Major breakthrough in treatment of AIDS: Second patient cured of HIV

London HIV patient's doctors found a donor with a gene mutation that confers natural resistance to HIV

Researchers say a London man appears to be free of the AIDS virus after a stem cell transplant.

It's the second such success including "Berlin patient" Timothy Ray Brown.

Such transplants are dangerous and have failed in other patients.

The new findings were published online Monday by the journal Nature.

The London patient has not been identified.

He was diagnosed with HIV in 2003. He developed cancer and agreed to a stem cell transplant to treat the cancer in 2016.

His doctors found a donor with a gene mutation that confers natural resistance to HIV.

The transplant changed the London patient's immune system, giving him the donor's HIV resistance.