Immunoglobulin production by coeliac biopsies in organ culture

The association between endometriosis and chronic endometritis

Objective

To evaluate the association between endometriosis and chronic endometritis.

Methods

Endometrial specimens were obtained from 71 patients, 34 with endometriosis (endometriosis group) and 37 without endometriosis (non-endometriosis group), who underwent hysterectomy, and the specimens were immunostained for the plasmacyte marker CD138. The rate of chronic endometritis was compared between the endometriosis group and the non-endometriosis group. Furthermore, the 71 patients were also divided into two groups, 28 with chronic endometritis (chronic endometritis group) and 43 without chronic endometritis (non-chronic endometritis group). Logistic regression analysis was performed with variables including age, body mass index (BMI), gravidity and parity, and diagnoses of leiomyoma, adenomyosis, and endometriosis on pathology to examine the independent effect of each variable on chronic endometritis. Patients suffering from cervical invasive carcinoma, endometrial carcinoma, and endometrial polyps or treated with gonadotropin-releasing hormone agonists, progestins, or oral contraceptives before surgery were excluded.

Results

Chronic endometritis was identified in 52.94% of the endometriosis group and 27.02% of the non-endometriosis group (p<0.05). Logistic regression analysis revealed that endometriosis was associated with chronic endometritis.

Conclusions

This result suggests a strong association between endometriosis and chronic endometritis.

Secretory IgA mediates retrotranscytosis of intact gliadin peptides via the transferrin receptor in celiac disease

Celiac disease (CD) is an enteropathy resulting from an abnormal immune response to gluten-derived peptides in genetically susceptible individuals. This immune response is initiated by intestinal transport of intact peptide 31-49 (p31-49) and 33-mer gliadin peptides through an unknown mechanism. We show that the transferrin receptor CD71 is responsible for apical to basal retrotranscytosis of gliadin peptides, a process during which p31-49 and 33-mer peptides are protected from degradation. In patients with active CD, CD71 is overexpressed in the intestinal epithelium and colocalizes with immunoglobulin (Ig) A. Intestinal transport of intact p31-49 and 33-mer peptides was blocked by polymeric and secretory IgA (SIgA) and by soluble CD71 receptors, pointing to a role of SIgA–gliadin complexes in this abnormal intestinal transport. This retrotranscytosis of SIgA–gliadin complexes may promote the entry of harmful gliadin peptides into the intestinal mucosa, thereby triggering an immune response and perpetuating intestinal inflammation. Our findings strongly implicate CD71 in the pathogenesis of CD.

Proteins specifically hyperexpressed in a coeliac disease patient with aberrant T cells

An aberrant T cell population is the basis for diagnosis of refractory coeliac disease and determines the risk of enteropathy-associated T cell lymphoma. This disease is serious with a poor survival. Pathogenetic mechanisms sustaining aberrant T cell proliferation remain unknown. Recently, alemtuzumab has been proposed as a promising new approach to treat these patients. Only few single cases have been tested at present; nevertheless, in all the cases a clinical improvement was observed. However, whether intraepithelial lymphocytes have been targeted effectively by alemtuzumab is still debated. This study reports, using two-dimensional difference gel electrophoresis (2D DIGE), hyperexpressed proteins associated specifically with aberrant T cells found in a patient with coeliac disease by comparison of the protein expression of this sample with that of patients with coeliac disease and polyclonal T cells or with control subjects. The data demonstrated a significantly higher expression of IgM, apolipoprotein C-III and Charcot-Leyden crystal proteins in a duodenal biopsy specimen of the patient with clonal T cells compared with that of other patients. These preliminary results allow hypothesizing different clinical effects of alemtuzumab in patients with coeliac disease and aberrant T cell proliferation, because as well as the probable effect on T cells, alemtuzumab could exert its effect by acting on inflammatory associated CD52(+) IgM(+) B cells and eosinophil cells, known to produce IgM and Charcot-Leyden crystal proteins, that we demonstrated to be altered in this patient. The results also emphasize the possible association of apolipoprotein with aberrant T cell proliferation.

