It was only an initial trial, but suramin’s effects were dramatic
.. Nobody is sure what causes autism. But one theory is that it stems from a phenomenon known as the “cellular danger response”. This involves compounds circulating in the blood, known as purines, which command cells to halt their normal activities and brace for an imminent viral attack. That response is normal and, provided it switches off when the danger has passed, beneficial. But some researchers believe that the mechanism can end up switched on permanently. This, they think, can encourage the development of autism... Suramin, which was discovered in 1916 and has long been used to treat the sleeping sickness spread by tsetse flies, blocks purines from binding to neurons.