fibrin and Keratosis

A 23-year-old Italian woman presented with asymptomatic, symmetric, hyperpigmented patches on her face. The dermatosis became exacerbated in summer and closely resembled melasma. The histologic examination and immunofluorescence studies revealed typical features of lichen planus. Actinic lichen planus mimicking melasma is a rare dermatosis occurring mostly in women of oriental origin. The differential diagnosis of further facial melanoses will be discussed.

Topics: Adult; Diagnosis, Differential; Facial Dermatoses; Female; Fibrin; Fluorescent Antibody Technique, Direct; Humans; Hyperpigmentation; Hyperplasia; Immunoglobulin A; Immunoglobulin M; Keratinocytes; Keratosis; Lichen Planus; Lymphocytes; Melanosis

Solar keratoses (SKs) may show basal cell liquefactive degeneration (BLD) and, when extensive, this can result in a superficial resemblance to lichen planus. The frequency of these phenomena and involvement of immune mechanisms in them have been investigated in this study. The prevalence of lichenoid keratosis (LK) was 6.1% in 212 SKs examined retrospectively and 10.7% in 28 examined prospectively. Histologic features were scored on analogue scales and their interrelationships examined. BLD could not be correlated with epidermal atypia, acanthosis, acantholysis, or inflammatory cellular infiltrate; a negative correlation occurred with parakeratosis. Immunoglobulins and/or fibrin and complement were found by immunofluorescence in 78.8% of the 28 specimens examined prospectively. Three LKs showed similar immunofluorescence findings to ordinary SKs. No circulating antibodies to epidermal structures were detected in patients with SKs. It is concluded that (1) no feature of SKs investigated predisposed to lichenoid change, (2) BLD was a frequent feature in SKs whereas full development of LK occurred much less frequently, and (3) immunoprotein deposits were not related to the development of BLD. Clinically, LKs could not be distinguished from ordinary SKs.

Topics: Fibrin; Humans; Immunoglobulins; Keratosis; Lichen Planus; Prospective Studies; Retrospective Studies

The possible presence of epsilon-(gamma-glutamyl) lysine covalent bonds in human epidermal proteins prompted a study of transamidase activity in human hair-free epidermis. Callus contains an enzyme which catalyzes the incorporation of radioactive putrescine into alpha-casein. The enzyme is active without prior treatment with exogenous proteolytic enzymes. The putrescine incorporation is calcium dependent and inhibited by iodoacetamide. The enzyme was partially purified (50-fold over starting material), and has an apparent molecular weight between 50,000 daltons and 55,000 daltons by agarose 0.5m gel filtration. The apparent molecular weight is unaltered by chromatography in the presence of 11 mMCaCl2, a condition known to dissociate plasma transglutaminase (Factor XIII) into its ultimate subunits. The enzyme is active over a wide pH range up to pH 10.4 The Km for putrescine varies by 1-fold over the pH range 6.0 to 10.2, although enzyme activity increases at least 20-fold over the same pH range. The human epidermal transamidase is similar to the guinea-pig hair follicle transglutaminase and cow snout transamidase in its ability to cross-link fibrin.

Topics: Animals; Calcium; Caseins; Cattle; Chemical Phenomena; Chemistry; Chromatography; Chromatography, Gel; Depression, Chemical; Edetic Acid; Electrophoresis, Disc; Enzyme Activation; Factor XIII; Fibrin; gamma-Glutamyltransferase; Humans; Hydrogen-Ion Concentration; Iodoacetamide; Keratosis; Metals; Putrescine; Skin; Sulfhydryl Compounds

Topics: Beta-Globulins; Electrophoresis; Erythrocytes; Fibrin; Fibrinogen; gamma-Globulins; Hemagglutination; Humans; Immunochemistry; Immunoelectrophoresis; Immunoglobulin G; Keratosis; Lipoproteins; Psoriasis; Serum Albumin; Skin; Skin Diseases; Solubility; Transferrin