T lymphocyte subsets and activation status in patients following liver transplantation

Changes in T-lymphocyte subsets have previously been shown to relate to clinical events following liver transplantation and be of prognostic significance following renal transplantation. The aim of this study was to examine T lymphocyte subsets, their activation status and the mean fluorescence intensity of cell surface markers by flow cytometric analysis, in peripheral blood of patients following liver transplantation. Stable transplant patients (n=11) had a significantly higher level of activation (HLA-DR expression ) of all T cell subsets: CD3, CD4 and CD8 compared to healthy controls: 17.5% +/- 14.0 (mean +/- SD) vs 4.7 +/- 1.8 (p=0.04), 13.7% +/- 10.3 vs 4.3 +/- 1.7 (p=0.03) and 23.8% +/- 19.9 vs 3.6 +/- 2.4 (p=0.02) respectively. A further increase in activation status occurred in all T cell subsets in association with acute cellular rejection, reaching significance for the CD4+ population: 13.7% +/- 10.2 vs 23.3% +/- 20.6 (p=0.04). The mean fluorescence intensity of the CD3+DR- and CD3+ DR+ populations were increased to 1397 +/- 869 and 1282 +/- 810 following liver transplantation compared to values of 425 +/- 204 and 376 +/- 166 respectively for controls (p<0.05). T-lymphocytes maintain a high level of activation following liver transplantation and continue to express high levels of the surface marker CD3, which may account for the occurrence of acute cellular rejection despite immunosuppression in these patients.

CD4+ CD8+ and CD8alpha+ beta- T lymphocytes in human small intestinal lamina propria

OBJECTIVE

To examine CD8 expression by T-lymphocyte subpopulations from disease-free human lamina propria.

METHODS

Single-cell suspensions were prepared from the epithelial layer and the lamina propria of small intestinal biopsies obtained endoscopically from disease-free patients. Monoclonal antibodies against CD3, CD4, CD8, CD56, CD8alphabeta, CD8alpha, TCR alphabeta and TCR gammadelta were used for dual and three-colour flow cytometric analysis.

RESULTS

In addition to classical CD4+ and CD8+ T lymphocytes a substantial proportion of lamina propria T lymphocytes were CD4+ CD8+ or 'double positive' (mean 14%, range 4-26%). This population was significantly lower in the epithelial layer of the same patients (mean 7%, range 3-21%, P < 0.007). Three-colour flow cytometric analysis revealed that expression of the CD8 molecule on double positive T cells in the lamina propria was limited to the CD8alpha chain. Furthermore, of the CD8+ population, CD8+ T cells which only expressed the alpha chain were present in greater numbers in the lamina propria (mean 35%, range 14-54%) than in the epithelial layer (mean 18%, range 5-37%, P < 0.02). NK (CD56+) cells were not detected and few gammadeltaTCR+ T lymphocytes were detected in the lamina propria (mean 2%, range 0.5-6.6%) when compared with the epithelial layer (mean 8%, range 0.2-14%, P < 0.008).

CONCLUSION

A significant population of CD4+ CD8alpha+ T lymphocytes which are CD8beta chain negative have been detected in the intestinal lamina propria. These cells form a more significant component of the lamina propria than the epithelial layer T-cell repertoire and may have a unique function in intestinal immunoregulation.

Changes in peripheral blood double-negative T-lymphocyte (CD3+ CD4- CD8-) populations associated with acute cellular rejection after liver transplantation

Circulating CD3+ T lymphocytes that express neither the CD4 nor CD8 surface molecules (double-negative T lymphocytes) are phenotypically and functionally distinct from single-positive CD3+CD4+ and CD3+CD8+ lymphocytes and are thought to represent a distinct T-cell lineage. The presence of low numbers of double-negative T cells in healthy individuals and the increase observed in association with lymphoproliferative disorders, graft-versus-host disease, and autoimmune diseases suggest a pathogenic or immunoregulatory role for this population of T lymphocytes. In this study, peripheral blood double-negative T cells were assessed quantitatively using three-color flow cytometry in 10 patients after liver transplantation during a 6-week period. During this time, 12 episodes of histologically proven acute cellular rejection occurred in 8 patients. The median postoperative baseline double-negative T-cell count expressed as a proportion of the CD3+ T cells was 2.4 +/- 1.2 (median +/- SD; n = 10), which was identical to a control group of healthy adults (2.5 +/- 2.4; n = 9). Circulating numbers of double-negative T cells were increased significantly during acute cellular rejection (6.8 +/- 6.7; P < .001; n = 12). After pulse corticosteroid therapy for rejection, there was a significant decrease in the double-negative T-cell population (3.5 +/- 5.0 v 6.8 +/- 6.7; P = .01). No significant changes occurred in the double-negative T-cell count in the absence of clinical events (2.4 +/- 3.5; n = 73). These findings are consistent with a role for double-negative T cells in the initiation of acute cellular rejection or a possible regulatory role in the immunologic changes associated with rejection.

