T lymphocyte subsets in inflammatory bowel disease: peripheral blood

Peripheral blood T lymphocytes and T lymphocyte subsets have been quantified in 28 patients with ulcerative colitis and 26 with Crohn's disease by an indirect immunofluorescence technique using monoclonal antibodies: OKT3, which detects all peripheral blood T lymphocytes; OKT4 (T cells of helper phenotype); and OKT8 (T cells of supressor-cytotoxic phenotype). Eighteen normal subjects and 16 patients with a variety of non-inflammatory gastrointestinal disorders were studied as controls. No significant differences were found between patient and control groups in the proportions of circulating T lymphocytes or their subsets. When compared with normal subjects, absolute numbers of T lymphocytes were reduced in patients with active ulcerative colitis or Crohn's disease (p less than 0.05). OKT4+ T cell numbers were reduced in ulcerative colitis, whether active (p less than 0.02) or inactive (p less than 0.05) and in active Crohn's disease (p less than 0.05) Numbers of OKT8+ T cells were reduced in active Crohn's disease (p less than 0.01). There were no differences in T lymphocyte numbers between the patient groups and the disease control subjects. The OKT4+:OKT8+ ratio in patients with inflammatory bowel disease did not differ from that in controls. No relation was found between any of the parameters studied and disease activity, site, or extent of disease, or treatment with sulphasalazine or corticosteroids. The presence of Ia-like, HLA-DR antigens on T cells was detected using a double marker immunofluorescence technique. In control subjects up to 7% of OKT3+ cells were HLA-DR+. In only three patients was the proportion of HLA-DR+ cells greater than in controls. These results indicate that the pathogenesis of ulcerative colitis or Crohn's disease does not depend upon an alteration in the proportion of circulating T lymphocytes nor upon an imbalance of T lymphocyte subsets as defined by monoclonal antibodies. The reduction in T lymphocyte numbers may result from mucosal infiltration. The findings also suggest that circulating T lymphocytes are not activated.     

Differential expression of CD25 (interleukin-2 receptor) on lamina propria T cells and macrophages in the intestinal lesions in Crohn's disease and ulcerative colitis.

Many interleukin-2 receptor (CD25) bearing cells can be identified by alkaline phosphatase immunohistochemistry in the diseased intestinal lamina propria of children with Crohn's disease or ulcerative colitis, but rarely in normal intestine. In both diseases, the CD25+ cells are present as aggregates in the lamina propria below the epithelium, and constitute a large proportion of the lamina propria mononuclear cells. In Crohn's disease, but not ulcerative colitis, CD25+ cells are abundant in the submucosa. The CD25+ cells in Crohn's disease are 58-88% CD3+, CD4+, CD8-, indicating that they are T cells, whereas in ulcerative colitis the CD25+ cells are greater than 80% CD3-, CD4+, HLA-DR+, indicating that they are macrophages. Thus, differential expression of CD25 on T cells and macrophages serves to distinguish the immunologic lesions in ulcerative colitis and Crohn's disease.     

Compared azathioprine efficacy in ulcerative colitis and in Crohn's disease

AIM: To compare the 6-month efficacy and tolerance of azathioprine in 68 patients with steroid-resistant or steroid-dependent chronic ulcerative colitis (n=30) or Crohn's disease (n=38).METHODS: Clinical remission was defined as a Crohn's Disease Activity Index<150 for Crohn's disease and number of non-bloody stools<=3/day for ulcerative colitis, associated with prednisone requirement<=10 mg/day.RESULTS: Seventy-three per cent of patients with ulcerative colitis had distal or left-sided colitis and 84% of patients with Crohn's disease had pancolitis. Azathioprine was discontinued early for side-effect in 8 (26.7%) patients with ulcerative colitis and in 8 (21.1%) patients with Crohn's disease (NS). In patients treated at least 6 months by azathioprine, clinical remission rates were 77.3% and 70% for chronic ulcerative colitis and Crohn's disease (NS). Complete corticosteroids weaning was obtained significantly more often in ulcerative colitis patients than in Crohn's disease patients (59.1% vs 30%; P<0.05).CONCLUSION: Azathioprine seems to be at least as effective and equally tolerated in steroid-resistant or steroid-dependent chronic ulcerative colitis or Crohn's disease patients.     

