Arginine deficiency caused by myeloid cells: importance, identification and treatment

Dietary arginine supplementation has been suggested as a means of improving T lymphocyte function and has found its greatest clinical utility in patients undergoing elective surgery. In other illnesses, arginine supplementation is controversial. Breakthroughs in understanding arginine metabolism have led to the identification of myeloid cells that express arginase 1, causing significant depletion of arginine - an essential amino acid for normal T lymphocyte function. Hence, myeloid cells expressing arginase 1 are also known as myeloid-derived suppressor cells. This chapter discusses the hypothesis that arginine replacement therapy may be necessary in arginine deficiency states.