Distinctive Pattern of Cytokine Production and Adhesion Molecule Expression in Peripheral Blood Memory CD4+ T Cells from Patients with Active Crohn’s Disease

An expansion of both circulating and intestinal lamina propria CD4⁺CD45RO⁺ T cells has been described in patients with Crohn’s disease. We studied both the cytokine profile and the expression of adhesion molecules on this T-cell subset. Peripheral blood CD4⁺CD45RO⁺ T cells from patients with Crohn’s disease (n=45) were assessed by flow cytometry and RT-PCR methods. The cytokine profile was also measured in intestinal lamina propria from seven patients. They were classified according to the CDAI and the results were compared with those of patients with ulcerative colitis (n=21) and noninflammatory intestinal conditions (n=15), and healthy controls (n=39). The mean percentage of circulating CD4⁺CD45RO⁺ T cells producing intracellular TNF was higher in active than in inactive Crohn’s disease patients (p < 0.001), active (p = 0.49) and inactive ulcerative colitis (p = 0.019), and healthy controls (p =0. 017). TNF expression correlated with CDAI (p < 0.001). An increased expression of intracellular IL-2, IL-6, and IL-10 in active Crohn’s disease patients was also found. CD62L was downregulated in active Crohn’s disease patients while no differences were observed in CD49d and CD11a expression. Lamina propria CD4⁺CD45RO⁺ T cells from active Crohn’s disease lesions showed an increased intracellular staining of TNF, IFN-γ, and IL-10. Both peripheral and intestinal mucosa CD4⁺CD45RO⁺ T cells from active Crohn’s disease patients show an increased production of TNF. In addition, the circulating CD4⁺CD45RO⁺ T-cell subset expresses a pattern of adhesion molecules that promotes homing to extranodal lymphoid tissues. This T-cell subset may play a relevant role in the immunopathogenesis of Crohn’s disease.Dr. García de Tena and Dr. Manzano are joint first authors     

Detection of galectin-3 in patients with inflammatory bowel diseases: new serum marker of active forms of IBD?

Objective  It is an open question whether multifunctional galectin-3 can be a serum marker in inflammatory bowel disease. Methods  Western blots and commercial ELISA detected and quantitated the lectin immunocytochemistry using double labeling localized it in tissue sections. Results  Serum concentrations were significantly increased in specimen of patients with active and remission-stage ulcerative colitis and Crohn’s disease, associated with emerging positivity of CD14⁺ cells. Conclusion  Enhanced concentration of galectin-3 in serum reflects presence of disease and points to its involvement in the pathogenesis.     

Clostridium difficile infection in Polish pediatric outpatients with inflammatory bowel disease

The prevalence of Clostridium difficile infection (CDI) in pediatric patients with inflammatory bowel disease (IBD) is still not sufficiently recognized. We assessed the prevalence of CDI and recurrences in outpatients with IBD. In addition, the influence of IBD therapy on CDI and antimicrobial susceptibility of the potentially causative C. difficile strains was assessed. This was a prospective, single-center, observational study. All specimens were obtained between January 2005 and January 2007 from the IBD outpatient service and screened for C. difficile and its toxins. C. difficile isolates were genotyped by PCR ribotyping. Diagnosis of Crohn’s disease (CD) and ulcerative colitis (UC) was based on Porto criteria. Severity of disease was assessed using the Hyams scale (for Crohn’s disease) and the Truelove–Witts scale (for ulcerative colitis). One hundred and forty-three fecal samples from 58 pediatric IBD patients (21 with Crohn’s disease and 37 with ulcerative colitis) were screened. The risk of C. difficile infection was 60% and was independent of disease type (CD or UC) (χ2 = 2.5821, df = 3, p = 0.4606). About 17% of pediatric IBD patients experienced a recurrence of CDI. All C. difficile strains were susceptible to metronidazole, vancomycin and rifampin. A high prevalence of C. difficile infection and recurrences in pediatric outpatients with IBD was observed, independent of disease type. There was no significant correlation between C. difficile infection and IBD therapy. PCR ribotyping revealed C. difficile re-infection and relapses during episodes of IBD in pediatric outpatients.     

