Fig. 1. Humoral alloimmune responses in the context of solid organ transplantation. Adaptive immune responses to alloantigens are initiated by the activation of alloreactive dendritic cells. Within secondary lymphoid organs, B cells that have engaged with alloantigens interact with cognate CD4+ T cells at the interface of the T cell zone and the follicle. This interaction prompts the B cells to proliferate and differentiate into either extrafollicular PCs or GC B cells. The latter undergo a mutation-prone proliferation process and eventually give rise to memory B cells and affinity-matured PCs. Whether generated by the extrafollicular or GC responses, most PCs are short-lived. However, a subset migrates to the bone marrow, which provides survival niches. In the bone marrow, they further differentiate into LLPCs. LLPCs can also be found in intragraft tissues, where they may develop in situ within tertiary lymphoid clusters that form in the graft, or they may migrate from secondary lymphoid organs. DC, dendritic cell; SLPC, short-lived plasma cell; eTFH, extrafollicular helper T cell; TFH, follicular helper T cell; GC, germinal center; FDC, follicular dendritic cell; SHM, somatic hypermutation; PC, plasma cell; TLC, tertiary lymphoid cluster; LLPC, long-lived PC.
Clin Transplant Res 2024;38:341~353 https://doi.org/10.4285/ctr.24.0047