The importance of peripheral immune cells in inflammatory bowel disease.

Background/aims: Inappropriate down regulation of an activated immune system is considered as the main pathogenetic mechanism in inflammatory bowel disease. Migration of circulating cells to a diseased intestine is considered as an important factor in the pathogenesis of inflammatory bowel disease. We aimed to evaluate some features of circulating immune cells in inflammatory bowel disease. Methods: Twenty-two control, 29 Crohn's disease and 17 ulcerative colitis patients were studied. CD2, CD3, CD4, CD8, CD11b, CD11c, CD25, CD45RA, CD45RO, CD54 and HLA DR on the surface of peripheral blood lymphocytes and CD11b, CD11c, CD45RA and CD45RO on the phagocytes were researched with two-color immunofluorescence flow cytometry. Results: The percentages of CD2+ and CD4+ lymphocytes were found significantly reduced in ulcerative colitis. CD3+ and CD8+ lymphocytes in inflammatory bowel disease were higher than in controls. CD45RA+ lymphocytes were found significantly decreased in ulcerative colitis and active Crohn's disease. CD45RO+ lymphocytes and CD45RO+, CD11b+ and CD11c+ phagocytes were significantly increased in Crohn's disease. Conclusions: We demonstrated that there were significant differences between ulcerative colitis and Crohn's disease in the expression of some important surface markers on the peripheral blood immune cells. It seems that circulating CD11b-CD11c and CD45RA-CD45RO expressing phagocytes are important in inflammatory bowel disease and may be useful in distinguishing Crohn's disease from ulcerative colitis. These findings may give us some clues about the immunopathogenesis of inflammatory bowel disease.     

Colon mucosa of patients both with spondyloarthritis and Crohn's disease is enriched with macrophages expressing the scavenger receptor CD163

BACKGROUND: Crohn's disease is associated with an increased number of macrophages in ileal and colonic mucosa. Data on macrophages in gut mucosa of patients with spondyloarthritis (SpA) are scarce. OBJECTIVE: To investigate macrophages and other antigen presenting cells in gut mucosa from patients with SpA and Crohn's disease, given the relationship between both entities. METHODS: Biopsy specimens from patients with SpA, Crohn's disease, ulcerative colitis, and from controls were immunohistochemically stained with different markers for macrophages and dendritic cells. Slides were scored semiquantitatively on a four point scale. RESULTS: SpA and Crohn's disease were associated with large numbers of CD68+ macrophages. Colon mucosa of both patients with SpA and Crohn's disease, but not ulcerative colitis, showed increased numbers of macrophages expressing the scavenger receptor CD163. CONCLUSIONS: Macrophages expressing the scavenger receptor CD163 are increased in colonic mucosa in SpA and in Crohn's disease, highlighting the relationship between these entities. The increased number of CD163+ macrophages in colon mucosa of patients with SpA suggests this is another argument for a role of macrophage scavenger receptors in this group of diseases.     

Diffuse gastroduodenitis associated with ulcerative colitis: Treatment by infliximab

Diffuse gastroduodenitis resembling ulcerative colitis in respect to macro‐ and microscopic findings occurs in ulcerative colitis, although it is rare. Reports of gastroduodenitis associated with ulcerative colitis treated with infliximab are rare. A 58‐year‐old man had tarry stool in March 2011. He had a history of ulcerative colitis that was diagnosed in 1984. He underwent subtotal colectomy in 1991. Endoscopy and radiography revealed diffuse friable mucosa throughout the duodenum and an ulcer in the middle of the descending portion, resulting in a narrow portion.In the stomach, numerous small aphthae were observed in the antrum. Biopsy specimens of the duodenum and antrum showed marked inflammatory cell infiltration in both areas and cryptitis in the duodenum. Standard induction therapy of infliximab was started in April. The ulcer in the descending portion became a scar without diffuse mucosal friability in September 2011.     

