Unique immunobullous disease in a child with a predominantly IgA response to three desmosomal proteins

Anti-Desmocollin Autoantibodies in Autoimmune Blistering Diseases

The presence of anti-desmocollin (Dsc) antibodies is rarely described in autoimmune blistering diseases patients. Moreover, several clinical phenotypes of pemphigus may be associated with these antibodies. In this review we analyze clinicopathological, immunologic and outcome features of anti-Dsc autoimmune blistering diseases patients, to improve their diagnosis and management. We conducted a systematic search of PubMed and Embase (1990-present) for studies reporting cases of autoimmune blistering diseases with anti-Dsc antibodies. We classified the selected patients as patients with exclusively anti-Dsc autoantibodies, and patients with anti-Dsc and other autoantibodies. Of 93 cases with anti-Dsc autoantibodies included, 38 (41%) had exclusively these antibodies. Only 18% of patients presented with the typical clinicopathological phenotype of pemphigus vulgaris or pemphigus foliaceous. Mucosal involvement was seen in approximately half of the patients. Up to 18% of cases were associated with neoplasms. Acantholysis was described in 54% of cases with histopathological information. Treatments and outcomes vary in the different clinical phenotypes. The presence of anti-Dsc antibodies must be suspected mainly in those patients with either atypical pemphigus, in special with clinical pustules, or in cases showing intraepithelial or dermal neutrophilic/eosinophilic infiltrate on histological examination and dual pattern by direct immunofluorescence examination.

IgA Pemphigus in a Child – a Case Report

IgA pemphigus (IGAP) is a rare autoimmune bullous disease characterized by IgA deposits on keratinocyte cell surfaces. The IGAP is classified into: 1) subcorneal pustular dermatosis (SPD) type, and 2) intraepidermal neutrophilic (IEN) IgA dermatosis type. So far, only 9 children with IGAP have been described in the literature, of whom only 3 with SPD type. We report a 3-year-old boy with SPD type of IGAP. Clinically, he presented with pruritic vesicles, pustules and erosions on the face, trunk, groin area, and extremities. Histopathology showed subcorneal pustules containing a few acantholytic cells. Direct immunofluorescence (DIF) test of Tzanck smear showed intercellular IgA deposits on the surface of the groups of epidermal cells. Oral dapsone and prednisone induced remission after two weeks; the treatment was discontinued 11 months later, and complete remission was achieved during 19 months without any treatment. Direct immunofluorescence of Tzanck smear is a simple, sensitive, rapid and non-aggressive test, very suitable for the diagnosis of IGAP in children.

Non-classical forms of pemphigus: pemphigus herpetiformis, IgA pemphigus, paraneoplastic pemphigus and IgG/IgA pemphigus

The pemphigus group comprises the autoimmune intraepidermal blistering diseases classically divided into two major types: pemphigus vulgaris and pemphigus foliaceous. Pemphigus herpetiformis, IgA pemphigus, paraneoplastic pemphigus and IgG/IgA pemphigus are rarer forms that present some clinical, histological and immunopathological characteristics that are different from the classical types. These are reviewed in this article. Future research may help definitively to locate the position of these forms in the pemphigus group, especially with regard to pemphigus herpetiformis and the IgG/ IgA pemphigus.

The expanding spectrum of IgA pemphigus: a case report and review of the literature

IgA pemphigus (IGAP) is a rare, distinct variant of pemphigus, currently classified, depending upon the histological features, immunofluorescence staining pattern and autoantibody profile, into two types: subcorneal pustular dermatosis (SPD) and intraepidermal neutrophilic IgA dermatosis. In a patient with a widespread blistering disease of the skin resembling SPD-type IGAP, we demonstrate the coexistence of IgA reactivity to both epidermal (desmocollins 2 and 3) and basement membrane-associated (BP180) proteins, suggesting the coexistence of atypical IGAP and linear IgA bullous dermatosis, respectively. This case, together with 20 previous reports of atypical IGAP, underscores the limitations of current classification schemes. Therefore, we suggest reclassifying these cases under the general term 'IGAP spectrum'.

