Frequency of clonal intraepithelial T lymphocyte proliferations in enteropathy-type intestinal T cell lymphoma, coeliac disease, and refractory sprue

BACKGROUND: Clonal T cell receptor (TCR) gene rearrangements and loss of T cell antigens such as CD8 and TCR-beta in intraepithelial lymphocytes (IELs) may indicate the development of an enteropathy-type intestinal T cell lymphoma (EITCL) in patients with refractory sprue. AIMS: To define the diagnostic value of these markers in duodenal biopsies from patients with villous atrophy as a result of various underlying disorders. PATIENTS AND METHODS: Duodenal biopsies from eight patients with coeliac disease and five patients with villous atrophy caused by defined disorders were compared with three patients with refractory sprue evolving into overt EITCL, two patients with ulcerative jejunitis, and with eight patients with overt EITCL, for expression of CD3, CD4, CD8, and TCR-beta in IELs using immunohistochemistry and for clonal TCR-gamma gene rearrangements using polymerase chain reaction. In addition, biopsies from six consecutive patients with refractory sprue of uncertain cause were examined. RESULTS: Clonal TCR-gamma gene rearrangements were found in all resected tumours of patients with EITCL, in 3/8 duodenal biopsies of patients with EITCL, in 2/2 patients with ulcerative jejunitis, in 2/3 patients with refractory sprue evolving into overt EITCL, and in 1/6 patients with refractory sprue. No rearrangements were found in biopsies from patients with refractory sprue caused by defined disorders or those with coeliac disease. Clonality in duodenal biopsies was associated with an abnormal phenotype of IELs in all cases and in all but one case in patients with evidence of underlying coeliac disease. Specificity for detection of an EITCL using immunohistology was 77% for CD8 and for TCR-beta staining, and 100% for detection of a clonal TCR-gamma gene rearrangement. Sensitivity was 62% for staining with CD8 and clonality investigation, while sensitivity reached 100% for TCR-beta staining in all investigated patients with EITCL. CONCLUSIONS: Clonal proliferations of phenotypically abnormal IELs in refractory sprue represent an early manifestation of EITCL, for which the term "sprue-like intestinal T cell lymphoma" is proposed. This constellation is also found in duodenal biopsies from patients with an overt EITCL and is not related to other sprue syndromes, resulting in a high specificity for detection of an EITCL or refractory sprue evolving into EITCL. Overt EITCL may develop directly from coeliac disease without a precursor lesion (refractory sprue with clonal IELs) being demonstrable in duodenal biopsies or via a "sprue-like intestinal T cell lymphoma". This latter entity is a complication of coeliac disease.     

Epithelium derived interleukin 15 regulates intraepithelial lymphocyte Th1 cytokine production, cytotoxicity, and survival in coeliac disease

BACKGROUND AND AIMS: Epithelium derived interleukin (IL)-15 signalling via IL-15Ralpha is critical for the development, activation, and survival of intraepithelial lymphocytes (IEL). We aimed to better understand the IL-15 driven effects on IEL underlying mucosal damage and lymphomagenesis in coeliac disease (CD). METHODS: Enterocytes, IEL, and lamina propria mononuclear cells (LPMC) were isolated from 46 patients with uncomplicated CD (25 untreated and 21 treated) and 22 controls. IL-15 and IL-15Ralpha expression were determined by immunoblotting. Secretion of IL-15, interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), and granzyme B into cell culture supernatants was assessed by ELISA. The ability of IL-15 to regulate IEL proliferation, perforin/granzyme dependent cytotoxicity, and apoptosis was tested by adding different combinations of IL-15, IL-15 blocking antibody, or chloroquine to IEL cultured alone or with Caco-2 cells as target. IL-15 mucosal levels were also determined by ELISA in five patients with complicated CD (two ulcerative jejunoileites, one refractory sprue, and two enteropathy associated T cell lymphomas) tested for T cell receptor gamma chain clonality. RESULTS: IL-15 was overexpressed in untreated CD enterocytes and LPMC, and in the mucosa of complicated CD patients and uncomplicated untreated CD patients, where its levels correlated with the degree of mucosal damage. Enterocytes from untreated, but not treated, CD patients and controls secreted IL-15. Untreated CD IEL, characterised by higher IL-15Ralpha expression, showed increased proliferation, production of IFN-gamma and TNF-alpha, and perforin/granzyme dependent cytotoxicity, and a decreased propensity to apoptosis in response to IL-15. CONCLUSIONS: Our findings suggest that IL-15 plays a crucial role in the generation of epithelial damage in active CD. Its promotion of IEL survival in CD may predispose to the emergence of T cell clonal proliferations. Blocking IL-15, by suppressing uncontrolled IEL activation and survival, has the potential to provide new therapeutic tools to prevent tissue damage and lymphomagenesis in CD.     