Coexpression of CD4 and CD8 on peripheral blood T cells and lamina propria T cells in inflammatory bowel disease by two colour immunofluorescence and flow cytometric analysis.

Using two colour immunofluorescence with fluorescein isothiocyanate and phycoerythrin labelled monoclonal antibodies and multiparameter flow cytometry, we investigated the coexpression of CD4 and CD8 antigens on peripheral blood lymphocytes and lamina propria lymphocytes of patients with ulcerative colitis and Crohn's disease and normal control subjects. Both the absolute number and the proportion of peripheral blood CD4+, CD8+ cells in inflammatory bowel disease were small but significantly increased compared with those in normal control subjects. Peripheral blood lymphocytes activated with phytohaemagglutinin showed appreciably increased coexpression of CD4+, CD8+. These CD4, CD8 positive cells were large and granular. Thus the increased number of peripheral blood CD4+, CD8+ cells in inflammatory bowel disease suggests that chronic immune activation occurs not only in the active state of the disease but also in remission. The proportion of CD4+, CD8+ cells in the lamina propria was greater than in peripheral blood in normal subjects, suggesting chronic immune stimulation of the local immune system. This was also seen in patients with Crohn's disease or inactive ulcerative colitis. The proportion of CD4+, CD8+ cells was, however, significantly less in the lamina propria of patients with active ulcerative colitis. Whether this implies a possible defect in mucosal immunoregulation in active ulcerative colitis cannot be determined from these results.     

The role of CD40 in ulcerative colitis: histochemical analysis and clinical correlation

OBJECTIVES : CD40 co-stimulator seems to be implicated in the loss of tolerance against self-antigens in many autoimmune diseases. The evidence suggests that in the pathogenesis of ulcerative colitis there is an activity state against self-antigens of the gut wall and flora. The aim of this study was to analyse the expression of CD40 in ulcerative colitis, comparing it with Crohn's disease and nonspecific inflammation of the colon and to determine whether there is a relationship between its expression and the activity stage of the disease. METHODS : The expression of CD40 in the colonic samples of 51 patients (30 ulcerative colitis, 9 Crohn's disease and 12 nonspecific inflammation) was analysed by immunohistochemistry. Twenty-four patients with ulcerative colitis were scored according to clinical, endoscopic and histological classification. RESULTS : The mean percentage of CD40+ cells per field in the colonic mucosa was: ulcerative colitis 21 +/- 11%, Crohn's disease 24 +/- 9%, nonspecific inflammation 7 +/- 7%. The ulcerative colitis patients were statistically significantly different compared to the patients with nonspecific inflammation (P < 0.005), even when comparing the patients in remission (P < 0.05). The expression in Crohn's disease was similar to that in ulcerative colitis. The expression of CD40 in ulcerative colitis was directly proportional to the state of activity of the disease according to the clinical (P < 0.02), endoscopic (P < 0.01) and histological (P < 0.02) criteria. CONCLUSIONS : The expression of CD40 in the colonic mucosae of patients with ulcerative colitis is significantly increased and is proportional to the state of activity. The results seem to confirm the hypothesis that a loss of tolerance could be involved in the pathogenesis of this disease.     

Flow cytometric analysis of peripheral blood lymphocytes in ulcerative colitis and Crohn''s disease.