IgG/IgA pemphigus

IgG/IgA pemphigus has recently been described in the literature as an overlap of pemphigus vulgaris or pemphigus foliaceus with IgA pemphigus. There has also been some postulation that this IgG/IgA pemphigus may be associated with internal malignancy as well. Our case demonstrates the unique clinical, histopathological, and direct immunofluorescence findings of IgG/IgA pemphigus and further highlights the possibility of association of this disease with internal malignancy.

Acquired palmoplantar keratoderma and immunobullous disease associated with antibodies to desmocollin 3

We present a case of immunobullous disease with an impressive acquired palmoplantar keratoderma (PPK) and unique antigenicity. The palms of the patient showed hyperkeratotic ridges with a tripe pattern that decreased with the amelioration of the immunobullous condition. The histopathology of perilesional skin (blister) demonstrated eosinophilic spongiosis and suprabasal blistering as in pemphigus vulgaris. In palmar skin, acantholysis, intraepidermal pustules, papillomatosis and marked hyperkeratosis were observed. Direct and indirect immunofluorescence displayed intraepidermal intercellular IgG staining as well as linear IgG staining along the epidermal basement membrane zone. Immunochemical assays revealed IgG antibodies to the desmosomal protein desmocollin 3 and to the hemidesmosomal proteins BP230 and LAD-1. Affinity-purified antidesmocollin 3 serum IgG bound to monkey oesophagus in the typical pemphigus pattern. Desmocollins are transmembrane proteins of the desmosome. Desmosome diseases may cause hereditary PPK. In our patient with acquired PPK, we hypothesize that the antibodies to desmocollin 3 were, apart from their role in eliciting the pemphigus-like blistering disease, also implicated in the pathogenesis of the PPK.

IgA pemphigus--occurrence of anti-desmocollin 1 and anti-desmoglein 1 antibody reactivity in an individual patient

BACKGROUND

IgA pemphigus is a rare pustular autoimmune disease with exclusive IgA anti-keratinocyte cell surface antibody reactivity. Two subtypes have been discerned: in the subcorneal pustular dermatosis type, desmocollin 1 has been identified as a targeted autoantigen, while in few cases of the intraepidermal neutrophilic type, IgA anti-desmoglein 1 or IgA anti-desmoglein 3 reactivity has been demonstrated.

PATIENTS AND METHODS

A 48-year-old white male presented with generalized large confluent pustules. Skin pathology was assessed by histology and direct immunofluorescence analysis. IgG/IgA autoantibodies against desmoglein 1/3 and desmocollin 1 were measured by ELISA and indirect immunofluorescence using desmocollin 1 cDNA-transfected COS7 cells, respectively.

RESULTS

Histopathology revealed subcorneal pustules and direct immunofluorescence microscopy exclusively showed in vivo bound IgA with an intercellular pattern in the epidermis. Desmocollin 1 was identified as a target of IgA autoantibodies by indirect immunofluorescence microscopy utilizing desmocollin 1 cDNA-transfected COS7 cells. In addition, IgA anti-desmoglein 1 reactivity was demonstrated by ELISA. Neither IgA anti-desmoglein 3 nor IgG anti-desmoglein 1/3 autoantibodies were present.

CONCLUSIONS

Both desmocollin 1 and desmoglein 1 were autoantigens in this patient with IgA pemphigus and a distinct clinical presentation. To our knowledge, this is the first IgA pemphigus case with dual autoantibody reactivity.

Atypical IgA/IgG pemphigus involving the skin, oral mucosa, and colon in a child: a novel variant of IgA pemphigus?

Immune-mediated blistering diseases are rare in childhood, with the subset of IgA pemphigus being extremely uncommon. A child with a bullous disorder of the oral mucosa, skin, and colon is reported because of the unusual nature of the clinical and laboratory findings. Immunofluorescence studies demonstrated both intercellular epidermal and basement membrane zone deposition of IgA and IgG antibodies, as well as intercellular colonic deposition of IgA antibodies. IgA and IgG ELISA tests were positive for desmoglein 3 as the intercellular epidermal antigen. The generation of multiple antibodies against several potential antigenic targets suggests epitope spreading may play a role in this disease. We believe this represents a novel variant of IgA pemphigus.

