Dietary management of dermatitis herpetiformis

Dermatitis herpetiformis (DH) is an extremely itchy, papulovesicular skin disease characterized in part by the presence of IgA at the dermal-epidermal junction. Eighty-five percent to 90% of DH patients have granular deposits of IgA at the dermal-epidermal junction, and essentially all of these patients have an associated, for the most part asymptomatic, gluten-sensitive enteropathy (GSE). The association of GSE and DH suggested that the cutaneous manifestations of DH could be controlled by the use of a gluten-free diet. Institution of a gluten-free diet in patients with DH and granular IgA deposits has been shown to be effective in controlling the cutaneous eruption of DH. Seventy percent to 100% of patients who begin a strict gluten-free diet have been shown to be able to decrease the dosage of medication needed to control their DH after a mean of eight to 18 months on the diet. Furthermore, 40% to 70% of patients with DH can control their skin disease completely, without any medication, after longer periods of time on the gluten-free diet (two years and longer). Although the gluten-free diet has been shown to be of great benefit in the control of the skin manifestations of DH, at the present time there is no evidence to suggest that the gluten-free diet is in any way protective against the risk of intestinal lymphoma that has been documented in GSE. Evaluation of the cutaneous IgA deposits in DH skin after long periods of time on a gluten-free diet suggests that there may be a slight decrease in the intensity of the IgA deposits, but the true pathogenetic relationship between the cutaneous IgA deposits, the cutaneous manifestations of DH, and the associated GSE remains unknown.     

Soluble interleukin-2 receptor levels in patients with dermatitis herpetiformis

To determine the role of T-cell activation in dermatitis herpetiformis (DH), soluble IL-2R levels were measured by enzyme-linked immunosorbent assay (ELISA) in the sera of 30 patients with DH. Levels of this shed receptor are considered to be a measure of in vivo T-lymphocyte activation, and are elevated in the sera of many patients with inflammatory and immune-mediated diseases. Fifteen of the thirty (50%) patients with DH had elevated levels of soluble IL-2R compared to one of 31 (3%) healthy HLA-B8 or HLA-DR3 control subjects (p less than 0.00001) and one of 10 (10%) healthy non-HLA-B8/-DR3 subjects (p less than 0.0018). In addition, the mean soluble IL-2R level in the patients with DH (744 +/- 381 U/ml) was also significantly higher than that seen in 31 healthy HLA B8 or HLA DR3 individuals (388 +/- 160 U/ml, p = 0.0001) and 10 healthy non-HLA-B8/DR3 individuals (397 +/- 201 U/ml, p = 0.002). Only two of the 30 patients with DH had active skin lesions at the time of serum sampling, one of whom had elevated levels of IL-2R. Measurement of soluble IL-2R levels in sequential serum samples, available in four patients with DH at times of active and inactive skin disease, demonstrated a temporal association between soluble IL-2R level elevations and active skin disease in two patients and no association in two patients. In one patient a marked elevation in soluble IL-2R levels occurred with the onset of gastrointestinal symptoms, which decreased by 14% with institution of a gluten-free diet. In order to determine if soluble IL-2R levels are related to the mucosal immune response, the IL-2R levels were compared to the level of IgA antibodies directed against the dietary antigen beta-lactoglobulin. Ten of eleven (91%) patients with circulating IgA anti-beta lactoglobulin antibodies were also found to have elevated levels of IL-2R. In contrast, in the patients with no detectable IgA anti-beta lactoglobulin antibodies, only four of 16 (25%) had elevated levels of IL-2R (p = 0.001). Because IL-2R levels are not related to activity of the skin disease in patients with DH but are associated with the presence of IgA antibodies against the dietary antigen beta-lactoglobulin, these results suggest that some of the T-cell activation commonly present in DH reflects an ongoing immune response in the gastrointestinal tract.     

