In oncology, VHHs have been investigated for the treatment of tumors that overexpress HER2 and EGFR since their small size facilitates better tumor penetration and biodistribution in preclinical phases regard monoclonal antibodies; in autoimmune diseases, VHHs have been designed to target inflammatory cytokines such as TNF-α and IL-6 [45]. Here, IL6 is linked to autoimmune disease.