A comparison of expression of surface-bound immunoglobulin E on antigen-presenting cells in cutaneous tissue between patients with allergic, irritant and atopic dermatitis

Correlation between laser Doppler perfusion imaging and visual scoring of patch test sites in subjects with experimentally induced allergic and irritant contact reactions

PURPOSE

To compare laser Doppler perfusion imaging (LDPI) measurements in experimentally induced allergic contact reactions and irritant contact reactions. The degree of correlation between visual scores and LDPI measurements was also studied.

METHODS

Fifteen patients with known contact allergy to nickel or fragrance were patch tested with nickel sulfate 5% pet., fragrance mix 8% pet., sodium lauryl sulfate (SLS) 0.5% pet., SLS 1.0% pet. and two empty control chambers. Visual readings and LDPI measurements were taken at 0, 48 and 96 h.

RESULTS

There was a positive correlation between visual scores and LDPI measurement in the nickel sulfate and fragrance mix patch test sites. However, no correlation between visual scores and LDPI measurements was seen in the SLS 0.5% and SLS 1.0% patch test sites. There was no significant difference (P=0.125) in LDPI measurements between contact-allergic reactions and contact-irritant reactions.

CONCLUSION

LDPI correlates with visual scoring in contact-allergic reactions, but not in irritant reactions. LDPI is not useful in distinguishing between allergic and irritant reactions.

Atopic dermatitis: immunophenotyping of inflammatory cells in skin lesions

BACKGROUND

The ever increasing incidence of atopic dermatitis (AD) has stimulated many researchers to use various diagnostic procedures to obtain new data to help elucidate the pathogenesis of the disease.

AIMS

To perform cell immunophenotyping and to analyze the presence of inflammatory cell-surface markers in the biopsies of skin lesions from 15 AD patients and five healthy subjects.

METHODS

Immunohistochemical analysis was performed in a group of AD patients and compared with that in a control group of healthy subjects. Avidin-biotin immunoperoxidase staining of paraffin-embedded, 4 microm skin sections, with semiquantitative counting of cells labeled with anti-CD3, anti-CD8, anti-CD20, anti-HLA-DR (HLA, human leukocyte antigen), and anti-immunoglobulin E (anti-IgE) primary antibodies, was used.

RESULTS

The results of AD skin analysis showed a greater infiltration of CD3+ lymphocytes, especially of CD4+ subtype, compared with CD8+ lymphocytes. AD skin biopsy specimens also showed a higher intraepidermal HLA-DR+ Langerhans' cell count, the presence of HLA-DR on lymphocytes in the dermis, and higher intraepidermal expression of IgE+ cells compared with healthy controls.

CONCLUSIONS

A statistically significant difference (P < 0.05) was found between the two groups for intradermal and intraepidermal CD3, CD4, and HLA-DR, intradermal CD8, and intraepidermal IgE+ cells. Immunophenotyping was found to be a useful diagnostic method in AD patients.

Immunophenotyping of the cellular infiltrate in the early elicitation phase of contact dermatitis in the skin of presensitized atopic individuals

Little is known about the composition of the cellular infiltrate in the early elicitation phase of contact allergy in atopic individuals. Therefore, we rechallenged ten presensitized disease-free atopic volunteers with their known contact allergen and performed biopsies at time 0 and after 6 and 24 h. Ten patients with acute exacerbated atopic dermatitis in the early stage were chosen as a control group. Skin biopsy specimens were processed for immunohistochemistry (APAAP) and evaluated by computer-assisted morphometry. CD4+ and CD45R0+ cells were found to be significantly increased after 6 (t6) and 24 h (t24), and this was accompanied by an enhanced TCR alpha/beta receptor expression at t6-CD45O+ cells showed a marked influx into the epidermis at t24. CD8+ cells infiltrated the basal layer of the epidermis, thus changing the CD4/CD8 ratio from 4.6:1 at t0 to 2.2:1 at t6. CD1a+ epidermal dendritic cells increased significantly from 811 +/- 240/mm2 at t0, to 1210 +/- 333/mm2 at t24 (P < 0.01). At t6 and t24, a so-called 'epitope CD1a+ shedding' was observed into the intercellular spaces of keratinocytes as well as an elongation and enlargement of the dendrites of CD1a+ cells. In the upper dermis, the number of CD1a+ cells increased from 1098 +/- 485/mm2 at t0 to 2388 +/- 740/mm2 at t24 (P < 0.01). In 7/10 volunteers, IgE+ dendritic cells increased significantly in number at t6 (P < 0.02). The activation markers HLA-DR and CD25 were expressed most distinctly at t24. Interestingly, expression of ICAM-1 on keratinocytes occurred only in four of the ten atopic volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)

Absence of specific IgE antibodies in allergic contact sensitivity to formaldehyde

Immunologic reactions are customarily divided into two broad categories, cell-mediated and antibody-mediated. An interplay between these two pathogenetic principles is indicated by reactions such as cutaneous basophil hypersensitivity, late-phase reaction, and cutaneous lesions indistinguishable from regular allergic contact dermatitis lesions after sensitization with IgE antibodies against certain haptens. In the present study, 23 patients with a history of a positive epicutaneous test to formaldehyde participated. On retest, 15 showed a positive reaction. Eight patients were Phadiatop positive, indicating an atopic diathesis, and eight had a history of or ongoing atopic dermatitis. On RAST test, only two, nonatopic patients had specific IgE antibodies to formaldehyde. In the cellular infiltrates of biopsies from epicutaneous test sites, cells reactive with monoclonal antibodies against IgE were found in positive and negative formalin tests, both in atopics and nonatopics, as well as in control biopsies from nonlesional skin. Double immunofluorescence staining experiments showed that IgE occurred on Langerhans' cells. The proportion of IgE-positive cells correlated to the level of serum IgE, but not to atopy. These cells were also found both in the epidermis and in the dermis in nonatopic patients. ICAM-1 occurred on keratinocytes in all patient groups. This study does not support the hypothesis that specific IgE antibodies are active in the pathogenesis of contact sensitivity to formaldehyde either in atopic or in nonatopic patients.