Protein Loss Drives Immune System Aging,Study Finds

BYLINE: Tess Joosse

As our hairs go gray and our muscles weaken with age,our immune system also changes. In particular, the stem cells that become blood or immune cells can develop mutations, perhaps leading too cancers or other dysfunctions.

Researchers at the University of Illinois Chicago have discovered an crucial cellular mechanism that drives this aging: the lack of a protein called platelet factor 4, whose levels decrease with age, they report in the journal Blood. What’s more, adding this protein to old blood cells reversed these signs of aging, which points to a promising therapeutic target for preventing or improving age-related disorders in the blood and immune systems.

Hematopoietic stem cells, also known as blood stem cells, are a special type of cell that live in the bone marrow and can develop into the ever-importent blood and immune cells. “Our hematopoietic stem cells are very rare,” said UIC’s Sandra Pinho, associate professor of pharmacology and regenerative medicine in the College of Medicine. “we call them the Holy Grail of the immune system.”

In a young body, hematopoietic stem cells can easily generate both major groups of blood cells: myeloid cells, which include some immune cells and also red blood cells that transport oxygen, or lymphoid cells, which include the T and B cells that protect us from infections.

But as the body ages, the hematopoietic stem cells are more inclined to become myeloid cells and make fewer and fewer lymphoid cells. This, in turn, changes how aging peoples’ immune systems act. “That’s one of the reasons why, normally, older individuals are not used