Sorted B cell transcriptomes point towards actively regulated B cell responses during ongoing chronic hepatitis B infections

The natural course of chronic hepatitis B virus (HBV) infections follows distinct clinical disease phases, char-acterized by fluctuating levels of serum HBV DNA and ALT. The immune cells and their features that govern these clinical disease transitions remain unknown. In the current study, we performed RNA sequencing on pu-rified B cells from blood (n = 42) and liver (n = 10) of healthy controls and chronic HBV patients. We found distinct gene expression profiles between healthy controls and chronic HBV patients, as evidenced by 190 differentially expressed genes (DEG), but also between the clinical phenotypes of a chronic HBV infection (17?110 DEG between each phase). Numerous immune pathways, including the B cell receptor pathway were upregulated in liver B cells when compared to peripheral B cells. Further investigation of the detected DEG suggested an activation of B cells during HBeAg seroconversion and an active regulation of B cell signalling in the liver.