Antireticulin antibody: incidence and diagnostic significance

S2k guidelines (consensus statement) for diagnosis and therapy of dermatitis herpetiformis initiated by the European Academy of Dermatology and Venereology (EADV)

INTRODUCTION

Dermatitis herpetiformis (DH) is a chronic, pruritic, gluten-induced skin disorder characterized by subepidermal granular IgA deposition and a variable degree of enteropathy identical to that seen in coeliac disease. So far, there has been no European consensus about the management of DH.

METHODS

The guidelines were created by small subgroups of a guideline committee consisting of 26 specialists from various medical fields and one patients' representative. The members of the committee then discussed the guidelines and voted for the final version at two consensus meetings. The guidelines were developed under the support of the European Academy of Dermatology and Venereology (EADV) and in collaboration with the European Dermatology Forum (EDF).

RESULTS

The guidelines summarize evidence-based and expert-based recommendations (S2 level) for the management of DH (see Appendix).

CONCLUSION

These guidelines will improve the quality of management of DH and support dermatologists in their diagnostic and therapeutic decisions.

Overview of biomarkers for diagnosis and monitoring of celiac disease

Among the adverse reactions caused by wheat, celiac disease (CD) is the longest studied and best-known pathology. The more recently defined non-celiac gluten sensitivity (NCGS) presents with symptoms which are often indistinguishable from CD. Diagnosis of CD is based on serologic, molecular, and bioptic testing. The IgA anti-transglutaminase (tTG) test is considered highly important, as it shows high sensitivity and specificity and its levels correlate to the degree of intestinal damage. Small bowel biopsy can be avoided in symptomatic patients with IgA anti-tTG levels above 10× the manufacturer's cut-off. Recently, tests of anti-deamidated peptides of gliadin (DGP) have replaced classic anti-native gliadin (AGA) tests. DGP assays have a considerably higher diagnostic accuracy than AGA assays, especially in the IgG class, and can replace anti-tTG tests in patients with selective IgA deficiency. The combination of IgG anti-DGP plus IgA anti-tTG assays show greater sensitivity than a single test, with very high specificity. EMA tests have great diagnostic accuracy but are not recommended by all the latest guidelines because they are observer dependent. Biopsy must still be considered the gold standard for CD diagnosis. HLA-DQ genotyping can be used to screen asymptomatic children and in cases of histology/serology disagreement. About half of NCGS patients are DQ2 positive and have IgG AGA. To diagnose NCGS, first CD and wheat allergy must be excluded; then the wheat dependence of symptoms must be verified by a gluten-free diet and subsequent gluten challenge.

Ages of celiac disease: From changing environment to improved diagnostics

From the time of Gee’s landmark writings, the recent history of celiac disease (CD) can be divided into many ages, each driven by a diagnostic advance and a deeper knowledge of disease pathogenesis. At the same time, these advances were paralleled by the identification of new clinical patterns associated with CD and by a continuous redefinition of the prevalence of the disease in population. In the beginning, CD was considered a chronic indigestion, even if the causative food was not known; later, the disease was proven to depend on an intolerance to wheat gliadin, leading to typical mucosal changes in the gut and to a malabsorption syndrome. This knowledge led to curing the disease with a gluten-free diet. After the identification of antibodies to gluten (AGA) in the serum of patients and the identification of gluten-specific lymphocytes in the mucosa, CD was described as an immune disorder, resembling a chronic “gluten infection”. The use of serological testing for AGA allowed identification of the higher prevalence of this disorder, revealing atypical patterns of presentation. More recently, the characterization of autoantibodies to endomysium and to transglutaminase shifted the attention to a complex autoimmune pathogenesis and to the increased risk of developing autoimmune disorders in untreated CD. New diagnostic assays, based on molecular technologies, will introduce new changes, with the promise of better defining the spectrum of gluten reactivity and the real burden of gluten related-disorders in the population. Herein, we describe the different periods of CD experience, and further developments for the next celiac age will be proposed.

