Ayako Komai

Usefulness of enzyme-linked immunosorbent assay using recombinant desmogleins 1 and 3 for serodiagnosis of pemphigus

Pemphigus is an autoimmune blistering disease with two major subtypes, pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Patients with pemphigus have circulating antidesmoglein (Dsg)1 and/or anti‐Dsg3 IgG autoantibodies. We have previously developed enzyme‐linked immunosorbent assays (ELISAs) using recombinant Dsg1 and Dsg3 expressed by baculovirus as a diagnostic tool for pemphigus. The purpose of this study was to evaluate the practical application of these ELISAs for clinical use with a large number of serum samples. We used 81 PV sera, 48 PF sera, 114 bullous pemphigoid (BP) sera, 124 collagen disease sera, nine sera of other non‐pemphigus bullous diseases and 179 normal control sera. A cut‐off value was determined by receiver‐operating‐characteristic plots. Forty‐seven of 48 PF sera (97.9%) were positive in the Dsg1 ELISA and 79 of 81 PV sera (97.5%) were positive in the Dsg3 ELISA, while only two (1.1%) and four (2.2%) of 179 normal sera were positive in Dsg1 and Dsg3 ELISAs, respectively. However, some disease control sera of BP and collagen diseases exceeded the cut‐off value. Introduction of a grey zone helped to decrease the number of these false‐positive sera. Furthermore, in three patients studied, the respective Dsg1 and Dsg3 ELISA scores showed parallel fluctuation with the disease activity along the time course. We conclude that Dsg1 and Dsg3 ELISAs provide a simple, sensitive and highly specific assay for the diagnosis of patients with PV and PF and that these ELISAs may be a valuable tool to monitor the disease activity. We also propose diagnostic criteria for pemphigus based on ELISA reactivity: if a serum is positive against Dsg3 it indicates a diagnosis of PV, regardless of reactivity against Dsg1; if a serum is negative for Dsg3 and positive for Dsg1, it indicates a diagnosis of PF.

The clinical transition between pemphigus foliaceus and pemphigus vulgaris correlates well with the changes in autoantibody profile assessed by an enzyme‐linked immunosorbent assay

Background There are a number of reports of pemphigus with clinical shifting between pemphigus foliaceus (PF) and pemphigus vulgaris (PV). On the other hand, a novel enzyme‐linked immunosorbent assay (ELISA) against recombinant baculoproteins of desmoglein 1 (Dsg1) (PF antigen) and Dsg3 (PV antigen) has been established and found to be extremely sensitive and specific.

Antidesmoglein autoantibodies in silicosis patients with no bullous diseases.

Background: Pemphigus is an autoimmune bullous disease characterized by the presence of antidesmoglein autoantibodies. However, the mechanism of its autoantibody production remains unknown. In previous reports, we have described rare cases of pemphigus and pemphigoid associated with silicosis. It is well known that during long-term silicosis, some autoimmune diseases, such as systemic sclerosis, systemic lupus erythematosus or rheumatoid arthritis, can occur. Objective: The aim of this study was to explore the presence of pemphigus or pemphigoid autoantibodies in silicosis patients without clinical bullous diseases or collagen diseases. Method: The presence of pemphigus antibodies was examined in 54 silicosis patients with no associated bullous diseases, using immunofluorescence, the enzyme-linked immunosorbent assay (ELISA) for desmoglein 1 and 3, and immunoblotting methods. In the antibody-positive cases, HLA genotyping of peripheral lymphocytes was performed with PCR-RFLP. Results: Seven out of the 54 patients were found to be positive for pemphigus antibodies and 1 for bullous pemphigoid by immunofluorescence. In addition, by ELISA, 6 patients were found to be positive against the desmoglein 1 antigen, 2 against the desmoglein 3 antigen and 2 against both desmoglein 1 and desmoglein 3. Conclusion: The results of the present study strongly suggest the occurrence of pemphigus and pemphigoid autoantibodies in patients with silicosis. It remains unclear whether such patients will develop an autoimmune bullous disease in the future. Accordingly, long-term follow-up of antibody-positive patients is required.

A case of anti-p200 pemphigoid clinically mimicking inflammatory epidermolysis bullosa acquisita.