Using two colour immunofluorescence with fluorescein isothiocyanate and phycoerythrin labelled monoclonal antibodies, multi-parameter flow cytometry was used to examine the antigenic characteristics of peripheral blood lymphocytes in whole blood of patients with ulcerative colitis and Crohn's disease who were not taking immunosuppressive drugs. The numbers of CD4+ and CD8+ lymphocytes in patients with ulcerative colitis and Crohn's disease remained unchanged so that the CD4/CD8 ratio was the same as that of normal control subjects. In Crohn's disease there were many activated T cells (CD3+, CD25+). Although natural killer cells in active Crohn's disease were lower than in normal control subjects, cytotoxic T lymphocytes, as defined by CD3+, CD16+, did not differ in patients with inflammatory bowel disease compared with normal control subjects. For B cell subsets, there were differences in Leu-1+ B cells, Leu-8+ B cells, Fc epsilon R+B cells (Leu-16+, Leu-20+), and activated B cells (Leu-12+, Leu-21+) between patients with inflammatory bowel disease and normal control subjects. These differences are compatible with local activation of B cells in the inflamed colon.     

Increased numbers of macrophages in noninflamed gastroduodenal mucosa of patients with Crohn's disease

We investigated immunostained macrophages in the noninflamed mucosa of Crohn's disease patients. Biopsied specimens from endoscopically normal gastroduodenal mucosa of Crohn's disease, ulcerative colitis, and healthy control patients were studied. Sections were examined immunohistochemically using a monoclonal antibody specific for tissue macrophages (CD68). Immunostained mucosal macrophages in the second part of the duodenum, duodenal bulb, gastric antrum, and gastric body of the Crohn's disease group were more numerous than in the ulcerative colitis and control groups. The characteristic findings of Crohn's disease were aggregations, focal subepithelial dense accumulations, and infiltration throughout the mucosa of macrophages not accompanied by a lymphoid infiltrate. The number of macrophages in the gastroduodenal mucosa bore no relationship with the duration of symptoms, clinical activity, or affected site in the intestine. This suggests that the increased number of macrophages in noninflamed mucosa is a histological change characteristic for Crohn's disease that indicates a persistent latent abnormality involving the entire gastrointestinal tract.     

Focal-enhanced gastritis in regressive autism with features distinct from Crohn's and Helicobacter pylori gastritis

BACKGROUND: Immunohistochemistry allowed recent recognition of a distinct focal gastritis in Crohn's disease. Following reports of lymphocytic colitis and small bowel enteropathy in children with regressive autism, we aimed to see whether similar changes were seen in the stomach. We thus studied gastric antral biopsies in 25 affected children, in comparison to 10 with Crohn's disease, 10 with Helicobacter pylori infection, and 10 histologically normal controls. All autistic, Crohn's, and normal patients were H. pylori negative. METHODS: Snap-frozen antral biopsies were stained for CD3, CD4, CD8, gammadelta T cells, HLA-DR, IgG, heparan sulphate proteoglycan, IgM, IgA, and C1q. Cell proliferation was assessed with Ki67. RESULTS: Distinct patterns of gastritis were seen in the disease states: diffuse, predominantly CD4+ infiltration in H. pylori, and focal-enhanced gastritis in Crohn's disease and autism, the latter distinguished by striking dominance of CD8+ cells, together with increased intraepithelial lymphocytes in surface, foveolar and glandular epithelium. Proliferation of foveolar epithelium was similarly increased in autism, Crohn's disease and H. pylori compared to controls. A striking finding, seen only in 20/25 autistic children, was colocalized deposition of IgG and C1q on the subepithelial basement membrane and the surface epithelium. CONCLUSIONS: These findings demonstrate a focal CD8-dominated gastritis in autistic children, with novel features. The lesion is distinct from the recently recognized focal gastritis of Crohn's disease, which is not CD8-dominated. As in the small intestine, there is epithelial deposition of IgG.     

Loss of interleukin-2-producing intestinal CD4+ T cells in inflammatory bowel disease.