Refractory coeliac disease: a window between coeliac disease and enteropathy associated T cell lymphoma

The treatment of coeliac disease (CD) is straightforward and simple: life-long adherence to a gluten-free diet. However, in a small subgroup of patients, the clinical and histological abnormalities persist or recur. This non-responsiveness leaves a poorly understood syndrome known as refractory coeliac disease (RCD). A specific definition of RCD is lacking in the literature. We speculate that RCD may appear in a subgroup of coeliacs with persisting histologic abnormalities. In all patients screened for RCD we look for DQ2 and DQ8. In non-DQ2/DQ8 patients we reconsider the diagnosis of CD and of auto-immune enteropathy. Most of the patients referred to us because of suspicion of RCD are affected by other diseases. Probably the commonest cause of non-responsiveness is continued gluten intake. Exocrine pancreas insufficiency, hyperthyroid disease, collagenous colitis are other common explanations. RCD and enteropathy-associated T cell lymphomas (EATL) can be distinguished by intra-epithelial lymphocyte phenotyping and TCR-gamma gene rearrangements. In RCD, an unexplained sustained stimulation of T cell cytotoxic activity is present. Immunosuppressive treatment might moderate this. Cyclosporine has been reported as a resounding success in case reports; however, our results were disappointing. We suggest azathioprine and steroids in RCD without aberrant T-lymphocytes in their mucosa. However, in RCD with aberrant T-lymphocytes we suggest chemotherapy. As the prognosis of EATLs is extremely poor the early detection of RCD with aberrant T cells is crucial.     

Flow cytometric analysis of intestinal intraepithelial lymphocytes in the diagnosis of refractory celiac sprue

The etiology of refractory celiac sprue (RCS) is unclear. In a high proportion of cases, the clonal nature of intestinal intraepithelial lymphocytes (IEL) can be demonstrated and a pathogenetic implication of intestinal IEL has been postulated. The prognosis of this subgroup of RCS is poor, with a high risk to develop an overt lymphoma and uncontrolled malabsorption despite steroid/immunosuppressive therapy. Cases with a relatively indolent clinical course, however, exist and their early diagnosis may be difficult. To gain insight into the pathogenic implication of intestinal IEL in refractory celiac sprue, we have performed an extensive phenotypic and functional characterization of clonal intestinal IEL in a patient with an indolent form of refractory celiac sprue, using multiparametric flow cytometry. The abnormal lymphocyte infiltrate lacked surface membrane expression of CD3/T-cell receptor (TCR) complexes (TCR(-), CD4(-), CD8(-), sCD3(-)), but contained intracellular CD3(epsilon) (CyCD3(+)) and surface CD103(+) and CD7(+). In particular, these cells showed a unique spontaneous ex-vivo cytokine secretion profile with an increased percentage of CD3(-) IEL containing TNF-alpha and IL-10, in the absence of IL-2, IL-4 and IFN-gamma. Altogether our results suggest that flow cytometry immunophenotyping of intestinal IEL, in cases suspected of celiac disease and their complicated forms, could be of great help in the correct diagnosis of RCS and the understanding of the immunopathogenic mechanisms of the disease and their clinical and/or therapeutical implications.     

