CXCL13 and alkaline phosphatase measurement: 106). Tfh cells recruited CD8+ T cells and B cells by secreting CXCL13 (chemokine ligand 13) and promoted the maturation of B cells into antibody-producing plasma cells by secreting IL-21. An important number of Tfh are found in the peripheral blood circulation, fulfilling similar roles to germinal ones and releasing many cytokines like (IL-4, IL-6, IL-5, IL-13, IL-17, IL-21 and IL-22) (Ref. 107). Tfh cells increased significantly in patients with AP and have a significant role in the development and progression of AP, primarily through the implication of IL-6 and IL-21 (Ref. 107).