DRUGS used to treat HIV may also prove useful in combating cancer. This hope is raised by the discovery that HIV drugs, in particular the protease inhibitor nelfinavir, encourage the thymus gland to crank up its production of naive T-cells. These cells help marshal the immune system鈥檚 fightback against bacteria, viruses and cancer cells that the body has never encountered before.
Researchers had previously noticed that some people taking drugs to combat HIV infection produce more T-cells, but it was thought that the infection itself was responsible. Now immunologist David McKean of the Mayo Clinic in Rochester, Minnesota, and colleagues have found that the same happens in people who are HIV-negative (AIDS, vol 19, p 1467).
They studied healthcare workers who had been given large doses of HIV drugs to protect them after suffering needlestick injuries. All produced between 100 and 1000 times the normal quantity of naive T-cells after being given the drugs.
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McKean says that this boost to the immune system could amplify the power of cancer vaccines, which rely on naive T-cells to kill off tumour cells. 鈥淲e鈥檙e going to start testing the effect of the drugs given together with cancer vaccines in patients with advanced melanoma,鈥� he says. 鈥淚n addition to boosting the thymus, the drugs don鈥檛 appear to cause an increase in unwanted autoimmune reactions associated with boosting the immune system. So we鈥檙e very excited.鈥�
