A child with localized vulval pemphigoid and IgG autoantibodies targeting the C-terminus of collagen XVII/BP180

Childhood Vulvar Mucous Membrane Pemphigoid. J Pediatr Adolesc Gynecol 2022;35:171-173. [PMID: 34740758 DOI: 10.1016/j.jpag.2021.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

BACKGROUND

Autoimmune bullous diseases in childhood are a diagnostic challenge.

CASE

We present the case of an 11-year-old girl with recurrent vulvar erosions since early childhood. She had been referred to a child abuse unit under the suspicion of sexual abuse. She responded well to dapsone and topical corticosteroids.

SUMMARY AND CONCLUSION

Our review focuses on previously reported cases of pemphigoid (bullous or mucous membrane) in childhood with exclusively genital involvement. We also summarize mucous membrane pemphigoid cases diagnosed during childhood. There seems to be a differentiated form of pemphigoid predominantly affecting girls with exclusively vulvar involvement and with good prognosis. Dermatologic evaluation and a skin biopsy with direct immunofluorescence are key to diagnosing a mucous membrane pemphigoid. Further antigenic studies are needed to nosologically classify the disease properly.

Localised childhood vulvar pemphigoid: a rare case study

In this case report we present a young patient with localised childhood vulvar pemphigoid. It is a rare variant of bullous pemphigoid with mostly a favourable prognosis and prompt response to potent topical corticosteroids. She presented with relapsing vulvar pain and lesions. Our case enlightens the recognition of this unusual subtype and the importance of performing a cutaneous biopsy.

Localized vulvar bullous pemphigoid of childhood: A rare cause of persistent vulvar erosions in children

Localized vulvar bullous pemphigoid of childhood is an excessively rare variant of bullous pemphigoid and affects almost exclusively young girls of 7-12 years of age. In contrast to adult-onset bullous pemphigoid, a prompt response to potent topical corticosteroids is observed in the majority of cases, with a favorable prognosis and rare relapses. We report the case of a 7-year-old girl who presented with this condition. Our case reinforces the recognition of this rare subtype of childhood bullous pemphigoid as a distinct entity and enlightens the importance of performing a cutaneous biopsy when clinically indicated.

[Vulvar inflammatory dermatoses]

Vulvar skin disease is a common reason for consultation. The vulva, like the rest of the skin, can be affected by numerous diseases of various etiologies, but its particular anatomic and physiologic characteristics create additional diagnostic and therapeutic difficulties. The study of vulvar disease is emerging as a new branch of dermatology. In this article, we examine the characteristics of the normal vulva, and perform a brief, structured review of vulvar inflammatory dermatoses, which comprise a heterogeneous group of diseases in which a broad, multidisciplinary approach is essential.

Number III Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is a sub-epithelial vesiculobullous disorder. It is now quite evident that a number of sub-epithelial vesiculobullous disorders may produce similar clinical pictures, and also that a range of variants of MMP exist, with antibodies directed against various hemidesmosomal components or components of the epithelial basement membrane. The term immune-mediated sub-epithelial blistering diseases (IMSEBD) has therefore been used. Immunological differences may account for the significant differences in their clinical presentation and responses to therapy, but unfortunately data on this are few. The diagnosis and management of IMSEBD on clinical grounds alone is impossible and a full history, general, and oral examination, and biopsy with immunostaining are now invariably required, sometimes supplemented with other investigations. No single treatment regimen reliably controls all these disorders, and it is not known if the specific subsets of MMP will respond to different drugs. Currently, apart from improving oral hygiene, immunomodulatory-especially immunosuppressive-therapy is typically used to control oral lesions. The present paper reviews pemphigoid, describing the present understanding of this fascinating clinical phenotype, summarising the increasing number of subsets with sometimes-different natural histories and immunological features, and outlining current clinical practice.

Vulvar cicatricial pemphigoid of childhood

We report a 9-year-old girl with a vulvar autoimmune bullous dermatosis. A diagnosis of localized bullous pemphigoid or cicatricial pemphigoid was made on the basis of immunohistologic data. Since the lesions were unresponsive to topical corticosteroids but healed completely on dapsone at a dosage of 1.5 mg/kg/day, we favor the diagnosis of vulvar cicatricial pemphigoid. Only two such cases have been reported thus far. The diagnostic criteria and therapeutic modalities are discussed.

