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 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.     

Dermatitis herpetiformis: problems,progress and prospects

Dermatitis herpetiformis (DH) is an IgA mediated blistering skin disease characterized by the presence of granular deposits of IgA in papillary dermis. The major significant advances in our understanding of DH have been the demonstration that DH patients also have coeliac diseases (CD) and that the rash is also gluten dependent. As a result, it is now possible to cure patients by gluten withdrawal from the diet. The other major significant finding has been the presence of IgA in the uninvolved, now used as the diagnostic criterion for the disease. Despite the fact that it has been known for over fifty years that gluten causes the enteropathy of CD, and for over thirty years the rash of DH, it is still not known how gluten produces these effects. Future immunological studies may look at ways of inducing tolerance to gluten peptides once the toxic ones have been identified. Vaccination against gluten peptides may also be possible in those affected with gluten sensitive disorders.     

IgA anti‐epidermal transglutaminase autoantibodies: a sensible and sensitive marker for diagnosis of dermatitis herpetiformis in adult patients

Background Dermatitis herpetiformis (DH) is a rare gluten‐sensitive blistering itchy skin disease, strictly related to coeliac disease (CD). Direct immunofluorescence, demonstrating IgA granular deposits localized either in the dermal papillae or along the dermo‐epidermal junction, is currently the gold standard for diagnosis of DH. It has been shown that DH immunocomplexes contain epidermal transglutaminase (eTG) and that sera from patients with DH contain antibodies specifically directed against eTG. Objectives We studied the usefulness of serum eTG antibodies in discriminating between DH, CD and other gastrointestinal and dermatologic diseases. Methods eTG antibodies were tested in 308 adult patients’ sera: 44 patients with untreated dermatitis herpetiformis (UDH), 99 patients with untreated coeliac disease (UCD), 70 dermatological controls and 95 gastrointestinal controls. Results In UDH eTG antibody levels were significantly higher than in DH patients on gluten‐free diet, UCD, gastrointestinal controls and dermatological controls. In UCD eTG antibodies strongly correlated with tissue transglutaminase (tTG) antibodies, whereas in UDH no significant correlation was observed. Conclusion Serum IgA eTG antibody determination can efficiently distinguish UDH from other dermatological itchy diseases and is highly sensitive to gluten‐free diet.     

Dermatitis herpetiformis

The state of our understanding of the pathogenesis of DH relies on the integration of several key characteristics: (1) a high frequency of the HLA antigens HLA-B8, HLA-DR3, and HLA-DQw2, (2) an associated GSE, (3) the resolution of both the skin lesions and gut abnormalities in response to a gluten-free diet, and (4) the presence of granular deposits of IgA in normal and perilesional skin. The role of the HLA class II antigens expressed in patients with DH most likely relates to the afferent or initiating arm of the immune system. The association of the HLA-A1, -B8, -DR3, -DQw2 haplotype with Sjogren's syndrome, chronic hepatitis, Graves' disease, and other presumably immunologically mediated diseases, as well as the evidence that some normal HLA-B8, -DR3 individuals have an abnormal in vitro lymphocyte response to wheat protein and mitogens and have abnormal Fc-IgG receptor-mediated functions, suggests that this HLA haplotype or genes linked closely to it may confer a generalized state of immune susceptibility on its carrier, the exact phenotypic expression of which depends on other genetic or environmental determinants. It also is clear, from the association of DH with GSE and the ability to control the cutaneous manifestations of DH with a gluten-free diet, that the gut disease is a critical factor in the pathogenesis of DH. Several pathogenetic theories about the origin of the cutaneous IgA deposits in DH have been proposed, one of which states that the IgA is produced in the gut mucosa as a response to a dietary antigen or gut epithelial antigen and then cross-reacts with the skin of patients with DH. A second hypothesis is that the IgA produced in the gut binds to an antigen and is deposited in skin as an antigen-antibody complex. Finally, it could be that the gut mucosal abnormality simply allows an unknown antigen access to the central immune system where an IgA antibody is produced that binds to skin. The failure to detect circulating IgA anti-basement membrane zone antibodies in patients with DH suggests that either the structures to which the IgA binds are not present in normal skin without DH, that IgA cannot bind to these structures in vitro, or that the circulating IgA is too scant for detection with conventional methods. Finally, it must be considered that the IgA deposited in DH skin may bind as a result of non-antigen-antibody interactions that cannot be duplicated in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)     

