Non-pathogenic pemphigus foliaceus (PF) IgG acts synergistically with a directly pathogenic PF IgG to increase blistering by p38MAPK-dependent desmoglein 1 clustering

•PF sera contain both pathogenic and non-pathogenic anti-Dsg1 IgG.•A mixture of PF mAbs disrupted cell adhesion more than a single pathogenic mAb.•Increased pathogenicity was associated with p38MAPK-dependent Dsg1 clustering.•Not only pathogenic Abs but also non-pathogenic Abs coordinately act on PF blistering.