Most of the world’s adult population is latently infected by the BK polyomavirus. It causes asymptomatic infection in
healthy individuals but emerged as a threat to kidney transplant recipients because of virus-associated nephropathy caused
by immunosuppressive therapy. In these conditions, when a functional cellular response is impaired by
immunosuppression, neutralizing antibodies may play a major role because they can directly prevent infection of target
cells, independently of cell-mediated immunity, by binding to the viral particles. Studying the contribution of anti-BK virus
neutralizing antibodies in viral control has long been hampered by the lack of convenient in vitro models, but major
progress has been made in the past decade. The four BK virus genotypes have been demonstrated to behave as distinct
serotypes. A low recipient neutralizing antibody titer against the donor’s serotype before kidney transplant has been
significantly associated with BK virus replication after transplant. Different mechanisms exploited by the BK virus to evade
neutralizing antibodies have been described. Recent studies also support the potential benefit of administering
intravenous Igs or monoclonal neutralizing antibodies as a therapeutic strategy, and more interestingly, this could also be
used as preventive or preemptive therapy before advanced kidney damage has occurred. Besides, neutralizing antibodies
could be induced by vaccination. In this review, we summarize accumulated knowledge on anti-BK virus neutralizing
antibodies as well as their clinical importance and therapeutic potential for kidney transplant recipients.