Quick Answer. A low hemoglobin count, also known as anemia, is caused by pregnancy, a menstrual period, a diet low in iron, blood loss, or a disease that causes the body to produce fewer red blood cells or to destroy red blood cells. According to the Mayo Clinic, medications also sometimes cause anemia.
A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways.
Helper T (CD4+): activate other cells. Cytotoxic (CD8+): direct killing of virus-infected cells. Regulatory (CD4+25) control activity of other immune cells/allow immune tolerance. Natural Killer: direct killing of all bad stuff, part of innate immunity.