Usefulness of BP180 NC16a Enzyme-Linked Immunosorbent Assay in the Serodiagnosis of Pemphigoid Gestationis and in Differentiating Between Pemphigoid Gestationis and Pruritic Urticarial Papules and Plaques of Pregnancy

Abstract

Background: Pemphigoid gestationis (PG) is a rare pregnancy-associated subepidermal immunobullous disease that targets hemidesmosomal proteins, particularly BP180. Clinically, PG can resemble the eruption known as polymorphic urticarial papules and plaques of pregnancy (PUPPP), and accurate differentiation between these 2 pruritic pregnancy dermatoses has important implications for fetal and maternal prognoses. Results of epitope mapping studies show that IgG autoantibodies in up to 90% of PG serum samples target the well-defined membrane-proximal NC16a domain of BP180.Objective: To examine the usefulness of a commercially available NC16a domain enzyme-linked immunosorbent assay in the serodiagnosis of PG and in the differentiation of PG from PUPPP.Participants: A total of 412 women consisting of pre-treatment patients with PG (n=82), patients with PUPPP (n=164), and age-and sex-matched controls (n=166).Methods: All serum samples were assayed in duplicate. Receiver operating characteristic analyses were performed to determine a cutoff value for the diagnosis of PG and for differentiation from PUPPP and controls.Results: A cutoff value of 10 enzyme-linked immunosorbent assay units was associated with specificity and sensitivity of 96%. Conclusions:The NC16a enzyme-linked immunosorbent assay is highly sensitive and highly specific in differentiating PG from PUPPP, and it is potentially a valuable tool in the serodiagnosis of PG.

Enzyme‐linked immunosorbent assay (ELISA) and indirect immunofluorescence testing in a bullous pemphigoid and pemphigoid gestationis

“…Previous studies have emphasized the usefulness of this ELISA in distinguishing PG from pruritic urticarial papules and plaques of pregnancy. 20 ELISA was negative in our patient with probable enalaprilinduced BP. IIF testing of her serum was positive in high titer (at least 1 : 320) and DIF showed IgG deposition on the epidermal and dermal side of salt-split skin, suggesting that patients with drug-induced BP may have antibodies against other epitopes of BP180, other BP antigens such as BP 230, or against antigen(s) located in the lamina lucida.…”

The significance of preclinical anti-BP180 autoantibodies

“…showed that 14 (4.15%) of 337 unaffected subject sera were positive by BP180 NC16A ELISA, and the mean titer of ELISA-positive sera was 16.2 ± 6.3 (mean ± standard deviation, SD, cutoff value <9.0) ( 39 ). According to other studies, the mean titers of normal subjects by BP180 NC16A ELISA were 2.1–2.5 ( 35 , 37 , 43 ). The mean titer of ELISA-positive sera was higher in the Wieland et al.…”

Pemphigoid Gestationis

“…She was started on high-dose steroid therapy with improvement in the rash. ELISA (an enzyme-linked immunosorbent assay that measures autoantibody reactions to the bullous pemphigoid antigen [BP180] with 96% sensitivity and specificity for PG) showed our patient’s values elevated at 30.59 units (reference range less than 9.0 units) 1. By the 35th week of pregnancy, her rash had resolved while on a stringent steroid regimen.…”