Resident human hepatic lymphocytes are phenotypically different from circulating lymphocytes

BACKGROUND/AIMS

Murine and human studies have documented the existence of subpopulations of lymphocytes in particular tissues that differ phenotypically and functionally from those in peripheral blood and may mature locally. Since little is known about lymphocyte subpopulations in the normal human liver, we have analysed the surface phenotypes of lymphocytes isolated from liver specimens taken from 15 donors at the time of liver transplantation, and compared these with those of peripheral blood lymphocytes.

METHODS

Hepatic lymphocytes were prepared by mechanical dissociation and enzymatic digestion of liver tissue. The cells were stained with a panel of monoclonal antibodies (CD3, CD4, CD8, CD19, CD56, gammadeltaTCR, alphabetaTCR, CD8alpha-chain, CD8alphabeta dimer), and analysed by flow cytometry. In situ characterisation of hepatic lymphocytes was by haematoxylin and eosin staining of fixed liver sections and by immunohistochemical staining for common leukocyte antigen and CD3.

RESULTS

Significant numbers of hepatic T lymphocytes were localised to the portal tracts and parenchyma of normal liver specimens. Flow cytometry revealed that the CD4/CD8 ratio (1:3.5) was consistently reversed compared with that in peripheral blood (2:1). Other lymphocyte populations identified include double positive CD3+CD4+CD8+ cells which accounted for a mean of 5.5% (range 3-11.6%) of hepatic CD3+ cells compared with 1.3% in blood (range 0.7-3.6%; p < 0.007), and double negative CD3+ CD4-8- cells (14.5%; range 2.7-29% compared with 5.0%; range 2.1-10.8%, p < 0.02). Over 15% (range 6.8-34%) of all hepatic CD3+ cells expressed a gammadeltaTCR compared to 2.7% (range 0.9-4.7%) of CD3+ peripheral blood lymphocytes (p < 0.004) and almost 50% of these coexpressed CD8. The CD8 alpha-chain was expressed without the beta-chain (CD8alpha+beta-) by 15.4% (range 4-29.1%) of hepatic T cells, but this phenotype was undetectable among peripheral blood lymphocytes (p < 0.009). Cells expressing both the T cell marker CD3 and the natural killer cell marker CD56 constituted 31.6% (range 14-54%) of all hepatic CD3+ lymphocytes but were rarely present amongst peripheral blood lymphocytes (0-6%; p < 0.0001).

CONCLUSIONS

These data are the first to describe and quantify unconventional T lymphocyte subpopulations in the normal adult human liver which may have specialised functions in regional immune responses and which may differentiate locally. These findings have important implications for our understanding of hepatic immunoregulation and the pathogenic mechanisms involved in viral and immune-mediated liver disease and allograft rejection.

Human small intestinal epithelial cells secrete interleukin-7 and differentially express two different interleukin-7 mRNA Transcripts: implications for extrathymic T-cell differentiation

The small intestinal epithelium, composed of epithelial cells (EC) and intraepithelial T lymphocytes, is exposed to numerous ingested antigens. Small intestinal EC may act as accessory and/or antigen presenting cells for intestinal T cells, some of which may mature extrathymically and regulate local immunity and tolerance. Since interleukin-7 (IL-7) plays an essential role in T cell maturation and activation, we examined its expression by human small intestinal EC. IL-7 was detected by ELISA in supernatants from 4 of 4 epithelial layer (EpL) cultures. Using RT-PCR, IL-7 mRNA was detected in 4 EpL studied, and two distinct IL-7 transcripts were identified in 3 of the 4. The ratios of the intensities of the larger to the smaller bands varied amongst individuals. Furthermore, the intensity ratios were higher in whole-thickness intestine and lamina propria preparations than in their corresponding EpL. This is the first report of the expression of two IL-7 transcripts in human intestine and of IL-7 secretion by human small intestinal EpL cells. This supports the hypothesis that small intestinal EC may influence differentiation and/or activation of neighboring T cells. The differential expression of the two transcripts may have important implications for immune regulation in the intestinal epithelium.

