Clinical and immunological profiles of 25 patients with pemphigoid gestationis

Background: Systematic study of pemphigoid gestationis (PG) has not been performed owing to its rarity.

Objectives: To perform clinical and immunological analyses of 25 patients with PG.

Methods: In addition to clinical and histopathological assessments, we performed immunofluorescence (IF), immunoblotting (IB) and enzyme-linked immunosorbent assays (ELISAs).

Results: PG developed preferentially during the second or third trimester of pregnancy, with a mean age at onset of 30·5 years. Histopathology showed subepidermal blisters less frequently. Direct IF showed C3 deposition in the basement membrane zone (BMZ) in all patients, with rare reactivity with keratinocyte cell surfaces. Ninety-two per cent of patients showed circulating IgG anti-BMZ autoantibodies during indirect IF of either normal or 1 mol L(-1) NaCl-split skin. Complement IF revealed linear C3 reactivity with the BMZ of normal skin in 68% of patients, and all patients had C3 reactivity on the epidermal side of 1 mol L(-1) NaCl-split skin. IB and ELISA of the NC16a domain of BP180 recombinant protein was positive in 96% and 92% of patients, respectively, while only four patients had a positive ELISA for BP230. In IB tests, 28% of patients reacted with the C-terminal domain of BP180 and 20% reacted with leucocyte adhesion deficiency-1 protein. Multigravidae developed PG during a significantly (P < 0·01) earlier stage (21·1 weeks) of pregnancy than primigravidae (31·3 weeks).

Conclusions: IB and ELISA of the NC16a domain of BP180 were shown to be sensitive and diagnostic methods in PG. Patients with PG rarely reacted with BP230, suggesting a different pathogenesis between PG and bullous pemphigoid. Multigravidae developed PG skin lesions significantly earlier in pregnancy than primigravidae.