Photomicrograph of mesenteric (cortex area) lymph node. The expression of B-lymphocyte antigen (CD19) (black arrow) has shown (A) positive expression in control group, (B) weak expression in follicle area of hypothyrodism group, (C) moderate expression in the SC-SeNPs group, (D) positive expression in the levothyroxine group, and (E) positive expression in the SC-SeNPs+levothyroxine group.