# What we thought we knew about TNF—And what we now must re-learn

## TL;DR

This paper revises the understanding of TNF, showing it can have beneficial effects on hematopoietic stem cells under certain conditions.

## Contribution

The paper reveals that TNF can transiently reprogram hematopoietic stem cells without harming their regenerative potential.

## Key findings

- TNF's effects are context-dependent and not universally harmful.
- TNF can prune progenitors and reprogram hematopoietic stem cells temporarily.
- Long-term regenerative capacity of HSCs remains intact after TNF exposure.

## Abstract

Tumor necrosis factor (TNF) was long cast as a hematopoiesis villain, driving bone marrow and hematopoietic stem cell (HSC) suppression. We now see that TNF’s effects are cell type-, context-, and time-dependent. Rather than being simply “bad,” TNF can prune progenitors while transiently reprogramming HSCs without sacrificing long-term regenerative capacity.