In 2006, American HIV (human immunodeficiency virus) patient Timothy Brown, also known as the “Berlin patient”, received multiple bone marrow transplants for leukemia. The bone marrow, which came from a donor with a rare genetic HIV resistance, seemingly eradicated the HIV from Brown’s own system, thus leading his doctors to believe that they have stumbled upon a cure. In fact, they claimed as much in a peer-reviewed 2010 paper published in the medical journal Blood. However, medical experts are now arguing whether or not a cure was indeed discovered after the latest findings on Brown was presented in this year’s International Workshop on HIV & Hepatitis Virus. Held just last June 8 in Spain, the workshop brought together numerous respected authorities in the field, including virologist Steven Yukl of the University of California. Yukl was quoted as saying that at this point, they couldn’t definitely say whether or not the HIV in patient Timothy Brown has completely been eliminated. The point of presenting the most recent findings was to open the discussion on how to determine whether or not a cure has indeed been achieved. Apparently, the latest lab exams showed some persisting HIV DNA in Brown’s rectal cells. However, the found strains of DNA are definitely different from the strains that were initially discovered back in 2006. Alain Lafeuillade, from the General Hospital in Toulon (France), raises a good point; he writes that while these findings could be interpreted as proof that the HIV viremia found in the patient has persisted and evolved over the last 5 years, it could possibly be due to a re-infection. As can be expected, debate is currently raging over this question. As for natural immunity to HIV, it is currently being attributed to genetic mutation which prohibits the CCR5 molecule from appearing on the cell surface. This mutation occurs in about 1 out of 100 Caucasians.