Co-localization of IgA and TG3 on healthy skin of coeliac patients

BACKGROUND: Dermatitis herpetiformis (DH), the skin's expression of coeliac disease (CD), is induced by the presence of IgA antibodies and epidermal transglutaminase (TG3) as the main autoantigen, stored in the papillary dermis and on the vessel walls. AIMS: To evaluate the presence of IgA and TG3 deposits, considered to be the first step in inducing DH, in healthy skin of coeliac patients without cutaneous manifestations. METHODS: Punch biopsies were taken from 11 consecutive coeliac patients, two with DH and nine without cutaneous manifestations, three of whom were adhering to a gluten-free diet (GFD), and evaluated for the presence of deposits in the upper dermis and vessel walls by immunofluorescence and confocal microscopy. RESULTS: In coeliac patients affected by DH we found the presence of IgA and TG3 deposits mainly on the upper dermis, but also in vessel walls. In all coeliac patients without DH and also in those patients who were following a strict GFD, we found widely variable deposits of IgA and TG3 in both the papillary dermis and the vessel walls, although a lower intensity of the fluorescence signal was detected than with coeliac patients affected by DH. Double immunostaining with anti-IgA and anti-TG3 antibodies showed a strong co-localization in the upper dermis in patients with DH and a weaker co-localization in those without DH. CONCLUSIONS: We have demonstrated the presence of IgA and TG3 deposits in the healthy skin of coeliac patients, which are considered to play a central role in the pathogenesis of DH.     

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 (author's transl)]

Detailed investigations of 9 patients with dermatitis herpetiformis are presented. In all cases cutaneous lesions were controlled by dapsone alone or by dapsone and gluten free diet. Granular IgA deposits were found in 7 patients, linear IgA deposits in one, and C3 component of complement in one. 3 patients out of 8 tested, carried the specific HLA-B8 antigen. Despite an extensive investigation, no malabsorption was detected. Jejunal biopsies were performed in 8 cases. Jejunal villous flattening was observed in one patient. It improved after a 2 months gluten free diet on subsequent jejunal biopsies. D. H. seems peculiar in France as compared with case reports from other countries: low prevalence of gluten sensitive enteropathy; rare occurrence of the specific HLA-B8 antigen; incidence of D. H. seems to be low in France. It is noticeable that french incidence of coeliac disease is low as well. This suggests a genetic difference in the investigated population (low prevalence of HLA-B8 antigen) and/or different alimentary habits, particularly a low dietary gluten amount.     

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.     

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: an evaluation of diagnostic criteria

Forty-two patients in whom a clinical diagnosis of dermatitis herpetiformis (DH) had been, made, were studied. All patients had a small intestinal biopsy, a biopsy of uninvolved skin for detection of the presence of IgA deposits by immunofluorescence, serum and red cell folate estimations and examination of the serum for anti-reticulin antibody. The response of the skin eruption to dapsone was noted. Thirty patients had biopsies of skin lesions for routine histological examination. IgA deposits were found in the uninvolved skin of thirty-five of the forty-two patients. Evidence of an enteropathy was found in thirty-four of those thirty-five patients. Of the seven patients who did not have IgA in the uninvolved skin, only one showed evidence of enteropathy, which was slight, and this patient was shown subsequently to have pemphigus and not DH. Of the thirty biopsies of skin lesions, only five showed all the features usually considered to be characteristic of DH. And-reticulin antibody was found in eight patients, and in all of these IgA was present in the uninvolved skin. Low red cell folate levels were found in eleven patients (all of whom had an enteropathy and IgA in the uninvolved skin). Low serum folate levels were found in thirty-four patients, thirty-one of whom had IgA deposits in the uninvolved skin and an enteropathy; in the other three patients who did not have IgA deposits or an enteropathy, all were on dapsone and this may have accounted for the abnormal result. In forty-one of the forty-two patients the rash was dapsone responsive. The patient who showed no response to dapsone had no IgA in the uninvolved skin and no evidence of enteropathy. Follow-up showed that of the seven patients with no IgA in the skin, one had pemphigus, and in three the rash eventually cleared spontaneously and the patients no longer required treatment. There was no evidence of spontaneous remissions in the patients with IgA in the uninvolvcd skin. It would appear that the presence of IgA deposits in the uninvolved skin is part of the syndrome of DH and that the diagnosis should not be made unless these deposits are found.     