IgA class antibodies in dermatitis herpetiformis: reaction with tissue antigens

The mechanism for deposition of IgA in dermatitis herpetiformis (DH) remains unclear. To test the hypothesis that a circulating IgA class antibody in DH patients binds to constituents of normal human skin, we employed the highly sensitive methods of immunoblotting and indirect immunofluorescence. Sera from 64 DH patients, 67 randomly selected normal control subjects, 29 histocompatibility locus antigen (HLA) B8/DR3/DQw2 controls, and 12 psoriatic patients were tested for IgA binding to various substrates, including dermal and epidermal extracts, fibroblast and keratinocyte supernatants, monkey esophagus sections, and whole and saline-split normal human skin sections. Significant differences observed among the groups in the frequency of detectable IgA antibodies reacting with various substrates were as follows: 1) IgA antibodies in 30% of both DH and HLA B8/DR3/DQw2 sera bound to a 60-Kd protein in dermal extracts (p less than 0.25 versus non-HLA matched controls); 2) IgA antiendomysial antibodies were present in 38% of DH patients (predominantly those not on gluten-free diets), whereas both normal control groups had frequencies of 5-10% (p less than 0.025); 3) there was more nonspecific IgA antibody-binding to dermal, epidermal, and bovine proteins in DH and HLA control sera than in normal sera; and 4) IgA antibodies directed against the basement membrane were present with an increased frequency of 25% in both DH and HLA B8/DR3/DQw2 sera (p less than 0.1 versus non-HLA matched controls). Therefore, these results do not support the hypothesis that there is an unique antigen within normal human skin to which IgA antibodies from DH sera bind.     

An HLA class II region restriction fragment length polymorphism (RFLP) in patients with dermatitis herpetiformis: association with HLA-DP phenotype

Dermatitis herpetiformis (DH) is characterized in part by an associated gluten-sensitive enteropathy (GSE), and a strong association with the HLA antigens HLA-A1, -B8, -DR3, and -DQw2, essentially identical to that seen in patients with isolated GSE (celiac disease). A 4.0-kb RsaI RFLP has been identified using a DQ beta-chain cDNA and localized to the HLA-DP beta-chain region. This RFLP has been found more frequently in patients with isolated GSE than in normal HLA matched controls. We have analyzed genomic DNA from 24 patients with DH and 15 HLA-matched controls to determine if this 4.0-kb RsaI RFLP was present in patients with DH. Twenty-one of 24 (87%) of patients with DH were found to have this RFLP as compared to 7 of 10 (70%) HLA-DR3, -DQw2 matched control subjects (p = 0.23). Thus, the 4.0-kb RsaI RFLP detected in patients with isolated GSE is also present in patients with DH; however, its frequency in DH patients does not differ significantly from that of HLA matched controls. Family studies of patients with DH revealed that although the 4.0-kb RsaI RFLP segregated with the HLA-A1, -B8, -DR3, -DQw2 haplotype in one family, it did not segregate with this disease-associated haplotype in two other families. In both patient and control populations, this RFLP was associated with HLA-DPw1 or -DPw3 phenotypes; 25 of 26 (96%) HLA-DPw1 or -DPw3 subjects were found to have this RFLP compared to only 1 of 6 (17%) who did not express HLA-DPw1 or -DPw3 (pc = 0.0009). These population and family data suggest that this 4.0-kb RsaI RFLP is primarily associated with the HLA-DPw1, -DPw3 phenotype, rather than the clinical manifestations of DH. These data further document that the strongest association of DH with HLA antigens remains with HLA-DQw2 and HLA-DR3 antigens.     

TCR Vbeta expression in the small bowel of patients with dermatitis herpetiformis and gluten sensitive enteropathy. Limited expression in dermatitis herpetiformis and treated asymptomatic gluten sensitive enteropathy

Dermatitis herpetiformis (DH) is a blistering skin disease characterized by cutaneous deposits of IgA and an associated, most often asymptomatic, gluten sensitive enteropathy (GSE). Gluten sensitive enteropathy is also seen in patients that do not have skin disease or cutaneous IgA deposits, but do have significant gastrointestinal (GI) complaints. Patients with DH and with GSE without skin disease have similar small bowel morphologic changes and HLA associations and both the skin disease and the GI symptoms can be controlled by a gluten free diet. It is not known what factors allow almost all patients with DH to continue to eat gluten and not develop symptomatic gastrointestinal disease. We have examined the expression of the Vbeta T-cell receptor (TCR) in the small bowel of patients with DH (n=11) and of patients with both symptomatic (n=10) and asymptomatic (n=7) GSE without skin disease to determine if differences in the pattern of TCR Vbeta expression are associated with differences in the clinical manifestations of these diseases. TCR Vbeta expression was analyzed using RT-PCR from small bowel biopsies. Patients with DH and those with GSE without skin disease that were on a gluten free diet and asymptomatic were found to express 6.6 and 5.6 out of 20 Vbeta families respectively, with no single family preference. Examination of peripheral blood lymphocytes from these patients did not reveal any restriction of TCR Vbeta family expression. In contrast, patients with symptomatic GSE expressed 12.6 Vbeta families (P< 0.05), with no consistent preferential expression of any single Vbeta family between patients. Patients with DH, who are continuing to ingest wheat, show a more restricted pattern of TCR Vbeta utilization, similar to that of treated patients with GSE without skin disease, and significantly different from GSE without skin disease patients eating gluten. These findings suggest that the restricted nature of the TCR Vbeta expression may play a role in the different clinical manifestations of dermatitis herpetiformis and isolated gluten sensitive enteropathy.     

