Expression of interleukin-4 and interferon-gamma in the small bowel of patients with dermatitis herpetiformis and isolated gluten-sensitive enteropathy

Distinct eosinophil cytokine expression patterns in skin diseases - the possible existence of functionally different eosinophil subpopulations

BACKGROUND

The function of eosinophils has been attributed to host defense, immunomodulation, and fibrosis. Although eosinophils are found among infiltrating cells in a broad spectrum of skin diseases, their pathogenic role remains uncertain. This study aimed to analyze the cytokine expression by eosinophils in different skin diseases.

METHODS

Skin specimens from different skin diseases [allergic/reactive, infectious, autoimmune, and tumors/lymphomas (LY)] were stained by antibodies directed to eosinophil cationic protein, cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-5, IL-6, IL-10, IL-11, IL-13, IL-17, IL-25, IL-33, interferon-γ, transforming growth factor (TGF)-β, and thymic stromal lymphopoietin], eotaxins (CCL11, CCL24, and CCL26), metalloproteinase (MMP)-9 as well as extracellular matrix proteins (tenascin-C and procollagen-3) and then analyzed by laser scanning microscopy.

RESULTS

The number of eosinophils varied considerably in and between disease groups and did not correlate with the numbers of accompanying inflammatory cells. The expression of IL-5, IL-6, IL-11, TGF-β, CCL24, and MMP-9 by eosinophils significantly differed between disease groups. Eosinophils in tumors/LY predominantly expressed IL-6, TGF-β, and CCL24, but not IL-11. On the other hand, in autoimmune diseases, eosinophils largely contributed to MMP-9 production. IL-5-generating eosinophils were particularly obvious in allergic and infectious diseases.

CONCLUSION

In skin diseases, eosinophil expresses a broad spectrum of cytokines. The different cytokine expression patterns suggest distinct functional roles of eosinophils in these diseases that might be related to host defense, immunomodulation, fibrosis, and/or tumor development.

Pathophysiology of dermatitis herpetiformis: a model for cutaneous manifestations of gastrointestinal inflammation

Dermatitis herpetiformis (DH) is an autoimmune blistering skin disease in which antigen presentation in the gastrointestinal mucosa results in cutaneous IgA deposition and distinct, neutrophil-driven cutaneous lesions. Our findings suggest that the qualitatively different immune response to gluten in the intestinal mucosa of patients with DH results in minimal clinical symptoms, allowing the continued ingestion of gluten and the eventual development of DH. Our model may provide a new way to understand the pathogenesis of other skin diseases associated with gastrointestinal inflammation such as pyoderma gangrenosum or erythema nodosum, or explain association of seronegative inflammatory arthritis with inflammatory bowel disease.

A new model for dermatitis herpetiformis that uses HLA-DQ8 transgenic NOD mice

Dermatitis herpetiformis (DH) is an autoimmune blistering skin disorder that is associated with gluten sensitivity. It presents as a papulovesicular rash and is often associated with enteropathy. The rash resolves when the patient is placed on a gluten-free diet and/or dapsone. DH, as well as celiac disease, is tightly associated with DQ2 and DQ8. A novel mouse model for DH is described that utilizes the NOD background and the HLA-DQ8 transgene. The addition of DQ8 contributes sensitivity to gliadin, and the addition of the NOD background contributes to autoimmunity and pathogenesis. Fifteen NOD DQ8+ mice of 90 that were sensitized to gluten developed blistering pathology similar to that seen in DH. Neutrophil infiltration of the dermis, deposition of IgA at the dermal-epidermal junction, and a complete reversal of the blistering phenomenon with the administration of a gluten-free diet with or without dapsone were observed. None of the 3 blistering mice examined had small-bowel pathology. This animal model of DH will be useful to determine the specificity of the IgA deposits, as well as the pathogenic mechanisms that occur in the skin as a result of gluten ingestion.

Neutrophil CD11b, L-selectin and Fc IgA receptors in patients with dermatitis herpetiformis

BACKGROUND

The skin lesions found in patients with dermatitis herpetiformis (DH) are characterized by the presence of neutrophils at the dermal papillary tips in areas where the diagnostic cutaneous IgA deposits are found. Although the presence of the skin lesions of DH is known to be associated with gluten-sensitive enteropathy, the mechanisms that control the development of skin lesions are not known.

OBJECTIVES

To determine if circulating neutrophils from patients with DH have evidence of priming as shown by increased expression of CD11b, decreased expression of L-selectin and increased function of neutrophil Fc IgA receptor.

METHODS

Neutrophils from 12 normal subjects and 10 DH patients with active, ongoing disease and 14 DH patients with quiescent disease activity were examined by fluorescence-activated cell sorter for expression of cell surface CD11b, L-selectin expression, Fc IgA expression (CD89) and for the function of the Fc IgA receptor by determining the binding capacity of neutrophils for monoclonal human IgA.

RESULTS

Neutrophils from patients with active, ongoing DH had increased expression of CD11b when compared with patients with inactive DH or normal subjects [mean net geometric mean channel fluorescence (GMCF): active DH, 403.3; inactive DH, 237.8; normal subjects, 290.5; P < 0.05]. L-selectin expression in both groups of DH patients was significantly lower than that seen in normal subjects (mean net GMCF: active DH, 363.2; inactive DH, 375.2; normal subjects, 432.7; P < 0.05). No difference in CD89 expression was seen in any of the groups; however, the function of Fc IgA receptor was increased in patients with active DH when compared with patients with inactive DH and normal subjects.

CONCLUSIONS

Neutrophils from patients with active, ongoing DH show an increased expression of CD11b, decreased expression of L-selectin and increased ability to bind IgA, consistent with a pattern of priming of the neutrophils. This priming may occur in the gut as a result of the ongoing mucosal immune response that is present in patients with DH on a gluten-containing diet and may predispose neutrophils to localize in the skin of patients with DH.

Dermatitis herpetiformis: should direct immunofluorescence be the only diagnostic criterion?

We describe a 7-year-old boy with dermatitis herpetiformis (DH) diagnosed on clinical and histologic evidence, negative direct immunofluorescence (DIF) findings for junctional IgA deposits in uninvolved skin, positive IgA endomysial and gliadin antibodies, and jejunal biopsy revealing a gluten-sensitive enteropathy. Treatment with dapsone led to the disappearance of cutaneous lesions and pruritus within 48 hours. Demonstration of IgA immune deposits in the dermal papillae has been the only acceptable criterion for the diagnosis of dermatitis herpetiformis. However, considering several reports in the literature of DH with a negative DIF and our own case, we believe that in the absence of the characteristic DIF pattern, one needs the combination of clinical, histologic, and immunologic data to support the diagnosis of DH. We also discuss recent developments in the diagnosis of DH.