IgA anti-endomysial antibodies in dermatitis herpetiformis: correlation with jejunal morphology, gluten-free diet and anti-gliadin antibodies

Cutaneous Disorders Masking Celiac Disease: Case Report and Mini Review with Proposal for a Practical Clinical Approach

Celiac disease (CD) is an immune-mediated systemic gluten-related disorder characterized by a wide spectrum of intestinal and extra-intestinal manifestations, including damage to cutaneous and connective tissue. We report a rare case of chronic severe dermatitis involving connective tissue and cutaneous vascular vessels as the main clinical presentation of undiagnosed seronegative gluten disorder. A gluten-free diet dramatically improved the intestinal and cutaneous clinical damage in the patient. Pitfalls and the steps of differential diagnosis are described. We also review the literature regarding studies of CD and connective tissue diseases to extend the knowledge of these rare associations. We propose a practical diagnostic approach in suspected CD in autoimmune cutaneous disorders.

Diagnosis of autoimmune bullous diseases

Autoimmune bullous disorders (AIBDs) are a heterogeneous group of rare diseases clinically characterized by erosions and/or blisters on the skin and mucous membranes. AIBDs can be categorized into two groups: pemphigus diseases, characterized by intraepidermal blistering and autoantibodies against desmosomal proteins such as desmoglein (Dsg) 1, Dsg3, members of the plakin family, and subepidermal AIBDs, comprised of pemphigoid diseases and dermatitis herpetiformis. Autoantibodies in dermatitis herpetiformis target transglutaminases 2 and 3, while in pemphigoid disease, autoantibodies are directed against structural proteins of the dermal-epidermal junction. Although analysis of a perilesional biopsy with direct immunofluorescence (IF) microscopy is still the diagnostic gold standard, several assays have become widely available that allow serological diagnosis in the majority of patients. Standard serological diagnosis includes indirect IF on monkey esophagus and salt-split human skin. Assays to further characterize autoantibody specificity include ELISA systems based on recombinant forms of the immunodominant regions of the target antigens as well as multivariant indirect IF microscopy tests with several miniature substrates. These serological assays are complemented by various in-house assays using immunoblotting and ELISA, which are only available in specialized laboratories. Here we review new developments in the diagnosis of AIBDs and describe state-of-the-art diagnostic procedures for this group of diseases.

Diagnostik blasenbildender Autoimmundermatosen

Blasenbildende Autoimmundermatosen (BAIDs) sind eine heterogene Gruppe seltener Erkrankungen, die klinisch durch Erosionen und/oder Blasen an Haut und Schleimhäuten charakterisiert sind. BAIDs können in zwei Gruppen eingeteilt werden: Pemphigus-Erkrankungen, die durch intraepidermale Blasenbildung und Autoantikörper gegen desmosomale Proteine wie Desmoglein (Dsg) 1, Dsg3 und Mitglieder der Plakin-Familie charakterisiert sind, sowie subepidermale BAIDs, die Pemphigoid-Erkrankungen und die Dermatitis herpetiformis umfassen. Bei der Dermatitis herpetiformis greifen die Autoantikörper die Transglutaminasen 2 und 3 an, während sie bei Pemphigoid-Erkrankungen gegen Strukturproteine der dermoepidermalen Junktionszone gerichtet sind. Die Analyse einer periläsionalen Biopsie mittels direkter Immunfluoreszenzmikroskopie (IF-Mikroskopie) stellt zwar nach wie vor den diagnostischen Goldstandard dar, mittlerweile sind jedoch verschiedene Tests allgemein verfügbar, die eine serologische Diagnosefindung für den Großteil der Patienten ermöglichen. Zur serologischen Standarddiagnostik gehört die indirekte IF auf Affenösophagus und NaCl-separierter Spalthaut. Die Spezifität der Autoantikörper kann mit ELISA-Systemen, die auf rekombinanten Formen der immundominanten Regionen der Zielantigene basieren, sowie indirekter IF-Mikroskopie anhand multivarianter Tests mit mehreren multivariate näher charakterisiert werden. Diese serologischen Tests werden durch verschiedene hauseigene Immunoblotting- und ELISA-Systeme ergänzt, die nur in spezialisierten Laboratorien verfügbar sind. In diesem Review geben wir einen Überblick über neue Entwicklungen bei der Diagnose von BAIDs und beschreiben moderne Diagnoseverfahren für diese Krankheitsgruppe.