Rectal Epithelial γ/δ T-Lymphocyte Responses to Local Gluten Challenge in Coeliac Disease

Sturgess RP, Loft D, Kontakou M, Crowe P, Marsh MN, Ciclitira PJ. Rectal epithelial γ/δ T-lymphocyte responses to local gluten challenge in coeliac disease. Scand J Gastroenterol 1993;28:760-762.

The proportion of intra-epithelial lymphocytes (IEL) that utilize the γ/δ form of the T-cell receptor (TCR) is increased in coeliac disease, but their function remains unexplained. The response of intraepithelial lymphocytes to rectal gluten challenge in coeliac and control subjects was studied after a rectal challenge of 2 g of Frazer's fraction III. A marked rise in CD3+ IEL occurred after challenge in the coeliac patients, peaking at 6 h and returning to normal by 48 h, with no significant changes in the γ/δ TCR+ IEL. The IEL did not significantly change after gluten challenge in the controls. Acute gluten challenge induces infiltration of the rectal mucosa by T cells in coeliac patients, which is not accompanied acutely by increased numbers of γ/δ TCR+ IEL. This study supports the hypothesis that α/β TCR+ T cells may be of importance in the early response of coeliac patients to local gluten challenge.     

Coeliac disease: in vivo toxicity of the putative immunodominant epitope

BACKGROUND: Peptides from alpha-gliadins have been used to characterise the immunodominant coeliac toxic epitope. A peptide corresponding to amino acid residues 57-73 of A-gliadin causes peripheral blood mononuclear cells from coeliac patients to secrete interferon gamma (IFN-gamma); gluten specific small intestinal T cell clones proliferate in response to peptides corresponding to residues 57-68 and 62-75 of alpha-gliadins. We wished to investigate whether a peptide corresponding to residues 56-75 of alpha-gliadins exacerbates coeliac disease in vivo. METHODS: Four adults with coeliac disease, all of whom were on a gluten free diet, underwent three challenges. Peptic-tryptic gliadin (PTG 1 g) served as a positive control. The test peptide and a negative control peptide were studied on separate occasions. The peptides were instilled into the duodenum and biopsies were taken before the infusion, and two, four, and six hours after commencing the infusions, using a Quinton hydraulic multiple biopsy capsule. Biopsy specimens were assessed blindly for villus height to crypt depth ratio (VH:CD), enterocyte cell height (ECH), and intraepithelial lymphocyte (IEL) count. We used the Mann-Whitney U test, with 95% confidence intervals, for statistical analysis. RESULTS: VH:CD and ECH fell, and IEL increased significantly 4-6 hours after commencing infusions with both PTG and the test peptide in all subjects. The negative control peptide caused no significant changes to villus morphology, enterocyte height, or IEL count in any patient. CONCLUSION: We have confirmed that the putative immunodominant epitope, a peptide corresponding to residues 56-75 of alpha-gliadins, exacerbates coeliac disease in vivo.     

Refractory coeliac disease

A small proportion of coeliac disease (CD) patients fail to improve after a gluten-free diet (GFD) and may be considered as atypical regarding their outcome (refractory coeliac disease). The aim of this study is to diagnose and manage patients with CD who fail to improve after a GFD. Refractory coeliac disease (RCD) is a malabsorption syndrome defined by persisting villous atrophy with, usually, an increase of intraepithelial lymphocytes (IELs) in the small bowel in spite of a strict GFD and comprises a heterogenous group of diseases. Some of these diseases have to be excluded and can be treated by specific therapies like antibiotics in tropical sprue and giardiasis and immune globulin substitution in common variable immunodeficiency, while other malabsorption syndromes are less well defined and may require immunosuppressive therapy. Standardized treatment, however, has not been evaluated in such patients so far. In a subgroup of patients with RCD, an abnormal intraepithelial lymphocyte (IEL) population may be observed with the lack of surface expression of usual T-cell markers (CD3-CD8 and/or the T-cell receptor (TCR)) on IELs associated with T-cell clonality pattern suggest the presence of an early enteropathy-associated T-cell lymphoma (EATL) in a subgroup of patients with RCD. This hypothesis has been supported by studies, which revealed progression into overt intestinal T-cell lymphomas in a subgroup of RCD. Steroid treatment has been reported effective even in patients with underlying early EATL. However, long-term results are unsatisfactory in most of these patients with RCD and parenteral nutrition has to be applied in some of these cases. First results with more aggressive chemotherapies and use of cytokines are under way. Due to the difficulty of diagnostic and therapeutic regimens patients should be referred to tertiary centres for coeliac disease.     