SIR, Anti-p200 pemphigoid is a new disease entity, which was first described in 1996 by Hashimoto’s group. They described an unusual case with autoimmune subepidermal bullous lesions that clinically resembled bullous pemphigoid and a case with psoriasis vulgaris that developed extensive blister formation. Both the nonpsoriatic patient and the psoriatic patient were characterized by immunoglobulin (Ig)G autoantibodies against a novel 200-kDa lower lamina lucida component. To date, anti-p200 pemphigoid has been shown to present various clinical features. This new autoimmune bullous disease seems to be classified into three clinical forms: (i) coexistence with psoriasis, (ii) presenting the clinical features of vesicular pemphigoid, and (iii) presenting clinically atypical blistering features. In this report, we describe a new patient with anti-p200 pemphigoid clinically mimicking inflammatory epidermolysis bullosa acquisita (EBA). A 28-year-old Japanese male was referred to us because of numerous pruritic bullous skin lesions on the entire body of 2 weeks’ duration. Neither he nor his family had a past history of psoriasis. On physical examination, large, tense bullae and vesicles with erythema, and erosions similar to the skin lesions of bullous pemphigoid were found on his entire body (Fig. 1). The blisters tended to form in an annular arrangement resembling linear IgA bullous dermatosis or dermatitis herpetiformis. Oral and genital mucosae were not involved. Laboratory examinations revealed marked leukocytosis (21Æ8 · 10 L mm) and eosinophilia (37%). Because of the severe skin lesions, systemic prednisolone 100 mg daily was commenced; the dose was tapered down to 60 mg daily within 1 week. Because new blisters still appeared, the patient was treated with the combination therapy of prednisolone 60 mg and azathioprine 100 mg daily. Subsequently, no new bullae developed. The lesions healed, leaving mild scarring or milia formation. The prednisolone and azathioprine were gradually tapered down to 12Æ5 mg and 50 mg daily, respectively, and maintained at that dosage thereafter. Histology of lesional skin taken during the acute phase showed subepidermal blistering with abundant neutrophils, eosinophils and fibrin. Lymphocytes and eosinophils were found in the upper dermis. Direct immunofluorescence showed linear deposits of IgG and C3 at the dermo–epidermal junction. Indirect immunofluorescence using normal human skin sections as a substrate showed circulating IgG autoantibodies against the basement membrane zone (> 1 : 160), which were reactive exclusively with dermal side of 1 mol L NaCl-split human skin (> 1 : 40). Immunoblotting with epidermal and dermal extracts of normal human skin was performed using methods described elsewhere. The patient’s serum reacted with a 200-kDa protein of dermal extract (Fig. 2). The 290-kDa EBA antigen was not detected. Autoimmune subepidermal blistering disorders include bullous pemphigoid, pemphigoid gestationis, lichen planus pemphigoides, linear IgA bullous dermatosis, cicatricial pemphigoid, anti-p200 pemphigoid, anti-p105 pemphigoid, autoanti-p450 pemphigoid, EBA and bullous systemic lupus erythematosus. Anti-p200 pemphigoid has been identified as a new distinct entity and named by Zillikens et al. They identified IgG autoantibodies against a novel 200-kDa lower lamina lucida target antigen in nonpsoriatic bullous disease and a patient with coexisting bullous skin disease and psoriasis. They also described a predominance of neutrophils in the dermal infiltrate in the histology. Several other basement membrane zone components have been suggested as target antigens of autoimmune bullous dermatoses; however, the 200-kDa autoantigen seems to be different from laminins 1, 5 and 6, and type VII collagen. It has not been clearly suggested

IgG/IgA pemphigus with IgG and IgA antidesmoglein 1 antibodies detected by enzyme-linked immunosorbent assay.

Summary Pemphigus is an autoimmune mucocutaneous bullous disease characterized by autoantibodies against the cell surfaces of epidermal keratinocytes. Six cases with deposition of both IgG and IgA on keratinocyte cell surfaces have been reported in the recent literature. We provisionally termed these cases IgG/IgA pemphigus. We describe a 42‐year‐old Japanese woman with clinical and histopathological features resembling herpetiform pemphigus who demonstrated in vivo bound and circulating anticell surface autoantibodies of both IgG and IgA classes on immunofluorescence examination. Enzyme‐linked immunosorbent assay using baculovirus‐expressed recombinant desmoglein (Dsg) 1 and Dsg 3 showed that both IgG and IgA antibodies reacted with Dsg1. The reactivity was completely adsorbed with preincubation of serum with Dsg1 baculoprotein, further confirming the exclusive reactivity of both IgG and IgA antibodies with Dsg1. This is the second case of IgG/IgA pemphigus in which the human target antigens for both IgG and IgA antibodies have been unequivocally identified. This study provides further evidence that IgG/IgA pemphigus is a distinct disease entity.

Pemphigus foliaceus with prominent neutrophilic pustules.

