Autoimmune diseases are more likely to appear — years after having received cancer drugs of the class “checkpoint inhibitors”

It has long been known that successful cancer chemotherapy, especially in children, can lead subsequently to secondary tumors occurring later in life –– undoubtedly due to the mutagenic properties of the cancer-treating drug. The attached one-page article tells the story that disorders above-and-beyond secondary cancers can result from chemotherapy earlier in life. In this article, the focus is on type-1 diabetes and other autoimmune diseases that physicians are now seeing in patients that had been receiving “checkpoint inhibitors,” a specific class of anti-cancer drugs.

Thyroid disease, autoimmune myocarditis, and several forms of autoimmune colitis are also being seen. It appears that mutagenic effects of these chemotherapeutic agents are attacking genes in the histocompatibility locus (HLA locus that contains large numbers of genes that participate in the immune system), leading to such maladies. This would seem to make sense –– for any disease involving one or a small number of genes that might be mutated in somatic cells after birth. Congenital birth defects would not be in this category; nor would complex diseases (e.g. type-2 diabetes, schizophrenia, hypertension, mental depression, or coronary artery disease) that are caused by hundreds if not thousands of genes, plus epigenetic effects, plus environmental adversity occurring over decades of life. In other words, one or two specific genes might be altered in a cancer patient by a chemotherapeutic agent, but not large numbers of genes such as what is seen in complex diseases that are multifactorial traits.

Science 17 Nov 2o17; 358: 852

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