[Serological diagnosis of celiac disease]

Screening studies using high-sensitivity and specificity markers indicate a prevalence of celiac disease of up to 1% in European and North-American populations. Celiac disease is a frequent condition that has become an important public health issue. Yet the majority of cases remain undiagnosed due to the polymorphism of its clinical manifestations. The new insight in the pathogenesis of celiac disease has lead to the development of new diagnostic tools. Early screening of symptomatic patients and pre-identified at-risk groups significantly improves the quality of life while reducing morbidity and mortality. However, prophylactic benefits of early diagnosis by assessing the general population have not been shown in any study. French and Northern American scientific societies have introduced serological testing in their newly revised strategies to diagnose celiac disease. Older markers judged insufficiently accurate like anti-gliadin and anti-reticulin antibodies have recently been withdrawn from the list of reimbursed medical expenses in France. Anti-endomysium and tissue transglutaminase IgA antibodies have proven to be at this day the most sensitive and specific markers for the diagnosis and follow-up of patients on gluten-free diet, at the exception of IgA-deficient patients. Assays testing for IgG antibodies are recommended upon IgA-deficiency. Although very accurate, a better standardisation of current assays may enable serological testing to replace in a near future histological confirmation brought by small bowel biopsies which remains today the gold standard test to diagnose celiac disease. Indeed, serological testing represents and attractive alternative as it is less invasive, less expansive, laboursaving and more objective in interpretation.

Cutaneous manifestations in celiac disease

Celiac disease (CD) is an autoimmune gluten-dependent enteropathy characterized by atrophy of intestinal villi that improves after gluten-free diet (GFD). CD is often associated with extra-intestinal manifestations; among them, several skin diseases are described in CD patients. The present review reports all CD-associated skin manifestations described in the literature and tries to analyze the possible mechanisms involved in this association. The opportunity to evaluate the possible presence of CD in patients affected by skin disorders is discussed.

Histopathology of celiac disease

The diagnosis of celiac disease (CD) is based upon histologic findings in duodenal or jejunal biopsies. In the past few years it has turned out that the development of CD lesion in the small bowel is a dynamic process which may present in various histologic forms. At one end of the spectrum is a mucosa with normal architecture and an increase in intraepithelial lymphocytes (IEL), at the other end is the classical flat mucosa. Histologic features supporting the diagnosis of CD are architectural changes of the villi and/or crypts, an increase in lamina propria cell density and an increase in IEL counts. For diagnostic purposes and for monitoring CD patients an exact histologic classification of the histologic findings has to be given. This has become possible by using a modified Marsh classification. In the present paper the histologic presentation of CD is presented as well as the modified Marsh classification.

Dermatitis herpetiformis

Dermatitis herpetiformis (DH) is a relatively rare skin disorder with an estimated incidence of 1:10,000 in the UK. It is characterized by urticarial plaques and blisters on the elbows, buttocks, and knees, although other sites may also be involved. The eruption tends to be persistent: only 10-15% of patients have spontaneous remission over a 25-year study period. The disease is characterized by the presence of IgA deposits in the upper dermis of uninvolved skin and the diagnosis should not be made in the absence of these deposits. Two-thirds of patients have a small intestinal enteropathy with villous atrophy as seen in coeliac disease (CD). However, the remaining third also show evidence of a gluten sensitivity in the intestine, as judged by increased lymphocytic infiltration of the epithelium. Villous atrophy also ensues after gluten challenge in those patients with previous normal villous architecture. The initial treatment of the rash is with one of the following three drugs, dapsone, sulphapyridine or sulphamethoxypyridazine. However, the rash also clears with gluten withdrawal. It must be stressed, however, that the average time to achieve significant reduction in drug requirements is 6 months and it can be over 2 years before drugs are no longer required. On re-introduction of gluten the eruption recurs. Patients with DH have a high incidence of auto-immune disorders, thyroid disease, pernicious anaemia, and insulin-dependent diabetes, and should be screened for those diseases on a yearly basis. As with coeliac disease there is also an increased incidence of lymphoma and a gluten-free diet appears to protect patients from this complication. The mechanism by which gluten causes the skin lesions has still to be elucidated, but current investigations implicate lymphocytes and cytokines in the pathogenesis. The original hypothesis of an antigen-antibody reaction in the skin with complement activation causing the skin lesions, may not be correct.

