Pemphigus vulgaris is an autoimmune dermatosis, in which IgG-type autoantibodies lead to blistering in the epidermis. The target antigens of the autoantibodies are mainly the desmosomal cadherins, Dsg-1 and Dsg-3, in epidermal keratinocytes. The autoantibodies lead to a loss of desmosomal adhesion, with resulting blistering of the skin and/or mucous membranes. It has previously been shown that inhibition of IgG-type autoantibody binding to the neonatal Fc-receptor (FcRn) results in reduced recycling of these pathogenic antibodies, which reduces their half-life in the serum. One aim of this work was to produce Dsg-3-deficient HaCaT cells by CRISPR/Cas9 genome editing, to further analyze the function of Dsg-3 in human keratinocytes. However, no Dsg-3-deficient cells could be generated, as the knockout cells did not proliferate and eventually died. Another aim of this work was to elucidate the relevance of FcRn in human keratinocytes treated with recombinant anti-Dsg-3 antibodies. Instead of the murine anti-Dsg-3 antibodies, such as mAK23, that are frequently used in research but cannot bind to the human FcRn, the recombinant antibodies hAK23 IgG1 and h4B3 with a human Fc fragment were used. These pathogenic anti-Ds-g3 antibodies were shown to lead to altered Dsg-3 localization on the cell membrane, degradation of Dsg-3 and to a loss of adhesion in the keratinocyte-monolayer, indicating pathogenic changes in desmosomes. Activation of apoptotic proteins by recombinant anti-Dsg-3-antibodies was not detected. The drug Efgartigimod represents a modified Fc fragment, and is already undergoing clinical trials for pemphigus vulgaris, but also for other IgG-mediated autoimmune diseases. In my experiments, it could be shown that blocking the IgG-FcRn interaction by Efgartigimod leads to an improved intercellular adhesion of the keratinocyte monolayer, whereas Efgartigimod could not prevent the degradation of Dsg-3 by anti-Dsg-3 antibodies and also did not lead to an improved organization of Dsg-3 at the cell membrane. Surprisingly, it was also demonstrated that only the anti-Dsg-3 antibody h4B3 led to FcRn degradation, which was not prevented by Efgartigimod. The results of the present study indicate that FcRn may have a further function in keratinocytes, beyond its role in recycling of IgGs. Thus, stabilization of keratinocyte adhesion by inhibiting IgG-FcRn interaction may represent a new treatment option for pemphigus vulgaris.