Dietary gluten challenge does not influence the levels of circulating immune complexes in patients with dermatitis herpetiformis

To examine the relationship between the gluten-sensitive enteropathy (GSE) and IgA circulating immune complexes (CIC) in dermatitis herpetiformis (DH) a series of dietary gluten-challenge studies were performed in patients with DH and patients with ordinary GSE. Serial serum samples were monitored for IgA-, IgG-, and IgM-containing CIC levels. In the first study, 9 DH patients and 5 controls were fed 20 g of gluten flour as a breakfast meal on 1 of 2 consecutive study days. DH patients did not develop or increase their levels of CIC after gluten-challenge or gluten-free meals. There was no significant difference between the DH patients and the control group in regard to development of CIC. To evaluate the effect of dietary gluten in another form, 8 DH patients were given meals containing 100 g of boiled Canadian cracked wheat. Two patients with ordinary GSE were also challenged with cracked wheat. Again there was no elevation or induction of CIC above baseline determinations by gluten-challenge meals. These studies suggest that dietary gluten does not induce the formation of CIC in patients with DH.     

Dermatitis herpetiformis in two American blacks: HLA type and clinical characteristics

Dermatitis herpetiformis is a rare blistering skin disease characterized in part by granular IgA deposits at the dermoepidermal junction, an associated gluten-sensitive enteropathy, and a strong association with the human histocompatibility leukocyte antigen (HLA)-A1 (74% of patients with dermatitis herpetiformis), -B8 (88%), -DR3 (95%), and -DQw2 (100%). Dermatitis herpetiformis is rarely seen in American blacks and some investigators have postulated that this finding may be due to the decreased frequency of HLA-A1 and -B8 in American blacks compared with Caucasians (American blacks: HLA-A1 = 15.3%, HLA-B8 = 10.7%; Caucasian: HLA-A1 = 26.4%, HLA-B8 = 18.3%). This report describes two American blacks with dermatitis herpetiformis and reports the results of HLA typing of these subjects for HLA-A, -B, -C, -DR, and -DQ antigens. HLA typing revealed that neither patient expressed HLA-A1 or -B8; however, both patients did express the class II antigens most frequently seen in dermatitis herpetiformis, HLA-DR3 and -DQw2. Comparison of HLA class II antigen frequency in normal American blacks and Caucasians reveals a similar frequency of HLA-DR3 and -DQw2 (American blacks: HLA-DR3 = 27.6%, HLA-DQw2 = 40.9%; Caucasian: HLA-DR3 = 22.6%, HLA-DQw2 = 32.9%). These data confirm the importance of the HLA class II region in the pathogenesis of dermatitis herpetiformis. In addition, these data suggest that the rare occurrence of dermatitis herpetiformis in American blacks is not due to the decreased frequency of the HLA class I antigens -A1 and/or -B8 but rather is related to differences in the HLA class II region not detected by routine HLA typing.     

HLA ANTIGENS IN DERMATITIS HERPETIFORMIS AMONG JAPANESE

HLA-typing was performed on Japanese patients with dermatitis herpetiformis Duhring (DH). Only one of them showed granular deposition of IgA at dermal papillae whereas the rest showed linear IgA deposition. No statistically significant increase in the incidence of specific HLA antigen was noted. HLA-B8 was absent in both patients and healthy controls.     

