Immunopathology of bullous pemphigoid, an autoimmune and inflammatory skin blistering disease.
(49/380)
Bullous pemphigoid (BP) was first described by Lever in 1953 as a subepidermal blistering disease. Key immunohistological features of BP include dermo-epidermal junction (DEJ) separation, an inflammatory cell infiltrate in the upper dermis, and autoantibodies directed against two emidesmosomal antigens, BP230 and BP180. In 1993, an IgG passive transfer mouse model of BP was developed by administering rabbit anti-murine BP180 antibodies to neonatal mice. This model recapitulates the key features of human BP. Systematic dissection of this BP model has revealed that subepidermal blistering is initiated by anti-BP180 antibodies and mediated by complement activation, mast cell degranulation, and neutrophil infiltration. Proteinases and reactive oxygen species released by infiltrating neutrophils work together to damage the basement membrane zone (BMZ), causing a subepidermal blister. Recently, another novel mouse model for BP has been developed by active immunization. C57BL/6J mice actively immunized with murine BP180 develop BP-like skin lesions. The IgG passive transfer and active models of BP provide us with invaluable in vivo systems not only for dissecting cellular and humoral responses in BP but also for developing effective therapies for this disease. (+info)
Coevolution of markers of innate and adaptive immunity in skin and peripheral blood of patients with erythema migrans.
(50/380)
We used multiparameter flow cytometry to characterize leukocyte immunophenotypes and cytokines in skin and peripheral blood of patients with erythema migrans (EM). Dermal leukocytes and cytokines were assessed in fluids aspirated from epidermal suction blisters raised over EM lesions and skin of uninfected controls. Compared with corresponding peripheral blood, EM infiltrates were enriched for T cells, monocytes/macrophages, and dendritic cells (DCs), contained lower proportions of neutrophils, and were virtually devoid of B cells. Enhanced expression of CD14 and HLA-DR by lesional neutrophils and macrophages indicated that these innate effector cells were highly activated. Staining for CD45RO and CD27 revealed that lesional T lymphocytes were predominantly Ag-experienced cells; furthermore, a subset of circulating T cells also appeared to be neosensitized. Lesional DC subsets, CD11c(+) (monocytoid) and CD11c(-) (plasmacytoid), expressed activation/maturation surface markers. Patients with multiple EM lesions had greater symptom scores and higher serum levels of IFN-alpha, TNF-alpha, and IL-2 than patients with solitary EM. IL-6 and IFN-gamma were the predominant cytokines in EM lesions; however, greater levels of both mediators were detected in blister fluids from patients with isolated EM. Circulating monocytes displayed significant increases in surface expression of Toll-like receptor (TLR)1 and TLR2, while CD11c(+) DCs showed increased expression of TLR2 and TLR4; lesional macrophages and CD11c(+) and CD11c(-) DCs exhibited increases in expression of all three TLRs. These results demonstrate that Borrelia burgdorferi triggers innate and adaptive responses during early Lyme disease and emphasize the interdependence of these two arms of the immune response in the efforts of the host to contain spirochetal infection. (+info)
Bullous erythema ab igne.
(51/380)
Erythema ab igne is a localized, cutaneous condition, consisting of reticulate hyperpigmentation, dusky erythema, epidermal atrophy, and telangiectasia, all the result of repeated exposures to heat. We describe a patient with a bullous form of erythema ab igne: bullae and crusts within a localized area of reticular, brown, macular pigmentation on the lateral side of the left leg, an area that had repeated close exposure to an electrical heater over the previous 3 months. We believe that bullous erythema ab igne, something rarely reported in the literature, should be considered a well-defined variant of erythema ab igne; it may be more common than the literature suggests. (+info)
Kindler syndrome: two additional features.
(52/380)
Kindler syndrome is a hereditary condition that combines the features of blistering and photosensitivity in infancy and early childhood with progressive poikiloderma. We report additional features observed in one affected individual. (+info)
Pharmacokinetics and inflammatory fluid penetration of sparfloxacin.
(53/380)
A single 400-mg oral dose of sparfloxacin was given to each of six healthy male volunteers, and the concentrations of the drug were measured in plasma, cantharides-induced inflammatory fluid, and urine over the subsequent 52 h. The mean peak concentration in plasma of 1.6 micrograms/ml was attained at a mean time of 2.7 h postdose. The mean peak concentration in inflammatory fluid of 1.3 micrograms/ml was attained at a mean time of 5 h postdose. The mean elimination half-life in plasma was 17.6 h, and that in inflammatory fluid was 19.7 h. The overall penetration into inflammatory fluid was 117%. Urinary recovery within the first 52 h postdose was 8.8% of the administered dose. Our results indicate that a once-daily dosage of sparfloxacin should be adequate to treat systemic infections caused by most common bacterial pathogens. (+info)
Serum and blister fluid pharmacokinetics and bactericidal activities of ampicillin-sulbactam, cefotetan, cefoxitin, ceftizoxime, and ticarcillin-clavulanate.