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.     

Dermatitis herpetiformis. Part I. Epidemiology, pathogenesis, and clinical presentation

Dermatitis herpetiformis (DH) is an autoimmune disease that is linked to gluten sensitivity and has a clear relationship to celiac disease. Both conditions are mediated by the IgA class of autoantibodies and the diagnosis of DH is dependent on detection of granular deposits of IgA in the skin. There is an underlying genetic predisposition to the development of DH but environmental factors are also important. Typically, young adults present with excoriations only, as the severe pruritus effectively destroys any primary lesions. Based upon our experience with DH and a comprehensive literature review, we provide an update of DH epidemiology, pathophysiology, and clinical presentation.     

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.     

Dermatitis herpetiformis presenting as chronic urticaria

Childhood dermatitis herpetiformis (DH) is an immunobullous disease associated with gluten-sensitive enteropathy. This disease is rare in children and is typically characterized by intensely pruritic vesicles on the extensor surfaces. Definitive diagnosis of DH depends on the direct immunofluorescence finding of granular or fibrillar IgA deposits along the basement membrane zone of biopsied perilesional skin. We report an 11-year-old boy with an unusual presentation of DH characterized by a 7-month history of chronic urticaria-like skin lesions. He had evanescent, largely asymptomatic, urticarial wheals on his trunk, face, and extremities that were unresponsive to conventional therapy for urticaria. Skin biopsy specimen findings were consistent with DH and direct immunofluorescence of perilesional skin was diagnostic. The patient had no symptoms of gluten-sensitive enteropathy at the time of diagnosis, and his skin lesions rapidly cleared with dapsone therapy. This patient serves to highlight an unusual presentation of childhood DH and the need to consider this diagnosis when evaluating chronic urticarial lesions in children.     

IgA-binding structures in dermatitis herpetiformis skin are independent of elastic-microfibrillar bundles

Dermatitis herpetiformis (DH) is characterized in part by the presence of granular deposits of IgA in the papillary dermis just beneath the dermal-epidermal junction. The nature of the structures to which IgA binds in DH skin, however, has not been clearly demonstrated. Previous immunoelectron-microscopy studies using the peroxidase-antiperoxidase technique have concluded that the IgA may bind to abnormal elastic microfibrillar bundles. Recently, antibodies have been developed against a major component of the elastic microfibril bundles, fibrillin. In addition, another dermal matrix protein, hexabrachion, has been characterized and found in normal human skin in a distribution similar to the IgA deposits of DH. Utilizing antibodies against fibrillin, hexabrachion, and human IgA and immunoelectronmicroscopy with immunogold staining techniques, we have examined the skin from patients with DH in order to localize the IgA deposits. Normal-appearing skin from five patients with DH exhibited electron-dense patches within the dermis, which were not seen in skin from normal subjects. These structures were sometimes adjacent to the basement membrane zone, but appeared amorphous and without a well-defined fibrillar structure. The electron-dense patches were labeled with anti-human IgA, but not with antibodies to fibrillin or hexabrachion. The anti-IgA antibody did not label the normal basement membrane. These studies confirm the presence of abnormal electron-dense, amorphous structures in the skin of patients with DH. Due to this lack of association with the elastic microfibril bundles and the lack of labeling with antibodies against fibrillin, we suggest that these deposits are distinct from the microfibrillar bundles of elastic tissue and may represent IgA bound to degraded basement membrane or isolated dermal deposits of IgA.     

