Lin L, et al. - In this study with patients suffering an autoimmune skin disease, pemphigus vulgaris (PV), researchers focused on the potential role of environmental allergens in triggering autoantibody development. The reactivity against a panel of possible allergens, such as insects, pollens, epithelia, fungi and food antigens was assessed by testing revertant/germline monoclonal antibodies (mAbs) (with mutations on variable regions of heavy and light chains reverted to germline forms) of eight anti-desmoglein 3 pathogenic mAbs from PV patients. In PV, initiation of autoantibody development was possible by walnut antigens/allergens via a “hit-and-run” mechanism (where the inciting antigens that initiate autoimmune responses are not present at the time of overt autoimmune disease). A paradigm for the etiological investigation of other allergic and autoimmune diseases may be offered by the revertant/germline mAb approach.