Diagnostic immunology in celiac disease

Serum autoantibodies to transglutaminase and endomysium are found in the majority of patients with celiac disease, an autoimmune multisystem disorder affecting approximately 1% of Western and Middle-Eastern populations. Detection of these antibodies plays a crucial role in the diagnosis of celiac disease. The aim of this review is to summarize recent publications in this field, with particular focus on the applications and limitations of celiac autoantibody testing in routine clinical practice.

Clinical, pathologic, and immunopathologic features of dermatitis herpetiformis: review of the Mayo Clinic experience

BACKGROUND

Dermatitis herpetiformis (DH) is a cutaneous manifestation of gluten sensitivity, occasionally associated with other autoimmune disorders, and reportedly associated with an increased risk of lymphoproliferative disorders. We describe a series of patients with DH, focusing on associated disorders (particularly celiac disease), incidence of lymphoma, histopathology, and sensitivity of direct immunofluorescence (DIF) testing and serologic testing with antiendomysium antibodies for the diagnosis of DH.

METHODS

The medical records of 264 patients with DH diagnosed between 1970 and 1996 were reviewed retrospectively. In addition, the records of six patients evaluated before the advent of DIF testing between 1932 and 1969 were reviewed.

RESULTS

Established celiac disease was present in 12.6% of patients with DH, autoimmune systemic disorders in 22.2%, malignant neoplasms in 10.4%, sarcoidosis in four patients, and ulcerative colitis in six patients. Lymphoproliferative disorders were found in seven patients. The histopathologic examinations showed a marked predominance of neutrophils in the inflammatory infiltrate. DIF testing was positive in 92.4% of the patients tested. Indirect immunofluorescence assay indicated circulating antiendomysial antibodies in the sera of 40 of the 63 patients tested (63.5%).

CONCLUSIONS

In this large series of patients with DH from a single institution, patients had a low incidence of symptomatic gluten-sensitive enteropathy, low risk of lymphoproliferative disorders, and associations with other systemic autoimmune disorders. The value of DIF testing in the diagnosis of DH was confirmed. The detection of antiendomysial antibodies by indirect immunofluorescence was less sensitive than indicated by other reports.

Immunopathology and molecular diagnosis of autoimmune bullous diseases

Autoimmune bullous diseases are associated with autoimmunity against structural components maintaining cell-cell and cell matrix adhesion in the skin and mucous membranes. Pemphigus diseases are characterized by autoantibodies against the intercellular junctions and intraepithelial blisters. In pemphigoid diseases and epidermolysis bullosa acquisita, sub-epidermal blistering is associated with autoantibodies targeting proteins of the hemidesmosomal anchoring complex. The autoantigens in autoimmune blistering diseases have been extensively characterized over the past three decades. In general, the pathogenicity of autoantibodies, already suggested by clinical observations, has been conclusively demonstrated experimentally. Detection of tissue-bound and circulating serum autoantibodies and characterization of their molecular specificity is mandatory for the diagnosis of autoimmune blistering diseases. For this purpose, various immunofluorescence methods as well as immunoassays, including immunoblotting, enzyme-linked immunosorbent assay and immunoprecipitation have been developed. This review article describes the immunopathological features of autoimmune bullous diseases and the immunological and molecular tests used for their diagnosis and monitoring.

Mechanisms of blister induction by autoantibodies

Autoimmune diseases are characterized by defined self-antigens, organ specificity, autoreactive T cells and/or autoantibodies that can transfer disease. Autoimmune blistering diseases are organ-specific autoimmune diseases associated with an immune response directed to structural proteins mediating cell-cell and cell-matrix adhesion in the skin. While both autoreactive T and B cells have been detected and characterized in patients with autoimmune blistering diseases, current evidence generally supports a pathogenic role of autoantibodies for blister formation. The immunopathology associated with blisters induced by autoantibodies relies on several mechanisms of action. Autoantibodies from patients with pemphigus diseases can exert a direct effect just by binding to their target mediated by steric hindrance and/or by triggering the transduction of a signal to the cell. In most subepidermal autoimmune blistering conditions, in addition to the binding to their target antigen, autoantibodies need to interact with factors of the innate immune system, including the complement system and inflammatory cells, in order to induce blisters. Generally, decisive progress has been made in the characterization of the mechanisms of blister formation in autoimmune skin diseases. However, various aspects, including the exact contribution of steric hindrance and signal transduction for pemphigus IgG-induced acantholysis or the fine tuning of the inflammatory cascade triggered by autoantibodies in some subepidermal blistering diseases, still need to be addressed. Understanding the mechanisms by which autoantibodies induce blisters should facilitate the development of more specific therapeutic strategies of autoimmune blistering diseases.

