There was no significant difference in the participants' diagnostic ability using virtual slides compared with glass slides. Most participants agreed that virtual microscopy is a useful tool for learning and testing.

We report a case of a 75-year-old male with indolent chronic lymphocytic leukaemia (CLL) for 8 years, who presented with a 6-month history of a painful, zosteriform eruption in a T3-4 distribution that evolved into an unusual crop of papular nodules. Upon biopsy and immunostaining of these lesions CLL was proven consistent with leukaemia cutis related to varicella-zoster virus reactivation. In the absence of other treatment indices, he was commenced on chlorambucil with successful resolution of both his pain and the lesions.

Epidermolysis bullosa acquisita (EBA) is a chronic acquired blistering disease with characteristic clinical, pathologic, and immunopathologic features. The disease is characterized immunopathologically by circulating and tissue-bound IgG class autoantibodies (EBA antibodies) to the basement membrane zone of stratified squamous epithelium. Previous studies have shown that circulating and tissue-bound EBA antibodies are heterogenous in their ability to activate complement and have raised the possibility that functional heterogeneity might be related to IgG subclass restriction. In this study, we have characterized the IgG subclasses of the circulating and tissue-bound EBA antibodies by immunofluorescence and have examined the relationship between IgG subclass and complement binding. The results show that EBA antibodies belonging to all IgG subclasses are present in the skin of EBA patients. The results also show that EBA antibodies belonging to all IgG subclasses are present in the sera of most patients, including sera with and without complement binding EBA antibodies.

Epidermolysis bullosa acquisita (EBA) is an inflammatory subepidermal blistering disease characterized by circulating and tissue-bound autoantibodies specific for type VII collagen of the basement membrane zone. The antibodies consist of both complement- and noncomplement-binding populations and belong to all four subclasses of IgG. We investigated the presence of the membrane attack complex C3b, C5, and S protein in EBA and compared C3b and C5 in EBA and bullous pemphigoid. In 10 patients with EBA, these components were detected at the basement membrane zone as follows: membrane attack complex, 90%; S protein, 90%; direct C5, 90%; C3b, 100%; and C5 binding, 90%. In the patients with bullous pemphigoid, the results were as follows: direct C5, 58%; C3b, 33%; and C5 binding, 19%. These results provide additional evidence for complement activation at the basement membrane zone in EBA, show that complement activation in EBA proceeds to activation of terminal complement components, and suggest that EBA antibodies are more potent activators of C5 than are bullous pemphigoid antibodies.