Flow cytometrically-sorted residual HLA-DR+T6+ Langerhans cells in topical steroid-treated human skin express normal amounts of HLA-DR and CD1a/T6 antigens and exhibit normal alloantigen-presenting capacity

Controlled release of dexamethasone from subcutaneously-implanted biosensors in pigs: localized anti-inflammatory benefit without systemic effects

Chronically implanted biosensors typically lose sensitivity 1-2 months after implantation, due in large part to the development of a collagen-rich capsule that prevents analytes of interest from reaching the biosensor. Corticosteroids are likely candidates for reducing collagen deposition but these compounds have many serious side effects when given over a prolonged period. One method of assessing whether or not locally released corticosteroids have a systemic effect is to measure cortisol concentrations in venous serum. We hypothesized that a very low release rate of the potent corticosteroid, dexamethasone, would lead to a localized anti-inflammatory effect without systemic effects. We found that reduction in subcutaneous granulocytes (primarily eosinophils), and to a lesser extent, reduction of macrophages served as a good local indicator of the steroid effect. When released over a 28-day period, a total dexamethasone dose of < or =0.1 mg/kg led to a consistent reduction in the number of granulocytes and macrophages found in the local vicinity of the implant without a reduction of these cells at distant tissue locations. The lack of suppression of serum cortisol with these doses confirmed that low-release rates of dexamethasone can lead to consistent local anti-inflammatory effects without distant, systemic effects. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

Dendritic cells: emerging pharmacological targets of immunosuppressive drugs

Immunosuppressive drugs have revolutionized organ transplantation and improved the therapeutic management of autoimmune diseases. The development of immunosuppressive drugs and understanding of their action traditionally has been focused on lymphocytes, but recent evidence indicates that these agents interfere with immune responses at the earliest stage, targeting key functions of dendritic cells (DCs). Here, we review our present understanding of how classical and new immunosuppressive agents interfere with DC development and function. This knowledge might provide a rational basis for the selection of immunosuppressive drugs in different clinical settings and for the generation of tolerogenic DCs in the laboratory.

Huriez syndrome: case report with a detailed analysis of skin dendritic cells

We report a 60-year-old man with familial scleroatrophic syndrome of Huriez who developed squamous cell carcinomas on the affected skin of the right palm. Immunohistochemical analysis showed a marked reduction in the number of CD1a+, Lag+ and S100+ epidermal Langerhans cells, but not of CD1b+ and factor XIIIa+ dermal dendritic cells, limited to palmoplantar skin. The Langerhans cell depletion was not associated with an abnormal skin content of mRNA for factors involved in Langerhans cell development or recruitment in the epidermis, including granulocyte/macrophage colony-stimulating factor, transforming growth factor-beta1 and macrophage inflammatory protein-3alpha. The results indicate that other as yet unknown mechanisms may account for the reduced number of Langerhans cells in the affected skin of such patients.

Effect of coadministration of corticosteroids on the development of contact sensitization

BACKGROUND

Transdermal administration of drugs can increase patient compliance and reduce side effects, but it can also cause contact sensitization. Corticosteroids frequently are used to suppress the local immune response; however, their use as a pretreatment for transdermal system application sites is not practical.

OBJECTIVE

Our purpose was to determine the feasibility of suppressing contact sensitization by delivering a corticosteroid with the transdermal delivery systems.

METHODS

Materials were applied continuously for 3 weeks to the same (protocol SS) or different (protocol AS) skin sites. Skin flux and appearance of sensitization were determined.

RESULTS

Coadministration of hydrocortisone reduced the incidence of sensitization by d-chlorpheniramine and benzoyl peroxide from 45% to 7.5% and from 20% to 2.3%, respectively, under protocol SS. Under protocol AS, sensitization by d-chlorpheniramine was reduced from 15% to 1%. Frequent exposure to the sensitizer plus corticosteroid induced tolerance to the sensitizer.

CONCLUSION

Sensitization by moderately immunogenic drugs after any length of exposure may be reduced to acceptable levels by the coadministration of hydrocortisone.