Donor type microchimerism is an infrequent event following liver transplantation and is not associated with graft acceptance

Donor-type microchimerism, the presence of a minority population of donor-derived haematopoietic cells following solid organ transplantation, has been postulated as a mechanism for induction of donor-specific graft tolerance. The stability, frequency, and relevance of microchimerism with respect to long-term outcome, however, remains uncertain. Using a polymerase chain reaction (PCR)-based method of microsatellite analysis of highly polymorphic short tandem repeat sequences (STRs) to detect donor-type cells, DNA from 11 patients was analyzed prospectively at specific time points for 12 months following liver transplantation, and from a further six patients retrospectively 2 years after liver transplantation. Using a panel of STRs, transient peripheral blood donor microchimerism was detected in 2 of 11 patients at a single time-point following transplantation, but persistent evidence of donor-derived cells was not observed during the study period. Analysis of DNA extracted from skin and duodenum in two patients likewise failed to show donor-type cells at these sites. None of the six patients in the retrospective arm showed donor microchimerism, resulting in an overall detection rate of 1.58%. These results suggest that donor microchimerism following liver transplantation is an infrequent event, and that the generation of graft tolerance is independent of microchimerism.

RAG1, RAG2 and pre-T cell receptor alpha chain expression by adult human hepatic T cells: evidence for extrathymic T cell maturation

Flow cytometric analysis of cell suspensions obtained from normal adult liver tissue at the time of transplantation revealed significant populations of T lymphocytes. These were examined for molecular evidence of local T cell maturation using reverse transcription-polymerase chain reaction to detect expression of recombination activation gene 1 (RAG1), RAG2 and pre-T cell receptor alpha chain (pTalpha), which occurs only in early thymocyte development. Four specimens of whole liver were positive for RAG1 and RAG2 expression, whereas peripheral blood mononuclear cells from the same individuals were negative. To localize RAG expression, immature (CD2+CD7+) and mature (CD45R0+) T cell subpopulations were isolated by magnetic separation from hepatic and peripheral blood mononuclear cell preparations. We detected the expression of RAG1, RAG2 and pre-TCRalpha in five specimens of hepatic CD2+CD7+ but not in CD45RO+ hepatic lymphocytes. Four out of six specimens of CD2+CD7+ cells from the peripheral blood were negative for RAG1 and RAG2 while all six specimens were positive for pTalpha expression. These results suggest that pre-T cells are trafficking from the bone marrow or the thymus to other tissues to continue differentiation and selection in the context of an appropriate cellular and molecular environment. The presence of immature populations of T cells in the adult liver and high levels of RAG expression suggests that the adult liver provides such an environment for extrathymic T cell maturation. These findings may have important implications for tolerance induction after liver transplantation and offer help in understanding the etiology of autoimmune liver disease.

Increased HLA-DR and decreased CD3 on human intestinal intraepithelial lymphocytes: evidence of activation?

BACKGROUND

Activation of circulating T lymphocytes results in expression of HLA-DR, interleukin-2 receptor (IL-2R), transferrin receptor (TrR), and decreased amounts of surface CD3.

AIM

To examine the activation status of human intestinal intraepithelial lymphocytes (IELs) by flow cytometry.

PATIENTS AND METHODS

Duodenal biopsy specimens from 12 patients provided a source of intestinal lymphocytes. Dual colour analysis was used to compare activation marker expression by IELs with peripheral blood (PB) T lymphocytes from the same patients.

RESULTS

All human IEL populations express HLA-DR and their density of expression is lower than on the small population of HLA-DR+ resting PB T lymphocytes (mean fluorescence intensity (MFI) 52.9, range 19.8-94.8 v 152.6 range, 49.1-320.3; p < 0.01). The density of CD3 was significantly reduced on IELs (MFI 465.8, range 228.7-660), compared with PB T lymphocytes (756.3, range 444.5-1573.7; p < 0.009). IL-2R was not detected on IELs; nor were the activation markers, TrR, M21 C5, or M2 B3.

CONCLUSION

HLA-DR expression on IELs together with decreased CD3 expression suggest previous stimulation. However, the absence of additional markers of T cell activation may reflect a unique pathway of activation.