Concentrations of α- and β-defensins in plasma of patients with inflammatory bowel disease

Background:  Impaired production/release of defensins, representative endogenous antimicrobial peptides, is associated with the pathogenesis of inflammatory bowel disease (IBD). Material and methods:  Employing in house radioimmunoassay, we examined concentrations of the major forms α-defensins, human neutrophil peptides (HNP) 1–3 and human β-defensin (HBD)-2 in plasma of 55 IBD patients consisting of 29 patients with ulcerative colitis (UC) and 26 with Crohn’s disease (CD) and 57 controls. Results:  The circulating HNP 1–3, but not HBD-2, levels in IBD patients were significantly higher than those in controls. Plasma HNP 1–3 concentrations in CD patients significantly correlated with Crohn’s disease activity index, peripheral white blood cell counts, serum CRP values and TNF-α levels. Conclusions:  Elevation of circulating α-defensins levels is suggestive of their physiopathological roles in IBD. Plasma HNP 1–3 concentrations may be an indicator for CD activity and their association with CRP and TNF-α supports a possible association with the inflammatory process. Received 2 June 2008; returned for revision 20 June 2008; received from final revision 25 June 2008; accepted by C. Kasserra 19 August 2008     

Phenotypes and distribution of mucosal memory B-cell populations in the SIV/SHIV rhesus macaque model

As vaccine-elicited antibodies have now been associated with HIV protective efficacy, a thorough understanding of mucosal and systemic B-cell development and maturation is needed. We phenotyped mucosal memory B-cells, investigated isotype expression and homing patterns, and defined plasmablasts and plasma cells at three mucosal sites (duodenum, jejunum and rectum) in rhesus macaques, the commonly used animal model for pre-clinical vaccine studies. Unlike humans, macaque mucosal memory B-cells lacked CD27 expression; only two sub-populations were present: naïve (CD21⁺CD27⁻) and tissue-like (CD21⁻CD27⁻) memory. Similar to humans, IgA was the dominant isotype expressed. The homing markers CXCR4, CCR6, CCR9 and α4β7 were differentially expressed between naïve and tissue-like memory B-cells. Mucosal plasmablasts were identified as CD19⁺CD20^+/−HLA-DR⁺Ki-67⁺IRF4⁺CD138^+/− and mucosal plasma cells as CD19⁺CD20⁻HLA-DR⁻Ki-67⁻IRF4⁺CD138⁺. Both populations were CD39^+/−CD27⁻. Plasma cell phenotype was confirmed by spontaneous IgA secretion by ELISpot of positively-selected cells and J-chain expression by real-time PCR. Duodenal, jejunal and rectal samples were similar in B-cell memory phenotype, isotype expression, homing receptors and plasmablast/plasma cell distribution among the three tissues. Thus rectal biopsies adequately monitor B-cell dynamics in the gut mucosa, and provide a critical view of mucosal B-cell events associated with development of vaccine-elicited protective immune responses and SIV/SHIV pathogenesis and disease control.     

Anti-CD8 treatment reduces the severity of inflammatory arthritis, but not vasculitis, in mercuric chloride-induced autoimmunity

T cell hypersensitivity has been implicated in the tissue damage in Crohn's disease (CD). All studies to date have examined mucosal T cells, although much of the tissue damage occurs in the submucosa and muscle layers. The aim of this work was to study T cell proliferation throughout the intestinal wall in children with IBD. Surgical resection material from 19 children with CD (10 ileal, 10 colonic), seven with ulcerative colitis (UC), and 12 normal controls was studied. The distribution of dividing T cells was investigated by double-immunohistochemistry using Ki67 to identify proliferating cells, and CD3 to identify T cells. In ileal and colonic lamina propria virtually no Ki67⁺, CD3⁺ cells were seen in control, UC or CD tissue. In contrast, there were significantly more Ki67⁺, CD3⁺ cells within the lymphoid follicles of ileal and colonic CD than in the follicles in UC and controls. Increased numbers of Ki67⁺, CD3⁺ cells were present in the submucosa, muscle layers (M) and serosa in Crohn's ileitis and colitis compared with the lamina propria (LP), although only in the muscle of the colon was the difference statistically significant (LP, 0.4% (0–1%); M, 1.6% (0–5.2%); P = 0.03). Pooling data from ileal and colonic CD, however, did show significantly increased Ki67⁺, CD3⁺ cells in both serosa and muscle layers compared with the LP. Dividing T cells have been identified in the deeper layers of the gut wall in CD. These may contribute to the fibrosis and muscle hyperplasia characteristic of the condition.     

Circulating CD4+ and CD8+ T cells are activated in inflammatory bowel disease and are associated with plasma markers of inflammation

