An oncolytic parasite to treat polycythemia vera

An oncolytic parasite to treat polycythemia vera I n recent years, there has been a surge of clinical trials to treat various kinds of cancers with non-replicating versions of viruses (1). The most famous among these is the recent use of a genetically engineered poliovirus used to treat one of the most difficult-to-treat and recurring cancers Á Glioblastoma Multiforme (2, 3). In addition, various other modified viruses are being exploited to treat melanoma, lymphoma, and other tumors. To the best of our knowledge, there has been no report on the potential use of oncolytic parasites in the treatment of cancer. Here, we propose the use of a non-pathogenic strain of Plasmodium knowlesi to treat primary polycythemia vera (PV) or other myeloproliferative diseases (4). P. knowlesi was widely used to treat syphilis before the advent of penicillin (5, 6). A PV is a chronic myeloproliferative disorder of the total bone marrow without any evidence of invasiveness, in which erythrocytosis, leukocytosis, and thrombocytosis are simultaneously present (4, 7, 8). PV is a hematopoietic stem cell disorder characterized by a pan hyperplastic and neoplastic bone marrow and is classified as a myelo-proliferative disease. Polycythemia vera, also known as polycythemia rubra vera (PRV), is characterized by an elevated absolute red blood cell (RBC) mass because of unrestrained RBC production. The gold standard for therapy is systematic phlebotomy (8). In refractory cases, radioactive phosphorus is used (8). However, the radioactive therapy carries its own side effects (8). Similar to oncolytic viruses that enter a specific his-tological tumor cell type(s) that expresses a well-defined entry receptor(s) for the virus, P. knowlesi also targets RBC (9, 10). This oncolytic parasitic treatment for PRV may be looked upon as an innovative treatment of the 21st century since most contemporary physicians may be unaware of it. The Plasmodium-based treatment can be administered by intravenous injection of the cultured P. knowlesi as needed and it is non-pathogenic to humans. The parasite causes a high fever infecting RBC and, after few 24-h cycles of replication, self-terminates without any treatment. This parasite was used routinely from 1937 to mid-1950s to cure syphilis. In the pre-antibiotic era, the goal of 'malariotherapy' was to cause high fever that killed Treponema pallidum. This procedure can be repeated every few months, eliminating the need for phlebotomy. The treatment has high potential, in particular, in developing nations and remote rural areas of the globe where phlebotomy, using …