Impaired gut barrier function in malnourished patients

The gastrointestinal tract is essential to host defence, acting as a barrier to absorption and translocation of gut antigens, including bacteria. In experimental models, protein malnutrition is permissive to gut barrier failure and endogenous infection. A clinical correlate has not been described. Intestinal morphology and barrier function to food protein antigens was studied in malnourished patients. Thirty-five individuals were evaluated, 20 malnourished patients and 15 well nourished hospital controls. Morphology was assessed from endoscopic biopsies of the second part of the duodenum, and serum immunoglobulin (Ig) G antibodies to gliadin and beta-lactoglobulin were measured. No antibody to food proteins was evident in the control group. In contrast, serum IgG antibodies to at least one antigen were present in 15 malnourished patients and to both antigens in ten (P < 0.0001 versus controls). Severely malnourished patients were more likely to have both antibodies present than those with mild or moderate malnutrition (P < 0.05). Antibody-positive malnourished patients had significantly better nutritional status than antibody-negative patients with malnutrition (P < 0.05). In no group of patients was there morphological evidence of abnormal mucosa or an immunological infiltrate. Gut barrier function is compromised in malnourished patients which suggests a mechanism that may facilitate gut-derived infection and sepsis.

Collagenase and Dispase enzymes disrupt lymphocyte surface molecules

Collagenase and Dispase enzymes are often used to disaggregate tissue. In this study, we examined by flow cytometry the effects of these enzyme preparations on peripheral blood lymphocyte surface marker expression. Peripheral blood mononuclear cells (PBMC) were obtained from seven healthy volunteers. Cells were incubated with collagenase (128 U/ml, type 1 A) for 3 h and overnight and with Dispase (1.6 mg/ml, grade II) for 15 min, 30 min, 1 h, 3 h and overnight. The intensity of expression of CD3, CD4, CD8, alpha beta and gamma delta T cell receptors was decreased by 25-40% in all cases, while CD4+ and CD8+ lymphocyte populations were undetectable after treatment with Dispase. Moreover, reappearance of these surface molecules did not occur following the incubation of cells in culture medium for 3 h. The results of this study emphasise the importance of considering the influence of isolation procedures on cell characteristics.

RAG1 and RAG2 expression in human intestinal epithelium: evidence of extrathymic T cell differentiation

We examined the hypothesis that the adult human gastrointestinal tract is a site of extrathymic T cell differentiation. When T lymphocytes undergo gene rearrangement, the products of both RAG1 and RAG2 genes are expressed; RAG mRNA is present only in tissue governing lymphocyte maturation. In this study, reverse transcription polymerase chain reaction (RT-PCR) was used to detect RAG1-and RAG2-specific mRNA. Total RNA was purified from small intestinal samples from five adults. Peripheral blood mRNA from the same patient was used as a negative control in two cases. Bone marrow RNA preparations from two healthy donors were used as positive controls. cDNA synthesis was carried out using random hexamers. Primers for first round and nested PCR of RAG1 and RAG2 were synthesized. RAG1 and RAG2 mRNA was detected in all bone marrow preparations but was absent in all peripheral blood samples. RAG1 and RAG2 mRNA was detected in the small intestine of four of the five patients studied. RAG1 and RAG2 expression was localized in the epithelial layer and absent in the lamina propria. RAG1 and RAG2 expression in the epithelial layer is strong evidence that T cell differentiation occurs in the adult human intestine.

Adenovirus 12 E1A gene detection by polymerase chain reaction in both the normal and coeliac duodenum

A 12 amino acid sequence from the adenovirus 12 E1B protein is homologous at the protein level with a similar 12-mer derived from the wheat protein A-gliadin. It has been suggested that exposure to Ad 12 could sensitise individuals to gliadins with resultant gluten sensitive enteropathy. In this study, the polymerase chain reaction (PCR) was used to analyse duodenal biopsy tissue from patients with coeliac disease for the presence of Ad 12. The sensitivity of the assay system was at least 1 in 10(5) cells and specificity was confirmed both by probing with an internal oligonucleotide and by direct sequencing. Ad 12 sequences were detected in three of 17 patients with adult coeliac disease and in five of 16 adult controls with normal duodenal biopsies. Since exposure to the virus would be predicted to occur in infancy we also studied patients with childhood coeliac disease diagnosed at less than 1 year of age. Ad 12 was positive in three of 10 childhood coeliac patients and one of seven controls. In addition, we studied a cohort of patients who presented with a diarrhoeal illness and associated anti alpha gliadin antibodies in 1983. These patients had duodenal biopsies performed at this time. One of three patients with abnormal histology had detectable Ad 12 while two of 14 with normal findings were positive for Ad 12. Finally, the potential oncogenic nature of Ad 12 prompted examination of a group of patients with intestinal tumours. Ad 12 DNA was, however, in only two of 19 tumour samples tested. These data indicate that Ad 12 can be successfully detected using PCR on paraffin embedded tissue. Furthermore, Ad 12 was detected at a relatively high level in normal duodenum. The results do not, however, support the hypothesis that prior exposure to Ad 12 is implicated in the pathogenesis of coeliac disease.

