James Swann was skeptical when he was told to learn to code as a young Ph.D. student—"Ridiculous advice," he thought—but that leap into computational biology would eventually lead to a breakthrough at Columbia University that could reshape how we treat aging and blood cancer. Working alongside Emmanuelle Passegué and Raul Rabadan, Swann helped uncover a single molecular switch that activates emergency myelopoiesis, the body’s rapid-response system for producing immune cells during infection, injury, or surgery. This discovery, published in Cell Stem Cell, is more than a biological insight—it’s a beacon for future therapies. For decades, scientists assumed that different stressors triggered this emergency blood production through separate pathways, making treatment development seem impossibly complex. But Swann’s work reveals a unifying mechanism: one master switch controls the entire system.
That switch is now in the spotlight because when emergency myelopoiesis doesn’t turn off—or turns on without cause—it floods the body with inflammation, a driver of both aging and disease. The implications are profound. Chronic inflammation accelerates tissue decline and weakens immune resilience, contributing to age-related conditions. Even more urgently, this runaway process appears to be hijacked in acute myeloid leukemia (AML), one of the most aggressive blood cancers. Swann found that AML patient cells often carry a distinct molecular signature indicating the emergency system is stuck in the “on” position—and those patients face significantly worse outcomes. This link suggests that silencing the switch could not only slow aging but also disrupt cancer’s foothold.
The discovery was only possible through an unprecedented fusion of biology and computation. Using single-cell RNA sequencing, the team captured detailed snapshots of tens of thousands of individual cells in the bone marrow. But raw data wasn’t enough. To make sense of it, Swann collaborated with computational scientists Jun Hou Fung and Ziwei Chen from Rabadan’s lab to build HemaScribe, a unified classification system for blood cells, and HemaScape, a predictive map of how stem cells evolve into mature blood cells. "It really required both the expertise of the computational scientists and our biological understanding," Passegué says. Only with this combined lens could they trace how emergency signals reroute normal development and pinpoint the singular activation point.
Now, the focus shifts to therapy. While no drugs yet target this switch, the path forward is clearer: find inhibitors that can restore balance. "The blood system bathes the entire body," Passegué notes, "and it's clear that turning off runaway emergency myelopoiesis could be an important way to treat many conditions." From New York to labs worldwide, this finding opens a new front in the fight against cancer and the slow burn of aging—one where biology and code work in tandem to heal.