Endomysial antibody: is it the best screening test for coeliac disease?

The sensitivities and specificities of the IgA and IgG antigliadin antibody and the IgA antireticulin antibody have been compared with the recently described endomysial antibody directed against the basement membrane of smooth muscle in monkey oesophagus. One hundred and seventeen patients with adult coeliac disease (21 untreated), 84 patients with inflammatory bowel disease, systemic lupus erythematosus and rheumatoid arthritis (comprising the disease control group), 47 normal controls and a miscellaneous group of 29 patients, who were selected because of a positive reticulin staining pattern, were investigated. These results were correlated with the degree of abnormality of the intestinal mucosa in patients with adult coeliac disease. Endomysial antibodies were found in all patients with untreated coeliac disease and subtotal villous atrophy and in 47% of patients on a non-strict gluten free diet. One patient on a strict gluten free diet was positive and had partial villous atrophy while all patients in disease control groups were negative. Results were variable with the antireticulin and antigliadin antibodies. Sensitivity and correlation with subtotal villous atrophy in the untreated patients was 100%. It is concluded that the endomysial antibody is superior to other current antibody tests and should be used in preference for the diagnosis of coeliac disease.

IgA antiendomysial antibody test. A step forward in celiac disease screening

Serum IgA antiendomysial antibodies (EmA) were found in 61 (87%) of 70 adults and children with untreated celiac disease, whereas IgA antigliadin antibodies (AGA) and IgA R1-antireticulin antibodies (R1-ARA) were positive in 71% and 47%, respectively, of the same patients. Two of the nine untreated celiacs negative for IgA EmA showed positivity for IgA AGA. While IgA AGA and R1-ARA disappeared in all the celiacs tested one year after gluten-free diet, IgA EmA persisted at low titer in seven (18%) of these 38 subjects, although the jejunal biopsy showed a complete regrowth of jejunal villi. All the disease control patients as well as the blood donors tested were always negative for the three IgA antibodies. Our results state that the search for both IgA EmA and AGA gives the best results in the screening of celiac disease, since the positivity for at least one of these two antibodies allows identification with a 100% specificity of the 90% of untreated celiac patients.

Binding to human jejunum of serum IgA antibody from children with coeliac disease

Jejunal histology and the presence of serum IgA antibodies (JAB) binding to human jejunum in vitro were studied in 139 children with severe malabsorptive symptoms. Among 33 children with confirmed coeliac disease (ESPGAN criteria), 13 (93%) of 14 sampled before starting on a gluten-free diet had JAB, none of 21 sampled had JAB while on a gluten-free diet of long duration, and 90% of 30 sampled during gluten challenge had JAB. 53 children had severe jejunal villous atrophy (probable coeliac disease): 71% of those younger than 2 years and 94% of those aged 2-18 years had JAB during gluten intake. JAB could not be detected in 53 disease control patients (normal jejunal histology) and in 3 coeliac disease patients with selective IgA deficiency. Simultaneous determination of antigliadin (AGA) and antiendomysium (EMA) levels, and gliadin and tissue absorption studies, showed that JAB and AGA are different, whereas JAB and EMA are probably identical. IgA JAB could be the target-organ-related autoantibodies in coeliac disease.

