The quality of pharmaceutical products is one of the most important factors for assuring their safety and effectiveness. Only if these criteria are met patients and voluntary consumers can be confident in taking medication (1). This also applies to the microbiological quality of pharmaceuticals and there especially to donated blood and blood products which can carry various infectious agents and hold the risk of transfusion-transmitted infections (2). Due to its high propensity for persistence, the primarily pulmonary, obligate intracellular bacterium Chlamydia pneumoniae is refractory to the total eradication by common antibiotics (3) and is discussed to play a causal role in the establishment of chronic inflammatory diseases (e.g., atherosclerosis) by getting disseminated to extrapulmonary body sites through peripheral blood mononuclear cells (PBMC) (4). In regard to hemovigilance and due to the chlamydial ability to infect PBMC as well as survive phagocytosis by macrophages, this project aims to evaluate by applying qPCR methods and flow cytometry (FACS) if C. pneumoniae can be found in Finnish donated blood and blood products made of it. If yes, the prevalence, viability and infectivity of C. pneumoniae will be assessed. Studies to characterize infection-induced leukocyte-derived extracellular vesicles (EVs), using a nanoparticle tracker, will be conducted to employ an emerging field for quality control in blood products (5,6). The assessment of C. pneumoniae as potentially contaminating bacteria in blood products contributes to broadening the spectrum of pathogens which can be screened for in donated blood prior to transfusion in the future. Evaluating their infectivity will shed light on the possible risk of transfusion-transmitted infection, and is therefore of utmost relevance for assuring the microbiological quality and safety of blood products.

2024