The Dorsal Root Ganglia: From a Neuronal Relay to a Sensory Organ.

Somatosensory ganglia are often cast as passive relays, yet growing evidence shows the dorsal root ganglion (DRG) is a specialized sensory-immune organ. In the DRG, perineuronal and perivascular units act as sentinels that detect danger and calibrate immune tone. A permeable, macrophage-guarded blood-DRG barrier admits systemic cues, while neuron-glia microdomains set sensory gain and help restore homeostasis. Throughout the organ, neurons, glia, and vascular-stromal cells share immune receptors, enabling coordinated responses to infection, inflammation, and autoimmunity. In turn, neuronal signals reshape vascular tone and leukocyte trafficking, whereas immune mediators can promote recovery or drive pathology. Single-cell and spatial atlases reveal regenerative programs and zonation that organize these circuits. Together, these insights reframe the DRG as an integrator linking immune state to sensory encoding and pain. Preserving DRG structure-by fortifying barriers, stabilizing glial buffering, and steering macrophages toward resolution-could blunt maladaptive neuroimmune interactions and enable durable pain relief without compromising host defense.