Cells at Work!

Cells at Work! (はたらく細胞, Hataraku Saibou) is a manga by Akane Shimizu. It began its serialization in the manga magazine Monthly Shonen Sirius in March 2015. Kodansha Comics has licensed it for English release.

Plot
Strep throat! Hay fever! Influenza! The world is a dangerous place for an anthropomorphized red blood cell just trying to get her deliveries finished. Fortunately, she’s not alone... she’s got a whole human body’s worth of cells ready to help out! The mysterious white blood cell, the buff and brash killer T cell, the nerdy neuron, even the cute little platelets—everyone’s got to come together if they want to keep you healthy!

Official
Official English site