We describe four patients with generalized scaly and pustular skin lesions showing extensive neutrophilic infiltration in the subcorneal region of the epidermis. Immunofluorescence, immunoblot and enzyme‐linked immunosorbent assay analyses detected IgG antibodies reacting exclusively with desmoglein 1, the pemphigus foliaceus antigen. This study indicates that pemphigus foliaceus may show prominent neutrophilic pustular skin lesions.

A Case of Nonscarring Subepidermal Blistering Disease Associated with Autoantibodies Reactive with Both Type VII Collagen and Laminin 5

A 35-year-old Japanese woman had recurrent, pruritic, vesicular lesions on the face, neck and upper back as well as erosive lesions of the oral cavity and genitalia. The skin and mucosal lesions healed without scarring upon the systemic administration of corticosteroid and azathioprine. Direct immunofluorescence revealed linear deposits of IgG, IgA and C3 at the cutaneous basement membrane zone. Indirect immunofluorescence on 1 M NaCl-split human skin sections demonstrated that the patient’s IgG antibodies reacted with the dermal side of the split, while IgA antibodies weakly reacted with the epidermal side. By immunoblot analyses, the patient’s serum reacted with the NC1 domain of type VII collagen as well as both the α3- and β3-subunits of laminin 5. We regarded our case as a nonscarring subepidermal blistering disease with autoantibodies to both type VII collagen and two different subunits of laminin 5. Such a case has not been previously reported.

Pemphigoid nodularis with IgA autoantibodies against the intracellular domain of desmoglein 1.

Pemphigoid nodularis is a rare variant of bullous pemphigoid. We report a 49‐year‐old Japanese male with clinical and histopathological features of pemphigoid nodularis including circulating and in vivo‐bound IgG antibasement membrane zone antibodies and IgA anti‐intercellular antibodies. Although the precise molecular target of the IgG autoantibodies could not be determined, intriguingly, immunoblotting showed that the IgA in the patient’s serum reacted with the intracellular domain of desmoglein 1, the target antigen in cases of pemphigus foliaceus. However, the IgA did not react with the extracellular domain of desmoglein 1 in sensitive enzyme‐linked immunosorbent assay studies using a baculovirus system. These results suggest therefore that these IgA antibodies may possibly not be pathogenic. The mechanism for the production of different autoantibodies is unknown, but this case provides further illustration of the atypical skin immunoreactants often seen in this unusual subtype of bullous pemphigoid.

Bullous Pemphigoid Associated with Silicosis

Bullous pemphigoid (BP) has never before been reported to associate with silicosis, although there are numerous reports of silicosis accompanied by different autoimmune diseases, such as systemic sclerosis, systemic lupus erythematosus, dermatomyositis or rheumatoid arthritis. We report on a 63-year-old Japanese patient with silicosis who developed tensed bullae, erosions and macular pigmentation on the trunk and extremities. Indirect immunofluorescence revealed anti-basement-membrane-zone antibodies; immunoblotting analysis demonstrated that the patient’s serum reacted with the 230-kD BP antigen in the epidermal extracts, as well as a recombinant protein of the NC16a domain of 180-kD BP antigen. Clinical symptoms improved after treatment with systemic steroids. To the best of our knowledge, this is the first reported case of BP associated with silicosis.

Case of coexisting psoriatic arthritis and bullous pemphigoid improved by etanercept

lide acetate is a synthetic analog of GnRH and indicated in the treatment of premenopausal breast cancer. Injectable depot formulations deliver the drug over a period of 3 months. Larmore and Klein showed that estrogen, progesterone, and luteinizing and follicle-stimulating hormone levels are significantly suppressed as at menopause by 3 weeks after the initial dose and start to recover in 6 weeks after stopping depot injections. In this case, the timeline of precipitation and exacerbation of psoriatic lesions are coincident with sex hormone level changes in the patient. Movad et al. have reported psoriatic worsening at menopause. Also, it was suggested that elevated levels of progesterone and estrogen have a role in improvement of T-helper 1-mediated autoimmune diseases. In the present case, suppressed levels of hormones or ratio differences between progesterone and estrogen during leuprolide acetate treatment might have been responsible for psoriatic lesions. To conclude, the case presented is the first report of precipitation and/or exacerbation of psoriasis due to leuprolide acetate and supports the view that sex hormone level changes influence the precipitation and exacerbation of psoriasis. The chronological association between application of leuprolide acetate and severity of psoriatic lesions is documented in this case. The possible psoriasiform side-effects of drugs should be considered in hormonal therapy.