Comparative expression of bullous pemphigoid antigens in normal human epidermis and cultured keratinocytes

ACE inhibitors can induce circulating antibodies directed to antigens of the superficial epidermal cells

Drug-induced pemphigus has been reported in patients receiving angiotensin-converting enzyme inhibitors. The aim of this work was to study a group of hypertensive patients without skin diseases treated with angiotensin-converting enzyme (ACE) Inhibitors (I), to verify the presence of serum circulating anti-antibodies. The indirect immunofluorescence showed that 33 sera (52.38%) presented autoantibodies directed to an antigen of the cytoplasm of the superficial epidermal keratinocytes. Two of the 33 positive sera had antibodies to Dsg1 and/or 3 in ELISA. Immunoblot analyses were negative. All the 48 control sera were found to have no circulating antibodies using the three assays. Our results would confirm that ACEI drugs may trigger the production of circulating autoantibodies also in patients without clinical manifestations of pemphigus.

[Linear IgA bullous dermatosis in children with autoantibodies against 180 kDa pemphigoid antigen]

BACKGROUND

Linear IgA bullous dermatosis (LABD) is an autoimmune subepidermal blistering disease defined on the basis of direct immunofluorescence findings.

CASE REPORT

An 18 month-old girl suffering from LABD was studied by indirect immunofluorescence on salt-split skin and by Western blot in an attempt to characterize the involved autoantigen. Direct immunofluorescence showed an exclusive linear IgA deposit at the dermal-epidermal junction. Indirect immunofluorescence revealed circulating autoantibodies that reacted with the epidermal side of salt-split skin; they reacted by Western blot with a 180 kDa epidermal antigen, as in bullous pemphigoid.

CONCLUSION

This dermatosis fulfilling the clinical features and direct immunofluorescence criteria for childhood LABD seems to represent a case of IgA bullous pemphigoid. It further underscores the nosologic heterogeneity of LABD, which probably includes, apart from bullous pemphigoid, epidermolysis bullosa acquisita and cicatricial pemphigoid.

Linear IgA bullous dermatosis with autoantibodies to a 290 kd antigen of anchoring fibrils

We describe a patient with a papulovesicular eruption associated with scarring and severe mucosal lesions that led to blindness. Direct immunofluorescence showed linear IgA deposits at the dermoepidermal junction. Indirect immunofluorescence microscopy showed that the patient's serum reacted with the dermal side of salt-split skin. Direct immunoelectron microscopy showed the IgA deposits to be associated with anchoring fibrils, whereas with Western blot analysis the patient's serum reacted with a 290 kd dermal antigen. On the basis of these findings, we suggest that our case may represent a form of IgA-mediated epidermolysis bullosa acquisita.

Comparative study of indirect immunofluorescence and immunoblotting for the diagnosis of autoimmune pemphigus

The diagnosis of pemphigus relies on immunopathological criteria including the detection of circulating autoantibodies to desmosomal components. In the present work we compared the usefulness of immunoblotting (IB) and indirect immunofluorescence (IIF) in the diagnosis of pemphigus using monkey oesophagus (MO) and rabbit lip (RL) as epithelial substrates. Among 54 sera from patients with well-documented pemphigus (40 pemphigus vulgaris, PV, and 14 pemphigus foliaceus, PF), 46 (85%) proved positive by IIF (46 on MO and 41 on RL) as compared with 44 (81.5%) positive by IB. IIF and IB were equally sensitive (90%) for the diagnosis of PV whereas IIF (on RL) was more sensitive (71%) than IB (57%) for the detection of PF autoantibodies. However, when the two techniques were considered in combination, the sensitivity of the detection of pemphigus autoantibodies rose to 94.5%. An IB study would therefore be warranted in the presence of an (alleged) pemphigus serum that was IIF-negative since approximately 10% of these were found to be positive. Furthermore, the pattern of IB reactivity may assist in classification, since the 130- and the 160-kDa antigens seem specifically correlated with PV and PF, respectively.

Linear IgA bullous dermatosis of childhood with autoantibodies to a 230 kDa epidermal antigen

Linear IgA bullous dermatosis (LABD) is an autoimmune, subepidermal disease defined on the basis of direct immunofluorescence findings. However, more recent techniques used to study bullous dermatoses suggest that LABD may be heterogeneous. A patient with LABD of childhood (chronic benign disease of childhood, CBDC) was studied by indirect immunofluorescence on salt-split skin and by Western blot in an attempt to characterize the involved autoantigen. This young girl's periorificial (mouth, genitalia), erythematovesicular lesions were diagnosed initially as herpes simplex. Histologic examination revealed eosinophilic spongiosis, suggesting the diagnosis of an autoimmune blistering disease. Direct immunofluorescence showed an exclusive linear IgA deposit at the dermoepidermal junction. Indirect immunofluorescence revealed circulating IgA autoantibodies that reacted with the epidermal side of salt-split skin; these reacted by Western blot with a 230 kDa epidermal antigen, as in bullous pemphigoid. This case, fulfilling the diagnostic clinical and direct immunofluorescence criteria for LABD/CBDC, seems to represent IgA bullous pemphigoid. It further underscores the nosologic heterogeneity of LABD, which probably includes, apart from bullous pemphigoid, epidermolysis bullosa acquisita and cicatricial pemphigoid.

Serological diagnosis of bullous pemphigoid (BP): comparison of the sensitivity of indirect immunofluorescence on salt-split skin to immunoblotting

Specialized immunological assays are required for the accurate diagnosis of bullous dermatoses such as bullous pemphigoid (BP), epidermolysis bullosa acquisita and bullous lupus erythematosus. The aim of this study was to analyse and compare the sensitivity of indirect immunofluorescence (IF) on salt-split skin and immunoblotting for the detection of circulating autoantibodies in BP. Of the BP patients selected for the study, 74/79 (94%) had circulating autoantibodies detected by at least one of the two methods. Both methods had comparable sensitivity and detected BP-specific autoantibodies in 82-85% of the patients. Because 20% of the patients were found to be positive by only one of the methods, both methods should be used in the diagnosis of BP. Indirect IF on salt-split skin is easier to perform and is preferable in routine analysis, but Western blotting may be used as a complementary assay with sera showing no reactivity on salt-split skin.

Modulation of bullous pemphigoid antigens by gamma interferon in cultured human keratinocytes

We report the effects of human recombinant gamma interferon (gamma-IFN) on the expression of bullous pemphigoid (BP) antigens by human cultured keratinocytes. Secondary epidermal cell cultures were grown on 3T3 mouse fibroblasts; when confluent, some cultures were maintained in control medium while others were exposed to various concentrations of gamma-IFN (100, 200, 400 U/ml) for 14 days. The expression of BP antigens was analyzed by indirect immunofluorescence on epithelial sheets and immunoblotting of Tris, SDS, beta-mercaptoethanol culture extracts using different BP sera. Our results show that gamma-IFN alters the expression of BP antigens in a way varying according to the skin donor: we observed results ranging from complete loss and decreased expression to unchanged reactivity patterns. Thus, gamma-IFN modifies BP antigen expression; this behavior has been previously shown for other adhesion molecules such as fibronectin and thrombospondin. However, the observed variability of the expression of BP antigens according to the skin donor suggests an unexpected variability in keratinocyte sensitivity to gamma interferon, which remains to be explored both in vitro and in vivo.