The term cytokine is derived from a combination of two Greek words - cyto meaning cell and kinos meaning movement. Cytokines are cell signalling molecules that aid cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma.
Organs that have been successfully transplanted include the heart, kidneys, liver, lungs, pancreas, intestine, and thymus. Some organs, like the brain, cannot be transplanted. Tissues include bones, tendons (both referred to as musculoskeletal grafts), corneae, skin, heart valves, nerves and veins.
To date, most donor organs have come from deceased donors. Kidney transplants are the most common type of transplant surgery; the least common single-organ transplants are the intestines. Depending on the organ needed, organs are matched using several characteristics, including blood type and size of the organ needed.