CD40LG and rheumatoid arthritis: The level of IgG3 significantly increases and the level of IgG4 decreases post-chemotherapy in stage 3/4 tumors.60 Additionally, IgM, IgE, and IgD deposit in TME.60,61 Besides, in the transplanted heart with TLSs, IgM- and IgG-producing PCs increase the possibility of coronary artery damage.62 It was also observed in Sjögren syndrome.63 Importantly, CD138+ PCs around the follicle produce immune reactivity to citrullinated antigens (an antigen determinant for rheumatoid arthritis) by secreting ACPA IgG.