Devices, systems, and methods are described herein for controlling the level of one or more target cell types in the blood fluid and/or lymph fluid of a vertebrate subject. Devices and systems are provided that include a body defining at least one lumen configured for fluid flow; at least one controllable flow barrier to the at least one lumen; one or more sensor configured to detect one or more target cell types in blood fluid or lymph fluid of a vertebrate subject; at least one treatment region disposed within the at least one lumen; at least one reactive component disposed in the at least one treatment region, the at least one reactive component configured to modulate a physiological effect of the one or more target cell types in the vertebrate subject; and at least one controller in communication with the one or more sensor and in communication with the at least one controllable flow barrier to the at least one lumen; wherein the at least one controller is configured to open or close the at least one controllable flow barrier in response to the one or more sensor.