Upregulation of P-cadherin expression in the lesional skin of pemphigus, Hailey-Hailey disease and Darier's disease

BACKGROUND

Autoimmune blistering diseases, pemphigus vulgaris (PV) and pemphigus foliaceus (PF), are known to be caused by binding of autoantibodies to the desmosomal cadherins, desmoglein 3 and desmoglein 1, respectively. Recently, mutations in the genes coding Ca2+ pumps leads to inherited blistering diseases, Hailey-Hailey disease (HHD) and Darier's disease (DD). Cadherins are a family of Ca2+-dependent cell adhesion molecules and P-cadherin is one of the major cadherins expressed in the epidermis. Although detailed mechanisms of acantholysis of these blistering diseases have not been fully clarified, abnormal expression of cadherins caused by altered Ca2+ concentration due to the binding of autoantibodies to cell surface or by mutations in Ca2+ pumps is suggested to be involved in mechanisms of acantholysis of these autoimmune and inherited blistering diseases. The purpose of the present study was to determine whether altered P-cadherin expression is present in these diseases.

METHOD

Distribution patterns of P-cadherin in skin specimens from patients with PV (n=2), PF (n=2), HHD (n=4) and DD (n=3), were examined with confocal laser scanning microscopy using two anti-P-cadherin antibodies, 6A9 and NCC-CAD-299.

RESULTS

In normal control skin, P-cadherin expression was restricted to the basal layer. In contrast, positive immunostaining of P-cadherin was observed not only in the basal cells, but also in the suprabasal cells in lesional skin of all the acantholytic diseases.

CONCLUSIONS

The present results clearly demonstrated that upregulation of P-cadherin expression occurs in the acantholysis in all the four blistering diseases PV, PF, HHD and DD. Upregulation of P-cadherin may be involved in the pathomechanism of both the autoimmune blistering diseases and the inherited blistering diseases.

A case of generalized Hailey-Hailey disease with fatal liver injury

We report a case of a 59-year-old man with a severe generalized form of Hailey-Hailey disease that was complicated by fatal liver injury. Erosive lesions were first noted in the axillary and perianal regions at 15 year of age, and Hailey-Hailey disease was diagnosed based on the clinical features and histologic findings in skin biopsy specimens. The patient was treated with at first topical steroids and later a low dose of a corticosteroid, but the skin lesions gradually became generalized. At 45 years of age liver dysfunction was detected after azathioprine and vinblastine treatment for the generalized skin lesions. The liver injury gradually progressed and finally the patient died. The gene responsible for Hailey-Hailey disease was recently identified as ATP2C1, and it encodes a Ca(2+)-transport ATPase with broad expression, including in skin and liver. This finding suggests that mutation of the ATP2C1 gene may give rise to an extracutaneous phenotype, such as the liver dysfunction observed in severe cases, including our own. Further accumulation of cases is necessary to determine whether this is true.

Dissociation of intra- and extracellular domains of desmosomal cadherins and E-cadherin in Hailey-Hailey disease and Darier's disease

In order to clarify the pathomechanism of acantholysis in Hailey-Hailey disease (HHD) and Darier's disease (DD), the distribution of desmosomal and adherens junction-associated proteins was studied in the skin of patients with HHD (n = 4) and DD (n = 3). Domain-specific antibodies were used to determine the cellular localization of the desmosomal transmembrane glycoproteins (desmogleins 1 and 3 and desmocollin), desmosomal plaque proteins (desmoplakin, plakophilin and plakoglobin) and adherens junction-associated proteins (E-cadherin, alpha-catenin, beta-catenin and actin). A significant difference in staining patterns between intra- and extracellular domains of desmosomal cadherins and E-cadherin was demonstrated in acantholytic cells in both HHD and DD, but not in those in pemphigus vulgaris and pemphigus foliaceus samples used as controls. In acantholytic cells in HHD and DD, antibodies against attachment plaque proteins and intracellular epitopes of desmosomal cadherins exhibited diffuse cytoplasmic staining, whereas markedly reduced staining was observed with antibodies against extracellular epitopes of the desmogleins. Similarly, membrane staining of an intracellular epitope of E-cadherin was preserved, while immunoreactivity of an extracellular epitope of E-cadherin was destroyed. While the DD gene has been identified as ATP2A2, the gene for HHD has not been clarified. The dissociation of intra- and extracellular domains of desmosomal cadherin and E-cadherin is characteristic of the acantholytic cells in HHD and DD, and not of pemphigus. This common phenomenon in HHD and DD might be closely related to the pathophysiological mechanisms in both conditions.

Characterization of the amyloid fibril from primary localized cutaneous nodular amyloidosis associated with Sjögren's syndrome

BACKGROUND

Primary localized cutaneous nodular amyloidosis (PLCNA) is a rare disease, and its pathogenesis of amyloid deposition is still unknown.

OBJECTIVE

The purpose of this study was to know the origin of amyloid in PLCNA.

METHODS

Water-soluble amyloid fibrils were isolated from the skin and resolved on SDS-PAGE, then subjected to immunoblot analysis.

RESULTS

The major amyloid fibril protein was a 29-kD peptide which reacted with both anti-lambda- and anti-kappa-light-chain antibodies.

CONCLUSION

Amyloids in this particular case of PLCNA are derived from the polyclonal immunoglobulin light chain and some cases of PLCNA could be reactive diseases rather than neoplastic ones.