Pemphigoid gestationis (PG) is a subepidermal autoimmune blistering disease characterized by self-reactive T and B cells specific for the transmembrane hemidesmosomal protein type XVII collagen/BP180.
By the use of non-overlapping peptides of the NC16A domain, we previously demonstrated that autoantibodies from BP and PG patients mainly react with epitopes clustered within the N-terminus of this immunodominant site of BP180; antibodies from patients with LPP also recognized the C-terminal portion of NC16A.
In conclusion, there are now five bullous diseases that are associated with an autoimmune response to BP180: bullous pemphigoid; pemphigoid/herpes gestationis; cicatricial pemphigoid; linear immunoglobulin A disease; and lichen planus pemphigoides.
Pemphigoid gestationis autoantigen, transmembrane collagen XVII, promotes the migration of cytotrophoblastic cells of placenta and is a structural component of fetal membranes.
Autoantibodies against collagen XVII (BP180) are seen in bullous pemphigoid, pemphigoid gestationis, mucous membrane pemphigoid, linear IgA disease, lichen planus pemphigoides and pemphigoid nodularis.
These results indicate that the BP180 antigen recognized by BP and herpes gestationis autoantibodies is a unique hemidesmosomal polypeptide, distinguishable from the BP240 antigen.
Further, two distinct CP-reactive sites were identified on the extracellular domain of the BP180 protein, one located in the non-collagenous (NC) 16A domain (at or near the previously defined autoantibody-reactive site recognized by bullous pemphigoid and herpes gestationis sera) and the other in the carboxy-terminal region of this protein.
From 71 patients' sera submitted for herpes gestationis factor (HGF) testing over a 5-year period, 12 were consistent with PG demonstrating HGF and increased IgG BP180 antibody levels; these sera were tested for IgA and IgG endomysial antibodies (EMA), epithelial basement membrane zone and cell surface antibodies by indirect immunofluorescence, and for IgA and IgG tissue transglutaminase (transglutaminase 2 or TG2) antibodies, IgA epidermal transglutaminase (transglutaminase 3 or TG3) antibodies, IgG BP230, and IgG desmoglein 1 and desmoglein 3 antibodies by enzyme-linked immunosorbent assays (ELISAs).
Pemphigoid gestationis (PG), also known as <i>herpes gestationis</i>, is a rare autoimmune blistering disease specific to pregnancy, which usually presents in the second or third trimesters and, in 15%-25% of cases, during the immediate postpartum period.<sup>1</sup>Although the ethiopathogeny of PG is not fully clarified, most patients develop antibodies against a 180 kDa transmembrane hemidesmosomal protein (BP180; BPAG2; collagen XVII).<sup>2</sup> PG has a strong association with human leucocyte antigens DR3 and DR4.<sup>3</sup>We report a case of a 29-year-old female patient with PG successfully treated with intravenous immunoglobulin.