Relative deficiency in IgA production by duodenal explants from German shepherd dogs with small intestinal disease

Matched samples of serum, saliva and tears were collected from four groups of dogs; two of the groups were German shepherd dogs (GSDs) either with (Group 1) or without (Group 4) a variety of small intestinal disorders; the remaining two groups were dogs of other breeds, again with (Group 2) or without (Group 3) small intestinal disease. Capture ELISAs were used to measure IgG, IgM, IgA and albumin concentrations within these samples; intestinal humoral immune status of clinical cases was assessed by quantifying immunoglobulin production from duodenal explant cultures.There were no significant differences in IgG, IgM or IgA concentrations in serum, saliva or tears between the different groups of dog. Moreover, no significant differences were noted between groups for IgG, IgM and IgA salivary and tear secretory indices. IgA production by 24-h explant cultures was significantly lower in GSDs compared with non-GSDs with small intestinal disease (groups 1 and 2, respectively), but the numbers of lamina propria IgA(+) plasma cells in duodenal biopsies were not different between groups. These results suggest that there may be a relative deficiency in local IgA secretion in GSDs with small intestinal enteropathies, which is not reflected in either serum IgA concentrations, or in secretion at unaffected mucosal sites. It remains to be determined whether such a deficiency is a breed-related primary defect, or whether it arises secondary to the pathological processes within the intestinal mucosa.

Luminal immunity in small-intestinal bacterial overgrowth and old age

BACKGROUND

The independent influences of small-intestinal bacterial overgrowth and old age on mucosal immunoglobulin production and secretion have not been assessed. This is an important issue, since luminal IgA deficiency may exacerbate small-intestinal bacterial overgrowth, the prevalence of which is high in selected elderly populations.

METHODS

Proximal small-intestinal aspirates were obtained from 33 subjects for bacteriologic analysis and measurement of total IgA, IgM, total IgG. IgG subclass, and IgD concentrations. IgA subclasses were measured in 24 unselected subjects. Serum immunoglobulin and salivary IgA concentrations were measured in all subjects.

RESULTS

IgA2 and IgG3 were predominant IgA and IgG subclasses in proximal small-intestinal luminal secretions. Luminal concentrations of IgA2 and IgM, but not IgG3 or any other IgG subclass, were significantly increased in small-intestinal bacterial overgrowth, which was present in 19 of 33 (57.6%) subjects. Old age did not influence these levels. Luminal immunoglobulin concentrations did not correlate significantly with either serum or salivary values. IgD was not measureable in proximal small-intestinal secretions.

CONCLUSIONS

Increased luminal concentrations of the secretory immunoglobulins, IgA2 and IgM, occur in small-intestinal bacterial overgrowth. Local investigation is mandatory when assessing the mucosal immunopathology of this disorder. Luminal IgG3 is unlikely to be predominantly derived from serum. Old age does not independently influence luminal immunity.

Mucosal humoral immune response to Helicobacter pylori in patients with duodenitis

The humoral immune response to Helicobacter pylori infection in the duodenum has been investigated by short-term in vitro culture, ELISA, and immunoblotting techniques. H. pylori IgA secretion by duodenal bulb biopsies was significantly increased (P less than 0.001) in patients with duodenitis. The IgA response to H. pylori in patients with duodenitis was restricted to the first part of the duodenum; second part duodenal biopsies secreting significantly (P less than 0.001) less IgA during culture in vitro. H. pylori IgG antibody secretion by cultured biopsies was also significantly increased (P less than 0.01) in patients with duodenitis and those with gastric H. pylori infection but without duodenitis. Immunoblotting of duodenal bulb culture supernatants showed positive recognition by the mucosal IgA response of H. pylori antigens in the region of 120, 90, 61, and 31-26 kDa in patients with duodenitis. Serologically, such patients showed little evidence of IgA H. pylori antibodies by immunoblotting. These results demonstrate that the inflammatory response in the duodenal mucosa of patients with duodenitis represents a specific highly localized humoral response to H. pylori.