Immunoglobulin A deposition in jejunal mucosa of children with dermatitis herpetiformis

Previously we have shown by indirect immunofluorescence (IF) technique that a special IgA antibody in the sera of patients with dermatitis herpetiformis (DH) binds to the structures of the normal jejunum. Now we show by direct IF that specific IgA deposits are present in the proximal jejunum of 11/12 DH and 2/2 celiac patients before a gluten-free diet (GFD). The IgA deposition was in a tubular pattern underlying the villous and crypt epithelial basement membranes and in the lamina propria. This IgA deposition diminished or was not detectable in DH patients under a GFD for a year, and became detectable under gluten challenge in three DH patients. One patient with celiac disease and IgA deficiency, four with other intestinal diseases, and four without jejunal damage had neither jejunal IgA deposition nor circulating IgA anti-jejunal antibody. The deposition of IgA in the jejunum seemed to be correlated with the presence of IgA anti-jejunal antibody in the serum and with the presence of jejunal damage, but the degree of jejunal atrophy, the titer of the anti-jejunal antibody, and the intensity of jejunal IgA deposition in DH patient were not clearly related. Deposition of IgA in the jejunum in DH did not clearly correlate with the activity of the skin symptoms and thus may not be directly related to the pathogenesis of the skin disease of DH.     

Characterization of the mucosal immune response to dietary antigens in patients with dermatitis herpetiformis

The association of dermatitis herpetiformis (DH) with granular IgA deposits at the dermal-epidermal junction and a gluten sensitive enteropathy (GSE) suggests that a mucosal immune response may play an important role in the pathogenesis of DH. The degree of antigenic restriction, the immunoglobulin class and subclass response to dietary antigens, and the relationship of antibodies against dietary antigens to IgA-containing circulating immune complexes (CIC) in patients with DH, however, are not known. We have examined the serum of 33 patients with DH for IgG and IgA antibodies against gliadin, and against 3 dietary proteins not thought to be related to GSE, beta-lactoglobulin (beta-lacto), bovine gamma globulin (BGG), and casein. Eleven of 33 (33%) patients with DH had IgA anti-gliadin antibodies, whereas IgA antibodies against beta-lacto were found in 11 of 33 patients (33%), against BGG in 15 of 32 (47%), and against casein in 6 of 33 (18%); 17 of 32 (53%) patients had IgA antibodies against one or more of these dietary antigens. Significantly higher levels of IgA antibodies were detected against beta-lacto (2,500 +/- 2,320 ng/ml, mean +/- SEM) and BGG (2,340 +/- 1,890 ng/ml) than gliadin (1,250 +/- 851 ng/ml) in this group of antibody positive patients (p less than 0.05, Wilcoxon signed ranks test). Eleven of 17 patients with IgA antibodies against dietary antigens were found to have IgA-containing CIC, whereas only one of the 15 antibody negative patients had IgA-containing CIC (p = 0.0008, Fisher's exact test). IgA anti-gliadin antibodies were found to contain both IgA1 and IgA2 with a significantly increased proportion of IgA2 when compared with the IgA2 composition of the total serum IgA (IgA2: anti-gliadin antibodies = 34 +/- 4.2%; total serum IgA = 19 +/- 4.8%, p = 0.02, Students paired t test). IgG antibodies against these antigens were found to occur slightly more frequently in amounts not significantly greater than IgA antibodies. This data demonstrates that a serum IgA and IgG antibody response to dietary antigens occurs in approximately 50% of DH patients with a higher proportion of IgA2 than total serum IgA and does not appear to be restricted to gliadin. This is significantly different from the pattern of cutaneous immunoreactants in patients with DH, and suggests that the deposition of IgA in DH skin may be the result of an atypical mucosal immune response, a non-immunologic interaction of IgA1 and DH skin, or arise from a non-mucosal source.     

Alterations in HLA-DP and HLA-DQ antigen frequency in patients with dermatitis herpetiformis

