CXCL9 and infection: The main aim of this study was, first, to provide an analysis of the humoral immune response and B cell dynamics in a cohort of 60 COVID-19 patients who had different severity during the acute phase of infection, and second, to study the role of the chemokines CXCL9 and CXCL10 in the activation, differentiation, and modulation of antibody production.