Cytomegalovirus-specific neutralizing antibodies effectively prevent uncontrolled infection after allogeneic hematopoietic stem cell transplantation

Cytomegalovirus (CMV) infection remains one of the most frequent and life-threatening infectious complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Herein, we comprehensively compared the immune cells of patients with uncontrolled and controlled CMV infection post-allo-HSCT and found that B-cells were extraordinarily insufficient because of impaired B-cells reconstitution in the uncontrolled infection group. Furthermore, in the controlled infection group, reconstructed B-cells showed signatures of mature B-cells, high expression of CXCR4 and IFITM1, and enrichment of CMV-associated B-cell receptors, which were lacking in the uncontrolled infection group. Consistently, sera from the uncontrolled infection group failed to inhibit CMV infection via neutralizing virus in vitro because of its lower content of anti-CMV-specific immunoglobulin G (IgG) than the controlled infection group. Overall, these results highlighted the contribution of B cells and anti-CMV-specific neutralizing IgGs to the restraint of CMV infection post-allo-HSCT, suggesting their potential as a supplementary treatment to improve outcomes.