Anti-IgE monoclonal antibodies as tools for demonstration of cutaneous IgE bearing dendritic cells

Abundant immunoglobulin E-positive cells in skin lesions support an allergic etiology of atopic dermatitis in the elderly

Background/Objectives

Atopic dermatitis (AD) in the elderly is gradually increasing in industrialized countries in association with the aging of society. We report herein four cases of elderly AD {three extrinsic [immunoglobulin (Ig)E-mediated allergy]; one intrinsic (non-IgE-allergy)} in which we investigated the presence of IgE+ cells in lesional skin.

Methods/Results

Single immunohistochemical and double immunofluorescence stainings were performed for skin biopsy specimens from AD patients and non-atopic control subjects with chronic eczema. In the lesional lichenified skin of patients with extrinsic elderly AD, numerous IgE+ cells were found among inflammatory cells infiltrates in the upper dermis. Comparative analysis of single immunohistochemistry results using serial paraffin and/or frozen sections found that many IgE+ cells showed identical distributions to tryptase+ mast cells. IgE+ cells coincident with CD1a+ Langerhans cells in the epidermis were found in small numbers only in frozen sections. Double immunofluorescence staining for IgE and CD11c revealed cells coexpressing IgE and CD11c with a dendritic morphology in the papillary and upper dermis. These IgE+ mast cells and IgE+ CD11c+ cells were also found in cured normal-looking skin from a patient with extrinsic elderly AD after successful treatment. Although only a few weakly positive IgE+ cells were detected, no IgE+CD11c+ cells were found in specimens from patients with intrinsic elderly AD or non-atopic chronic eczema.

Conclusion

IgE-mediated allergic inflammation may play an important role in the pathobiology of elderly AD, similar to other age groups of AD.

Effects of long-term chronic exposure to sun radiation in immunological system of commercial fishermen in Recife, Brazil

BACKGROUND

Among the various occupations which necessarily require long-term and chronic sun exposure is that of a fisherman. However, clinical experience in dermatology earned over several years of medical practice does not seem to confirm this hypothesis.

OBJECTIVE

To evaluate clinical, histological and immunological effects of long-term and chronic exposure to ultraviolet radiation in fishermen.

METHODS

A prospective, cross-sectional and observational study characterized skin lesions, immunological markers and histological alterations in fishermen, as well as lymphocyte subpopulations compared to a control group. Mann-Whitney, Fisher's and Wilcoxon statistical tests were used at a significance level of 0.05.

RESULTS

There were significant differences between the exposed group and the group protected due to elastosis (p = 0.03), ectasia of dermal vessels (p = 0.012) and number of cells in the epidermal layers between cones (p = 0.029). Most common among fishermen were CD45RO, CD68 + and mastocytes in the skin (p = 0.040, p <0.001, p = 0.001) and CD3CD8CD45RO in the blood (p = 0.016).

CONCLUSION

The alterations suggest that long-term and chronic sun exposure promotes tolerance to ultraviolet radiation, which protects against immunosuppression.

Occurrence of IgE-bearing epidermal Langerhans cells in atopic eczema: a study of the time course of the lesions and with regard to the IgE serum level

Uninvolved and lesional skin of untreated and treated patients with atopic eczema has been investigated immunohistochemically to determine the conditions in which IgE-bearing CD1a+ Langerhans cells/indeterminate cells (LC/IC) occur in this disease. IgE-bearing epidermal dendritic cells were present in patients with elevated IgE serum level (greater than 300 UI/ml) and the staining pattern was stronger in lesional skin. On double immunostaining, a subpopulation of CD1a+ LC/IC was found not to bear IgE molecules as determined by the ratio IgE+/CD1a+ cells on serial sections as well. The ratio IgE+/CD1a+ cells decreased in patients who underwent a local therapy with glucocorticosteroids. These results suggest that the expression of IgE receptors and/or binding of IgE molecules on epidermal LC/IC in atopic eczema may be controlled by a complex network of mediators from the epidermis or the inflammatory infiltrate, or both, and that this phenomenon could be down regulated by glucocorticosteroids.