Upregulation of cathepsin W-expressing T cells is specific for autoimmune atrophic gastritis compared to other types of chronic gastritis

AIM: To investigate a pathophysiological role of cathepsin W (CatW), a putative thiol-dependent cysteine protease, which is specifically expressed in cytotoxic lymphocytes, in different types of chronic inflammation of the gastric mucosa. METHODS: Gastric and duodenal biopsies of patients with Helicobacter py/ori(Hpy/ori)-associated active gastritis (Hp, n = 19), chemically induced reactive gastritis (CG, n = 17), autoimmune atrophic gastritis (AIG, n = 20), lymphocytic corpus gastritis (LG, n = 29), celiac disease (CD, n - 10), and corresponding controls (n = 24) were analyzed by immunohistochemistry for the expression of CatW and CD45. Furthermore, immunohistochemical double staining with anti-CD3 and anti-cathepsin was performed for the samples of AIG. RESULTS: Median values of CatW-expressing cells among CD45-positive immune cells were between 2% and 6% for normal gastric mucosa, CG, and LG, whereas the corresponding value was significantly increased for AIG (24.7%,P<0.001) and significantly decreased for HP (0.7%, P<0.05). Double staining with anti-CD3 and anti-CatW antibodies revealed that >90% of CatW-expressing cells in gastric mucosa of AIG were T cells. Duodenal mucosa had significantly more CatW/CD45-positive cells than normal gastric mucosa (median: 17.8% vs 2%,P<0.01). The corresponding proportion of CatW/CD45-positive cells was decreased in CD compared to duodenal mucosa (median: 2.1% vs 17.8%, P<0.05). CONCLUSION: The opposite findings regarding the presence of CatW-positive cells in AIG (increase) and CD (decrease) reflects the different cellular composition of immune cells involved in the pathogenesis of these diseases.     

High-sensitive immunophenotyping and DNA ploidy studies for the investigation of minimal residual disease in multiple myeloma.

Sensitive techniques for monitoring minimal residual disease (MRD) in multiple myeloma (MM) are needed to evaluate the effectiveness of new intensive treatment strategies. The aim of the present study was to explore the applicability and sensitivity of flow cytometry immunophenotyping and DNA ploidy studies for the investigation of residual myelomatous plasma cells (PC) in MM patients. Bone marrow (BM) samples from 61 untreated MM patients were immunophenotypically analysed with a panel of 21 monoclonal antibodies, using a high-sensitive method based on a two-step acquisition procedure through a SSC/CD38 -CD138+ 'live-gate'. Overall, in 87% of MM cases, PC displayed an aberrant phenotype at diagnosis. The most important aberrant criteria were: antigen over-expression of CD56 (62%), CD28 (16%) and CD33 (6%) and asynchronous expression of CD117 (28%), sIg (21%) and CD20 (10%). DNA aneuploidy was found in 62% of cases. The simultaneous use of these two techniques allowed the detection of aberrant/aneuploid PC in 95% of the cases. Based on dilutional experiments, the detection limit of both techniques ranged from 10(-4) to 10(-5). In 29 stem cells harvests and 19 BM samples obtained 3 months after autologous transplantation, we have investigated the presence of residual myelomatous PC; they were detected in 44% of the stem cell collections and in 61% of the BM samples obtained after transplant. The percentage of pathological PC did not significantly change during the days of harvest. In summary, the present study shows that the combined use of immunophenotyping and DNA ploidy studies is a suitable approach for MRD investigation in MM patients based on their applicability (95% of cases) and sensitivity (up to 10(-5)).     