Antireticulin antibody in systemic sclerosis

The prevalence, immunoglobulin class, and IgG subclass of antireticulin antibody in the serum samples of 32 patients with systemic sclerosis were investigated by indirect immunofluorescence on unfixed rodent tissue. Antireticulin antibody was present in 22/32 (69%) of patients and belonged to the IgG class in 19/22 (86%), the IgA class in 13/22 (59%), and the IgM class in 6/22 (27%) of positive sera. IgG1 was the predominant subclass of IgG antireticulin antibody, occurring either alone or in association with IgG3 in 12/19 cases (63%). Thus antireticulin antibody of the IgG and IgA classes is found in most patients with systemic sclerosis. The finding of an autoantibody with reactivity for collagen-like fibres in systemic sclerosis indicates that the antibody has a potential role in the pathogenesis of the disease, and as it belongs to the IgA class this suggests that it arises in response to antigens presented to the immune system at the mucosal level.

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.

Comparison of IgA-class reticulin and endomysium antibodies in coeliac disease and dermatitis herpetiformis

The occurrence of IgA class reticulin and endomysium antibodies was examined with the standard immunofluorescence method in coeliac disease and dermatitis herpetiformis. Similar high antibody frequencies were detected in 32 untreated adults (91%) and 18 children (100%) with coeliac disease and in 14 dermatitis herpetiformis patients with subtotal villous atrophy (reticulin antibodies 93% and endomysium antibodies 100%). The specificity of IgA class reticulin antibodies and endomysium antibodies was high because all 45 adult patients with ulcerative colitis or Crohn's disease, 24 non-coeliac children with abdominal symptoms and 99/100 healthy blood donors were negative for these antibodies. The only positive blood donor had both IgA class reticulin antibodies and endomysium antibodies but also she was found to have coeliac disease. IgA class reticulin antibodies and endomysium antibodies declined in parallel during treatment with a gluten free diet and increased on gluten challenge. This suggests that these antibodies can be used to screen for gluten sensitive enteropathy and to monitor dietary treatment. To characterise the tissue specificity of reticulin antibodies and endomysium antibodies four positive sera were absorbed with human and several rodent liver homogenates. Absorption with rat or other rodent livers removed the rodent-specific reticulin antibodies but not the reticulin antibodies detectable with human tissues or the endomysium antibodies detectable with monkey oesophagus. These results show that reticulin antibodies can be divided into the rat and human subtypes. The human subtype could not be separated from endomysium antibodies in the present absorption experiments.

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.

The immunology of coeliac disease

Coeliac disease is defined as that disorder in which there is an abnormality of the small intestinal mucosa manifested by contact with the gluten of wheat and certain other cereal grains. In the immunological theory of the pathogenesis of coeliac disease, gluten, or a component, is viewed as the antigen responsible for the immune response. The search for the gluten component responsible for 'toxicity' and, by implication, antigenicity, is described. The antigen may be presented differently to the immune system by an abnormal cell membrane, either of the enterocyte, lymphocyte or macrophage. Alternatively, increased amounts of antigen may be absorbed due to increased membrane binding or permeability, either of which could be genetically determined. As a further possibility, coeliac disease may occur because the patients are immunologically hyperresponsive and this too appears to be genetically determined. The perturbations which occur in the mucosal immune system and the systemic immune system are described. It is conceivable that the major complications described (intestinal ulceration, malignancy and splenic atrophy) result from immunological disturbances. The incidence of childhood coeliac disease is declining, which may be due to altered exposure to, or increased protection from, the antigen in infancy, or to changes in environmental factors. The immunological mystery of coeliac disease continues to excite interest and fascination, and has certainly been a stimulus to our deeper understanding of gastrointestinal immunology.

Gliadins bind to reticulin in a lectin-like manner

It has previously been reported that gliadins bind to reticulin in tissue sections. Three lines of evidence are reported in this study which indicate that the gliadins bind to reticulins because they are lectins which bind to sugars expressed on glycoproteins in reticulin and other sites. First, immunofluorescence studies on tissue sections showed that although gliadin binding is largely confined to areas rich in reticulin, it is, nonetheless, also seen in one or two other sites devoid of reticulin. Second, by using fluorescein-labelled lectins of known specificity, it has been shown that the areas to which gliadins bind in tissue sections (including those sites devoid of reticulin) are rich in particular sugars. Third, it has been shown that one of these sugars, alpha-D-mannose, partially inhibited gliadin binding to tissue sections.