Adhesion molecules utilized in binding of intraepithelial lymphocytes to human enterocytes

The expression of adhesion molecules by human duodenal intraepithelial lymphocytes (IEL) was examined by two-color flow cytometry. Resting IEL expressed LFA-1, HML-1, CD44. Stimulation with phytohemagglutinin (PHA) resulted in down-regulation of expression of these molecules with induction of expression of ICAM-1 and VLA-4. VLA-4 expression was also found on non-activated IEL from patients with celiac disease. In addition, IEL expressed an antigen recognized by a novel monoclonal antibody D2.1. The molecular mass of D2.1 is heterogeneous: 82 kDa in peripheral blood lymphocytes and 44 kDa in an IEL line. Expression of this antigen was also up-regulated by PHA. To determine the involvement of these antigens in binding of IEL to human enterocytes, we developed a system based on adherence of an IEL cell line to the I407 fetal intestinal cell line. Monoclonal antibodies VLA-4, D2.1 and to a lesser extent ICAM-1 blocked adherence of IEL to I407 cells. These data suggest that VLA-4 and D2.1 may be involved in adherence of IEL to human enterocytes or secreted matrix molecules in vivo.

Flow cytometric analysis of surface major histocompatibility complex class II expression on human epithelial cells prepared from small intestinal biopsies

A technique for preparing viable, single cell suspensions of the epithelial layer of small intestinal tissue obtained endoscopically is described. Constant agitation of four biopsies for 60 min in the presence of chelating and reducing agents gave yields of 1.2-6.7 x 10(6) cells, of which 11-30% were intraepithelial lymphocytes (IEL). Passage through a nylon wool column removed dead cells. This preparation was suitable for flow cytometric analysis. Using this technique, surface MHC class II molecule expression was studied in 14 patients with normal small intestinal mucosa. Fluorescence labelling of these cells showed strong HLA-DR expression by epithelial cells (EC), DP was expressed less strongly, while little DQ expression could be detected. This technique demonstrates that small intestinal biopsies taken during routine endoscopy can yield adequate numbers of viable epithelial cells to perform flow cytometric analysis.

Food intolerance in rheumatoid arthritis

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Intestinal gluten sensitivity: snapshots of an unusual autoimmune-like disease

Gluten-sensitive disease is activated in genetically susceptible individuals by the ingestion of wheat protein (gluten). Breakdown in normal tolerogenic processes to dietary gluten is likely to play a primary pathogenic role. The disease is characterized by several autoimmune-type features and provides a model for studying autoimmune processes. A recent meeting emphasized the need for a clearer picture of the molecular interactions between disease triggering agents, molecules of the immune system and other products of disease susceptibility genes.

Oral ingestion of egg yolk immunoglobulin from hens immunized with an enterotoxigenic Escherichia coli strain prevents diarrhea in rabbits challenged with the same strain

White Leghorn hens were immunized with enterotoxigenic Escherichia coli B16-4 with heat-labile enterotoxin and colonization factor antigen I in Freund's adjuvant. Specific antibodies were detected by an enzyme-linked immunosorbent assay in the serum after 8 days and in eggs after 10 days, with levels reaching peaks at 15 and 20 days after the first immunization, respectively. The protective effects of the egg yolk antibodies were tested in the rabbit reversible ileal tie model of diarrhea. Five control rabbits developed severe diarrhea within 72 h after inoculation with enterotoxigenic E. coli B16-4. Oral ingestion of egg yolks from immunized hens for 4 days prior to inoculation protected five rabbits from diarrhea after challenge with the same strain of E. coli. The rabbits showed no adverse effects from the ingestion of the egg yolks. Four rabbits fed control eggs were also afforded some protection in that three rabbits developed mild diarrhea and one rabbit remained entirely well. In vitro experiments showed that immunoglobulin from egg yolks interfered with the binding of E. coli to purified small bowel mucins; immunoglobulin from immunized hens reduced binding more than immunoglobulin from nonimmunized hens. These findings indicate that eggs from hens immunized with appropriate antigens have potential as a useful source of passive immunity.

Gliadin antibodies identify gluten-sensitive oral ulceration in the absence of villous atrophy

This study demonstrates gluten-sensitive recurrent oral ulceration (ROU) in the absence of gastrointestinal abnormalities which is associated with a humoral response to wheat protein. Ten patients with severe ROU were investigated; all had normal small intestinal biopsies. Four patients had raised levels of antibodies to alpha gliadin, a wheat protein fraction; in three of these four, the ulceration remitted on treatment with a gluten-free diet (G.F.D.) and relapsed on gluten challenge. None of the remaining six patients had raised alpha gliadin antibody (AGA) levels and none responded to G.F.D. Thus raised AGA levels can be used to identify patients with ROU who are likely to respond to a GFD.