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.

Recognition and management of the cutaneous manifestations of celiac disease: a guide for dermatologists

In celiac disease, the ingestion of gluten-containing cereals, such as wheat, rye, and barley, results in small-bowel mucosal inflammation and villous atrophy with crypt hyperplasia. The prevalence of the condition may be as high as 1% in the adult population. The disease can also embrace various extraintestinal manifestations, of which dermatitis herpetiformis is the best known. Earlier, dermatitis herpetiformis was considered a skin disease occurring often concomitantly with celiac disease. At present, a body of evidence shows that dermatitis herpetiformis is a cutaneous manifestation of celiac disease, and affects approximately 25% of patients with celiac disease. Both conditions can appear in the same family and are closely linked to HLA class II locus in chromosome 6; 90% of patients have HLA DQ2 and, almost all the remainder, HLA DQ8. All patients with dermatitis herpetiformis have at least some-degree of mucosal inflammation or lesion consistent with celiac disease. The etiology of celiac disease in not fully understood, but tissue transglutaminase seems to be the predominant autoantigen both in the intestine and the skin. Serum antibodies against tissue transglutaminase can be used in the serologic screening and follow-up of dietary compliance of patients with celiac disease. Gluten-free diet is essential in the treatment of both conditions, and oral dapsone is usually needed in newly detected dermatitis herpetiformis in order to alleviate symptoms. Oral mucosal lesions, alopecia areata, and vitiligo probably occur more frequently in patients with dermatitis herpetiformis than in the general population. By contrast, the reported association of celiac disease with psoriasis seems to be coincidental.

Concordance of dermatitis herpetiformis and celiac disease in monozygous twins

Celiac disease can be defined as the classical manifestation of gluten sensitivity, which primarily affects the small intestine. Gluten sensitivity has also a skin manifestation, i.e., dermatitis herpetiformis. Both diseases have a strong genetic association with HLA DQ on chromosome 6. In this study we tried to estimate how much different clinical expressions of gluten sensitivity are determined by genetic factors, and hence how feasible they are for genetic mapping; therefore, we studied all six monozygous twin pairs found among 1292 prospectively collected patients of dermatitis herpetiformis in Finland. Three of the six twin pairs were concordant for dermatitis herpetiformis and for simultaneous enteropathy, celiac disease. Two other twin pairs were partially discordant, one of each pair had dermatitis herpetiformis and celiac disease, whereas the other had solely the gut manifestation of gluten sensitivity, i.e., celiac disease. Only one pair was found to be discordant for gluten sensitivity. All the pairs had typical risk alleles for gluten sensitivity, i.e., either HLA DQ2 or DQ8. These results demonstrate that the genetic component in gluten sensitivity as broadly defined is very strong (5/6 concordant). Genetically identical individuals can have clearly distinguished phenotypes, either dermatitis herpetiformis or celiac disease, suggesting that environmental factors determine the exact phenotype of this multifactorial disease. These findings are of importance in genetic linkage analyses, which focus to only certain phenotypic properties of a complex trait.

The neurology and neuropathology of coeliac disease

A number of neurological syndromes have been described in association with coeliac disease. These include disorders of the central nervous system encompassing epilepsy, myoclonus, ataxia, internuclear opthalmoplegia, multifocal leukoencephalopathy and dementia. Most of these associated conditions show a poor response to gluten restriction. Peripheral neuropathies, of axonal and demyelinating types, have also been reported and may respond to elimination of gluten from the diet. The mechanism underlying these processes remains obscure but may be immunological or related to trace vitamin deficiencies. Controversially, it has also been claimed that occult coeliac disease accounts for a substantial proportion of patients with neurological dysfunction of unknown cause. Some authorities recommend that cryptogenic ataxias and neuropathies should be routinely screened for the presence of gluten-sensitivity but this remains contentious and has not been universally accepted. This review will attempt to review the clinical and pathological findings in this condition and speculate on pathogenesis and directions for future research.

