Sepsis is one of the most expensive medical conditions in the world – new research clarifies how it can lead to cell death

Sepsis is a major medical concern, affecting 750,000 people in the US and nearly 50 million people globally each year.

Sepsis is a life-threatening condition arising from the body’s overreactive response against an infection, leading it to injure its own tissues and organs.

The first known reference to “sepsis” dates back more than 2,700 years, when the Greek poet Homer used it as a derivative of the word “sepo,” meaning “I rot.” Despite dramatic improvements in understanding the immunological mechanisms behind sepsis, it still remains a major medical concern, affecting 750,000 people in the US and nearly 50 million people globally each year.

Sepsis accounted for 11 million deaths worldwide in 2017, and is the most expensive medical condition in the US, costing over tens of billions of dollars annually.

We are researchers who study how certain types of bacteria interact with cells during infections. We wanted to understand exactly how an overreactive immune response can result in detrimental and even lethal effects like sepsis. In our newly published research, we discovered the cells and molecules that potentially trigger death from sepsis.

The body’s response to infection starts when immune cells recognise components of the invading pathogen. These cells then release molecules like cytokines that help eliminate the infection. Cytokines are a broad group of small proteins that recruit other immune cells to the site of infection or injury.

While cytokines play an essential role in the immune response, excessive and uncontrolled cytokine production can lead to a dangerous cytokine storm associated with sepsis.

Cytokine storms were first seen in the context of graft versus host disease, arising from transplant complications. They can also occur during viral infections, including COVID-19. This uncontrolled immune response can lead to multi-organ failure and death.