Selena Gomez faced the biggest health crisis of her life when she went through a kidney transplant, and for a time, she feared she would die during the operation, according to her best friend Francia Raisa. Gomez, 25, has long suffered from a serious case of lupus, an autoimmune disease that can attack internal organs like the kidneys. Raisa donated a life-saving kidney to the singer. Selena turned to her to express her fears. She was worried the operation might not go as planned.