DNA was extracted from the remains of 35 ground sloths from various parts of North and South America. Two specimens of Mylodon darwinii, a species that went extinct at the end of the last glaciation, yielded amplifiable DNA. However, of the total DNA extracted, only -1/1000 originated from the sloth, whereas a substantial part of the remainder was of bacterial and fungal origin. In spite of this, >1100 bp of sloth mitochondrial rDNA sequences could be reconstructed from short amplification products. Phylogenetic analyses using homologous sequences from all extant edentate groups suggest that Mylodon darwinii was more closely related to the two-toed than the three-toed sloths and, thus, that an arboreal life-style has evolved at least twice among sloths. The divergence of Mylodon and the two-toed sloth furthermore allows a date for the radiation of armadillos, anteaters, and sloths to be estimated. This result shows that the edentates differ from other mammalian orders in that they contain lineages that diverged before the end of the Cretaceous Period.

Anti-p200 pemphigoid is a recently defined autoimmune subepidermal blistering disease characterized by circulating and tissue-bound autoantibodies to a 200-kDa protein (p200) of the dermal-epidermal junction (DEJ). This DEJ constituent is thought to be important for adhesion of basal keratinocytes to the underlying dermis. While the exact identity of p200 remains unknown, it has been demonstrated to be immunologically and biochemically distinct from all major autoantigens of the DEJ, including bullous pemphigoid antigens 180 and 230, laminin 1, 5 and 6, alpha6beta4 integrin, and type VII collagen. Clinically, most reported cases present with tense blisters as well as urticarial papules and plaques, closely resembling bullous pemphigoid. Histopathological examination of lesional skin biopsies shows subepidermal split formation and superficial inflammatory infiltrate typically dominated by neutrophils. Immunopathologically, linear deposits of immunoglobulin (Ig)G and C3 are detected along the DEJ by direct immunofluorescence microscopy of perilesional skin. Indirect immunofluorescence microscopy of patients' sera on NaCl-split human skin demonstrates circulating IgG autoantibodies labeling the dermal side of the split. By immunoblotting, these autoantibodies recognize a 200-kDa protein of human dermis. Biochemical characterization of the p200 molecule revealed a noncollagenous N-glycosylated acidic protein with an isoelectric point of approximately 5.5. We present an overview of the pathogenesis, clinical features, diagnosis and treatment of this new disease entity.

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