In 1982, Robert Gallo from the National Cancer Institute in the USA, put forward the hypothesis that the cause of AIDS is a retrovirus. One year later, Myron Essex and his colleagues (1) found that AIDS patients had antibodies to the Human T-cell Leukemia virus Type-1 (HTLV-I), a virus discovered by Gallo a few years earlier. At the same time, Gallo and his colleagues (2) reported the isolation of HTLV-I from AIDS patients and advocated a role for this retrovirus in the pathogenesis of AIDS. This hypothesis however, was not without a few problems: 1. While HTLV-I was accepted to induce T4-cell proliferation and cause adult T-cell leukaemia,(3) the "hallmark" of AIDS was T4-cell depletion, and the incidence of leukaemia in AIDS patients was no higher than in the general population; 2. The highest frequency of antibodies to this virus was found in Japan, yet no AIDS cases had been reported from that country;(4) 3. In the same month in which Gallo's and Essex's groups reported their data, Luc Montagnier and his colleagues from the Pasteur Institute, described the isolation of a retrovirus, later known as Lymphadenopathy Associated Virus (LAV), from the lymph nodes of a homosexual patient with lymphadenopathy.(5) Although this virus was similar to HTLV-I, one of its proteins, a protein with a molecular weight of 24,000 (p24), did not react with monoclonal antibodies to the HTLV-I p24 protein. Samples of this virus were, on several occasions, sent to Gallo's laboratory. In May 1984, Gallo, Popovic and their colleagues published four papers in Science in which they claimed to have isolated from AIDS patients, another retrovirus, which they called HTLV-III.(6,7,8,9) On the 23rd of April 1984, before the Science papers were published, Gallo and Margaret Heckler, the then Health and Human Services Secretary called a press conference to announce that Gallo and his co-workers had found the cause of AIDS and had developed a sensitive test to show...
