London — An HIV-positive man in the UK has become the second known adult worldwide to be cleared of the AIDS virus after he received a bone marrow transplant from an HIV-resistant donor, his doctors said. Almost three years after he received bone marrow stem cells from a donor with a rare genetic mutation that resists HIV infection — and more than 18 months after he came off antiretroviral drugs — highly sensitive tests still show no trace of the man's previous HIV infection. "There is no virus there that we can measure. We can't detect anything," said Ravindra Gupta, a professor and HIV biologist who co-led a team of doctors treating the man. HIV/AIDS experts said the case is proof of the concept that scientists will one day be able to end HIV/AIDS, and marks a "critical moment" in the search for an HIV cure, but does not mean that cure has already been found. Gupta described his patient as "functionally cured" and "in remission", but cautioned: "It's too early to say he's cured." ...