Immunoglobulin secretion by isolated intestinal lymphocytes: spontaneous production and T-cell regulation in normal small intestine and in patients with coeliac disease

The in vitro secretion of immunoglobulins by small intestinal lymphocytes isolated from 47 patients with normal histology and 23 patients with treated and untreated coeliac disease was examined using an enzyme linked immunosorbent assay. In control patients, duodenal lymphocytes spontaneously secreted higher levels of IgM than jejunal lymphocytes (p less than 0.05). Significantly higher levels of both IgA (p less than 0.05) and IgM (p less than 0.001) were secreted by jejunal lymphocytes of 10 patients with untreated coeliac disease than cells isolated from normal jejunal tissue. IgM and IgA secretion by duodenal lymphocytes isolated from control patients was increased in a dose dependent manner by coculture with autologous peripheral blood T lymphocytes. This effect was not observed with jejunal lymphocytes of control or treated coeliac patients. Peripheral T-cells of untreated coeliac patients, however, showed significant helper effects (p less than 0.05) for IgM and IgA secretion by autologous jejunal lymphocytes. The results suggest that jejunal lymphocytes of patients with untreated coeliac disease show major differences in their capacity to synthesise and secrete immunoglobulins in vitro and the enhanced secretion might result from changes in T-cell immunoregulatory function.

Production of antibodies to gliadin in intestinal mucosa of patients with coeliac disease: a study at the single cell level

Lymphocytes obtained after enzymatic digestion of intestinal biopsies from patients with coeliac disease were examined for the presence of gliadin specific antibody secreting cells by means of the ELISPOT technique. This technique permits enumeration of gliadin antibody secreting immunocytes, differentiated with regard to immunoglobulin class. Patients with coeliac disease were found to have high (834/10(6) cells) numbers of antigliadin spot forming cells (SFC) in gut mucosa. IgG and IgM antigliadin antibody secreting cells were infrequently shown whereas IgA antigliadin SFC predominated in all patients tested (average 68% of total SFC). Ten control patients were investigated in parallel with the coeliac patients and showed only low numbers of gliadin antibody secreting cells in gut mucosa (49/10(6) isolated cells). Antigliadin antibody secretion by peripheral blood mononuclear cells was shown in only two of six coeliac patients tested and in none of the control patients. The findings suggest that the intestinal mucosa is a major site for antigliadin antibody production and that IgA is the dominating Ig-class of these antibodies. The high sensitivity and accuracy of the ELISPOT technique may provide a useful instrument for future studies of antibody production and regulation of the gut immune response to gluten and other alimentary antigens in coeliac and other intestinal diseases.

Jejunal plasma cells and in vitro immunoglobulin production in adult coeliac disease

IgA, IgE, IgG and IgM plasma cells in small bowel mucosal biopsies from 15 controls, 16 untreated and 14 treated coeliac patients and five patients with selective serum IgA deficiency (four of whom also had coeliac disease) were quantified using an indirect immunoperoxidase technique. The IgA, IgG and IgM plasma cell counts were significantly increased in the untreated coeliac patients. The cell counts were intermediate in the treated coeliac group. These changes were in parallel to production in vitro of IgA and sIgA, IgG, and IgM by cultured mucosal biopsies from the same patients. The IgA deficient patients had very few mucosal IgA cells but elevated IgG and IgM plasma cell numbers; again these changes were reflected in the production in vitro of immunoglobulins. IgE plasma cell counts were very low in all patients and there were no differences between patient groups. The changes in cell counts and mucosal immunoglobulin production were not reflected in serum IgA, IgM and IgG concentrations but serum secretory IgA was significantly elevated in the untreated coeliac patients compared with controls, with the treated coeliac patients being intermediate. The raised mucosal plasma cell counts reflect the local mucosal production of immunoglobulin but not the immunoglobulin concentrations of serum, emphasising the importance of studying the immune function of the gut itself in coeliac disease rather than immunological abnormalities in serum.

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.

ELISA for measurement of secretory IgA distinct from monomeric IgA

A micro enzyme-linked immunoassay (ELISA) is described for the quantitation of secretory IgA as distinct from monomeric IgA. The assay is sensitive (linear down to 30 ng/ml) and reproducible (inter-assay variation: 17.0%; intra-assay variation: 11.5%). The assay has the further advantages of rapidity, the ability to handle large numbers of samples, and uses commercially available reagents throughout. Minimal interference from a large (greater than 25-fold) excess of monomeric IgA was observed. The results obtained for serum secretory IgA concentrations by this method correlated well with those reported by other workers for normal control patients, patients with IgA deficiency and patients with liver disease.