Interleukin-2 receptor expression and interleukin-2 production in bullous pemphigoid

Expression of the JAK/STAT Signaling Pathway in Bullous Pemphigoid and Dermatitis Herpetiformis

A family of eleven proteins comprises the Janus kinases (JAK) and signal transducers and activators of transcription (STAT) signaling pathway, which enables transduction of signal from cytokine receptor to the nucleus and activation of transcription of target genes. Irregular functioning of the cascade may contribute to pathogenesis of autoimmune diseases; however, there are no reports concerning autoimmune bullous diseases yet to be published. The aim of this study was to evaluate the expression of proteins constituting the JAK/STAT signaling pathway in skin lesions and perilesional area in dermatitis herpetiformis (DH) and bullous pemphigoid (BP), as well as in the control group. Skin biopsies were collected from 21 DH patients, from 20 BP patients, and from 10 healthy volunteers. The localization and expression of selected STAT and JAK proteins were examined by immunohistochemistry and immunoblotting. We found significantly higher expression of JAK/STAT proteins in skin lesions in patients with BP and DH, in comparison to perilesional skin and the control group, which may be related to proinflammatory cytokine network and induction of inflammatory infiltrate in tissues. Our findings suggest that differences in the JAK and STAT expression may be related to distinct cytokines activating them and mediating neutrophilic and/or eosinophilic infiltrate.

Bullous Pemphigoid

Bullous pemphigoid (BP) is a chronic, autoimmune, blistering disease observed primarily in the elderly population. Several clinical variants have been described, including classic (bullous), localised, nodular, vegetating, erythrodermic, erosive, childhood and drug-induced forms. Autoantibodies target the BP230 and BP180 antigens, located in the hemidesmosomal complex of the skin basement membrane zone. Subsequent complement activation recruits chemical and cellular immune mediators to the skin, ultimately resulting in blister formation. Both autoantibodies and complement may be detected by various immunofluorescent, immune electron microscopy and molecular biology techniques. Recent trials suggest that potent topical corticosteroids should be considered as first-line therapy. Tetracycline with or without nicotinamide may benefit a subset of patients with mild BP. Oral corticosteroids should rarely exceed 0.75 mg/kg/day and corticosteroid-sparing agents may be useful for recalcitrant disease.

Re-evaluation of the natural course of bullous pemphigoid. A prospective study

BACKGROUND

Few studies of prospectively collected data regarding the natural course of bullous pemphigoid have been performed.

METHODS

The following factors were combined both quantitatively and qualitatively to obtain results: gender, clinical activity based on the estimation of the body area involvement, disease duration, relapses, coexistence with other disease states, and serology Twenty-seven consecutive patients were followed up for 1 year.

RESULTS

Most disease activity (85.2%) is exhibited in the first year after onset. There is a lack of parameters with clear predictive significance. The extent and severity of skin involvement are equally distributed between the sexes and not affected by the disease duration. The generalized form of the disease is predominant (86.5%). The average clinical activity in relapses within the year of follow-up is 48% of the initially observed attack. The probability for recurrence is higher in seropositive patients (overall 37%). Coexistence with other disease states seems to be a random chance event.

CONCLUSIONS

The lack of parameters with predictive importance underlines the necessity of a thorough follow-up to prevent treatment-related complications in elderly patients.

Increased serum levels of interleukin (IL)-5, IL-6 and IL-8 in bullous pemphigoid

Some cytokines have been suggested to take part in the blister formation in bullous pemphigoid (BP). However, the roles of the cytokines are only partly understood. To elucidate the involvement of cytokines in the immunological mechanisms in BP, we investigated the serum levels of interleukin (IL)-2, IL-4, IL-5, IL-6, IL-8, IL-13, soluble IL-2 receptor and soluble CD23 in patients with BP, and the correlation between cytokine levels and other clinical and laboratory data. Serum levels of these cytokines and soluble receptors were determined by enzyme-linked immunosorbent assay in 19 patients with BP and in 16 normal control subjects. Serum levels of IL-5 (P < 0.0001), IL-6 (P < 0.01) and IL-8 (P < 0.05) were significantly higher in BP patients than in the control subjects. Other cytokines and soluble receptor levels were not significantly different. Serum levels of IL-6 (P < 0.05) and IL-8 (P < 0.05) were significantly decreased after treatment when skin lesions disappeared. These results suggest that serum levels of IL-6 and IL-8 could be indicators of disease activity of BP.

