Washington (CNN) -- Timothy Brown sounds like a pretty common name, so it might not mean much to you.
But one special Timothy Brown appeared at the International AIDS conference in Washington today.
He's allegedly the only person ever cured of HIV.
Brown -- also known as "the Berlin Patient"-- was HIV positive and fighting leukemia in 2007.
Doctors in Germany wiped out his immune system with chemotherapy and radiation.
Then, they gave him two rounds of stem-cell transplants.
German researchers say the donor had a rare, inherited gene mutation that makes stem cells naturally resistant to infection with HIV.