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The thymus is a pinkish-gray organ that sits just below the sternum. It functions as a school for your immune system’s T cells, creating them from blood stem cells, then educating them to seek and destroy infections such as viruses, bacteria and fungi as well as cancer cells. But the thymus naturally shrinks throughout life, and that largely corresponds with the body’s declining ability to fight off pathogens. Resear

Every year, at least 30,000 people — and possibly 10 times that — are infected with the bacterium that causes Lyme disease, most in the Northeast and upper Midwest. Symptoms can include fatigue, joint pain, memory problems and even temporary paralysis. In a small minority of cases, the malaise can persist for many months. So it’s worrisome that in recent decades, Lyme cases have surged, nearly quadrupling in Michigan