Phenotypical characteristics of the immune cells in allergic contact dermatitis, atopic dermatitis and pityriasis rosea

Endothelial Protein C Receptor and 3K3A-Activated Protein C Protect Mice from Allergic Contact Dermatitis in a Contact Hypersensitivity Model

Endothelial protein C receptor (EPCR) is a receptor for the natural anti-coagulant activated protein C (aPC). It mediates the anti-inflammatory and barrier-protective functions of aPC through the cleavage of protease-activated receptor (PAR)1/2. Allergic contact dermatitis is a common skin disease characterized by inflammation and defective skin barrier. This study investigated the effect of EPCR and 3K3A-aPC on allergic contact dermatitis using a contact hypersensitivity (CHS) model. CHS was induced using 1-Fluoro-2,4-dinitrobenzene in EPCR-deficient (KO) and matched wild-type mice and mice treated with 3K3A-aPC, a mutant form of aPC with diminished anti-coagulant activity. Changes in clinical and histological features, cytokines, and immune cells were examined. EPCRKO mice displayed more severe CHS, with increased immune cell infiltration in the skin and higher levels of inflammatory cytokines and IgE than wild-type mice. EPCR, aPC, and PAR1/2 were expressed by the skin epidermis, with EPCR presenting almost exclusively in the basal layer. EPCRKO increased the epidermal expression of aPC and PAR1, whereas in CHS, their expression was reduced compared to wild-type mice. 3K3A-aPC reduced CHS severity in wild-type and EPCRKO mice by suppressing immune cell infiltration/activation and inflammatory cytokines. In summary, EPCRKO exacerbated CHS, whereas 3K3A-aPC could reduce the severity of CHS in both EPCRKO and wild-type mice.

Capsaicin induces atopic dermatitis-like manifestations through dysregulation of proteolytic system and alteration of filaggrin processing in rats

Atopic dermatitis (AD) is a complex disease featuring pruritic skin inflammation. Many animal models have been developed. In a rat model, subcutaneous capsaicin injection within 48 hours after birth induces AD-like skin manifestations of dermatitis and scratching behaviour 3 weeks after the injection. When 2- to 4-week-old rats were injected with capsaicin, the lag period was shortened, and the severity of skin manifestations was significantly reduced, suggesting influences of postnatal development. Lgr6 is an epidermal stem cell marker that is normally restricted to the isthmus area of hair follicles at postnatal 2 weeks. Lgr6 persisted in the interfollicular epidermis of capsaicin-injected rats beyond 3 weeks after birth, indicating that capsaicin-induced skin manifestations were influenced by postnatal epidermal development. Capsaicin injection induced alteration of proteolytic processing of filaggrin and corneodesmosin, suggesting epidermal barrier dysfunction. Inappropriate degradation of matriptase was observed. Degrees of proteolysis of these proteins were corelated with the severity of manifestations, suggesting that inappropriate proteolysis might be a possible cause of the skin manifestations. These results strongly suggest that capsaicin may dysregulate the protease system, resulting in alteration of profilaggrin and corneodesmosin proteolysis and skin manifestations. These events may be influenced by postnatal epidermal development.

The role of kinin B1 and B2 receptors in the mouse model of oxazolone-induced atopic dermatitis

This study evaluated the role of kinin B₁ and B₂ receptors in the pre-clinical mouse model of oxazolone-induced atopic dermatitis. The B₁ R715 or B₂ HOE140 receptor antagonists were dosed at different schemes of treatment. After assessment of clinical lesion scores and pruritus, lesional skin samples were collected for histopathological analysis. The plasma extravasation and the expression of the metalloproteinase ADAMTS5 were also assessed. The immunopositivity for kinin receptors was evaluated in the skin, dorsal root ganglion (DRG), thoracic spinal cord and brain cortex sections. Marked upregulation of B₁ and B₂ receptors was observed in the skin of oxazolone-treated mice. The induction of atopic dermatitis led to a downregulation of both receptors in the DRG, without any alteration in the spinal cord and brain cortex. The repeated administration of HOE140 (50 nmol/kg; i.p.) partially inhibited the oxazolone-related pruritus, associated with a reduction of ADAMTS5 immunolabelling in the skin. Alternatively, R715 (438 nmol/kg; i.p.) produced a mild inhibition of plasma extravasation in oxazolone-challenged mice. Noteworthy, the repeated i.d. injection of R715 (30 nmol/site) or HOE140 (3 nmol/site) significantly reduced the histiocyte numbers, according to the histopathological analysis. Either B₁ or B₂ kinin antagonists, irrespective of the protocol of treatment, did not alter any other evaluated clinical or histological parameters. Data brings novel evidence about the role of kinin receptors in allergy-related conditions, such as atopic dermatitis. Further studies to test different protocols of treatment with kinin antagonists on in-depth cellular alterations underlying oxazolone-induced atopic dermatitis remain to be performed.