The effect of a single oral dose of prednisolone or cetirizine on inflammatory cells infiltrating allergen-induced cutaneous late-phase reactions in atopic subjects

The effect of a single dose of prednisolone (20 mg) or cetirizine (10 mg) on the immunohistology of the cutaneous late-phase reaction was determined in a double-blind, placebo-controlled, cross-over study in 12 atopic allergic individuals. The subjects were challenged with intradermal allergen (30 BU) 2 hr after ingestion of the drugs or placebo. The magnitude of the cutaneous reactions were determined at 15 min, 6 and 24 hr, and skin biopsies performed at 24 hr. Cetirizine produced a 50% average inhibition of the immediate weal and flare response (P = 0.001) and a 27% average inhibition of the 6 hr late-phase induration (NS). Prednisolone reduced the immediate (27%, P = 0.03) and significantly inhibited the late-phase reaction (53%, P = 0.02). Prednisolone significantly inhibited infiltration of CD45+ (total leucocytes), neutrophil elastase+, EG2+ (activated eosinophils) and CD25+ (IL-2R) cells (P = 0.017, 0.005, 0.005 and 0.032 respectively). CD3, CD4, CD8 and HLA-DR expression was also inhibited but this was not significant. Cetirizine also reduced the numbers of EG2+ cells, particularly those with high counts before treatment but the overall results were not significant. No other changes in the cellular infiltrate were demonstrated when cetirizine was compared with placebo. These findings indicate a single dose of prednisolone significantly reduces leucocyte infiltration and activation as well as the magnitude of the cutaneous late-phase reaction.

Inhibitory effect of 8-methoxypsoralen plus ultraviolet-A on interleukin-1 production by murine keratinocytes

We report the effects of 8-methoxypsoralen (8-MOP) plus ultraviolet-A (UV-A) irradiation on interleukin-1 (IL-1) production by murine epidermal keratinocytes, correlating its effect on IL-1 with cell viability, DNA synthesis, and 8-MOP-DNA photoadduct formation. Freshly isolated murine keratinocytes were treated with various doses of 8-MOP (5-100 ng/mL; incubation time, 30 min) plus 1 J/cm2 UV-A and cultured for 1-3 days. The IL-1/epidermal cell-derived thymocyte-activating factor (ETAF) activity in both supernatant and cell extract was reduced proportionately with increasing doses of 8-MOP/UV-A. Interleukin-1 inhibitors induced by 8-MOP plus UV-A were not detected in either supernatant or cell extract. A clear reduction of the IL-1 production was induced by the treatment as low as 15 ng/mL 8-MOP plus 1 J/cm2 UV-A, which led to the formation of 0.52 8-MOP photoadducts per million DNa bases and affected neither cell viability nor DNA synthesis of the treated cells. Cells treated with 100 ng/mL 8-MOP and 1 J/cm2 UV-A exhibited 57% suppression of IL-1 production in both 2- and 3-day culture samples. This treatment resulted in the formation of 3.8 photoadducts per million bases as well as significant abrogation of DNA synthesis although cell viability was unchanged. These observations provide some insights into the phototoxicity mechanisms of 8-MOP and the effect of PUVA therapy on the cytokine regulation in keratinocytes.

Absence of tumor necrosis factor-alpha in suction blister fluids and stratum corneum from patients with psoriasis

Tumor necrosis factor (TNF)-alpha is a cytokine with multiple biological properties, particularly proinflammatory, apart from the induction of tumor necrosis. In order to elucidate the role of TNF-alpha in the pathogenesis of psoriasis, we have carried out bioassay and enzyme-linked immunosorbent assay for TNF-alpha in suction blister fluids and horny tissue extracts from psoriatic skin. Although bioassay showed some activities in the suction blister fluids and horny tissue extracts, there were no significant differences between the levels of activities from normal and psoriatic skin. They were at the background level and pretreatment of the samples with anti-TNF-alpha antiserum failed to abrogate the activities. ELISA confirmed the absence of TNF-alpha. Therefore, the present study could not verify that TNF-alpha plays a major role in the pathogenesis of psoriasis.

Flow cytometric analysis and sorting of HLA-DR+CD1+ Langerhans cells

There is a considerable need for reliable methods for enumeration and enrichment of Langerhans cells (LCs), since they continue to be the subject of intensive investigation in normal and diseased skin. It has been claimed that standard labelling with either anti-HLA-DR or OKT6 antibodies alone may fail to identify potentially important subsets of LCs with the phenotypes HLA-DR+CD1- and HLA-DR-CD1+. We report here on flow cytometric analysis of suction blister-derived normal epidermal cell (EC) suspensions, double stained with phycoerythrin-conjugated anti-HLA-DR and fluoresceinated OKT6. In seven separate experiments, no evidence for the existence of either HLA-DR+CDI- or HLA-DR-CDI+ ECs was obtained. We found that HLA-DR+CDI+LCs, which constituted a mean of 2.5% (+/- 0.3 SEM) of all ECs, could be readily identified on the basis of fluorescence, and that their light scatter characteristics were those of moderately sized cells of low granularity. We further describe our method for flow cytometric enrichment of such HLA-DR+CDi+ LCs for functional studies, based on selection on both fluorescence and light scatter criteria. Enrichment is to greater than 90% purity, and the method is applicable to the small number of ECs (approximately 1 x 10(6] obtained from a suction blister.