Detection of elevated levels of IL-4, IL-6, and IL-10 in blister fluid of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease with autoantibodies directed against antigens associated with hemidesmosomes of basal keratinocytes. In addition to autoantibodies and activated complement, cellular mechanisms are crucial for blister formation in this disease. Mononuclear cells, which are the first cells infiltrating BP lesions, mainly belong to CD3, CD4+ T-helper (Th) cells. Elevated concentrations of IL-2, IFN gamma, TNF beta, and IL-5 have been recently demonstrated in BP blister fluid. In this study, we were interested in levels of other Th-type cytokines, including IL-3, IL-4, IL-6, IL-10, and GM-CSF in blister fluid of BP. Cytokines were determined by ELISA or bioassay. Levels in the blister fluid from ten BP patients were compared with those in serum samples taken at the time of blister puncture and with those in suction blister fluid of ten healthy volunteers. In blister fluid of BP, we found significantly elevated concentrations of IL-4, IL-6, and IL-10 relative to both concurrent serum samples and suction blister fluid from controls. No differences were detected for either IL-3 or GM-CSF. Our results suggest that IL-4, IL-6, and IL-10 are released at the site of blister formation in BP.

Peripheral blood mononuclear cells from patients with bullous pemphigoid have an increased frequency of response to synthetic peptides encoded by BPAG1

We determined the response of peripheral blood mononuclear cells from patients with bullous pemphigoid and normal subjects to synthetic peptides encoded by BPAG1. Peripheral blood mononuclear cells from patients and normal subjects were cocultured in the presence of 15-22-amino-acid-long amphipathic and hydrophilic peptides selected from the BPAG1 sequence. Seven of 10 patients (70%) with bullous pemphigoid had an increased response of peripheral blood mononuclear cells (> 3.25/10(6) cells) when cultured with amphipathic sequences encoded by BPAG1 compared to 3 of 10 (30%) normal subjects. Peripheral blood mononuclear cells from 3 of 15 (20%) patients and 3 of 15 normal subjects (20%) demonstrated an increased response when cultured with hydrophilic peptides. Peptides associated with an increased peripheral blood mononuclear cell response in patients with bullous pemphigoid were adjacent to regions of BPAG1 recently demonstrated to contain epitopes recognized by circulating autoantibodies in the sera of patients with bullous pemphigoid. Increased peripheral blood mononuclear cell responses were more commonly observed in patients with bullous pemphigoid with generalized disease and those who had their disease for longer than 2 months (p < 0.05). The observation that increased duration and generalized disease was associated with increased peripheral blood mononuclear cell responses to peptides encoded by BPAG1 supports the hypothesis that responses to BPAG1 may occur as a consequence of ongoing inflammation at the basement membrane.

Granulocyte activation in bullous diseases: release of granular proteins in bullous pemphigoid and pemphigus vulgaris

BACKGROUND

Eosinophil and polymorphonuclear granulocytes may be involved in the formation of blisters in bullous dermatoses, particularly bullous pemphigoid.

OBJECTIVE

Our purpose was to evaluate the role of granulocyte activation in the pathogenesis of pemphigus vulgaris and bullous pemphigoid.

METHODS

Levels of eosinophil cationic protein (ECP) and neutrophil-derived myeloperoxidase (MPO) in blister fluid and serum and levels of serum IgE were determined in patients with bullous pemphigoid (n = 12), those with pemphigus vulgaris (n = 9) and healthy volunteers (n = 12).

RESULTS

In blister fluid and serum of patients with bullous pemphigoid, significantly elevated concentrations of ECP, MPO and IgE were detected as compared with controls. In contrast, ECP, MPO, and IgE levels in blister fluid and serum of patients with pemphigus vulgaris did not significantly differ from controls. Moreover, the MPO/ECP ratio in serum of patients with bullous pemphigoid was significantly decreased as compared with controls, whereas the MPO/ECP ratio in pemphigus vulgaris did not differ from controls, indicating a preferential activation of eosinophils in bullous pemphigoid only. In patients with bullous pemphigoid, serum levels of ECP and MPO significantly decreased during immunosuppressive therapy to levels similar to those of controls.

CONCLUSION

Activated granulocytes, releasing their granular contents such as ECP and MPO, may be of importance for blister formation in bullous pemphigoid and may be useful for monitoring disease activity.

