Interferon-gamma in the treatment of atopic dermatitis: influence on T-cell activation

Atopic dermatitis: systemic immunosuppressive therapy

Atopic dermatitis (AD) is a pruritic, relapsing skin disorder that negatively impacts the quality of life of those affected and that of their families. Treatment options for AD encompass a variety of emollients, topical corticosteroids, topical immunomodulators, phototherapy, and systemic agents. Such agents as systemic corticosteroids, cyclosporine, azathioprine, interferon-gamma, methotrexate, and mycophenolate mofetil have been shown to be efficacious in the treatment of moderate-to-severe AD but are not officially approved for this purpose. In this article, we review some of the data supporting efficacy of these medications and discuss some of the adverse events associated with their use.

Off-label uses of biologics in dermatology: Interferon and intravenous immunoglobulin (Part 1 of 2)

The introduction of a number of biologic therapies into the market has revolutionized the practice of dermatology. These therapies include interferons, intravenous immunoglobulin, infliximab, adalimumab, etanercept, efalizumab, alefacept, and rituximab. Most dermatologists are familiar with the Food and Drug Administration-approved indications of these medications. However, numerous off-label uses have evolved. As part 1 of a 2-part series, this article will review the literature regarding the off-label uses of the interferons and intravenous immunoglobulin in dermatology.

A clinician's paradigm in the treatment of atopic dermatitis

Successful management of atopic dermatitis requires a multipronged approach that includes skin barrier function care, use of topical or systemic agents, and identification and elimination of precipitating or exacerbating factors. Because the origin of atopic dermatitis is multifactorial and trigger factors differ among patients, treatment plans must be specific to the individual patient. This article offers an example of a permutational, or flexible, treatment paradigm. The approach utilizes 4 topical regimens--high-potency topical corticosteroids, lowest effective potency topical corticosteroids, topical calcineurin inhibitors (TCIs), or topical corticosteroid/TCI combinations--as initial therapy in a variety of induction protocols, as determined by the severity of a patient's condition and history. The paradigm permits treatment to progress from a chosen induction therapy to maintenance therapy. During the patient's induction therapy, as soon as an acceptable level of clearance is achieved, therapy should be adjusted to a maintenance regimen, such as monotherapy with either a TCI or a lowest effective potency topical corticosteroid (the latter used intermittently) or an alternation of the two agents. If there is no clearance or positive response with the initial induction protocol, the clinician should move to one of the alternative regimens.

Alteration in the production of IL-10 and IL-12 and aberrant expression of CD23, CD83 and CD86 by monocytes or monocyte-derived dendritic cells from atopic dermatitis patients

Atopic dermatitis (AD) is characterized by the presence of Th2-type cells in the skin infiltration as well as in the peripheral blood, although a predominant infiltration of interferon-gamma (IFN-gamma)-producing cells is also reported in the chronic skin lesions of AD. Recently it has become clear that the development of Th1 or Th2 is strongly influenced by factors produced by the antigen presenting cells (APCs). To clarify whether APCs from AD patients play a favorable role in the differentiation of Th2 cells, we compared the production of cytokines and the expression of co-stimulatory molecules by monocytes (MOs) and monocyte-derived DCs (MoDCs) after stimulations with various reagents between 13 AD patients and 13 age-matched healthy controls. We examined their production of IL-1 beta, IL-10, IL-12p40, and IL-12p70, and their expression of CD23, CD40, CD54, CD80, CD83, CD86 and HLA-DR. We stimulated them with superantigens, lipopolysaccharide (LPS), agonistic anti-CD40 antibody, phytohemagglutinins (PHA), IL-1beta/TNF-alpha, IL-4, or IFN-gamma. The following results were obtained (1): IL-10 production was significantly enhanced in AD MOs after LPS stimulation. In contrast, IL-12p40 production was significantly lower in AD MOs than in HC MOs after a variety of stimulations (2). IL-12p40 was also significantly lower in AD MoDCs after LPS stimulation (3). The induction of CD23 with IL-4 was significantly higher in AD MOs. and finally (4), AD MoDCs augmented the expression of CD83, CD86, and HLA-DR less significantly than HC MoDCs after anti-CD40 Ab stimulation. These data indicate that AD APCs show some responses different from those observed in HC APCs after several stimulations, such as LPS, IL-1 beta/TNF-alpha, IL-4, or anti-CD40 Ab, and that these responses might play a role in the polarizing process of helper T cells into Th2 cells as recognized in AD patients.

Mast cells regulate IFN-gamma expression in the skin and circulating IgE levels in allergen-induced skin inflammation

BACKGROUND

Mast cells are important effector cells in IgE-mediated allergic reactions. They are present in normal skin and increased in skin lesions of patients with atopic dermatitis (AD).

