TNFSF13B and HIV-1 infection: BAFF can induce IL-10+ Breg in mice and support human Breg survival.90,93 Human PD-L1hi Breg have been shown to preferentially sequester BAFF via BAFF-R, eliciting a potential survival advantage.90 However, loss of immunoregulatory capacity of human precursor marginal zone Breg appears to be directly related to an excess of BAFF in the context of HIV-1 infection.94 Careful evaluation of these B-cell survival factors in ex vivo protocols may improve the expansion and viability of a human Breg-cell therapy product.