CD8 cells, also called suppressor and cytotoxic T-cells, play a role in fighting viral infections such as HIV. A T lymphocyte that secretes large amounts of gamma-interferon, a lymphokine involved in the body’s defense against viruses. CD8 cells prevent the unnecessary formation of antibodies. A healthy adult usually has between 150 and 1,000 CD8 cells per cubic millimeter. In contrast to CD4 cells, people with HIV often have elevated numbers of CD8 cells, the significance of which is not well understood. Lab reports may also list the T-cell ratio, which is the number of CD4 cells divided by the number of CD8 cells. Since the CD4 count is usually lower and the CD8 count higher than normal, the ratio is usually low in people with HIV. A normal T-cell ratio is usually between 1.5 and 2.5 to 1. The expected response to effective combination anti-HIV treatment is an increase in CD4 count, a decrease in CD8 count, and an increase in the T-cell ratio.