Interleukin-2 activity of intestinal lamina propria mononuclear cells is decreased in Crohn's disease and ulcerative colitis patients compared with control patients with noninflammatory bowel disease. Factors that might be responsible for this phenomenon were investigated. Most interleukin-2 activity was produced by helper (CD4+) T cells. These were present in comparable numbers in both inflammatory bowel disease and control cultures, but the frequency of interleukin-2-producing cells was significantly (3-4 times) lower among Crohn's disease and ulcerative colitis than control cells. In agreement with this finding, levels of interleukin-2 messenger RNA were substantially decreased in both forms of inflammatory bowel disease compared with controls. Mucosal CD8+ T cells and plastic-adherent cells were unable to suppress interleukin-2 activity by autologous or allogeneic CD4+ T cells. The rate of interleukin-2 absorption was similar for inflammatory bowel disease and control cells. Induction of interleukin-2 by different stimuli (phorbol ester, phytohemagglutinin, or anti-CD3 monoclonal antibody) before or after incubation under basal conditions ("resting") failed to normalize the capacity to generate interleukin-2 by Crohn's disease and ulcerative colitis cells. Prostanoids (prostaglandin E2 and 6-keto-prostaglandin F1 alpha) were produced in large amounts in cultures of inflammatory bowel disease cells, but inhibition by indomethacin failed to restore interleukin-2 activity to control levels. Finally, supernatants from Crohn's disease and ulcerative colitis cell cultures failed to suppress interleukin-2 production by control CD4+ T cells. Our results show that the low interleukin-2 activity detected in inflammatory bowel disease mucosa is not caused by activated suppressor cells, excessive lymphokine utilization or immune stimulation, a defective response to activation signals, or production of inhibitory substances. Rather, the low interleukin-2 activity appears to be related to a loss of interleukin-2-producing mucosal CD4+ T cells. It is concluded that abnormalities of intestinal CD4+ T-cell function are associated with the immunopathogenesis of Crohn's disease and ulcerative colitis.     

Obliterative arteritis with nitric oxide synthase and HLA-DR expression in Crohn's colitis

BACKGROUND/AIMS: To cast light on whether inflammatory vascular injury is a possible pathogenic mechanism in Crohn's disease, the histological characteristics of vascular lesions were investigated. METHODOLOGY: Affected vessels in surgically resected colons from 23 patients with Crohn's disease, 20 with ulcerative colitis, 7 with ischemic colitis, and 9 normal controls were analyzed by Victoria blue and hematoxylin and eosin staining as well as immunohistochemistry for HLA-DR, nitric oxid synthase, vascular endothelial growth factor and E-cadherin. RESULTS: Inflammatory-cell infiltrates affecting arteries, accompanied by obliterative intimal thickening, were more frequent in Crohn's disease cases than in the other groups (P < 0.05-0.0001). Crohn's disease activity was positively correlated with the degree of obliterative arteritis. Granulomatous vasculitis was found exclusively in Crohn's disease (10 cases; 43.5%). In addition, focally enhanced endothelial staining of HLA-DR, with expression in granulomas adjacent to vessels was occasionally observed. In the endothelium of affected vessels, strong expression of HLA-DR was more prevalent in Crohn's disease and/or ulcerative colitis as compared with the ischemic colitis and controls (P < 0.05-0.01). In the involved arteries, enhanced endothelial nitric oxide synthase expression was most common in Crohn's disease among the groups (P < 0.05). A few cases of Crohn's disease, ulcerative colitis and ischemic colitis were positive for inducible nitric oxide synthase, vascular endothelial growth factor or E-cadherin in the vessel walls. CONCLUSIONS: The presence of characteristic obliterative arteritis and granulomatous vasculitis, a possible cause of ischemic injury, supports, in part, a vascular hypothesis for the pathogenesis of Crohn's disease. Enhanced expression of endothelial nitric oxide synthase and HLA-DR possibly reflects compensatory endothelium-mediated vasodilation and amplification of the immune response, respectively.     