The detection of IgG and IgA autoantibodies to desmocollins 1-3 by enzyme-linked immunosorbent assays using baculovirus-expressed proteins, in atypical pemphigus but not in typical pemphigus

BACKGROUND

We have shown previously that human desmocollin (Dsc) 1 is recognized by IgA autoantibodies of subcorneal pustular dermatosis (SPD) type IgA pemphigus. However, the presence of IgG anti-Dsc autoantibodies is still controversial, and antibodies to Dsc2 and Dsc3 have not been clearly identified.

OBJECTIVES

To investigate this by producing recombinant proteins consisting of the entire extracellular domains of human Dsc1, 2 and 3 in baculovirus, and to use them to establish an enzyme-linked immunosorbent assay (ELISA).

METHODS

By this ELISA, we examined in total 165 cases of various types of autoimmune bullous diseases, as well as 23 normal controls.

RESULTS

None of 45 sera of classical pemphigus showed either IgG or IgA antibodies to any Dsc. In contrast, one atypical pemphigus serum showed both IgG and IgA antibodies to Dsc1, which were adsorbed by incubation with Dsc1 baculoprotein. Furthermore, this ELISA detected both IgA and IgG anti-Dsc3 antibodies in one atypical case, and IgA antibodies to both Dsc2 and Dsc3 in another. This reactivity was confirmed by positive IgA immunofluorescence with Dsc2 and Dsc3 expressed on COS-7 cells. These results show that both IgG and IgA autoantibodies against all of Dsc1-3 are present in the sera of particular cases of nonclassical pemphigus, except for IgG antibodies to Dsc2, but that they are not detected in classical pemphigus. Unexpectedly, although IgA antibodies of all of eight SPD type IgA pemphigus sera reacted with Dsc1 expressed on COS-7 cells, only one serum was positive in Dsc1 ELISA for IgA.

CONCLUSIONS

This result indicates either that Dscs expressed by baculovirus may not adopt the correct conformation or that Dscs may need association with other molecules to express all the epitopes for autoantibodies.

Exacerbation of paraneoplastic pemphigus by cyclophosphamide treatment: detection of novel autoantigens and bronchial autoantibodies

A 48-year-old woman with a follicular, grade III, B-cell non-Hodgkin lymphoma developed clinical, immunopathological and histological features of paraneoplastic pemphigus. The skin symptoms flared after repeated cyclophosphamide infusions, and were preceded and accompanied by a progressive dyspnoea. Although the skin and oral mucosal disease went into remission with high-dose steroid and intravenous immunoglobulin therapy, the severe alveolitis led to death. Immunoblotting of human epidermal extracts showed that the patient's serum IgG reacted with the 210-kDa envoplakin, 190-kDa periplakin, as well as the recombinant protein of BP180 NC16a domain. IgG and IgA enzyme-linked immunosorbent assays for desmoglein 3 were positive, too. Indirect immunofluorescence studies on COS-7 cells transiently transfected with desmocollin 1-3 cDNAs showed that the patient's serum contained IgG and IgA antibodies to desmocollin 3 as well as IgG antibodies to desmocollin 2. Serum IgG and IgA strongly stained rat bronchial epithelium, corresponding to autoantibodies possibly involved in the pathomechanism of the severe lung disease. In this case, which was characterized by a mixed IgA/IgG antibody panel displaying known and unique antigenicity, the serious episodes of paraneoplastic pemphigus flared after cyclophosphamide treatment.

Paraneoplastic pemphigus with bronchiolitis obliterans in a child

Paraneoplastic pemphigus (PNP) is a rare blistering autoimmune disease associated with an underlying neoplasm, mucous membrane erosions, and occasionally bronchiolitis obliterans. Most cases have been reported in adults and the number of childhood cases in the current literature is limited. We describe a young patient with PNP who was initially misdiagnosed as having recurrent Stevens-Johnson syndrome. This patient had an underlying inflammatory myofibroblastic tumor and subsequently developed fatal progressive bronchiolitis obliterans.

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

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.