Our results confirmed that BP180 is a major autoantigen targeted by the sera of patients with MMP. The disease-prevalent HLA class II alleles and humoral autoimmune response against the particular subsets of antigenic epitope(s) within BP180 ectodomain may contribute to the clinicopathological significance and disease severity of MMP.

Our results suggest that the BP180-NC16a ELISA is a useful tool for the detection of pathogenic anti-BP180 IgG autoantibodies at the initial disease stage of BP. Because it is not only highly sensitive and specific, but is also easy to perform, is objective, and semiquantitative, the ELISA may provide valuable information for the accurate and reliable serodiagnosis of BP.

Collagen XVII, or BP180, is a collagenous transmembrane protein and a structural component of the dermoepidermal anchoring complex. Molecular studies reveal that it has a globular cytosolic amino-terminal domain and flexible-rod extracellular carboxyterminal domain. The extracellular portion of collagen XVII is constitutively shed from the cell surface by ADAMs (proteinases that contain adhesive and metalloprotease domains). Cell biological analyses suggest that collagen XVII functions as a cell-matrix adhesion molecule through stabilization of the hemidesmosome complex. This concept is supported by investigations into human diseases of the dermoepidermal junction, in which collagen XVII is either genetically defective or absent (as in some forms of nonlethal junctional epidermolysis bullosa). Autoantibodies against collagen XVII (BP180) are seen in bullous pemphigoid, pemphigoid gestationis, mucous membrane pemphigoid, linear IgA disease, lichen planus pemphigoides and pemphigoid nodularis. In vivo and in vitro studies provide evidence for a pathogenic role of these autoantibodies, and suggest that the serum level and epitope specificity of these antibodies influences disease severity and phenotype. This review summarizes the structural and biological features of collagen XVII and its role in diseases of the basement membrane zone.

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.

We report a patient with chronic lymphocytic leukaemia who developed paraneoplastic pemphigus (PNP) soon after the initiation of fludarabine therapy. He presented with severe oral and cutaneous erosions. Initially, he had high titres of circulating autoantibodies as detected by indirect immunofluorescence (IF) on multiple epithelial substrates (normal human skin, monkey oesophagus, and rat bladder) and by desmoglein 1 and 3 enzyme-linked immunosorbent assays (ELISAs). His oral erosions have subsequently progressed into unusual hyperplastic papillomatous lesions affecting the inner aspect of lips and buccal mucosae, histologically consistent with pemphigus vegetans. Desmoglein 1 antibodies and IF on rat bladder substrate have become negative after 18 months of therapy. Several agents had been initiated to bring the disease under control originally, but a partial remission was achieved and maintained with mycophenolate mofetil and low-dose prednisolone.

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Lichen planus pemphigoides (LPP) and pemphigoid nodularis are rare clinical variants of bullous pemphigoid (BP), which are characterized by histological findings of lichen planus (LP) and nodular prurigo, respectively, and the finding of linear deposits of IgG and/or C3 at the basement membrane zone in perilesional skin. In both cases bullae may arise at the site of pre-existing LP-like or nodular prurigo-like eruptions, and clinically uninvolved skin. The disease spectrum of LPP and pemphigoid nodularis differs from that of classical BP phenotype, and their presentations are often indolent. LPP may predominantly affect a younger age group and is responsive to standard treatments used in acquired autoimmune bullous diseases, while pemphigoid nodularis is more common in elderly women and is relatively resistant to therapy. We describe a patient who had LPP for nearly two decades and subsequently developed a nodular eruption with a concurrently detected antibullous pemphigoid antigen 2 (BP180) autoantibody. His overall clinicopathological features were indicative of LPP evolving into another BP variant, pemphigoid nodularis.

Intravascular large B-cell lymphoma (IVL) is a rare systemic disease characterized by clonal proliferation of neoplastic lymphoid cells within the capillary lumina of small blood vessels. The most common sites of involvement are cerebrovascular or sinusoid areas, resulting in a wide variety of neurologic deficits. Herein we describe a case of IVL that presented with multiple internal and external organ involvements, including the skin, bilateral kidneys, and lung, and with an aggressive clinical course. The confirmative diagnosis was based on the microscopic findings of the skin lesion with a B-cell immunophenotype. The patient suffered from repeated severe dyspnea, hypoxemia, and high-grade fever with a simultaneous increase in serum lactate dehydrogenase and soluble IL-2 receptor levels. These manifestations responded dramatically to intravenous injection of corticosteroid (500 mg/day for 3 days). Despite various clinical presentations, no neurological abnormality was observed until the patient died 12 months after the initial combination chemotherapy.