Tissue Carcinoembryonic Antigen, Dysplasia, and Disease Duration in Colonic Inflammatory Bowel Disease

Tissue carcinoembryonic antigen (CEA) was studied in five groups of patients: eight ulcerative colitis patients with mild or no dysplasia, five ulcerative colitis patients with severe dysplasia, seven Crohn's disease patients with nondiseased colon, nine Crohn's disease patients with diseased colon., and 18 colorectal cancer patients from the noncancerous colon resection margins. CEA levels were significantly lower in the normal colon Crohn's group than all other groups (p < 0.05). CEA levels were significantly higher in the severe dysplasia ulcerative colitis group than all other groups (p < 0.05). The Crohn's disease patients with diseased colon, the ulcerative colitis patients with mild or no dysplasia, and the colorectal cancer group with noncancerous colon all had similar intermediate CEA levels.     

Inflammatory Bowel Disease in Kuwait

Inflammatory bowel disease is considered to be rare or nonexistent in some Arab countries. During a period of 6 years, 91 patients with ulcerative colitis and 17 with Crohn's disease were seen for initial diagnosis in the Gastroenterology Department of Amiri Hospital, which serves 55% of the population of Kuwait. From this group, 43 patients with ulcerative colitis and 14 patients with Crohn's disease were followed up for an average of 30.9 months. In the remaining 51 patients, the diagnosis was established in the same manner as in this series, hut these patients were sent back to the referring physicians and therefore were not available for follow-up. The severity of the disease in the majority of patients with ulcerative colitis was mild to moderate. Nine of 14 patients with Crohn's disease underwent surgery as a diagnostic procedure in an acute abdominal emergency or for treatment of complications. The duodenum was involved in two patients with Crohn's disease and the endoscopic picture and histology of these were initially interpreted as immunoproliferative small intestinal disease which is highly prevalent in this area. We suggest that the assumption that inflammatory bowel disease is uncommon in our population is wrong.     

Leukocytapheresis Therapy for Severe Ulcerative Colitis

Abstract: Severe attacks of ulcerative colitis are medical emergencies, and surgical treatment is indicated when glucocorticoid therapy is not effective. We have carried out an open clinical study of patients with severe attacks of ulcerative colitis to find out whether leukocytapheresis (LCAP) therapy can improve their outcomes. Nine patients were enrolled in this study. Seven of the nine patients had failed to respond to an intensive intravenous regimen before LCAP. LCAP was performed once a week for 4–5 weeks as intensive therapy using a leukocyte apheresis filter. Six of the 9 patients had an overall improvement after intensive therapy. Three patients reached the remission stage. The percentages of HLA-DR+, HLA-DR+ CD3+, HLA-DR+ CD4+, and HLA-DR+ CD8+ cells in the peripheral blood were higher in the responders than in the nonresponders, but there were no significant differences. In conclusion, LCAP therapy is useful for patients with severe attacks of ulcerative colitis, even those patients who failed to respond to glucocorticoid therapy.     

Immunohistochemical analysis of the distribution of measles related antigen in the intestinal mucosa in inflammatory bowel disease

BACKGROUND: Measles virus is implicated in the aetiology of Crohn's disease. This measles hypothesis is mainly supported by immunohistochemical findings that the measles related antigen is present in the intestine of patients with Crohn's disease. Recently we isolated this antigen from the intestine of a patient with Crohn's disease using a molecular cloning technique and produced the monoclonal antibody against it (designated 4F12). AIM: To discover whether the measles related antigen is uniquely present in Crohn's disease. SUBJECTS/METHODS: Colonic mucosa samples from 20 patients with Crohn's disease, 20 with ulcerative colitis, 11 with non-inflammatory bowel disease (IBD) colitis, and nine controls were immunohistochemically stained with the anti-measles monoclonal antibody 4F12. The numbers of positive cells, the ratio of positive cells to nucleated cells, and the staining intensity of the positive cells were compared. Furthermore, the distribution of the measles antigen in other human organs was examined. RESULTS: Both the number of positive cells and the ratio of positive cells to nucleated cells were significantly increased in Crohn's disease, ulcerative colitis, and non-IBD colitis compared with controls (p<0.05) but were similar among the three disease groups. The staining intensity of the positive cells was also similar among the three disease groups. Small numbers of positive cells were observed in the oesophagus, stomach, duodenum, jejunum, and lung. CONCLUSIONS: The presence of the measles related antigen in the colonic mucosa was not unique to Crohn's disease. These results, together with the observation that such a measles related antigen was derived from host protein, do not support the hypothesis that measles virus causes Crohn's disease.     

