this double approach (but not with dengue) was used against Joy's sister's cancer, and no it did not work.
The technique, developed by American start-up PrimeVax, involves a two-pronged approach. It would begin by taking a sample of the tumour, and collecting dendritic cells from the patient’s blood. These cells help coordinate the immune system’s response to a threat, and by exposing them to the tumour in the lab, it is possible to programme them to recognise the cancerous cells. Meanwhile, the patient is given a dose of dengue fever, a disease normally carried by mosquitoes, before they are injected with the newly trained dendritic cells.
Under the supervision of doctors in a hospital, the patient would begin to develop a 40.5C fever, combined with the widespread release of inflammatory molecules – putting the rest of the immune system on red alert. Where the tumour was once able to lurk under the radar, it should now become a prime target for an intense attack from the immune cells, led by the programmed dendritic cells. “Dengue fever crashes and regroups the immune system, so that it is reset to kill tumour cells,” says Bruce Lyday at PrimeVax.
so don't get your hopes up...
However, malaria was once used to destroy syphillis of the brain which was fatal in the bad old days before Salvarsan and Penicillin.