Subsets of T lymphocytes in the lesional skin of pityriasis rosea

BACKGROUND

Pityriasis rosea is a common papulosquamous disorder. However, its etiology and pathogenesis remain unclear.

OBJECTIVE

We investigate the types of inflammatory cells infiltrating the lesional skin of pityriasis rosea and demonstrate whether T-cell-mediated immunity is involved in the pathogenesis of this condition or not.

METHODS

The biopsies were taken from the lesional skin of 35 cases of patients diagnosed with pityriasis rosea. The specimens were prepared in paraffin sections, then submitted to routine immunohistochemistry procedures using monoclonal antibodies directed against CD3, CD4, CD8, CD20 and CD45RO and horseradish peroxidase-labeled goat anti-human antibodies. The positive sections were determined by the ratio and staining intensity of positive inflammatory cells.

RESULTS

The mean score of positive CD3, CD4, CD8, and CD45RO staining was respectively 3.74±3.88, 5.67±4.40, 2.94±3.42 and 7.68±4.33 in these pityriasis rosea patients (P<0.001). The percentage of positive staining was 54.29% (19/35), 69.7% (23/33), 40% (14/35) and 79.41% (27/34) (P<0.05). However, the staining of CD20 was negative in all samples. The mean score of CD3 staining in patients with time for remission ≤60 days (4.90±4.21) was higher than that in patients with time for remission >60 days (2.00±2.5) (P<0.05), whereas no statistical difference in the mean score of CD4, CD8 and CD45RO staining was observed. study liMitations: The sample size and the selected monoclonal antibody are limited, so the results reflect only part of the cellular immunity in the pathogenesis of pityriasis rosea.

CONCLUSION

Our findings support a predominantly T-cell mediated immunity in the development of pityriasis rosea.

Relationships among plasma granzyme B level, pruritus and dermatitis in patients with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease characterized by skin barrier dysfunction, allergic inflammation and intractable pruritus resistant to conventional antipruritic treatments, including H₁-antihistamines. Granzymes (Gzms) are a family of serine proteases expressed by cytotoxic T lymphocytes and natural killer cells that have been shown to modulate inflammation. However, the relationship between Gzms and pathology in AD remains unclear.

OBJECTIVE

This study assessed the correlation between plasma GzmB levels and severity of pruritus and dermatitis, in AD patients.

METHODS

Plasma was collected from 46 patients with AD, 24 patients with psoriasis, and 30 healthy controls. AD severity was assessed with the scoring atopic dermatitis (SCORAD) index, psoriasis severity with the psoriasis area and severity index (PASI), and degree of pruritus by visual analogue scale (VAS) score. GzmA, GzmB and gastrin releasing peptide (GRP) levels were measured by enzyme-linked immunosorbent assays.

RESULTS

Plasma GzmB concentrations were significantly higher in patients with AD and psoriasis than in healthy controls. Correlation analyses showed that plasma GzmB concentrations positively correlated with SCORAD and serum levels of severity markers such as thymus and activation-regulated chemokine, and lactate dehydrogenase in AD patients. Moreover, plasma levels of GRP, an itch-related peptide, were higher in patients with AD, positively correlating with VAS score and plasma GzmB level. In addition, plasma GzmB concentration was significantly lower in the treatment group than the untreated group with AD. Meanwhile, there were no correlations among GzmB levels, VAS score and PASI score in patients with psoriasis. In contrast to the results of plasma GzmB, plasma GzmA levels were unchanged among AD, psoriasis and healthy groups, and showed no correlations with VAS score and SCORAD index in patients with AD.