Evidence for cell-mediated immune mechanisms in the pathology of pemphigus

Pemphigus is an autoimmune blistering disease in which autoantibodies have clearly been shown to be pathogenic. Because autoantibodies are also found in uninvolved skin, further mechanisms may be important in the development of pemphigus lesions. In addition to granulocytes, mononuclear cells are commonly found in pemphigus lesions. To elucidate the role of mononuclear cells in the pathology of this disease, we determined the levels of soluble interleukin-2 receptor in blister fluid and serum samples from pemphigus patients prior to treatment. The interleukin-2 receptor (IL-2R) is expressed on activated mononuclear cells. Depending on its rate of synthesis, a portion is released from the cell surface in a soluble form (sIL-2R). In blister fluid, sIL-2R levels were 2186 +/- 288 U/ml (+/- SD), which was significantly higher than levels in concurrently obtained serum samples (1299 +/- 165 U/ml; P < 0.001). In suction blisters in volunteers, and in patients with second-degree burns or friction-induced bullae, sIL-2R levels were normal in both blister fluid and serum. In pemphigus patients, sIL-2R serum levels continuously declined during systemic therapy, correlating with disease activity. Immunohistological studies demonstrated a marked increase in IL-2R+ cells in both the epidermis and dermis of lesional skin compared with perilesional skin. In the dermis, CD3+ T cells predominated, whereas monocytes/macrophages were most frequent in the epidermis. In pemphigus vulgaris, monocytes/macrophages were restricted to the basal keratinocytes, whereas in pemphigus foliaceus, they were found throughout the lesional epidermis. Our data indicate that activated mononuclear cells are present in lesional skin of pemphigus patients, and may contribute to the pathology of this disease.

The interleukin-2 receptor in lesions and serum of bullous pemphigoid

The interleukin-2 receptor (IL-2R) is mainly expressed on activated T cells. Depending on its rate of synthesis, a portion is released from the cell surface as soluble IL-2R (sIL-2R). Since the role of mononuclear cells in the pathology of bullous pemphigoid (BP) is not well understood, we determined the sIL-2R in both blister fluid and serum of 15 BP patients with generalized disease before initiating systemic treatment. In addition, we obtained both lesional and perilesional skin biopsies and examined the mononuclear infiltrate with a panel of monoclonal antibodies. In BP blisters, sIL-2R levels were significantly increased (2070 +/- 350 U/ml), (+/- SEM) compared with serum samples taken at the time of blister puncture (1340 +/- 290 U/ml). In six patients with blisters due to second-degree burns or friction and in five suction blister volunteers, sIL-2R levels were normal in both blisters and serum. In BP, elevated serum levels decreased to normal during therapy, correlating with disease activity. The immunohistology showed that 30% of mononuclear cells in the dermal infiltrate of lesional skin expressed the IL-2R, whereas only 15% were positive in perilesional skin. IL-2R-positive cells are the most likely source of the shed receptor in BP blisters. Our results indicate the presence of activated T cells in lesions and peripheral blood of BP and thus underline the importance of cell-mediated immune mechanisms in the pathology of this disease.

Epidermal keratinocytes of bullous pemphigoid express intercellular adhesion molecule-1 (ICAM-1)

Intercellular adhesion molecule-1 (ICAM-1) is the ligand for lymphocyte function associated antigen-1 (LFA-1), mediating the adhesion of lymphocytes to vascular endothelium. Keratinocytes are known to express ICAM-1 in some inflammatory dermatoses. Using an indirect immunofluorescence method, we examined the patterns of ICAM-1 and LFA-1 staining in bullous pemphigoid (BP) lesions and compared them to pemphigus vulgaris (PV) cases. ICAM-1 was expressed on the cell surface and in the cytoplasm of epidermal keratinocytes at the sites of erythematous and bullous lesions of BP. LFA-1 molecules were expressed on T cells at the basement membrane zone. In addition, HLA-DR-positive keratinocytes were observed in the basal layer. ICAM-1 was not, however, expressed on epidermal keratinocytes in uninvolved skin from BP patients, PV or normal control skin. It is known that ICAM-1 is expressed on keratinocytes at the site of lymphoid infiltration in cutaneous dermatoses and that LFA-1-positive T cells can bind to interferon gamma-induced ICAM-1-positive keratinocytes. Our results suggest that cellular immunity involving ICAM-1 and LFA-1 may play a part in the pathogenesis of bullous pemphigoid.