The pathogenesis of dermatitis herpetiformis: recent advances

Over the last two decades a rapid expansion of our knowledge regarding dermatitis herpetiformis has occurred, including the discovery of IgA in the skin, the discovery of an associated gluten-sensitive enteropathy, the noting of an increased prevalence of the human lymphocyte antigens (HLA)-B8 and -DRw3, and the documentation that the skin disease of many dermatitis herpetiformis patients can be controlled by a gluten-free diet. It has also been noted that two distinct forms of dermatitis herpetiformis occur, those with granular deposits of IgA at the dermoepidermal junction (85%-95% of dermatitis herpetiformis patients) and those with linear IgA deposits (10%-15% of dermatitis herpetiformis patients). These findings are reviewed with particular emphasis on the form of dermatitis herpetiformis associated with granular IgA deposits. The current findings regarding the nature and origin of the cutaneous IgA deposits, the role of the gluten-sensitive enteropathy, and the spectrum of both the immunologic and the nonimmunologic abnormalities associated with dermatitis herpetiformis are presented, and from these data pathophysiologic mechanisms are proposed that may be involved in dermatitis herpetiformis.

Dermatitis herpetiformis: extraction of intact IgA from granular deposits in dermal papillae

Dermatitis herpetiformis (DH) is characterized by the granular deposition of IgA in the dermal papillary tips. The source and antigenic specificity of this IgA are unknown, largely because of the previous inability to isolate it for study. These granular IgA deposits, pathognomonic of DH, have been specifically isolated from 4-mm punch biopsies. Specific isolation was achieved by removing contaminating serum IgA by a combination of washes in saline and sodium dodecyl sulfate without a reducing agent present and mechanical isolation of papillary dermis. The tissue IgA was then solubilized by a buffer containing 1% sodium dodecyl sulfate and 0.2 mM dithiothreitol, a reducing agent. Immunoreactive alpha chains were recovered in eluates of DH skin in 6-fold greater amounts than in eluates of normal skin, coincident with disappearance of immunofluorescent-staining granular deposits of IgA. Extracted specific IgA was recovered in sufficient quantity for detection by immunoenzymatic stain, was partially composed of a native (165 Kd) molecular mass, and had alpha and kappa staining material, all indicating that the extracted immunoglobulin was in part intact.

Anti-reticulin antibodies: a diagnostic and monitoring test for childhood coeliac disease

The importance of anti-reticulin antibodies (ARA)--R1 pattern--has been evaluated as a diagnostic and monitoring test for childhood coeliac disease. A prospective study was performed in 140 patients: 68 children with coeliac disease, 32 with miscellaneous diarrhoea, and 40 controls. An indirect immunofluorescent test was used for ARA screening. The indirect correlation found in our study between the presence of ARA and coeliac disease in children on a normal diet and after gluten challenge and between the absence of ARA and coeliac disease in children on a gluten-free diet seems to be of value in the diagnosis of coeliac disease and in monitoring the response to treatment in coeliac disease children.

Does the reticulin binding property of cereal proteins demonstrable in vitro have pathogenetic significance for coeliac disease?

We used an indirect immunofluorescence technique, using rabbit antisera against cereal protein extracts, to determine which cereal proteins bind to reticulin in tissue sections and which do not. Wheat albumin extracts and globulins and gliadin extracts from a range of different wheat varieties, and prolamine extracts of barley and rye each bound to reticulin in vitro, while prolamine extracts of maize and rice did not. Wheat gluten subfractions were also tested. Subfractions B and C and subfractions B2 and B3 did bind, but fraction A and subfraction B1 did not. The results suggest an association between in vitro reticulin binding and the ability to induce gluten sensitive enteropathy on feeding.