CONCLUSION

Plasma GzmB levels may reflect the degree of pruritus and dermatitis in patients with AD.

Red Cell Distribution Width and Mean Platelet Volume in Patients With Pityriasis Rosea

Background

Pityriasis rosea (PR) is an inflammatory skin disorder of unknown etiology. However, it is suggested to be related with the reactivation of human herpes virus 7 (HHV-7) and/or HHV-6. It is sometimes diffucult to distinguish PR from PR-like drug eruptions and other inflammatory disorders, so we need new parameters which are cheap and easy in determining PR. Red blood cell distribution width (RDW) and mean platelet volume (MPV) have been studied as inflammatory markers in recent studies. However, the RDW and MPV in PR patients have not been investigated. This is the first study investigating RDW and MPV parameters in PR.

Methods

This was a retrospective study of 127 patients and 127 healthy controls. MPV, RDW and the other laboratory tests were recorded.

Results

RDW levels of patients with PR were significantly lower than those of the controls (13.66 ± 2.68 and 14.00 ± 1.39, P < 0.01). The other inflammatory markers such as MPV (9.97 ± 0.99 and 10.0 ± 1.06, P = 0.7) and platelet (2.66.29 ± 62.85 and 277.41 ± 63.50, P = 0.3) were studied and statistically significant differences were not obtained. There were no significant differences found between the patient group and healthy controls in terms of hemoglobin, hematocrite, C-reactive protein (CRP), sedimentation, mean corpuscular volume (MCV), aspartate aminotransferase (AST), red blood cell (RBC), alanine aminotransferase (ALT), blood urea nitrogen (BUN), and creatinine parameters (P > 0.05).

Conclusion

RDW can be used as a marker in diagnosing PR.

Evaluation of clinico-epidemiological and histopathological features of pityriasis rosea

Introduction

Pityriasis rosea is a sudden-onset and self limiting disease with specific skin rash. The exact etiology is still not clear.

Aim

To determine epidemiological, etiological, clinical and histopathological features in pityriasis rosea (PR).

Material and methods

Fifty two patients (older than 18 years) with PR were included in this study. Patients were examined for epidemiological and etiological features. Biopsy specimens obtained from secondary eruptions were histopathologically evaluated with hematoxylin-eosine and immunohistochemically evaluated with CD3 and CD20 monoclonal antibodies.

Results

Age range of patients was 18–53, mean age was 29.3 ±9.5 and women-to-men ratio was 1.08/1. Thirty-nine (75%) patients had a history of wearing new clothes, 27 (51.9%) patients had a history of recent respiratory tract infection, 15 (28.8%) patients had a history of recent gastrointestinal infection. Eczematous changes were detected in biopsy materials by histopathological evaluation, and cellular infiltrate was positively stained with pan T-cell marker CD3 and negatively stained with B lymphocyte marker CD20 in all biopsy materials in immunohistochemical examination.

Conclusions

In our study, frequency of pre-disease infection and prodromal symptoms history were determined to be higher than the results of similar studies in the literature. These higher results suggest that PR may be delayed-type hypersensitivity to an infectious factor. However, positive staining of all biopsy materials with pan T lymphocyte marker CD3 supports the association with cellular immunity. We believe that more extensive studies are needed on this issue.

Is dermatitis palmaris sicca an irritant contact dermatitis?

BACKGROUND

Dermatitis palmaris sicca (DPS) is a common dry-fissured palmar dermatitis in Asian women. It may be an irritant contact dermatitis, but the immunophenotype of the cells in its infiltrate is unknown.

OBJECTIVE

The aim of this study was to evaluate the role of inflammatory cells in the pathogenesis of DPS.

