Kusne, Yael

Objective To evaluate the efficacy of cytokine‐directed therapies in VEXAS (vacuoles, E1 enzyme, X‐linked, autoinflammatory somatic) syndrome using previously proposed treatment response criteria. Methods All patients with genetically confirmed VEXAS syndrome who received targeted therapies with JAK inhibitors (JAKi), tumor necrosis factor α inhibitors (TNFαi), or interleukin‐1 (IL‐1) or IL‐6 inhibitors were identified. Clinical and biochemical data were recorded for patients at time of targeted therapy initiation, and at 3‐, 6‐, and 12‐month follow‐up time points. Treatment response was labeled as complete response (CR; normalization of C‐reactive protein [CRP], prednisone <10 mg/day, and resolution of disease activity), partial response (PR; >50% improvement in CRP, >50% prednisone dose reduction, improvement or resolution of disease features), treatment failure (TF; worsening CRP, increasing prednisone, worsening of disease features), or no response (not meeting criteria for CR, PR, or TF). Results Overall, 52 patients received an IL‐1i, IL‐6i, or JAKi therapy. At six‐month follow‐up, 3 of 19 IL‐6i patients experienced CR, 4 of 19 experienced PR, and 7 of 19 experienced TF. 2 of 17 patients receiving JAKi experienced CR, 3 of 17 experienced PR, and 6 of 17 experienced TF. No patients receiving IL‐1i or TNFαi experienced CR, and only 1 of 5 IL‐1i patients experienced PR. Among those still receiving biologic therapy at 12 months, only 1 of 11 receiving IL‐6i and 0 of 7 receiving JAKi experienced CR. Conclusion IL‐6i and JAKi therapies demonstrated limited, unsustained efficacy for management of VEXAS syndrome. IL‐1i and TNFαi therapies were not efficacious. Useful application of previously reported treatment response criteria was demonstrated, but future incorporation of hematologic parameters may be beneficial.

Background: Telomeres are repetitive sequences at the end of linear chromosomes that preserve genetic information. Patients with telomere biology disorders (TBDs) are subject to multiorgan manifestations, which include the liver. However, due to the rare nature of the disorder, these manifestations are not fully characterized. Methods: Here, we describe the hepatic manifestations of patients with TBD at a large tertiary center within a specialized TBD clinic; 121 consecutive patients with TBD seen from 2017 to 2024 were included. The median age of the TBD diagnosis was 43 years old, with 60% male. The most common pathogenic/likely pathogenic variant was TERT (25%), followed by RTEL1 (10%) and TERC (7%). Results: Evidence of hepatic involvement in TBD was observed in 60% of patients (73 of 121), as determined by imaging studies or abnormal liver chemistries. Hepatic steatosis was the most prevalent imaging finding (56%), while a cholestatic pattern of liver injury was the predominant laboratory abnormality (73%). Biopsy-proven portosinusoidal vascular disorder was present in 4 patients. Findings of portal hypertension were observed in 25 patients (34%), with decompensation observed in 12 patients (16%). Traditional liver imaging modalities (computer tomography, ultrasound, and MRI) were compared with magnetic resonance elastography in 41 patients. Of these, 7 patients had abnormal magnetic resonance elastography with normal traditional imaging (17%), indicating higher sensitivity of magnetic resonance elastography to detect liver involvement. Conclusions: This study describes the liver manifestations within a cohort of patients with TBD with findings of portosinusoidal vascular disorder and hepatopulmonary syndrome similar to other cohorts and a noted higher prevalence of hepatic steatosis as compared with the general population. Liver stiffness measurements, integrated with imaging and laboratory testing, further improve characterization of hepatic manifestations in TBD.

Abstract Germline variants in DDX41 are the most frequent genetic predisposition to adult hematologic malignancies. The most common variants are truncating, implicating loss of function in the pathogenesis. However, non-truncating variants account for 30-40% of cases, and their impact on essential DDX41 functions remains unknown. We utilized a genetic complementation assay to assess the functionality of 10 recurrent germline non-truncating variants of DDX41. All variants restored viability to Ddx41 -deficient hematopoietic progenitor cells at exogenous expression levels. In contrast, the hotspot mutant p.R525H, which is somatically acquired at disease onset in >50% of patients, failed to restore viability. CRISPR-based modeling in cell lines and mice revealed heterogeneity: some variants were non-functional at endogenous expression levels whereas others maintained complete functionality, supporting normal cell proliferation and even lifelong hematopoiesis in a homozygous setting. Notably, co-expression of p.R525H with some variants caused impaired hematopoietic progenitor cell viability, indicating a dominant-negative effect of p.R525H. In contrast, other variants, all classified as variants of unknown significance, were unaffected by the presence of p.R525H. A screen of 100 disease-associated variants confirmed that many non-truncating germline variants are susceptible to p.R525H-mediated dominant-negative effects, whereas wild-type DDX41 is not. These findings indicate that DDX41 variant curation is complicated by variable effects on functionality and variant-specific interactions with somatically-acquired DDX41 mutations. The dominant-negative effect of p.R525H provides a mechanistic basis for the conclusion of recent patient cohort analyses that co-occurrence with a somatic hotspot mutation is a reliable indicator of DDX41-driven disease in carriers of non-truncating variants.