Dermatitis herpetiformis and vitiligo: report of a case and review of the literature

We describe the case of a 53-year-old woman presenting papulous and papulovesicular lesions that were highly pruritic, localized mostly in the achromic areas of vitiligo and symmetrically distributed on the elbows, the buttocks, the shoulders and the neck. The histopathological examination performed on the elbow's lesional skin showed the presence of neutrophils and fibrin microabscesses at the tips of dermal papillae, with a few eosinophils, and small separations between the dermis and epidermis just over the infiltrate. The overlying epidermis was uninjured. The performed tests detected IgA anti-endomysium, anti-thyrogloblin, anti-smooth muscle and anti-microsomal fraction autoantibodies; DIF showed the presence of IgA granular deposits at the dermo-epidermal junction, prevalently at the tips of dermal papillae. This is the tenth case reported of an association between dermatitis herpetiformis and vitiligo. Although the two disorders both have immunological pathogeneses, we think that the topographic coexistence of both disorders is coincidental.

Antibodies to tissue transglutaminase as serologic markers in patients with dermatitis herpetiformis

Dermatitis herpetiformis is a gluten-sensitive disease with a symmetrically distributed blistering over extensor surfaces. The association with celiac disease is further supported by the high rate of immunoglobulin A autoantibodies to endomysium in patients with dermatitis herpetiformis, which are highly specific and sensitive indicators of celiac disease. Therefore, we determined immunoglobulin A antibodies to tissue transglutaminase, the recently discovered endomysial autoantigen in celiac disease, in patients with dermatitis herpetiformis and controls. Sera of 61 patients with dermatitis herpetiformis, as characterized by granular immunoglobulin A deposits in the subepidermal basement membrane and known endomysial antibody titers (determined by indirect immunofluorescence) as well as 84 control sera of patients with dermal or intestinal diseases unrelated to dermatitis herpetiformis, were analyzed for circulating immunoglobulin A antibodies to tissue transglutaminase by enzyme-linked immunosorbent assay. Immunoglobulin A anti-tissue transglutaminase titers in patients with dermatitis herpetiformis were significantly elevated above the controls. Furthermore, the immunoglobulin A anti-tTG titers showed a positive correlation with semiquantitative endomysial antibody data. Compared with endomysial antibodies, determination of immunoglobulin A anti-tissue transglutaminase reached a specificity and sensitivity of 97.6% and 89.1%. Patients with dermatitis herpetiformis have elevated immunoglobulin A autoantibodies to tissue transglutaminase, confirming its pathogenic relation with celiac disease and further supporting the usefulness of this novel assay for screening and therapy control.

IgA endomysium antibodies on human umbilical cord: an excellent diagnostic tool for celiac disease in childhood

BACKGROUND

An improvement in screening for celiac disease has recently been described that uses human umbilical cord as a substitute for monkey esophagus to determine IgA endomysium antibodies in adults. As using monkey esophagus is ethically questionable for large-scale screening, we studied whether substitution of umbilical cord would be suitable for pediatric patients as well.

METHODS

Serum from 53 children with untreated celiac disease, 22 in remission and 13 on challenge, were screened for antigliadin IgA, antigliadin IgG, and IgA reticulin antibodies, in addition to IgA endomysium antibodies tested both on monkey esophagus and on human umbilical cord. Controls included 20 patients with cow-milk-sensitive enteropathy, 23 with inflammatory bowel disease, and 23 with diabetes mellitus, and 48 patients who were biopsied to exclude celiac disease either because of positive gliadin antibody test or disturbed growth.

RESULTS

Sensitivity (0.94) and specificity (1.0) were similar for umbilical cord and esophageal determinations in active celiac disease. Both substrates detected identical positive cases and neither gave false-positive results. In celiac patients on a gluten-free diet, endomysium antibodies with either substrate were positive in seven identical cases and negative in 15 of 22 cases. Correlations with reticulin antibodies were comparable with human umbilical cord and monkey esophagus (0.83 and 0.85, respectively; Spearman Correlation Section Pair-Wise deletion).

CONCLUSIONS

Human umbilical cord is an excellent substitute for monkey esophagus to determine endomysium antibodies in celiac diagnosis in children and adolescents.

Autoantibodies and immunoglobulins in collagenous colitis

BACKGROUND

The aetiology and pathogenesis of collagenous colitis are unknown. Autoimmunity has been suggested, but no serological findings have supported such a theory.