Antibodies to gliadin detected by immunofluorescence and a micro-ELISA method: markers of active childhood and adult coeliac disease

Antibodies to gliadin have been detected by immunofluorescence (IFL-AGA) and a micro-ELISA method (ELISA-AGA) in 45 out of 47 (96%) sera from patients with active childhood and adult coeliac disease. The two methods were more sensitive than R1-reticulin antibodies (R1-ARA) which were found only in 28 of the same patients (60%). R1-ARA were always negative in the 26 sera from patients with childhood coeliac disease and adult coeliac disease after gluten free diet, while IFL- and ELISA-AGA were respectively found in three (12%) and in four (15%) out of these patients. Moreover, while R1-ARA and IFL-AGA were strictly confined to coeliac disease. ELISA-AGA were occasionally found in patients with control diseases. These 'false positive' antibodies were all of IgG class and had low titres. In our experience IFL- and ELISA-AGA of IgA class were strictly confined to active childhood coeliac disease and adult coeliac disease. The detection of AGA is useful in monitoring the diet and in the follow up of coeliac disease. IFL- and ELISA-AGA, then, are to be preferred to R1-ARA for the screening of coeliac patients.

IgA anti-endomysial antibody detection in the serum of patients with dermatitis herpetiformis following gluten challenge

This study reports the appearance of IgA-class anti-endomysial antibodies in the serum of 8 out of 12 patients with dermatitis herpetiformis who were challenged with gluten after a number of years of control of the rash with a strict gluten-free diet. Although there was no evidence for the antibodies having any pathogenic role in the rash of dermatitis herpetiformis, their presence may be related to the deterioration in the gluten-sensitive enteropathy.

Evaluation of a serum IgA-class reticulin antibody test for the detection of childhood celiac disease

Serum IgA class reticulin antibody (RA) was found in 28 (97%) of 29 children with flat small bowel mucosa, and in low titer in four (2%) of 245 with normal or near normal mucosa on small intestinal biopsy. Thus the sensitivity of the IgA-RA fluorescent antibody test for screening of celiac disease was 97% and the specificity 98%. IgA-RA was superior to IgG-RA for the detection of celiac disease. During follow-up of patients receiving a gluten-free diet, the IgA-RA rapidly decreased and in most cases disappeared within a year, suggesting that the test may be useful for clinical follow-up of celiac disease as well.

IgA anti-endomysium antibody. A new immunological marker of dermatitis herpetiformis and coeliac disease

The recently described IgA anti-endomysial antibodies (IgA-EmA) are directed against the intermyofibril substance of the smooth muscle, which may correspond either to a reticulin-like structure or a surface component of smooth muscle fibrils. These antibodies occurred in about 80% of sera of thirty-eight patients with dermatitis herpetiformis (DH), in about 70% of twenty-eight patients with coeliac disease and in about 20% of nine patients with other enteropathies. IgG class anti-gliadin antibodies (AGA) also occur in each of these diseases. Both antibodies were detected on monkey oesophagus by immunofluorescence. The IgA-EmA could not be detected in 122 control sera from patients with other gut or skin diseases, including fifteen cases with ulcerative colitis and fifteen cases with linear IgA bullous dermatosis (LABD). The presence and the titre of IgA-EmA and AGA paralleled the severity of the jejunal changes in patients with coeliac disease.

Coeliac disease presenting with intestinal pseudo-obstruction

A 22 year old woman presenting with recurrent intestinal pseudo-obstruction is reported. Jejunal biopsy showed subtotal villous atrophy which improved markedly during a period of total parenteral nutrition and with steroid treatment. It did not relapse on a gluten free diet. The reasons why this patient represents a case of coeliac disease with secondary pseudo-obstruction, rather than primary intestinal pseudo-obstruction with secondary bacterial overgrowth, is discussed.