OBJECTIVE

We used mice deficient in mast cells (W/W(v)) to assess the role of these cells in a murine model of allergen-induced skin inflammation induced by repeated epicutaneous sensitization with ovalbumin (OVA); the model exhibits many of the characteristics of AD.

METHODS

Mice deficient in mast cells were sensitized with OVA. Histologic and immunohistochemical examinations, as well as measurements of IL-4 and IFN-gamma mRNA, were performed on OVA-sensitized skin. Total and antigen-specific serum IgE levels were determined.

RESULTS

Infiltration in W/W(v) mice by mononuclear cells, T cells, and eosinophils in OVA-sensitized skin was comparable to that in wild-type (WT) controls. Expression of IL-4 mRNA in sensitized skin sites was similarly increased in WT and W/W(v) mice. However, IFN-gamma mRNA expression was significantly increased in sensitized skin of W/W(v) mice but not in that of WT controls. IL-4 mRNA was readily detectable in unsensitized skin of WT controls but not in that of W/W,(v) mice, whereas expression of IL-12 p40 mRNA was significantly increased in unsensitized skin of W/W(v) mice in comparison with WT controls. Total serum IgE levels were significantly increased after epicutaneous sensitization in W/W(v) mice in comparison with WT controls.

CONCLUSION

These results suggest that mast cells regulate IFN-gamma expression in the skin and IgE levels in the circulation in a model of allergen-induced skin inflammation with similarities to AD. This is important, given the role of IFN-gamma in keratinocyte injury in AD and the role of IgE-mediated reactions in exacerbating AD.

Functional human IgE specific for Dermatophagoides farinae antigen is produced in SCID mice reconstituted with peripheral mononuclear cells derived from healthy persons and patients with asthma

BACKGROUND

Whether normal peripheral blood mononuclear cells (PBMCs) transferred to severe combined immunodeficient (SCID) mice produce specific IgE remains unclear.

METHODS

Mice received injections of Dermatophagoides farinae antigen (Df)-stimulated PBMCs from healthy persons (IgE RAST score of 0).

RESULTS

High titers of Df-specific IgE were detected. The Df-specific IgE activity produced was comparable to or higher than that produced by cells from patients with asthma although the time to maximal production was longer. IgE derived from PMBCs of healthy persons or patients with asthma induced histamine release from cultured human basophils that had been stimulated with Df antigen or an anti-IgE antibody. Treatment of Df-stimulated PBMCs with a high dose, but not a low dose, of interleukin-4 stimulated production of Df-specific IgE by PMBCs from healthy persons or patients with asthma. In contrast, intravenous injection of IFN-gamma into reconstituted SCID mice decreased Df-specific IgE production by PBMCs from patients with asthma. In PMBCs from healthy persons, IgE class-switching may occur later and block the effects of treatment with IFN-gamma.

CONCLUSIONS

PBMCs from healthy persons and persons with asthma have clones reactive to allergen and produce functional IgE specific for relevant antigens in mite-sensitive bronchial asthma.

Interferon-gamma is involved in photoimmunoprotection by UVA (320-400 nm) radiation in mice

Ultraviolet B radiation not only inflicts tumor-initiating DNA damage, but also impairs T cell-mediated immunity relevant to survival of the initiated cells. We have reported, however, that ultraviolet A radiation, in contrast, is immunologically innocuous in hairless mice and opossums, but renders the animals resistant to the immunosuppression by ultraviolet B, or its mediator cis-urocanic acid. Ultraviolet B irradiation of skin causes abundant release of numerous cytokines (interleukin-1, interleukin-6, interleukin-10, tumor necrosis factor-alpha); notably interleukin-12 and interferon-gamma do not appear to be upregulated. A recent report has indicated that interleukin-12 protects from photoimmunosuppression in mice, but it remains unclear whether interleukin-12 acts directly or via interferon-gamma, which it is known to stimulate. Here we investigate the possible role of interferon-gamma in UVA photoimmunoprotection, using interferon-gamma gene knockout mice in comparison with control C57/BL6 mice, and the systemic contact hypersensitivity reaction (induced by sensitization through a nonirradiated skin site) to measure immunity. interferon-gamma-/- mice raised normal contact hypersensitivity responses, and were unaffected, as were C57BL control mice, by ultraviolet A exposure. In response to ultraviolet B irradiation or topical cis-urocanic acid treatment, control mice became immunosuppressed by 69% and 27%, respectively, and interferon-gamma-/- mice by 79% and 27%. When ultraviolet B exposure or cis-urocanic acid was followed by ultraviolet A irradiation, however, contact hypersensitivity was totally restored in control mice, but remained suppressed by 55% and 25%, respectively, in interferon-gamma-/- mice. Injection of recombinant interferon-gamma in the interferon-gamma-/- mice restored the ultraviolet A protective effect against cis-urocanic acid-induced immunosuppression. These observations suggest that interferon-gamma plays a part in ultraviolet A immunoprotection from the suppressive effect of ultraviolet B radiation and, and that the mechanism appears to be via antagonism by this cytokine of the cis-urocanic acid immunosuppressive action.

