SDC1 and periodontitis: IL-37-producing plasma cells (CD138+CD38+PIL-37) expressing IL-37 and IL-37/IL-35-coproducing plasma cells (CD138+CD38+PIL-35/IL-37) expressing both of them (96) are denoted as IgG+ plasma cells, and reduce periodontitis by suppressing the loss of alveolar bone by blocking osteoclast formation (96).