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.
Pemphigoid gestationis autoantigen, transmembrane collagen XVII, promotes the migration of cytotrophoblastic cells of placenta and is a structural component of fetal membranes.
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.
Autoantibodies against collagen XVII (BP180) are seen in bullous pemphigoid, pemphigoid gestationis, mucous membrane pemphigoid, linear IgA disease, lichen planus pemphigoides and pemphigoid nodularis.
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.
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.
These results indicate that the BP180 antigen recognized by BP and herpes gestationis autoantibodies is a unique hemidesmosomal polypeptide, distinguishable from the BP240 antigen.