IgA rheumatoid factor and IgG dietary protein antibodies are associated in rheumatoid arthritis

This study sought to determine whether patients with rheumatoid arthritis (RA) were immunologically sensitised to dietary protein (DP). Using an enzyme linked immunosorbent assay (ELISA), antibodies to milk and wheat proteins were measured in 93 unselected out-patients with classical or definite RA. Of these 93, 53 had raised levels of IgG antibodies to one or both dietary proteins (DP). In the DP antibody positive group, 48 patients (90%) also had raised levels of IgA rheumatoid factor (measured by ELISA) while only 7 (17%) of the 40 DP antibody negative patients had detectable IgA RF; P less than 0.02. There was no association between IgM rheumatoid factor and dietary protein antibodies. These results demonstrate that in RA, raised levels of IgA RF are associated with an increased IgG response to antigens which enter the body through the gastrointestinal tract. A breakdown in gastrointestinal tolerance to dietary antigens may play a role in the immunopathogenesis of RA in these patients who might therefore benefit from dietary manipulation.

Altered gastrointestinal immune response in sarcoidosis

Because of the possible clinical association between coeliac disease and sarcoidosis, the incidence of humoral sensitivity to dietary proteins was examined in patients with sarcoidosis. Raised concentrations of circulating IgG antibodies to alpha gliadin were found in 41/99 sarcoid patients whereas antibody levels to casein, beta lactoglobulin and ovalbumin were similar to normal controls. Subsequently, a group of 26 sarcoid patients were selected for small intestinal biopsy; 11 had raised and 15 normal alpha gliadin antibody (AGA) levels. One AGA positive patient had villous atrophy consistent with coeliac disease. Intraepithelial lymphocyte (IEL) counts were raised in AGA positive (median 30; 95% confidence limits 22-46) and AGA negative (median 24; 95% confidence limits 19-32) sarcoid patients when compared with a control group (median 13.5; 95% confidence limits 10-18) p less than 0.01. Serum IgG concentrations were raised in 11/52 patients tested but there was no correlation between IgG levels and the presence of IgG antigliadin antibodies. HLA Dr typing was done in 21 of the 26 biopsied patients. The coeliac disease associated antigen Dr3 was present in eight of 21 (38%) which is very similar to the prevalence in unselected blood donors (34%). There was no significant difference in IEL counts between Dr3 positive and Dr3 negative sarcoid patients. These findings suggest that in patients with sarcoidosis, there is an altered gastrointestinal mucosal immune response, accompanied in about 40% of patients by specific sensitisation to wheat protein.

Association between villous atrophy in rheumatoid arthritis and a rheumatoid factor and gliadin-specific IgG

93 patients with rheumatoid arthritis (RA) were examined for histological or other evidence of gut abnormalities. 44 had raised levels of IgG to gliadin, and of these 38 (86%) were also positive for IgA rheumatoid factor (RF). 24 patients (15 with raised levels of IgA RF and wheat protein IgG [AB+] and 9 with normal levels of both antibodies [AB-]) underwent jejunal biopsy. 6 of the AB+ and 1 of the AB- patients had villous atrophy. The AB+ group had lower villous surface/volume ratio and small intestinal lactase concentrations than did the AB- group or age-matched controls. There was no significant difference between the two groups of RA patients in disease severity or treatment regimen. The findings suggest that the gut may play a more important part in the immunopathogenesis of some cases of RA than in others, and that the former may be identified by raised levels of IgA RF and wheat protein IgG.

Impaired neutrophil function during anesthesia and surgery is due to serum factors

Neutrophil function was assessed in patients undergoing anesthesia and surgery using a chemiluminescence (CL) assay. With the anesthetic agents enflurane and nitrous oxide, peroperative CL (99.1 mV; 13.8 SEM: postinduction but prior to surgery) was significantly lower than the preoperative value (146.5 mV; 14.1 SEM) with a mean fall of 30% (P less than 0.001). CL measurements taken 24 hr postoperatively were significantly increased (193.9 mV; 16.4 SEM) over the pre- and peroperative values, showing mean increases of 32 and 96%, respectively (P less than 0.001 in both cases). The inhibitory influence on CL appeared to be due to serum factors since peroperative patients' sera inhibited control neutrophils. Significantly depressed levels of the complement component C3 and IgG detected during the peroperative period (P less than 0.05) may explain this phenomenon. Postoperatively, C3 and IgG levels returned to normal. The transient decrease in peroperative neutrophil function may be a contributory factor to the establishment of postoperative sepsis in surgical patients.

