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Being Alive
UNDERSTANDING MAC INFECTION: How does someone become infected with MAC?

March 5, 1993
Being Alive 1993 Mar 5: 15

MAC organisms usually enter the body in food, water or inhaled dust or air containing water droplets. These organisms are difficult to avoid because they are commonly found throughout the world in water supplies, dust and soil. In an individual with a healthy immune system, MAC organisms are inhibited or destroyed by macrophages (another type of white blood cell). The T4 cells (T-helper cells) described earlier assist macrophages in their ability to fight invading organisms.

When an immune system is weakened by HIV, there are insufficient T4 cells to assist in this function, and MAC organisms establish themselves as parasites inside the body's cells and multiply. MAC appears to initially invade the cells within the intestine or lungs, but the infection tends to disseminate, which means it spreads widely throughout the body infecting the blood, spleen, liver, bone marrow, and lymph nodes.