Diagnostics for Dermatologic Diseases with Autoantibodies.

Background: Dermatologic diseases with autoantibodies were recognized early as autoimmunity became accepted as a pathogenic immunologic concept. Laboratory testing to identify disease-defining autoantibodies and investigate their role in pathophysiology has evolved since.

Content: Blistering dermatologic diseases, profiled by autoantibody production, target epithelial components critical in cell-cell and cell-matrix adhesion, resulting in epithelial separation and other characteristic features of the disorders.

Cutaneous manifestations of Corynebacterium jeikeium sepsis.

Corynebacterium jeikeium is a rare but increasingly important cause of septicemia in neutropenic patients that can present with characteristic cutaneous findings. A 61-year-old man with myelodysplastic syndrome developed C. jeikeium sepsis and an erythematous papular eruption while neutropenic from induction chemotherapy.

Opposing activities of two novel members of the IL-1 ligand family regulate skin inflammation.

The interleukin (IL)-1 family members IL-1alpha, -1beta, and -18 are potent inflammatory cytokines whose activities are dependent on heterodimeric receptors of the IL-1R superfamily, and which are regulated by soluble antagonists. Recently, several new IL-1 family members have been identified. To determine the role of one of these family members in the skin, transgenic mice expressing IL1F6 in basal keratinocytes were generated.

Shining light on lupus and UV.

People exposed to sunlight can develop erythema, DNA damage, and photoimmunosupression. Extended exposure of normal epidermis to sunlight will induce dysmorphic keratinocytes with pyknotic nuclei scattered throughout the spinous layer. These 'sunburn cells' are apoptotic keratinocytes and are usually cleared within 48 hours after sunburn.

Expression and characterization of constitutively active human caspase-14.

Caspase-14 is a cysteine endoproteinase that is expressed in the epidermis and a limited number of other tissues. It is activated during keratinocyte differentiation by zymogen processing, but its precise function is unknown. To obtain caspase-14 for functional studies, we engineered and expressed a constitutively active form of human caspase-14 (Rev-hC14) in Escherichia coli and cultured mammalian cells.

Neonatal eosinophilic pustulosis.

A pre-term, 7-week-old male infant presented with a recurrent pustular eruption involving his face and scalp with associated peripheral blood eosinophilia. Skin biopsy revealed spongiosis with numerous dermal and epidermal eosinophils without predominant follicular involvement. Immunohistology showed deposition of eosinophil granule major basic protein and eosinophil derived neurotoxin in the dermis and epidermis.

Processing of native caspase-14 occurs at an atypical cleavage site in normal epidermal differentiation.

Caspase-14, a cysteinyl aspartate-specific protease expressed during epidermal differentiation, is detected exclusively in the cytosolic fraction of epidermis as a complex of procaspase-14 together with caspase-14 large and small subunits. On non-denaturing protein gels, native caspase-14 has a relative electrophoretic mobility of approximately 80kDa, which resolves into caspase-14 proform, large and small subunit in SDS-polyacrylamide. Purification of caspase-14 from native skin with subsequent N-terminal sequencing of the small subunit and tryptic digest analysis of the large subunit revealed an atypical processing site between Ile152 and Lys153, which distinguishes it from other caspases described to date that are processed at aspartate residues.