Remembering Jean-Francois Bach

Jean-Francois Bach, MD, DSc 1940-2023

It with a sense of great loss that I am writing to let you know of Jean-Francois Bach’s passing last week at his home in Paris at the age of 83. His passing was after a long struggle with cancers.

Dr. Bach was one of the towering figures of our field – much of what we now take for granted about the mechanisms of Type 1 diabetes, other autoimmune diseases, vaccines, and transplantation grew from his studies and writings. The following are a few of his notable achievements that have directly impacted our work. In 1977 he discovered and isolated thymulin, a hormone produced by the thymic epithelium which induces differentiation of T cells and had effects on “suppressor” T cells that had been described in the 1970’s. (Before our contemporary notion of regulatory T cells.) Indeed, he demonstrated remarkable effects of certain thymic derived cells to regulate autoimmune diabetes which, in the past several years, has led to studies to expand and administer regulatory T cells for control of the disease.  His notions about the autoimmune nature of Type 1 diabetes led him, with colleagues, in 1985, to carry out a randomized placebo controlled trial of Cyclosporine A and showed how this treatment could induce “remission” of the disease. That study, with those from the Canadian group are the foundation for all of our clinical studies.

In the early 1990’s, with Lucienne Chatenoud, he showed how anti-CD3 mAb could reverse spontaneous diabetes in NOD mice. These initial studies in mice were the beginnings of what ultimately led to the approval of teplizumab. He was a strong advocate for investigations to understand the mechanisms of the therapeutic efficacy and his own investigations were the background for our current ideas.

In addition to these achievements in the laboratory and the clinic, his concepts about T1D and autoimmune diseases in general were paradigm shifting. He developed the notion of T1D as an autoimmune emergency, which demanded treatment with therapies to arrest the rapidly ongoing beta cell destruction that occurred at the time of diagnosis. He focused our attention on the relationships between infections and the increase in rates of autoimmune diseases i.e. the “hygiene hypothesis” in a landmark paper in the NEJM in 2002.  He authored or co-authored nearly 700 articles.

In addition to his service to humanity through his science, he also led efforts the improve public health in several important general ways.  In 1985, he was elected to the Academy of Sciences. He was one of two Secretaire Perpetuels Honoraire of that society. In 2011 he created the science ethics and society committee, to address questions of scientific integrity. In 2014, he set up the Science and Biosecurity Committee of the Academy of Sciences to warn of the dangers of biological threats hovering over human societies. He served as director of Inserm Unit 25 and Claude Bernard Association on autoimmune diseases. He was director of the Claude Bernard Association’s center on autoimmune diseases. He was the recipient of numerous international awards including the Barbara Davis prize from the Univ of Colorado in 2000.

Those of us who knew him, I am sure, feel the loss of not only a great mentor and colleague but a friend who enthusiastically engaged in our efforts to treat and prevent T1D and other autoimmune diseases. His easy going nature and sense of humor was welcoming. His perpetual curiosity and conceptual thinking was inspirational. Our work is the legacy of his contributions. I know that he would take great satisfaction in seeing us continue in the path he rooted.