Histology of the terminal ileum in coeliac disease

BACKGROUND: The histological lesion of gluten sensitivity primarily affects the proximal small bowel. The purpose of this study was to assess whether there were features of gluten-sensitive enteropathy in biopsies taken from the terminal ileum during colonoscopy/ileoscopy. Specific and sensitive abnormalities might facilitate diagnosis of coeliac disease in patients undergoing colonoscopy as their initial procedure or help select those who should proceed to upper gastrointestinal endoscopy and duodenal biopsy. METHODS: Terminal ileal biopsies, taken from 30 patients with duodenal villous atrophy consistent with coeliac disease and from 60 control patients with no evidence of coeliac or inflammatory bowel disease, were reviewed blindly and compared. Biopsies were assessed for the presence or absence of villous atrophy and crypt hyperplasia, and counts were made of intraepithelial lymphocytes (IELs). RESULTS: One patient only, in the coeliac group, had partial villous atrophy with crypt hyperplasia in the terminal ileum. IEL counts were significantly higher (P< 0.005) in the coeliac group than among controls (mean per 100 enterocytes 26 versus 10). An ileal IEL count > or =25 had a sensitivity for duodenal villous atrophy (VA) of 60% and specificity of 100%. CONCLUSIONS: Coeliac disease may affect the entire small bowel. Increased IEL density in the terminal ileum is associated with duodenal VA and should prompt a search for coeliac disease by serology and duodenal biopsy. Conversely, a normal IEL count does not allow the exclusion of coeliac disease with confidence.     

Intraepithelial lymphocyte mitosis in a jejunal biopsy correlates with intraepithelial lymphocyte count, irrespective of diagnosis.

When there is villus atrophy in a jejunal biopsy, intraepithelial lymphocyte (IEL) mitosis correlates with a diagnosis of coeliac disease. We have examined the significance of IEL mitosis in jejunal biopsies with normal villi. Counts of IEL per 100 villus enterocytes, and IEL mitosis per 1000 IEL, were carried out in 81 jejunal biopsies. Thirty one were from patients with coeliac disease or dermatitis herpetiformis, and many of these, from treated patients, were histologically normal; 40 were from patients with other diagnoses, selected to include biopsies with a high IEL count (greater than 40 IEL per 100 enterocytes) but normal villi. Three coeliacs and 10 dermatitis herpetiformis patients had an IEL count of less than 40, and no IEL mitoses were found in these biopsies. Two dermatitis herpetiformis patients had IEL counts of 43.7% and 43.9%, with no IEL mitoses, but in all other coeliac and dermatitis herpetiformis biopsies high IEL counts were associated with IEL mitotic indices between 0.05% and 1.77%. In the non-coeliac, non-dermatitis herpetiformis group, no IEL mitoses were found in the 22 biopsies with IEL count less than 43%. In the others, IEL counts ranged from 44.8% to 127.0%, and IEL mitoses were present, with mitotic indices ranging from 0.06% to 0.49%. This work shows that IEL mitosis in a jejunal biopsy is not specific for coeliac disease, but occurs whenever there is an increased density of IEL within the villus epithelium.     

Histology of the terminal ileum in coeliac disease

Background: The histological lesion of gluten sensitivity primarily affects the proximal small bowel. The purpose of this study was to assess whether there were features of gluten‐sensitive enteropathy in biopsies taken from the terminal ileum during colonoscopy/ileoscopy. Specific and sensitive abnormalities might facilitate diagnosis of coeliac disease in patients undergoing colonoscopy as their initial procedure or help select those who should proceed to upper gastrointestinal endoscopy and duodenal biopsy. Methods: Terminal ileal biopsies, taken from 30 patients with duodenal villous atrophy consistent with coeliac disease and from 60 control patients with no evidence of coeliac or inflammatory bowel disease, were reviewed blindly and compared. Biopsies were assessed for the presence or absence of villous atrophy and crypt hyperplasia, and counts were made of intraepithelial lymphocytes (IELs). Results: One patient only, in the coeliac group, had partial villous atrophy with crypt hyperplasia in the terminal ileum. IEL counts were significantly higher (P?Conclusions: Coeliac disease may affect the entire small bowel. Increased IEL density in the terminal ileum is associated with duodenal VA and should prompt a search for coeliac disease by serology and duodenal biopsy. Conversely, a normal IEL count does not allow the exclusion of coeliac disease with confidence.     