Blood eosinophils and serum IgE as predictors for prognosis of interferon-gamma therapy in atopic dermatitis

BACKGROUND

Interferon-gamma (IFN-gamma) therapy has been reported to be effective in atopic dermatitis. However, IFN-gamma therapy in atopic dermatitis has not yet been well established. In this study, immunologic variables were evaluated as predictors for the prognosis of IFN-gamma therapy in atopic dermatitis.

METHODS

Sixty-eight atopic dermatitis patients were each treated 18 times with 2 x 10(6) units/m2 IFN-gamma. Blood IgE level, eosinophil percentage, eosinophil count, and levels of IFN-gamma, interleukin-4 (IL-4), IL-5, and IL-10 were investigated. According to clinical responses, patients were classified into three groups: patients with improved clinical severity scores of over 20% were included in group A; those with improved scores of 20% or less in group B; and those with no improvement in group C.

RESULTS

Serum IgE levels and blood eosinophil percentages were the lowest in group A. Most atopic dermatitis patients with an eosinophil percentage over 9% and IgE level over 1500 IU/ml did not respond to IFN-gamma therapy. Initial IL-10 levels were the highest in group A. IL-4 levels in group A, and IL-5 and IL-10 levels in all groups were significantly decreased by IFN-gamma therapy.

CONCLUSIONS

IFN-gamma therapy may be recommended for atopic dermatitis patients with blood eosinophil percentages less than 9% and serum IgE levels less than 1500 IU/ml.

Interferon-gamma pretreatment of peripheral blood mononuclear cells partially restores defective cytokine production in children with atopic dermatitis

Interferon-gamma (IFN-gamma) is considered an important determinant of the balance between T-helper type 1 and 2 cytokines and has been used experimentally for the treatment of atopic dermatitis. However, contrasting results have been reported relative to the Th-1/Th-2 cytokine profile in atopic patients. In this study, we examined cytokine production by polyclonally activated peripheral blood mononuclear cells (PBMC) from children with atopic dermatitis, and assessed the influence of in vitro IFN-gamma pretreatment on these cells. A fraction of PBMC isolated from children with severe atopic dermatitis, as well as from age-matched controls, was initially exposed to IFN-gamma. After washing, both treated and untreated cells were then put into culture either alone or with the addition of phytohemagglutinin (PHA) or phorbol myristate acetate (PMA) plus ionomycin. IL-4, IL-5, IL-10 and IFN-gamma production were measured in the supernatants using commercially available ELISAs. PBMC from atopic patients produced more IL-4 (P = 0.04) and IL-10 (P = 0.03) and less IFN-gamma (P = 0.01) than controls, when stimulated with PHA. Interestingly, in PMA + ionomycin stimulated cultures, the atopic cytokine profile was different with more IL-5 (P = 0.0068) and less IFN-gamma production (P = 0.00046) than the control group. When cells were pretreated with IFN-gamma, there were no significant differences between patients and controls. PBMC from children with atopic dermatitis show alterations in cytokine production, compatible in general terms with the Th-1/Th-2 model. Exposure of PBMC to IFN-gamma before activation results in a reduction of these differences, so that cytokine production becomes similar in the atopic and normal groups.

Gamma interferon administration to patients with atopic dermatitis inhibits fibrinolysis and elevates C1 inhibitor

Recombinant human gamma interferon was used to treat 10 atopic dermatitis patients. Recombinant gamma interferon was administered weekly for three consecutive days at 50 microg/M2 SQ for four weeks. All patients' dermatitis improved with recombinant gamma interferon therapy and plasma tumor necrosis factor-alpha levels rose with treatment. Recombinant gamma interferon treatment positively correlated with reduced total plasma fibrinolysis as measured by the fibrin lysis plate, plasmin-alpha2antiplasmin complexes, and tissue type plasminogen activator levels. Accordingly, plasminogen activator inhibitor levels increased. Treatment also was associated with a transient increase in thrombin-antithrombin III complexes. Recombinant gamma interferon resulted in a significant increase in C1 inhibitor antigen but not activity. Plasma prekallikrein, high molecular weight kininogen, and factor XII levels were not decreased. However, 5 of the 10 atopic dermatitis patients before therapy had circulating cleaved plasma high molecular weight kininogen detected on immunoblot, indicating prior kallikrein formation. The cleaved, circulating plasma high molecular weight kininogen disappeared in four out of the five original patients who were reexamined at one year after treatment. These combined data indicated that recombinant gamma interferon treatment reduced total plasma fibrinolysis. In untreated atopic dermatitis, circulating cleaved high molecular weight kininogen also may be a presenting manifestation.