(54/380)
Ampicillin-sulbactam, ticarcillin-clavulanate, cefoxitin, cefotetan, and ceftizoxime are promoted for the treatment of mixed aerobic-anaerobic bacterial infections. Their activities have been compared in vitro but not in vivo. In order to assess the in vivo activities of these agents in serum and interstitial fluid, we administered single, intravenous doses of these antimicrobial agents to healthy subjects. Concentrations of the antimicrobial agents in serum and suction-induced blister fluid and bactericidal activity were measured by high-pressure liquid chromatography and the standard methodology of the National Committee for Clinical Laboratory Standards, respectively. The organisms used for bactericidal activity tests were one isolate each of Staphylococcus aureus, Klebsiella pneumoniae, and Bacteroides fragilis. Pharmacokinetic parameters in serum and blister fluid were similar to those derived in other investigations. Of note were the high and prolonged concentrations of ticarcillin and cefotetan in blister fluid, despite high-level serum protein binding. The bactericidal activities in serum and blister fluid reflected the relative in vitro activities and kinetic dispositions of the various antimicrobial agents except for the bactericidal activity of cefotetan, which was substantially lower in blister fluid than serum, despite a blister fluid:serum area under the concentration-time curve ratio of 1.5. Similarly, the activity of ticarcillin-clavulanate in blister fluid was also substantially less than would have been predicted by the blister fluid:serum ratio of the area under the concentration-time curve of 1.1, possibly because of the low concentrations of clavulanate in blister fluid. The rankings of the in vivo bactericidal activities of the five drugs were as follows: for S. aureus, ampicillin-sulbactam > ticarcillin-clavulanate > ceftizoxime > cefoxitin > cefotetan; for K. pneumoniae, ceftizoxime > cefotetan > ampicillin-sulbactam = ticarcillin-clavulanate > cefoxitin; and for B.fragilis, ticarcillin-clavulanate > cefotetan > ceftizoxime > ampicillin-sulbactam = cefoxitin. (+info)
Selective up-regulation of matrix metalloproteinase-9 expression in human erythema migrans skin lesions of acute lyme disease.
(55/380)
Despite the absence of enzymes that digest extracellular matrix, Borrelia burgdorferi spreads in the skin to form erythema migrans (EM) lesions and then disseminates to other organs. We studied the induction by bacteria of host matrix metalloproteinases (MMPs) in EM skin lesions of patients with acute Lyme disease. In blister fluid from the EM lesions, the expression of MMP-9 was selectively increased by 1900%+/-1037%, compared with blister fluid from the surrounding normal-appearing skin. The expression of all other MMP messenger RNAs was similar in the EM lesions and normal-appearing skin. Selective up-regulation of MMP-9 in the EM lesions was found. Fibroblasts and, to a lesser degree, mononuclear cells were the sources of local MMP-9 production. These results demonstrate specific up-regulation of MMP-9 in the EM skin lesions of patients with acute Lyme disease. Bacterial induction of host proteases may play a role in the dissemination of B. burgdorferi. (+info)
Targeted inactivation of murine laminin gamma2-chain gene recapitulates human junctional epidermolysis bullosa.
(56/380)
Junctional forms of epidermolysis bullosa (JEB) are associated with mutations in six distinct genes expressed in the cutaneous basement membrane zone; these include LAMA3, LAMB3, and LAMC2, which encode laminin 5 subunit polypeptides, the alpha3-, beta3-, and gamma2-chains, respectively. Here we generated a mouse model for JEB by inactivating the laminin gamma2-chain gene by targeted frameshift deletion of exon 8 in Lamc2. Heterozygous mice were phenotypically normal, whereas the majority of Lamc2-/- mice showed blistering phenotype on days 1 to 2 and died within 5 days of birth. The Lamc2-/- mice demonstrated absent expression of laminin gamma2-chain on the basement membrane zone as well as attenuated expression of alpha3- and beta3-chains of laminin. Transmission electron microscopy revealed rudimentary, poorly developed hemidesmosomes. The epidermis of the Lamc2-/- mice revealed induced apoptosis in the basal cells of the blistered skin, suggesting that cell-matrix adhesion provided by laminin 5 plays a role in cell survival in vivo. Cultured Lamc2-/- keratinocytes demonstrated slightly positive staining with gamma2-chain-specific antibodies, which could be explained by the presence of a transcript with partial restoration of the reading frame owing to alternative splicing in vitro. These cells proliferated in different matrices and attached to type IV collagen and Matrigel as efficiently as the wild-type keratinocytes, whereas their attachment on plastic and laminin was significantly weaker. In summary, Lamc2-/- mouse recapitulates human JEB and provides novel insight into the role of laminin 5 in keratinocyte biology. (+info)