Intraepithelial and lamina propria lymphocytes show distinct patterns of apoptosis whereas both populations are active in Fas based cytotoxicity in coeliac disease

BACKGROUND: Lamina propria (LPLs) and intraepithelial (IELs) lymphocytes are markedly increased in coeliac mucosa, and are thought to play a crucial role in the generation of villous atrophy in coeliac disease (CD). However, the mechanisms by which they mediate the killing of enterocytes in this condition are still poorly characterised. AIM: We investigated Fas mediated cytotoxicity and apoptosis of both LPLs and IELs, isolated from 10 untreated coeliac patients, 10 coeliac patients on a gluten free diet, and 10 biopsied controls. METHODS: Fas and Fas ligand expression were assessed by flow cytometry and immunocytochemistry. Lymphocyte cytotoxicity against Fas expressing Jurkat cells was determined by the Jam test. The effect of the antagonist ZB4 anti-Fas antibody on apoptotic activity exerted by coeliac lymphocytes against enterocytes was analysed. Lymphocyte apoptosis was assessed by oligonucleosome ELISA. RESULTS: LPLs and IELs showed increased apoptotic activity and higher levels of Fas ligand expression in untreated CD compared with treated CD patients and controls. Enterocyte apoptosis observed after coculturing coeliac lymphocytes and enterocytes in the presence of ZB4 antibody was reduced. In active CD, LPLs manifested increased apoptosis whereas IELs showed decreased apoptosis. CONCLUSIONS: Our results support the involvement of the Fas/Fas ligand system in CD associated enterocyte apoptosis. Increased LPL apoptosis is likely to downregulate mucosal inflammation whereas decreased IEL apoptosis could be responsible for autoimmune and malignant complications of CD.     

Effects of Helicobacter pylori eradication on the natural history of lymphocytic gastritis

BACKGROUND: Lymphocytic gastritis is characterised by an accumulation of lymphocytes in the surface epithelium of the stomach. Lymphocytic gastritis has been linked to coeliac disease and Helicobacter pylori infection. AIMS: To determine whether H pylori eradication leads to resolution of the lymphocytic infiltrate and clinical improvement in patients with lymphocytic gastritis, and to determine their HLA status. METHODS: The Leeds Dyspepsia Questionnaire (LDQ) was administered to 13 patients with lymphocytic gastritis. H pylori serology, (13)C urea breath test (UBT), and upper gastrointestinal endoscopy with sampling of the duodenum, antrum, and corpus were done in all cases and the HLA status was determined. Eleven patients had at least one positive test for H pylori. Patients with lymphocytic gastritis and H pylori infection were treated with a one week course of omeprazole, clarithromycin, and metronidazole. Gastric and duodenal intraepithelial lymphocyte (IEL) counts were performed, along with histological assessment of gastric and duodenal biopsies before and after H pylori eradication. RESULTS: Two months after treatment there was a significant reduction in gastric IEL counts in both antrum and corpus. There was no significant change in duodenal IEL counts before and after eradication. According to the Sydney grading there was significant improvement in corpus inflammation after eradication. The patients histologically H pylori positive before treatment became H pylori negative. Dyspepsia scores also improved significantly after treatment. CONCLUSIONS: H pylori eradication treatment in patients with lymphocytic gastritis causes significant improvement in the gastric IEL infiltrate, corpus inflammation, and dyspeptic symptoms. H pylori serology is frequently positive when histology and UBT are negative. Lymphocytic gastritis may represent a specific immune response to H pylori infection.     