Immunoglobulin, complement and epidermal transglutaminase deposition in the cutaneous vessels in dermatitis herpetiformis

BACKGROUND: Recently, epidermal transglutaminase (TG) has been identified within the papillary IgA granules in dermatitis herpetiformis (DH). Although IgA type autoantibodies to tissue and epidermal TGs are characteristic serological markers for DH, these antibodies do not bind to normal papillary skin structures. AIMS: To test the possibility of IgA immune complex precipitation within the vessel walls as a first step in the pathogenesis of skin symptoms, we analysed immunoglobulin, complement, and epidermal TG deposition along the vascular system of DH skin. METHODS: Punch biopsy specimen were taken from 116 DH patients' skin, and evaluated for the presence of vascular immune precipitates by direct immunofluorescence. Skin samples from 16 DH patients were also studied for tissue and epidermal TGs. RESULTS: In 74 (64%) of the 116 DH skin studied, significant vascular staining accompanied the DH-specific granular IgA fluorescence (IgA and C3 in 39 patients; IgA alone in 18; IgA, C3 and IgM together in five; IgM alone in 12). In most cases (92%), the precipitates were detected in the small vessels of the papillary dermis; however, a subpapillary vascular fluorescence was also observed in a few patients (8%). Skin IgA colocalized with epidermal TG in the vessel walls and within the scattered papillary peri- and intervascular DH bodies. Tissue TG did not colocalize either with the immunoglobulins or with the complement precipitates of the dermis. Furthermore, we could not detect keratinocyte TG in the DH bodies nor in the vessel walls. CONCLUSIONS: These findings support possible immune complex precipitation in the vessel walls of DH skin and further confirm the significance of epidermal but not tissue TG in the pathomechanism of skin symptoms.     

Dermatitis herpetiformis: selective deposition of immunoglobulin A1 in granular deposits in clinically normal skin

The subclass composition of IgA in granular deposits in the papillary dermis of clinically normal skin taken from 12 patients with dermatitis herpetiformis (DH) was determined using monoclonal IgA-subclass specific antibodies and immunofluorescence microscopy. In skin from one patient with extensive deposits of IgA minute amounts of IgA2 could be detected whereas IgA1 was found in all the biopsies examined. These findings favour the postulation that properties of certain IgA-molecules other than their antigen-binding specificity may cause their deposition in DH.     

Dermatitis herpetiformis bodies. Ultrastructural study on the skin of patients using direct preembedding immunogold labeling

Skin samples from three adult patients with dermatitis herpetiformis (DH) and granular IgA deposits in the papillary tips were studied using ultrastructural immunogold technique. IgA positive, so-called DH bodies were identified as amorphous clumps--most probably immunocomplex aggregates--scattered throughout the upper papillary dermis. Dermatitis herpetiformis bodies were seen underneath the basement membrane, sometimes along microfibrillar bundles, as well as adjacent to the papillary collagen fibers and within the surface (microfibrillar) region of elastic tissue. Some DH bodies, however, were not related to any fibrillar components. The collagen and elastic fibers, microfibrillar bundles, anchoring fibrils, and elastic microfibrils themselves were unlabeled. Dermatitis herpetiformis bodies were not found in normal human skin. The results of our ultrastructural study indicate that DH bodies either are bound to a nonfibrillar component of dermal connective tissue or represent deposits of immune complexes trapped in DH skin.     

Dermatitis herpetiformis

Dermatitis herpetiformis (DH) is a cutaneous manifestation of coeliac disease (CD), which causes an itching and blistering rash, typically on the elbows, knees and buttocks. DH and CD share a similar genetic background, small bowel mucosal alterations, and an autoimmune response against tissue transglutaminase in the serum and small bowel. DH is typically diagnosed during adulthood, and it is slightly more common among males than females. The incidence of DH seems to be decreasing, in contrast to the detected four‐fold increase in the incidence of CD. In addition to typical clinical picture, diagnosis of DH relies on the demonstration by direct immunofluorescence of pathognomonic granular IgA deposits in the papillary dermis. Circulating tissue transglutaminase antibodies support the diagnosis, but their absence does not exclude DH. Obtainment of small bowel mucosal biopsies is not necessary when DH is diagnosed, but if performed, the majority of patients are found to have villous atrophy, and even those with normal villous architecture evince CD‐type inflammation. The treatment of choice in DH is a strict, life‐long adherence to a gluten‐free diet (GFD). In addition to alleviating the symptoms of DH and healing the small bowel mucosal damage, a GFD increases the quality of life for patients, and decreases the risk for lymphoma in DH. Further, the mortality rate of patients with DH treated with a GFD seems to be lower than that of the general population. However, as changing to a GFD has a rather slow effect on the DH rash, patients with severe skin symptoms should additionally be treated with dapsone medication. This review article is based on a presentation given at the British Society for Medical Dermatology blistering skin diseases meeting 2019.