Increased expression of VEGF and CD146 in patients with inflammatory bowel disease

BACKGROUND: Angiogenesis has been suggested as an integral part of inflammatory bowel disease pathology. Vascular endothelial growth factor has long been considered to play a central, specific role in angiogenesis. Endothelial junction adhesion molecules, such as CD146, have recently been suggested to play a potent role in angiogenesis. CD34 is expressed on vascular endothelium, and it has been reported to be upregulated on endothelium in IBD. We investigated the expression of tissue vascular endothelial growth factor, CD34 and CD146 in the inflamed mucosa of patients with active inflammatory bowel disease compared with no inflamed mucosa of healthy controls. METHODS: Forty-two IBD patients [23 ulcerative colitis, 19 Crohn's disease] and ten healthy controls were included in the study. In colonoscopically obtained biopsies, CD34, CD146 and vascular endothelial growth factor expression were evaluated by immunohistochemistry. RESULTS: Vascular endothelial growth factor was detected in the mucosa of all groups, and its expression was significantly higher in both Crohn's disease and ulcerative colitis compared with controls (p<0.05). Immunohistochemical staining for CD146 in the inflamed mucosa was significantly higher in both Crohn's disease and ulcerative colitis compared with controls (p=0.002). A trend of higher CD34 expression in Crohn's disease and ulcerative colitis compared with controls was also found, but the difference among the three groups was not statistically significant (p=0.09). CONCLUSIONS: Inflamed mucosa of patients with active Crohn's disease and ulcerative colitis showed a markedly enhanced expression of VEGF and CD146, than normal mucosa of controls, indicating a possible role of angiogenesis in the pathogenesis of inflammatory bowel disease.     

Soluble interleukin 2 and CD8 and CD4 receptors in inflammatory bowel disease.

Serum levels of soluble interleukin 2 receptor (sIL-2R) have been proposed as a clinical marker of inflammatory bowel disease. The source of sIL-2R in patients with Crohn's disease and ulcerative colitis is unknown, and other soluble receptors have not been investigated. In the present study, sIL-2R and soluble CD8 and CD4 levels were measured in plasma and culture supernatants of peripheral blood and intestinal mucosal mononuclear cells from patients with inflammatory bowel disease, surgical controls, and healthy subjects. Level of plasma sIL-2R was significantly higher in patients with Crohn's disease and ulcerative colitis than in healthy volunteers. Intestinal cells always produced more sIL-2R than peripheral cells. Spontaneous sIL-2R production by mucosal cells was significantly elevated in Crohn's disease but not in ulcerative colitis supernatants compared with levels of surgical controls. Soluble CD8 and CD4 were poor indicators of systemic or mucosal immunity. A positive correlation was found between plasma sIL-2R and spontaneous production by intestinal cells of patients with Crohn's disease and surgical control patients, whereas ulcerative colitis plasma sIL-2R correlated with spontaneous production by peripheral cells. The association of plasma or spontaneous sIL-2R levels with the degree of intestinal inflammation was weak, and there was a wide overlap with control values. Therefore, caution should be used before considering sIL-2R an accurate marker of inflammatory bowel disease activity.