Intestinal antibody pattern of coeliac disease: association with gamma/delta T cell receptor expression by intraepithelial lymphocytes, and other indices of potential coeliac disease.

Patients with coeliac disease have IgM antibodies and IgA anti-gliadin antibody in gut secretions, and also high counts of intraepithelial lymphocytes (IEL) that express the gamma/delta T cell receptor. These features of intestinal immunity may be markers of latent coeliac disease. Their occurrence was examined in 77 patients referred for jejunal biopsy, in whom biopsy histology was normal, to establish the extent to which these, and other candidate markers (high total IEL count, serum IgA anti-gliadin antibody (AGA), and increased permeability) coexist in the same patient. Twelve patients had high serum anti-gliadin antibody titres and nine increased permeability. The gamma/delta IEL count was high (> 5.5 per mm villus epithelium) in nine patients, the intestinal antibody pattern was positive in 21, and the total IEL count was high (> 40 per 100 enterocytes) in 13. Overall, 31 patients had positive indices, but in 19 only a single test was abnormal. High gamma/delta IEL counts were found in six of 21 intestinal antibody positive patients, but in only two of 56 who were intestinal antibody negative (p < 0.001); there were no other significant associations. Clinical tests of gluten sensitivity will be required to establish the prevalence of latent gluten sensitive enteropathy in the 40% of patients referred for jejunal biopsy in whom one or more of the immunological indices of potential coeliac disease is present.     

Human immunodeficiency virus-related anemia of chronic disease: relationship to hematologic,immune, and iron metabolism parameters,and lack of association with serum interferon-gamma levels

Anemia of chronic disease (ACD) is frequent in patients with human immunodeficiency virus (HIV) and its etiology is multifactorial. In a group of 111 patients with HIV, 19 were diagnosed with ACD. Parameters related to iron metabolism, such as serum iron (SI), serum ferritin (SF), and soluble transferrin receptor (sTfR) were correlated to levels of interferon-gamma (IFN-gamma) and results compared to a group of 42 nonanemic patients with HIV. Measurements of erythropoietin (EPO), CD4/CD8 T-cell ratio, and reticulocyte count (RTC) were determined to verify aspects related to severity of disease and bone marrow response. The results showed higher SF concentrations in ACD patients and normal or slightly increased sTfR measurements in both groups. There was no correlation between IFN-gamma and SF and between IFN-gamma and sTfR determinations. Lower CD4/CD8 values were obtained in ACD, and an inverse correlation was observed between IFN-gamma and CD4/CD8 in groups with and without anemia. RTC counts and EPO concentrations were similar in both groups: immature RTC were increased in patients with anemia, indicating an apparent attempt of marrow response to compensate the increased demand. Our data showed no correlation between IFN-gamma levels and iron disturbances in ACD, but results reinforced the observation of enhanced immunologic system deterioration in patients with HIV and ACD.     

Susceptibility to tuberculosis in patients with coeliac disease

An increased prevalence of past tuberculosis is reported in an adult coeliac population. Of 76 adult coeliac disease patients, 6 had had a history of tuberculosis. This compared with the finding of no cases in a population of 81 patients with non-inflammatory bowel diseases, (p = 0.023), which was matched for age, sex, smoking, ethnic origin and social class. The 'expected' number of cases of tuberculosis amongst ACD patients has also been calculated based on local annual notification rates; this was 2.9. Radiological evidence of past tuberculosis was found in 13 (17%) ACD patients, compared with 4 (5%) control patients (p less than 0.05). It is postulated that the increased prevalence of past tuberculosis in ACD patients is the result of depressed cell mediated immunity and/or malnutrition.     

