Top Italian immunologist and former centre-right politician Fernando Aiuti died after falling down stairs at a hospital in Rome on Wednesday. Aiuti, 83, would go on to die of complications due to the fall (he had been at Rome’s Gemelli Hospital for treatment of a heart condition). Rome prosecutors are investigating the death and police are not ruling out suicide.

As well as being a world-renowned immunologist who pioneered AIDS treatment, he was an expert on the retrovirus and a former member of three-time premier and media magnate Silvio Berlusconi’s now-defunct People of Freedom party.

Born in the Marche town of Urbino in 1935, he graduated with a degree in medicine from Sapienza University of Rome. In 1991, while the possibility of AIDS being transmitted orally was being discussed, Aiuti suddenly took Rosaria Iardino, an HIV-positive woman, and kissed her on the mouth, trying to convince public opinion that the virus could not be transmitted that way. A journalist photographed the scene and the photo became internationally famous.

Aiuti was head of the People of Freedom (PdL) list in 2008 and was elected to the municipal council of Rome for the PdL along with Mayor Gianni Alemanno, serving until 2013.

Rest in peace. Our hearts go out to his family and friends.