Dermatitis herpetiformis (DH) is associated with a markedly increased frequency of the HLA class II antigens DR3 and DQw2. To investigate a possible role of HLA-DP (or closely associated genes) in the pathogenesis of DH as well as to confirm the previously described alterations of HLA-DR3 and HLA-DQw2 antigen frequency, we have typed 43 patients with DH for HLA-DP, HLA-DQ, and HLA-DR antigens. All patients with DH had typical clinical and histologic features, as well as granular deposits of IgA at the dermal-epidermal junction by direct immunofluorescence. HLA-DR3 was expressed in 41 of 43 (95%) DH patients, whereas HLA-DQw2 was expressed in all 43 (100%). The overall distribution of HLA-DP antigens in patients with DH was significantly different from that seen in all controls and in HLA-DR3 and HLA-DQw2 controls (p less than 0.02). Examination of the frequency of individual DP antigens revealed that HLA-DPw1 was increased (42% of patients with DH vs 11% of all controls and 26% of DR3 positive controls), but this increase was not statistically greater than that expected due to the disequilibrium linkage of DPw1 with DR3/DQw2. Patients with DH, however, did have a statistically significant decreased frequency of DPw2 (14% of patients vs 31% of all controls and 41% of DR3 positive controls) (pc less than 0.05). Studies of three informative families demonstrated that the DPw2 genes of the DH patients were not present on the haplotype thought to carry a DH susceptibility gene (HLA-A1, HLA-B8, HLA-DR3, HLA-DQw2). A role of HLA-DP region genes in the pathogenesis of DH is further suggested by the observation that HLA-DPw1 was expressed in 82% (9 of 11) of DH patients with IgA antibodies against dietary antigens as compared with only 33% (4 of 12) of patients without IgA antibodies. HLA-DP genes or genes closely linked to them may be important in DH either as markers of the disease haplotype or by direct involvement in its pathogenesis.     

A comparative serological and molecular study of linear IgA disease and dermatitis herpetiformis

The class I and class II HLA serologically defined antigens and DQ alpha and DX alpha restriction fragment length polymorphism (RFLP) in 23 patients with linear IgA disease (LAD) were determined and their frequencies compared with those in a group of patients with dermatitis herpetiformis (DH) and healthy controls. In LAD there was a significant increase in HLA-B8 and DR3 and a larger increase in the DQw1-DR2/DRw6 related DQ alpha 6.2 kb and 6.8 kb RFLP. In DH there was a significantly increased frequency of HLA-A1, B8, DR3, and DQw2 with a concomitant increase in the DR3-DQw2 related DQ alpha 4.6 kb RFLP. The difference in DR3 frequencies and the increased frequency of DQw1 rather than DQw2 in LAD indicates that different susceptibility genes operate in the two diseases.     

Gluten-free diet for dermatitis herpetiformis: the long-term effect on cutaneous, immunological and jejunal manifestations

In 32 patients with dermatitis herpetiformis (DH) we studied the effect of gluten-free (22 patients) and gluten-reduced (10 patients) diet for periods ranging between 15 and 43 months. Variables such as cutaneous manifestations, dependence on dapsone, IgA deposits in the skin, small-bowel function, and jejunal mucosal morphology were studied. 59% of the patients on gluten-free diet could stop dapsone medication and remain symptom-free, compared with 10% on gluten-reduced diet. The time needed to achieve this therapeutic response varied from 5 to 31 months. IgA decreased in the skin to a degree which roughly paralleled the morphological normalization of the jejunal mucosa. In no patient, however, did the IgA completely disappear. It is suggested that IgA is not the main factor inducing DH symptoms, but rather a secondary phenomenon. Repeated jejunal biopsies revealed normalization of the mucosal histology in 52% of the patients on gluten-free diet, compared with none in the gluten-reduced diet group.     

Review: dermatitis herpetiformis

Dermatitis herpetiformis (DH) or Duhring-Brocq disease is a chronic bullous disease characterized by intense itching and burning sensation in the erythematous papules and urticarial plaques, grouped vesicles with centrifuge growth, and tense blisters. There is an association with the genotypes HLA DR3, HLA DQw2, found in 80-90% of cases. It is an IgA-mediated cutaneous disease, with immunoglobulin A deposits appearing in a granular pattern at the top of the dermal papilla in the sublamina densa area of the basement membrane, which is present both in affected skin and healthy skin. The same protein IgA1 with J chain is found in the small intestinal mucosa in patients with adult celiac disease, suggesting a strong association with DH. Specific antibodies such as antiendomysium, antireticulina, antigliadin and, recently identified, the epidermal and tissue transglutaminase subtypes, as well as increased zonulin production, are common to both conditions, along with gluten-sensitive enteropathy and DH. Autoimmune diseases present higher levels of prevalence, such as thyroid (5-11%), pernicious anemia (1-3%), type 1 diabetes (1-2%) and collagen tissue disease. The chosen treatment is dapsone and a gluten-free diet.     