METHODS

Patch testing was done in 68 patients with DPS, 87 subjects with hand eczema, and 31 healthy subjects. Immunophenotyping of cutaneous inflammatory cells was performed in 8 patients with DPS, 10 subjects with hand eczema, and 8 healthy individuals.

RESULTS

Positive patch rates were higher in patients with DPS and those with hand eczema compared with healthy controls, but strong positive (++ or +++) reactions in DPS were fewer compared with hand eczema. Density of CD3, CD4, CD8, and CD68 cells in skin lesions of DPS and hand eczema was significantly higher than that in normal skin. Sparse CD20 cells were present only in hand eczema. Compared with hand eczema, the number of CD3, CD8, CD68, and dermal CD1a cells decreased, but epidermal CD1a cells and CD4/CD8 ratio increased in DPS.

CONCLUSIONS

The absolute lack of CD20 cells and relative scarcity of dermal CD8 and CD1a cells in skin lesions might be insufficient to induce contact hypersensitivity, so DPS may be an irritant but not allergic contact dermatitis.

A time-lapse approach to examine chromium and nickel effects on wound healing in vitro

Chromium and nickel cause allergic contact dermatitis, a common biological skin response to sensitizing agents. This study used a conventional in vitro wounding model to study the impact of sensitizing agents on the innate immune response of human keratinocytes. Experiments were designed to evaluate the involvement of specific Toll-like receptors and metalloproteinases as effectors molecules downstream, at a molecular level. Further, keratinocytes were co-cultured with monocytes (THP-1 cells) to reproduce an inductive stimulus on monocytes made by metals. Human keratinocytes (HaCat) were grown on plates covered with collagen type I, chemically treated, and then mechanically injured with a sterile pipette tip. Restoration of the monolayer integrity was monitored by time-lapse video microscopy. Effector gene expression was evaluated by real-time PCR. The presence of chromium significantly dropped the rate of wound closure, while nickel-induced hyper-proliferation ended in an acceleration of the healing process, an event that does not occur in vivo. This latter outcome led to considering nickel as an unsuitable example for use in the experimental model. Focusing solely on the chromium aspect of this study, RNA profiles of selected molecular markers were generated to ascertain if the detrimental stimulus from chromium was eliminated or persisted both in keratinocytes alone and/or during co-cultures of keratinocytes and monocytes. Monocytes accelerated the process of wound repair. This in vitro experimental model highlighted the involvement of innate immunity in response to chromium and might be useful for test molecules of therapeutic interest for the treatment of skin lesions. However, the experience with nickel reveals that there are limitations to the utility of this wound model system after all.

Intracellular versus extracellular granzyme B in immunity and disease: challenging the dogma

The cytotoxic granzyme B (GrB)/perforin pathway has been traditionally viewed as a primary mechanism that is used by cytotoxic lymphocytes to eliminate allogeneic, virally infected and/or transformed cells. Although originally proposed to have intracellular and extracellular functions, upon the discovery that perforin, in combination with GrB, could induce apoptosis, other potential functions for this protease were, for the most part, disregarded. As there are 5 granzymes in humans and 11 granzymes in mice, many studies used perforin knockout mice as an initial screen to evaluate the role of granzymes in disease. However, in recent years, emerging clinical and biochemical evidence has shown that the latter approach may have overlooked a critical perforin-independent, pathogenic role for these proteases in disease. This review focuses on GrB, the most characterized of the granzyme family, in disease. Long known to be a pro-apoptotic protease expressed by cytotoxic lymphocytes and natural killer cells, it is now accepted that GrB can be expressed in other cell types of immune and nonimmune origin. To the latter, an emerging immune-independent role for GrB has been forwarded due to recent discoveries that GrB may be expressed in nonimmune cells such as smooth muscle cells, keratinocytes, and chondrocytes in certain disease states. Given that GrB retains its activity in the blood, can cleave extracellular matrix, and its levels are often elevated in chronic inflammatory diseases, this protease may be an important contributor to certain pathologies. The implications of sustained elevations of intracellular and extracellular GrB in chronic vascular, dermatological, and neurological diseases, among others, are developing. This review examines, for the first time, the multiple roles of GrB in disease pathogenesis.