IGA ANTIKERATINOCYTE SURFACE AUTOANTIBODIES FROM 2 TYPES OF INTERCELLULAR IGA VESICULOPUSTULAR DERMATOSIS RECOGNIZE DISTINCT ISOFORMS OF DESMOCOLLIN

We previously proposed the term intercellular IgA vesiculopustular der matosis (IAVPD) for cases showing IgA antikeratinocyte surface autoant ibodies, This condition is divided into two subtypes: intraepidermal n eutrophilic IgA dermatosis (IEN), showing pustule formation in the ent ire epidermis, and subcorneal pustular dermatosis (SPD) showing pustul e formation in the uppermost epidermis, We have previously reported th at serum from certain IAVPD patients reacts with bovine desmocollin (D sc), a desmosomal cadherin, In this study we showed that two Dsc isofo rms with a slightly different molecular weight were recognized by the serum from these patients, Further analysis revealed that serum from p atients with the SPD type, which stained the cell surface in the upper most epidermis with immunofluorescence, seem to react with Dsc1. By co ntrast, serum from patients with the IEN type, which stained the cell surface at all levels of the epidermis with immunofluorescence, seemed to react with Dsc3, This difference of distribution between the two d istinct Dsc molecules may contribute to the different clinicopathologi cal features between the IEN and SPD type of IAVPD.