score (76%), and bone marrow involvement (74%). CD52 expression was not significantly correlated with diagnostically relevant pathologic features such as morphology, cytogenetic findings or other immunophenotypic features, but was notably present in all cases lacking CD20 expression (n = 6). We propose that CD52 expression status be evaluated on a case-by-case basis to guide eligibility for clinical trial enrollment. [ABSTRACT FROM AUTHOR]

Phenotype-based screening of bacterial metagenomic libraries provides an avenue for the discovery of novel genes, enzymes, and metabolites that have a variety of potential clinical and industrial uses. Here, we report the identification of a functionally diverse collection of antibacterially active enzymes from the phenotypic screening of 700 000 cosmid clones prepared from Arizona soil DNA and hosted in Ralstonia metallidurans. Environmental DNA clones surrounded by zones of growth inhibition in a bacterial overlay assay were found, through bioinformatics and functional analyses, to encode enzymes with predicted peptidase, lipase, and glycolytic activities conferring antibiosis. The antibacterial activities observed in our R. metallidurans-based assay could not be replicated with the same clones in screens using Escherichia coli as a heterologous host, suggesting that the large-scale screening of metagenomic libraries for antibiosis using phylogenetically diverse hosts should be a productive strategy for identifying enzymes with functionally diverse antibacterial activities. [ABSTRACT FROM AUTHOR]

Clones that encode the biosynthesis of long-chain N-acyl amino acids are frequently recovered from activity-based screens of soil metagenomic libraries. Members of a diverse set of enzymes referred to as N-acyl amino acid synthases are responsible for the production of all metagenome-derived N-acyl amino acids characterized to date. Based on the frequency at which N-acyl amino acid synthase genes have been identified from metagenomic samples, related genes are expected to be common throughout the global bacterial metagenome. Homologs of metagenome-derived N-acyl amino acid synthase genes are scarce, however, within the sequenced genomes of cultured bacterial species. Toward the goal of understanding the role(s) played by N-acyl amino acids in environmental bacteria, we looked for conserved genetic features that are positionally linked to metagenome-derived N-acyl amino acid synthase genes. This analysis revealed that N-acyl amino acid synthase genes are frequently found adjacent to genes predicted to encode PEP-CTERM motif-containing proteins and, in some cases, other conserved elements of the PEP-CTERM/exosortase system. Although relatively little is known about the PEP-CTERM/exosortase system, its core components are believed to represent the putative Gram-negative equivalent of the LPXTG/sortase protein-sorting system of Gram-positive bacteria. During the course of this investigation, we were able to provide evidence that an uncharacterized family of hypothetical acyltransferases, which had previously been linked to the PEP-CTERM/exosortase system by bioinformatics, is a new family of N-acyl amino acid synthases that is widely distributed among the PEP-CTERM/exosortase system-containing Proteobacteria. [ABSTRACT FROM AUTHOR]