Dermatitis herpetiformis

Dermatitis herpetiformis (DH) is a chronic, polymorphic, pruritic skin disease that develops mostly in patients with latent gluten-sensitive enteropathy. DH patients usually present with skin manifestations only and are not aware of the underlying small-bowel problems. Owing to the granular immunoglobulin (Ig) A deposition at the tips of the papillary dermis and to the subepidermal blister formation associated with neutrophilic accumulations underlying the basement membrane, DH is considered to be an autoimmune blistering disease. Contrary to the other bullous disorders, DH patients have no circulating autoantibodies binding to the cutaneous basement membrane components or to other adherent structures of the skin, but they have gluten-induced IgA autoantibodies against transglutaminase (TG) 2 and TG3. The serum IgA against tissue TG2 is a most specific and sensitive serologic marker of gluten-sensitive enteropathy and is equivalent to the perviously described IgA endomysium antibodies. DH could be a cutaneous IgA-epidermal TG3 immunocomplex disease, developing only in a few patients with gluten-sensitive enteropathy as a second gluten-dependent disease. The main treatment of DH today is a strict, life-long gluten-free diet. Untreated DH patients should be regularly monitored for malabsorption and lymphomas. Associated autoimmune diseases are more common among DH patients. Family screening for gluten sensitivity is also strongly suggested.     

Dermatitis herpetiformis in Japan: an update

BACKGROUND: Although dermatitis herpetiformis (DH) is a relatively common disease in Caucasian populations, it is rare in Asian populations including the Japanese. We encountered a Japanese case of DH which showed granular IgA and C3 deposits in the papillary dermis and which was associated with gluten-sensitive enteropathy but no HLA-B8/DR3/DQ2. OBJECTIVE: The purpose of this study is to describe the characteristics of Japanese DH cases, since most of them have been reported in Japanese language and dermatologists outside Japan are not familiar with the characteristics of Japanese DH. METHODS: We have reviewed all 34 Japanese DH cases reported previously. RESULTS: We found several features of Japanese DH compared with Caucasian DH, such as a high frequency of the fibrillar pattern, rarity of gluten-sensitive enteropathy and an absence of the HLA-B8/DR3/DQ2 haplotype. CONCLUSION: There might be significant differences in pathophysiology between Caucasian and Japanese DH cases.     

Cutaneous endothelial cell activation in normal skin of patients with dermatitis herpetiformis associated with increased serum levels of IL-8, sE-Selectin, and TNF-alpha

The mechanisms that lead to the development of skin lesions in patients with dermatitis herpetiformis (DH) are not known. We hypothesized that an ongoing immune response in the gut of patients with DH would result in an increase in circulating cytokines and be associated with endothelial cell activation, creating a proinflammatory environment in the skin. Skin biopsies from the normal-appearing inner arm of 11 DH patients, with no active skin lesions, and 12 normal subjects were analyzed for E-selectin (E-sel) and ICAM-1 mRNA. DH patients' skin expressed markedly increased levels of E-sel mRNA. Mean E-sel mRNA expression in DH skin was 1,271 (range 63.78-5861) times greater than that of a control, normal skin (P<0.001) with no significant increased expression of ICAM-1 mRNA. Serum levels of soluble E-selectin (sE-sel), IgA anti-tissue transglutaminase antibodies, and serum IL-8 levels were significantly increased in patients with DH. These studies demonstrate that patients with DH have evidence of endothelial cell activation in the skin and systemic manifestations of the ongoing inflammation associated with the mucosal immune response. Endothelial cell activation may play a critical role in the development of skin lesions in patients with DH and may represent a common mechanism for cutaneous manifestations of inflammatory gastrointestinal diseases.     

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. Cutaneous deposition of polyclonal IgA1

Dermatitis herpetiformis (DH) is a pruritic papulovesicular skin disorder of unknown cause, characterized by granular IgA deposits in the dermis along the dermoepidermal junction. It is associated with gluten-sensitive enteropathy and increased IgA production by gut lymphoid tissue. We report four cases of immunologically documented DH studied by immunofluorescence technique. Monoclonal antibodies against the IgA subclasses IgA1 and IgA2 were used. IgA1 without IgA2 was found in the cutaneous deposits in each case. The IgA1 had both kappa and lambda light chains in approximately equal quantities. Because normal gut-associated lymphoid tissue produces 70% IgA1 and 30% IgA2, while circulating IgA is primarily IgA1, it could be concluded that the IgA in the skin of DH patients is not produced in the gut. However, the subclass restriction of the IgA produced by pathologic gut-associated lymphoid tissue is unknown. Alternatively, both IgA1 and IgA2 may be produced by the gut, but only IgA1 is involved in the production of cutaneous lesions.     

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.