U-serrated IgG basement membrane zone antibody staining in epidermolysis bullosa acquisita by DIF microscopy

The positive DIF staining along the basement membrane zone in this section of a perilesional skin specimen demonstrates what is described as a u-serrated linear pattern interspersed with segments of true linear IgG basement membrane zone antibody reactivity. This pattern is characteristically thicker than the n-serrated pattern in bullous pemphigoid and is associated with epidermolysis bullosa acquisita and bullous systemic lupus erythematosus.