Histological changes associated with wheat protein antibodies in the absence of villous atrophy

A retrospective study was conducted to assess the association of alpha-gliadin antibodies with intraepithelial lymphocyte counts. Twelve subjects with apparently normal small intestinal histology and raised alpha-gliadin antibody titres had significantly increased intraepithelial lymphocyte counts (42 (SEM) 5.9) when compared with 16 subjects with normal alpha-gliadin antibody titres (17 (3.2); p less than 0.001). These findings show that in the absence of gross pathology raised alpha-gliadin antibody titres are associated with increased numbers of intraepithelial lymphocytes and may reflect continuous immunological processes in the small intestine.

Humoral response to alpha gliadin as serological screening test for coeliac disease

The diagnostic value of measuring alpha gliadin antibodies in children with suspected coeliac disease has been evaluated prospectively. Jejunal biopsy and alpha gliadin antibody measurements were performed in 77 consecutive children who were being investigated for a suspected malabsorption syndrome. The typical small intestinal histological lesion of coeliac disease was found, and this diagnosis was subsequently confirmed clinically in 20 children. Raised IgG alpha gliadin antibody concentrations were found in 19 (95%). Fifty of 57 patients (88%) with a normal jejunal mucosa had normal alpha gliadin antibody concentrations. These results are similar to those previously reported in a prospective study of adult patients with coeliac disease and indicate that measurement of alpha gliadin antibody is a highly sensitive and specific screening test for childhood coeliac disease.

Immunoperoxidase demonstration of the cellular composition of the normal and coeliac small bowel

Immunohistological analysis of the cellular composition of the small intestinal mucosa in a group of untreated and treated coeliac patients and non-coeliac control subjects was performed using monoclonal antibodies and an immunoperoxidase technique. A characteristic cellular distribution was observed within the normal mucosa. The intraepithelial and lamina propria compartments were occupied mainly by T suppressor/cytotoxic and T helper/inducer cells respectively. Further subdivision of lamina propria T helper/inducer cells with the Leu 8 antibody revealed that these were of the Leu 3a+ Leu 8- phenotype. Macrophages, defined by the RFD7 antibody, were seen to occupy the same microenvironment as T helper/inducer cells. T cells expressing the T cell activation antigen defined by anti-Ta1 were found with the normal lamina propria, although few cells were identified by the anti-Tac antibody. HLA-Dr antigens were expressed by stellate cells within the lamina propria, and also by the epithelial cells of the villi, but not by normal crypt epithelial cells. In untreated coeliac patients the distribution of the various cell types was essentially unchanged, although the number of these cells was markedly increased, including those which expressed the Ta1 antigen. A significant deviation from normal in the expression of HLA-DR antigens was found in the coeliac small bowel: these antigens were expressed not only on the villous epithelial cells but also on the epithelial cells of the crypts. Immunohistological findings in the treated coeliac patients were intermediate between the normal and untreated coeliac groups, and were completely normal in those patients with complete histological resolution of their disease. These results suggest that coeliac disease is accompanied by an enhanced stimulation of the normal mucosal immune response and do not imply a primary pathogenic role for the immune system in this disease.

Humoral response to wheat protein in patients with coeliac disease and enteropathy associated T cell lymphoma

Features that might distinguish uncomplicated coeliac disease from enteropathy associated T cell lymphoma were investigated. Of 76 patients with coeliac disease, 71 (93%) had raised levels of alpha gliadin antibody and all responded clinically and histologically to treatment with a gluten free diet. In contrast, none of 16 patients with enteropathy associated T cell lymphoma had raised levels of alpha gliadin antibody, and treatment with a gluten free diet resulted in histological improvement in one and transient clinical improvement in six patients. The ratio of women to men was 2.2:1 in the group with coeliac disease and 1:1.6 in the patients with enteropathy associated T cell lymphoma. Thus patients with enteropathy associated T cell lymphoma do not display a humoral immune response to wheat protein (alpha gliadin), rarely respond to a gluten free diet, and are often men. Patients with uncomplicated coeliac disease usually have raised levels of alpha gliadin antibody, always respond to a gluten free diet, and are frequently women. These findings suggest the presence of two separate forms of enteropathy: one is benign and sensitive to wheat protein whereas the other runs a malignant course.