Increased prevalence of coeliac disease in diabetes

A total of 215 diabetic children were screened for coeliac disease by determination of class specific serum reticulin antibody. Nine children were positive for reticulin antibody and all underwent biopsy of the small intestine. Four new cases of coeliac disease were found; all of these children had IgA reticulin antibody. Two of three other children with a low titre of IgA reticulin antibody had partial villous atrophy. It was concluded that IgA class reticulin antibody was a good marker of coeliac disease in diabetic children. The prevalence of coeliac disease in these children was 1:43 (including one previously diagnosed case) and we suggest that diabetic children be screened routinely for reticulin antibody.

R2 anti-reticulin antibody in a mixed hospital population

R2 anti-reticulin antibody was detected in 15 of the 9,500 serum samples examined (0.16%) from a mixed hospital population. The antibody titre varied from 1:40 to 1:320, and the R2 was of the IgG class in 13 of the 15 positive samples. All the 15 serum samples with R2 were negative on human liver, confirming the lack of cross reaction of this antibody. The reactivity of R2 was not absorbed by soluble fractions of type I collagen, showing that this antibody is not directed against this antigen. R2 was confined to two groups of pathological conditions: connective tissue and digestive tract diseases. Four of 15 patients with R2 had rheumatoid arthritis and in two of these four cases the antibody was of the IgA class.

Linear IgA disease in adults

A multi-centre study is described in which thirty-five adult patients with papillary IgA dermatitis herpetiformis (DH) were compared with forty-two patients with linear IgA deposits, of whom thirty-four had homogeneous-linear (HL) and eight had granular-linear (GL) IgA deposits. The three groups were similar with regard to age of onset, presence of circulating immune complexes and auto-antibodies, incidence of spontaneous remission, histology of lesional skin and response to dapsone. There was a female predominance in the HL group in contrast to the male predominance in the other two. It was not possible to diagnose the HL group clinically. Some patients had a rash typical of DH whilst others resembled pemphigoid. In the majority, however, no specific diagnosis could be made with confidence. The GL group clinically resembled the DH group. The incidence of positive potassium iodide patch tests was greater in the DH group than in the other two. An associated enteropathy was found in 24% of patients in the HL group, 30% of patients in the GL group and 85% of patients in the DH group. Fifty-six percent of HL patients had HLA-B8 compared with 50% in the GL group and 88% in the DH group. Patients with linear IgA deposits may not be a uniform group, but until they can be divided into specific subgroups (e.g. by ultrastructural localization of the deposit or by response to a gluten-free diet) we propose that the term adult linear IgA diseases should be used to distinguish these patients from those with papillary IgA deposits.

Anti-gliadin antibodies and small intestinal mucosal damage in dermatitis herpetiformis

Sera from forty-six patients with dermatitis herpetiformis (DH) were examined for anti-gliadin antibodies (AGA) by the enzyme linked immunosorbent assay (ELISA) test and by a simple new immunofluorescent (IF) test. AGA were present in fifteen out of thirty-two patients taking a normal diet, but in none of the fourteen taking a gluten-free diet (GFD). The presence of circulating AGA was related to the severity of the enteropathy. AGA were present in all ten patients with a flat mucosa and in four of six with a convoluted mucosa, but in only one out of thirty patients with normal morphology of the small intestine. However, in those patients taking a normal diet and with a normal morphology of the intestine there was evidence of gluten sensitivity compared to those taking a GFD, as the intraepithelial lymphocyte count (IELC) was significantly raised in the peri-nuclear and supra-nuclear positions. The study shows that the presence of AGA in the serum is a good indication of the degree of gluten sensitivity as expressed by severe mucosal damage in patients with DH.

