The following clinical case has just been published in the British Journal of Haemathology : A 61-year-old man with swollen glands and weight loss was receiving hemodialysis for end-stage renal failure after a failed kidney transplant. You are diagnosed with stage III classic Hodgkin lymphoma (the lymphoma affects nodal areas located on either side of the diaphragm or above the diaphragm and in the spleen).
Shortly after diagnosis, he was admitted with shortness of breath and was diagnosed with PCR-positive SARS-CoV-2 pneumonia. After eleven days, he was discharged to convalesce at home. Corticosteroids and immunochemotherapy were not administered.
Four months later, the swollen nodes had reduced and a PET scan revealed a generalized remission of the lymphoma.
According to the authors, the hypothesis is that the SARS-CoV-2 infection triggered an antitumor immune response: the inflammatory cytokines produced in response to the infection could have activated specific T cells with tumor antigens and natural killer cells against the tumor. SARS-CoV-2 had cured his lymphoma.
Potato magic?
Apparently, a similar case had already been described in other types of lymphomas that had remitted spontaneously before treatment due to the antitumor effect of infectious pneumonia and Clostridium difficile colitis.
Ultimately this is not so surprising. Microorganisms can not only cause cancer, they can also help cure it. In the late 1800s, a New York physician named William B. Coley developed a cancer treatment with a bacterial preparation called Coley’s toxins.
This doctor found that cancer patients who also had an infection responded better than patients without infection. Coley thought that the infection stimulated the immune system to fight cancer and so he developed a cocktail of bacteria Streptococcus pyogenes and Serratia marcescens , which he injected directly into the tumor. For years in the US, patients for some incurable cancers were treated with preparations of bacteria and toxins, in many cases successfully.
However, the criticism and especially the success of the new chemo and radiotherapy treatments caused Coley’s toxins to fall into oblivion. However, it has now been proven that the basic principle of Coley’s treatment was correct and that some cancers are sensitive to stimulation of the immune system.
Ultimately everything is related: microbes, the immune system, the inflammatory response and cancer, but we still don’t really know how. In recent decades, the Calmette-Guerin bacillus, better known by its acronym BCG, has been used as a treatment for bladder cancer. BCG is actually an attenuated extract of the bacterium Mycobacterium bovis that is used as a vaccine against tuberculosis.
BCG stimulates an immune response and causes inflammation of the bladder wall that ends up destroying cancer cells within the bladder, at least in the early stages of the tumor. In fact, this is what immunotherapy is based on, which is so fashionable today. Coley’s intuition was correct: stimulating the immune system can be effective in treating cancer. That’s why William B. Coley is called “the father of immunotherapy.”
Ignacio López-Goñi, Professor of Microbiology, University of Navarra
This article was originally published on The Conversation. Read the original.