Gliadin antibody detection in gluten enteropathy

Circulating antigliadin antibody has been described in patients with gluten enteropathy although the prevalence varies in different studies. It has been suggested that the investigation for antigliadin antibody might be useful as a screening test. The object of the present study was to evaluate two different techniques for assaying these antibodies - an indirect immunofluorescent method and an enzyme-linked immunosorbent assay (ELISA). Antibodies were assayed in the sera of 102 patients in whom jejunal biopsies were also obtained. The specificity of both tests was greater than 95%, and the correlation between the presence of antibody and histology was significant (p < 0.005), though the sensitivity of each test was less than 70%.

Suppressor-cell activity in coeliac disease induced by alpha-gliadin, a dietary antigen

The wheat protein antigen alpha-gliadin, a fraction derived from gluten of molecular weight 60 000, activated suppressor cells from patients with coeliac disease but not from normal subjects or patients with Crohn's disease. Two other dietary antigens, casein and beta-lactoglobulin, failed to produce suppressor-cell activation. Since this phenomenon appears to be specific to coeliac disease, it may be of pathogenetic significance.

Increased concanavalin A induced suppression in treated and untreated coeliac disease

The generation of suppression by concanavalin A in peripheral blood mononuclear cells in treated and untreated coeliac subjects using an in vitro assay was found to be significantly increased when compared with controls. The response of peripheral blood mononuclear cells to the plant mitogen concanavalin A (con A) was also significantly depressed in both groups of coeliac patients. It is proposed that the depressed cell mediated immunity found in this and other studies in coeliac patients is because of increased suppression. The possible connection between these findings and the increased incidence of malignancy also found in coeliac disease is discussed.

The specificity of wheat protein reactivity in coeliac disease

The purpose of this study was to compare the effects of seven wheat protein fractions on the cell-mediated immune response of coeliac patients and normal individuals, by means of the leukocyte migration inhibition factor (LMIF) assay. Two preparations of milk protein were used as control antigens. Whereas milk protein had no effect on the release of LMIF by cells from either normal or coeliac patients, wheat protein preparations stimulated two types of response. A non-specific reaction was elicited from both coeliac and normal cells by crude preparations such as gliadin and Frazer's fraction III (an enzyme digest of gluten), whereas purified fractions (alpha gliadin and alpha-pel) stimulated a specific response from the cells of coeliac patients only. These results suggest that only a pure wheat protein preparation such as alpha gliadin or alpha-pel is of value in studying immunological parameters in coeliac disease.

Alpha gliadin antibody levels: a serological test for coeliac disease

The diagnostic value in coeliac disease of circulating antibodies to casein, crude gliadin, and alpha gliadin was assessed using an adaption of the enzyme linked immunosorbent assay system. alpha Gliadin was the only antigen which consistently separated 26 patients with untreated coeliac disease from 26 normal controls and 13 patients with chronic inflammatory bowel disease. The mean assay index for the 26 patients was 3.1 (SD 1.2) compared with 1.05 (0.5) for the normal controls and 1.1 (0.6) for patients with chronic inflammatory bowel disease. The alpha gliadin antibody levels of six patients with coeliac disease who had maintained a gluten free diet for at least two years were not significantly higher than normal (1.0 (0.4)). The validity of the test was determined in 90 consecutive patients who were being investigated for the presence of coeliac disease. Levels of alpha gliadin antibody were raised in 36 out of 44 patients found to have histologically proved coeliac disease and in six out of 46 subjects whose jejunal mucosa was normal. Serial alpha gliadin concentrations were measured in 12 patients with coeliac disease who had repeat jejunal biopsies performed six months after starting a gluten free diet. The levels of antibody fell in seven of the eight patients whose jejunal mucosa improved on maintaining the diet. They remained raised in four patients who did not adhere to the diet and whose mucosa did not improve. Although a test measuring alpha gliadin antibodies is unlikely to replace jejunal biopsy in the diagnosis of coeliac disease it may be useful in screening for the disease among outpatients.

Cellular response to alpha-gliadin in untreated coeliac disease

An improved technique for the detection of alpha-gliadin sensitised mononuclear cells in the peripheral blood of untreated coeliac patients is described. This method is a modification of the direct LMIF assay, and involves exposure of lymphocytes to alpha-gliadin and the assay of the resultant lymphokine produced using normal leucocytes as indicator cells. All untreated coeliac patients, 14 of 15 treated patients, and two of 28 controls responded to alpha-gliadin. The direct LMIF assay in comparison is less sensitive, and detected sensitivity to alpha-gliadin in only four out of eight patients with untreated coeliac disease. Use of the indirect LMIF technique demonstrates that in untreated as well as treated coeliac patients there are cells sensitised to alpha-gliadin circulating in the peripheral blood. These findings may have pathogenic and diagnostic significance.