Interferon-alpha Forces Mutant Stem Cells into Short-Lived Neutrophils in Essential Thrombocythemia

Weill Cornell investigators profiled thousands of bone marrow cells from essential thrombocythemia patients at baseline, during interferon-alpha therapy, and after withdrawal. Single-cell transcriptomes, surface proteins, and lineage tracing revealed that interferon triggers an emergency granulopoiesis program, accelerating mutant stem cells into neutrophils whose brief lifespan reduces clonal burden. Non-mutant cells showed milder shifts, explaining selective therapeutic pressure. The same treatment suppressed inflammaging signatures and increased lymphoid output, correcting the myeloid bias characteristic of myeloproliferative neoplasms.

These mechanistic details extend prior clinical observations that interferon achieves molecular responses in roughly 20-30% of patients yet often causes flu-like toxicity. The single-cell resolution identifies the precise differentiation bottleneck and differential susceptibility that bulk assays missed. It also suggests why JAK2 inhibitors, which suppress proliferation without forcing terminal differentiation, rarely eradicate clones.

The findings point toward narrower agonists that mimic only the granulopoietic or lymphoid-rebalancing arms of interferon signaling. Such agents could be tested first in patients already showing partial interferon responses, using mutant allele fraction decline as the primary endpoint within 12 months.

Next steps require prospective cohorts that pair serial single-cell sampling with clinical outcomes to confirm whether early neutrophil skewing predicts sustained molecular remission or resistance.