AIMS AND METHODS

Serum from 38 collagenous colitis patients and 38 matched healthy controls was analysed for autoantibodies--that is, antinuclear antibodies, antineutrophil cytoplasmic antibodies, smooth muscle and mitochondrial antibodies, rheumatoid factor and antibodies to thyroglobulin and microsomal antigen, together with antibodies to endomysium, gliadin, and cardiolipin. The serum values of IgA, IgG, IgM, and IgG-subclasses, and complement factors C3 and C4 were also determined.

RESULTS

In patients with collagenous colitis the mean value of IgM was significantly increased 2.5 g/l (95% CI; 1.9, 3.2) compared with 1.4 g/l (95% CI; 1.2, 1.7) in controls (p = 0.002). Antinuclear antibodies occurred in nine of 38 patients compared with three of 38 controls, this difference was not statistically significant (p = 0.11). The results of all other immunoglobulins, complement factors, and specific antibodies showed no statistical difference between patients and controls.

CONCLUSIONS

No firm evidence for an autoimmune genesis in collagenous colitis is found in this study, although the findings of a positive ANA-titre in some patients and an increased IgM level might give some support for this hypothesis.

Endomysium and gliadin IgA antibodies in children with coeliac disease

The diagnostic sensitivity and specificity of IgA endomysium antibodies (EmA) and IgA gliadin antibodies (AGA) for coeliac disease (CD) were studied in Swedish children. Indirect immunofluorescence was used for demonstration of EmA and the diffusion-in-gel enzyme-linked immunosorbent assay method for AGA. Serum samples were collected and analysed from 77 consecutive children undergoing small-intestinal biopsy on recognized clinical indications. The diagnostic sensitivity for CD was 98.1% for EmA and 86.5% for AGA. The specificity of the two tests was 92.7% for EmA and 92.7% for AGA in paediatric patients. In addition, 115 sera from control children showed 2.6% positive for EmA and 0.9% positive for AGA.

Increased jejunal intraepithelial lymphocytes bearing gamma/delta T-cell receptor in dermatitis herpetiformis

T-cell receptor 1 (gamma/delta) expression was studied in 19 jejunal or duodenal specimens from patients with dermatitis herpetiformis and in 16 jejunal or duodenal specimens showing normal histology. In normal specimens, gamma/delta+ cells represented 10.8% of intraepithelial CD3+ lymphocytes. Around 50% of these cells were recognized by the A13 monoclonal antibody, which detects products of the V gamma 1/V delta 1 gene rearrangement and the non-disulfide-linked form of T-cell receptor 1. The remaining 50% reacted with the BB3 monoclonal antibody, which recognizes products of the V gamma 9/V delta 2 rearrangement and the disulfide-linked form of receptor. Very few gamma/delta+ cells were observed in the lamina propria. In jejunal specimens from patients with dermatitis herpetiformis, a significant increase in the prevalence of gamma/delta+ intraepithelial lymphocytes was observed (P less than 0.001). This finding was largely accounted for by an increase in those cells recognized by the A13 monoclonal antibody, thus possibly expressing the V gamma 1/V delta 1 rearrangement and the nondisulfide-linked form of receptor. These data suggest that similar pathogenetic mechanisms may be active in determining the jejunal damage in celiac disease and dermatitis herpetiformis.

IgA antiendomysial antibodies in dermatitis herpetiformis

Sera from 24 patients with dermatitis herpetiformis and 80 control subjects (patients with other bullous diseases, nonbullous dermatoses, and noncutaneous diseases) were studied to determine the usefulness of assay for IgA antiendomysial antibodies (IgA-EMA) in the diagnosis of dermatitis herpetiformis. The overall sensitivity of IgA-EMA for the diagnosis of dermatitis herpetiformis was 79% and the specificity was 96%. When the three patients with dermatitis herpetiformis who were faithfully following gluten-free diets were excluded, the sensitivity was 90% and the specificity was 96%. No patient in the bullous disease control group (including patients with linear IgA bullous dermatosis) had circulating IgA-EMA. One patient, who did not have direct immunofluorescence evidence for dermatitis herpetiformis but had IgA nephropathy, had a positive IgA-EMA result, an interesting association in light of the rare reports of dermatitis herpetiformis in patients with IgA nephropathy and IgA antigliadin antibodies associated with IgA nephropathy. Although direct immunofluorescence testing of skin biopsy specimens remains the most definitive diagnostic test for dermatitis herpetiformis, indirect immunofluorescence assay of serum for IgA-EMA is a minimally invasive study with a high sensitivity and specificity for dermatitis herpetiformis.