CD4+CD8+ human small intestinal T cells are decreased in coeliac patients, with CD8 expression downregulated on intra-epithelial T cells in the active disease

BACKGROUND/OBJECTIVE: The intestinal lesion of coeliac disease is thought to be initiated and exacerbated by dysregulation of local T-lymphocyte sub-populations. This study examines changes in intestinal T cells from coeliac patients, with a particular focus on CD4CD8 T cells, immunoregulatory cells normally found in relatively high proportions in the small intestine. METHODS: Cells were obtained from duodenal biopsies from active and treated coeliac patients using chelating and reducing agents (epithelial layer) followed by collagenase treatment (lamina propria). Cell yield and viability were assessed and flow cytometric analysis was used to examine CD4CD8 T cells and to quantify CD8 expression. RESULTS: Surprisingly, total T-cell yields in the epithelial layer did not increase in active coeliac disease although enterocyte counts decreased significantly, giving an appearance of infiltration. In active coeliac patients, CD4CD8 T cell percentages were significantly decreased in both the epithelial layer and lamina propria. Levels of CD8 expression by CD4CD8 T cells in the epithelial layer were decreased significantly in patients with active coeliac disease. CD4CD8 T cell proportions did not return to normal in treated coeliac patients whose villous architecture had responded to gluten withdrawal. CONCLUSIONS: No increase of intra-epithelial lymphocytes in the coeliac lesion may require us to reconsider the definition of coeliac disease as an inflammatory condition. Low CD4CD8 populations in treated as well as untreated coeliac patients indicate that these T cells are inherently absent in individuals genetically predisposed to coeliac disease.     

FIV infection induces unique changes in phenotype and cellularity in the medial iliac lymph node and intestinal IEL

Studies of human immunodeficiency virus-1 (HIV-1)-infected patients and simian immunodeficiency virus (SIV)-infected macaques have identified profound depletion of CD4(+) T cells and expansion of CD8(+) T cells in the gastrointestinal lamina propria. Less attention has been given to CD8(+) intraepithelial lymphocytes (IEL), and no studies have concurrently examined inductive sites such as draining lymph nodes. Our preliminary data in the feline immunodeficiency virus (FIV) animal model suggested additional changes in IEL, and marked differences in the responses of lymph nodes draining different mucosal sites. To address this, we quantified the absolute leukocyte yield and examined the phenotype of cells from small intestinal IEL, mesenteric lymph node (MLN), and medial iliac lymph node (ILN) from chronically FIV-infected cats. The cellularity of the ILN was increased 530% in FIV-infected animals with an expansion of CD62L(+) cells, suggesting an increased population of naive T cells. The number of CD4(+), as well as CD8(+), T cells was increased in the ILN, resulting in a CD4:CD8 ratio greater than 1:1. In contrast, reduced cellularity, specific loss of CD4(+) T cells, and inversion of the CD4:CD8 ratio was observed in the MLN, which drains the intestine. In IEL, loss of CD8alpha, CD8beta, and CD4-expressing T cells was found in FIV-infected cats. Furthermore, expression intensity of CD8alpha and CD5, markers known to be important in T cell function, was markedly decreased on IEL. These findings expand the array of immune alterations induced by lentiviral infection and indicate that characterization of multiple mucosal sites will be necessary to fully understand the pathogenesis of HIV-1 infection.     

Epithelial cells bearing class II molecules stimulate allogeneic human colonic intraepithelial lymphocytes.

HLA-DR+ gut epithelial cells may present antigen to intraepithelial lymphocytes (IEL). This study aimed to isolate an IEL population from the human colon to activate CD3 + IEL by a human colonic epithelial cell line (HT-29), bearing different concentrations of class II antigen (HLA-DR). IEL were isolated by a mechanical method from six patients with ulcerative colitis (UC) and from 14 control patients. IEL were cocultured with HT-29 which had been induced to express class II molecules by gamma-interferon (IFN-gamma) in a dose dependent manner. The phenotype and the subsequent expression of activation markers by the IEL were determined to two colour flow cytometry. The IEL population had a CD4/CD8 ratio similar to that seen in tissue sections. In the mixed cell culture, the degree of IEL activation showed a positive correlation with the degree of HLA-DR expression by the HT29 cells and the IEL secreted a IFN-gamma like factor that in turn stimulated the HT-29. Thus, depending on their expression of HLA molecules, colonic epithelial cells are able to activate CD3+CD8+IEL.