New immunofluorescent blood test for gluten sensitivity

A new test for the detection of antibodies to gliadin in the sera of children who are gluten sensitive is described. This test is based on the observation that wheat protein binds selectively to connective tissue fibres in cryostat sections of mammalian tissues. Sera containing antibodies to gliadin give a reticulin pattern of staining on section pretreated with wheat gliadin if tested by indirect immunofluorescence. Antibodies to gliadin were detected in this manner in sera fom all of 32 children with coeliac disease, in 16 of whom a provisional diagnosis had been given and in 16 an established diagnosis confirmed by gluten challenge. The incidence of reticulin antibodies detected on untreated sections (in the absence of gliadin) was only 28%. Gliadin antibodies were also present in sera from 15% of 152 children with gastroenterological disorders other than coeliac disease, but most of these non-positive results for coeliac disease were in patients with transient gluten in tolerance, cows' milk-sensitive enteropathy, or Crohn's disease. This new test, although not specific for coeliac disease, promises to be of value as an indicator of gluten sensitivity, and when negative excludes a diagnosis of coeliac disease. It may also be useful in monitoring diet, and in determining when rebiopsy after gluten challenge in appropriate.

Childhood dermatitis herpetiformis. Review of the new aspects and report of a case

Dermatitis herpetiformis (DH) of linear IgA type occurred in a 6-month-old boy shortly after initiating sulfisoxazole therapy for a urinary tract infection. Generalized pruritic bullae on erythematous bases were present on his trunk and extremities. There were no clinical or laboratory findings suggestive of gastrointestinal involvement. Direct immunofluorescent studies of skin biopsies taken early in the course of the disease and while the child was on systemic corticosteroid therapy were negative. Eventually a linear deposition of IgA at the dermoepidermal junction of involved skin on direct immunofluorescence was demonstrated. No circulating antibodies to the basement membrane were found. Because of close proximity of the initiation of sulfisoxazole (Gantrisin) therapy and the eruption of the initial bullous lesions, this case also presents an interesting diagnostic and therapeutic problem. Negative assays of lymphocyte migration inhibition factor (LMIF) to sulfisoxazole indicated that the likelihood of a hypersensitivity reaction to sulfa drugs was slight. The patient's clinical response to dapsone therapy was dramatic. The conflicting views of subepidermal bullous dermatosis of childhood and the difficulties in confirming a diagnosis of DH are discussed. We contend that when DH is suspected in children, various laboratory tests should be repeated several times before the diagnosis can be confirmed. The case presented here is the youngest child reported with this type of DH.

Binding of wheat gliadin in vitro to reticulum in normal and dermatitis herpetiformis skin

We have demonstrated by indirect immunofluorescence that wheat gliadin binds in vitro to reticulin-like fibrils present in cryostat sections of human skin, and rat liver, kidney and stomach. Gliadin was seen to bind to fibrils throughout the dermis of both normal and dermatitis herpetiformis skin, and this was particularly striking in the dermal papillae. Serum from 2 dermatitis herpetiformis patients who did not have antireticulin antibody gave reticulin staining when retested by immunofluorescence on cryostat sections of rat tissue pretreated with gliadin. Gliadin treated sections may prove useful in screening patients with gluten sensitive enteropathy for anti-gliadin antibody. Binding of gliadin to skin sites in dermatitis herpetiformis patients and subsequent deposition of antigliadin antibody at these sites may be involved in the development of skin lesions.

Circulating immune complexes of IgA type in dermatitis herpetiformis

There is some evidence that dermatitis herpetiformis may be mediated by circulating immune complexes. This study attempts to define the antibody class of these complexes. All patients studied demonstrated granular deposition of IgA in the papillary dermis on direct immunofluorescence. Serum immune complexes were detected using the qualitative Raji cell immunofluorescent assay, as well as the quantitative immunoradiometric assay. A group of 25 dermatitis herpetiformis patients was found to have higher levels of IgA containing complexes compared to a group of normals (p < .01). Higher levels of IgG containing complexes were also noted in dermatitis herpetiformis patients at a low level of statistical significance (p < .1). The relationship of these complexes to the pathogenesis of dermatitis herpetiformis is yet to be determined.

Circulating reticulin autoantibodies of IgA class in dermatitis herpetiformis

Circulating reticulin autoantibodies of IgA class and anti-nuclear antigen antibodies were found in a high frequency in dermatitis herpetiformis patients as compared with age- and sex-matched controls.