Helena Alpkvist from the Infectious Diseases and Dermatology Unit at the Department of Medicine, Huddinge, is defending her thesis titled "Damage-associated molecular patterns and pathogen-associated molecular patterns in severe bacterial infections," on 22 November, 2024. The main supervisor is Kristoffer Strålin (MedH). What is the main focus of your thesis? Bacterial infections can range from a mild cold to severe, life-threatening sepsis.

But why do some infections become so dangerous? The key might lie in the interaction between substances produced by our own bodies and those produced by bacteria. When we fall ill with a bacterial infection , our immune system responds to molecules that signal danger—these molecules are collectively known as damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). DAMPs are endogenous molecules released from tissue damage , while PAMPs come from the bacteria that have invaded the body.

My thesis investigates the concentrations of these molecules in severe bacterial infections such as pneumonia and bacteremia, and whether they can be linked to disease severity . What are the most important results? The level of pneumococcal DNA, a form of PAMP, in the airways correlated with disease severity in patients with pneumococcal pneumonia, with higher levels of bacterial DNA linked to more severe illness . In bacterial infections with bacteremia, we found that nuclear DNA (nDNA) was the DAMP most strong.