Responses of CD27 + CD38 + plasmablasts, and CD24 hi CD27 hi and CD24 hi CD38 hi regulatory B cells during primary dengue virus 2 infection

Humoral immunity is thought to play a central role in mediating the immunopathogenesis of dengue virus (DENV) infection; however, the B-cell responses elicited by primary DENV2 infection are incompletely understood. Follicular helper T cells (Tfh) are important to promote B-cell activation and differentiation. The present study analyzed the detailed dynamic changes of circulating B-cell subsets and Tfh (cTfh) using flow cytometry to explore their responses to DENV2 infection. Thirty-six patients with DENV2 and 21 healthy individuals were included. The results showed that CD27 CD38 plasmablasts emerged after DENV2 infection, and correlated with CXCR5 PD-1 or CXCR5 ICOS PD-1 cTfh, which increased after DENV2 infection, and correlated with DENV2 RNA viral loads. Significantly low levels of CD27 naïve B cells, and CD24 CD27 and CD24 CD38 regulatory B cells (Breg) were observed after DENV2 infection, which correlated negatively with CXCR5 PD-1 or CXCR5 ICOS PD-1 cTfh cells. Overall, these results provide insights into the DENV2-elicited B-cell response and revealed previously unidentified CD24 CD27 and CD24 CD38 Breg responses to DENV2 infection.