Search PubMedSearch

Biomedical subjects

Johannes C Hellmuth

Publications and source records attributed to Johannes C Hellmuth.

2 recordsLinked to original sources

MRD-2 in the GHSG HD21 trial assessed by a validated circulating tumor DNA sequencing assay.

Beyond cure, major goals in patients with Hodgkin lymphoma (HL) are tailoring treatment to a patient's individual risk for relapse to reduce acute and late toxicities, identifying candidates for early incorporation of novel agents, and making treatment affordable on a global level. Minimal residual disease (MRD) assessment by circulating tumor DNA (ctDNA) sequencing emerged as a promising strategy to achieve these goals; however, previous studies differed in sampling time points, assay validation, and definitions for MRD negativity. Here, we applied LymphoVista, a validated ctDNA sequencing assay for genotyping and MRD monitoring in lymphoma, to samples obtained from the German Hodgkin Study Group (GHSG) HD21 trial after 2 cycles of treatment (MRD-2) using a case-cohort design. Patients with positive MRD-2 result were at higher risk for relapse, progression, or death compared with MRD-2-negative patients (4-year progression-free survival [PFS], 36.7% vs 82.2%; hazard ratio, 5.3; 95% confidence interval, 2.0-13.8; P = .0008). After inverse probability weighting accounting for the number of events in the full reference set, patients with positive and negative MRD-2 results had 4-year PFS rates of 72.2% vs 95.3%. Combining MRD-2 with positron emission tomography after 2 cycles of BrECADD/eBEACOPP (PET-2) can identify patients at very low and patients at very high risk of relapse, progression, or death. In summary, these results suggest that MRD-2 assessment by LymphoVista allows for early outcome prognostication in patients with HL and could be used as a tool to improve treatment guidance on its own or in conjunction with PET-2.

Humans

OCT2 pre-positioning facilitates cell fate transition and chromatin architecture changes in humoral immunity.

During the germinal center (GC) reaction, B cells undergo profound transcriptional, epigenetic and genomic architectural changes. How such changes are established remains unknown. Mapping chromatin accessibility during the humoral immune response, we show that OCT2 was the dominant transcription factor linked to differential accessibility of GC regulatory elements. Silent chromatin regions destined to become GC-specific super-enhancers (SEs) contained pre-positioned OCT2-binding sites in naive B cells (NBs). These preloaded SE 'seeds' featured spatial clustering of regulatory elements enriched in OCT2 DNA-binding motifs that became heavily loaded with OCT2 and its GC-specific coactivator OCAB in GC B cells (GCBs). SEs with high abundance of pre-positioned OCT2 binding preferentially formed long-range chromatin contacts in GCs, to support expression of GC-specifying factors. Gain in accessibility and architectural interactivity of these regions were dependent on recruitment of OCAB. Pre-positioning key regulators at SEs may represent a broadly used strategy for facilitating rapid cell fate transitions.

Animals