Childhood bullous pemphigoid: a clinicopathologic study and review of the literature

Bullous pemphigoid (BP) is an acquired bullous disorder that predominantly affects the elderly. It is rare in children but when it occurs, there is considerable clinical and histologic overlap with other acquired or congenital blistering disorders. A definitive diagnosis of childhood BP requires direct immunofluorescence and, in some cases, characterization of the target antigen. Three cases of childhood BP are presented, with their histologic and immunofluorescence findings. The first was a 5-month-old male infant who presented with erythema and bullae of the palms and soles and was found to have linear deposition of IgG and C3 along the dermoepidermal junction on direct immunofluorescence (DIF). Histopathologic examination revealed a subepidermal blister containing eosinophils. Type IV collagen was demonstrated along the floor of the blister cavity by a direct immunoperoxidase technique. The second case was an 8-month-old female infant who presented with a blistering eruption of her palms and soles that then became widespread. Direct immunofluorescence showed linear IgG and C3 at the dermoepidermal junction, with laminin deposition at the base of the blister. The third case was a 7-year-old female with bullae and erosions on the vulva and vaginal mucosa. A subepidermal blister was seen on microscopic examination whereas immunofluorescence demonstrated linear IgG and C3 deposition at the basement membrane zone (BMZ). A literature review uncovered 50 cases of childhood BP confirmed by direct or indirect immunofluorescence, or both, and often with evidence of autoantibodies against either the 180 kD or the 230 kD human bullous pemphigoid antigens (BP180 or BP230). This review was used to delineate characteristics of childhood BP, including the newly proposed subtypes: infantile BP and childhood localized vulval BP. Infantile BP presents within the first year of life and is characterized by BP-like lesions on erythematous or normal acral skin. Localized vulval BP is a self-limited, nonscarring BP-like process that involves only the vulva. Both subtypes are normally self-limited and respond well to either topical or systemic steroids, if treatment is initiated before the disease becomes widespread.

Severity and phenotype of bullous pemphigoid relate to autoantibody profile against the NH2- and COOH-terminal regions of the BP180 ectodomain

Bullous pemphigoid, the most common autoimmune subepidermal bullous disorder, is associated with autoantibodies targeting antigenic sites clustered within the extracellular domain of BP180. To investigate epitope and subclass specificity of autoantibodies in bullous pemphigoid, we developed an enzyme-linked immunosorbent assay utilizing baculovirus-expressed recombinant forms of the NH2- and COOH-terminal regions of the extracellular domain of BP180 and examined sera obtained from patients with active bullous pemphigoid (n=116) and controls (n=100). Ninety-three (80%) and 54 (47%) of the 116 bullous pemphigoid sera recognized the NH2- and COOH-terminal regions, respectively, of the extracellular domain of BP180. Detailed analysis demonstrates that (i) this novel enzyme-linked immunosorbent assay is highly specific (98%) and sensitive (93%) as 108 of 116 bullous pemphigoid sera reacted with at least one of the baculovirus-derived recombinants, (ii) in active bullous pemphigoid, autoantibodies against the NH2-terminus of the extracellular domain of BP180 were predominantly of the IgG1 class, whereas a dual IgG1 and IgG4 response to this region was related to a more severe skin involvement, (iii) autoreactivity against both the NH2- and COOH-terminal regions was more frequently detected in patients with mucosal lesions, and (iv) levels of IgG (and IgG1) against the NH2-terminal, but not against the COOH-terminal portion of the extracellular domain of BP180, reflected disease severity indicating that autoantibodies against the NH2-terminus are critical in the pathogenesis of bullous pemphigoid. In conclusion, this novel enzyme-linked immunosorbent assay represents a highly sensitive and specific assay for rapid diagnosis of bullous pemphigoid and related disorders and may provide predictive parameters for the management of bullous pemphigoid patients.

The shed ectodomain of collagen XVII/BP180 is targeted by autoantibodies in different blistering skin diseases

Collagen XVII/BP180, an epidermal adhesion molecule, exists as a full-length transmembrane protein and as a soluble 120-kd ectodomain that is shed from the keratinocyte surface by furin-mediated proteolysis. Despite a number of studies on autoantibody targets in blistering skin diseases, it has remained unclear whether the physiologically shed ectodomain of collagen XVII plays a role as an autoantigen. Here we isolated the authentic, soluble form of human collagen XVII and showed that it is an autoantigen recognized by IgG and IgA autoantibodies in different blistering skin diseases and is, in some cases, the preferential target. The ectodomain was isolated from the epidermis, keratinocyte media, amniotic fluid, and pemphigoid blister fluid, and autoantibodies affinity-purified with this ectodomain bound to the proximal surface of the epidermis in normal skin but not in collagen XVII-deficient skin. The antibody reactivity was not dependent on the native conformation or the N-glycosylation of the soluble ectodomain, but was abolished by collagenase treatment. Sera of 81 patients with a clinically active blistering skin disease were reacted with full-length collagen XVII, the authentic soluble ectodomain, and recombinant fragments. In bullous and cicatricial pemphigoid, IgG reactive with full-length collagen XVII also recognized the soluble ectodomain. In linear IgA dermatosis and chronic bullous dermatosis of childhood, IgA targeted the soluble ectodomain more efficiently than the full-length protein. The use of recombinant fragments demonstrated that epitopes were present in several noncollagenous and collagenous subdomains of the molecule, and that a significant portion of the sera targeted Col15 domain, a hitherto unrecognized epitope region.