Whole-exome sequencing of memory NK cells from 81 CMV-seropositive donors reveals dominant somatic clones, early-life origin, and positive selection, with Kmt2d loss shifting mouse NK fitness.

bioRxiv · Sep 18, 2026 · PreprintImmunology✦ In-depth digest

STAT3 operates as an inflammation-dependent transcriptional switch

Simon A. Grassmann, Hyunu Kim, Christin Friedrich, Marine Pujol, Sherry Fan, Jennifer Zhang, Giorgi Beroshvili, Veit R. Buchholz, Georg Gasteiger, Joseph Chai-Yuen Sun

This study shows STAT3 acts as an inflammation-dependent transcriptional switch in NK cells, regulating differentiation through MYB and BLIMP-1 under different inflammatory conditions.

bioRxiv · Sep 26, 2025 · PreprintImmunology

An IFN-STAT1-CYBB Axis Defines Protective Plasmacytoid DC to Neutrophil Crosstalk During Aspergillus fumigatus Infection.

Yahui Guo, Mariano A. Aufiero, Kathleen A M Mills, Simon A. Grassmann, Hyunu Kim, Mergim Gjonbalaj, Paul Zumbo, Audrey Billips, Katrina B. Mar, Yao Yu, Laura C. Echeverri Tirado, Lena J. Heung, Amariliz Rivera, Doron Betel, Joseph Chai-Yuen Sun, Tobias M. Hohl

The paper identifies an IFN-STAT1-CYBB axis that mediates protective crosstalk between plasmacytoid dendritic cells and neutrophils during Aspergillus fumigatus infection.

Journal of Clinical Investigation · Aug 5, 2025Peer-reviewedImmunology

An epigenetically distinct HSC subset supports thymic reconstitution

Harold Kunal Elias, Sneha Mitra, Marina Burgos da Silva, Adhithi Rajagopalan, Brianna Gipson, Nicole MynYi Lee, Anastasia I. Kousa, Mohamed Ashraf Ali, Simon A. Grassmann, Rhoshini Raghuraman, Xiaoqun Zhang, Susan DeWolf, Melody M. Smith, Hana Andrlová, Kimon V. Argyropoulos, , Marcel R.M. van den Brink

This study identifies an epigenetically distinct HSC subset, Kitlo, that supports better thymic and T-cell reconstitution in mice and humans.

Nature Communications · Jul 4, 2025Peer-reviewedImmunology

IL-21 Shapes the B Cell Response in a Context-Dependent Manner

Youngjun Kim, Francesca Manara, Simon A. Grassmann, Kalina T. Belcheva, Kanelly Reyes, Hyunu Kim, Stephanie Downs‐Canner, William T. Yewdell, Joseph Chai-Yuen Sun, Jayanta Chaudhuri

This study reveals that IL-21 regulates B cell fate through context-dependent effects on apoptosis and proliferation, using a conditional knock-out model and ex vivo cultures.

Cell Reports · Jan 1, 2025Peer-reviewedImmunology