Inflammatory bowel disease (IBD) is characterized by damage to the gut mucosa and systemic inflammation. We sought to evaluate the role of chronic inflammation on circulating T‐cell activation in human subjects with Crohn's disease and ulcerative colitis. We studied 54 patients with IBD and 28 healthy controls. T‐cell activation and cycling were assessed in whole blood samples by flow cytometry. Levels of lipopolysaccharide (LPS) were measured in serum by Limulus amoebocyte lysate assay, and plasma levels of inflammatory markers and LPS‐binding proteins were measured by ELISA. The proportions of circulating CD4⁺ and CD8⁺ T lymphocytes in cycle (Ki67⁺) are increased in patients with IBD compared with these proportions in controls. CD8⁺ T cells from patients with IBD are also enriched for cells that expressed CD38 and HLA‐DR, and proportions of these cells are related to plasma levels of interleukin‐6 and C‐reactive protein in these patients. Intracellular interleukin‐2 and interferon‐γ levels were elevated in resting and polyclonally activated CD4⁺ and CD8⁺ T cells in patients with IBD when compared with levels from healthy controls. Surprisingly, we did not find increased levels of LPS in the serum of patients with IBD. We did, however, find a signature of recent microbial translocation, as levels of LPS‐binding protein are increased in the plasma of patients with IBD compared with plasma levels in healthy controls; LPS‐binding protein levels are also directly related to proportions of CD38 HLA‐DR‐expressing CD4⁺ and CD8⁺ T cells. Local damage to the gastrointestinal tract in IBD may result in systemic inflammation and T‐cell activation.     

Exhaled carbon monoxide concentration is not elevated in patients with inflammatory bowel disease

The present study was initiated to examine whether the concentration of CO in the breath is elevated in patients with inflammatory bowel disease (IBD). Twenty-three clinically stable patients with IBD in the outpatient clinic (11 with Crohn’s disease, 12 with ulcerative colitis), who are non-smokers and non-passive smokers, were selected and the concentration of CO in their breath was measured using a breath gas analyser (TRI lyser mBA-3000). The concentration of CO in the breath of 23 patients with IBD was 2.5±0.9 (1.1–4.3) ppm. This concentration comes within the range of standard values in our previous reports (2.5±2.2 ppm). Any significant difference was not observed between 2.4±0.9 (1.5–4.3) ppm for the 11 Crohn’s disease patients and the 2.6±1.0 (1.1–3.9) ppm for the 12 ulcerative colitis patients. The results suggest that clinically stable patients with IBD do not show high values for concentration of CO in the breath.     

CD83+CCR7− Dendritic Cells Accumulate in the Subepithelial Dome and Internalize Translocated Escherichia coli HB101 in the Peyer’s Patches of Ileal Crohn’s Disease

Recurrent Crohn’s disease originates with small erosions in the follicle-associated epithelium overlying the Peyer’s patches. Animal studies have illustrated mucosal immune regulation by dendritic cells located in the subepithelial dome. The aim of this study was to characterize the dendritic cells at this specific site in patients with Crohn’s disease. Ileal tissues were obtained after surgery performed on Crohn’s patients; ileal samples from noninflammatory bowel disease and ulcerative colitis served as standard and inflammatory controls, respectively. Flow cytometry of isolated intestinal mononuclear cells showed a larger subset of dendritic cells in Crohn’s samples compared with controls. This finding was corroborated by confocal microscopy, showing enhanced infiltrates of cells positive for the dendritic cell markers, DC-SIGN⁺ and CD83⁺, in the subepithelial dome. Moreover, the CD83⁺ cells in Crohn’s tissues showed reduced expression of the lymph node migratory receptor, CCR7, possibly contributing to the high numbers of dendritic cells. After exposure to nonpathogenic Escherichia coli in Ussing chambers, dendritic cells in the subepithelial dome of Crohn’s disease demonstrated increased co-localization with translocated bacteria. Immunohistochemical results revealed that DC-SIGN⁺ cells in Crohn’s tissues were found to express toll-like receptor 4 and produce tumor necrosis factor-α. In conclusion, nonmigrating dendritic cells that accumulate in the subepithelial dome and internalize nonpathogenic bacteria may be important for the onset and perpetuation of mucosal inflammation in Crohn’s disease.     

Significance of increased proliferation of immature plasma cells in the appendix of patients with ulcerative colitis

The etiology of ulcerative colitis (UC) is not known. Recent studies support a primary role of the appendix in the pathogenesis of UC, however phenotypical studies of proliferating cells in the appendix have not been reported. We report phenotypical studies of lymphocytes and of proliferating subpopulations in the appendix of patients with inflammatory bowel disease and of controls. Surgical samples of the appendix were obtained from 5 patients with colon cancer, 5 with acute appendicitis, 12 with UC and 7 with Crohn's disease (CD). Frozen sections were cut from fixed samples, and immunostained with lymphocyte markers and anti-Ki-67 antibodies. The number of Ki-67(+) proliferating cells, CD19, and CD138 cells was significantly higher in the appendix of patients with UC than in controls, patients with acute appendicitis, and patients with CD. Immunohistological double staining revealed significant proliferation of CD3, CD19, and CD138 cells in the appendix of patients with UC. The proportions of Ki-67(+) cells in CD3, CD19, and CD138 cells were significantly higher in both total UC patients and patients in remission-stage UC, than in controls, patients with acute appendicitis, and patients with CD. Lamina propria cells in the appendix of patients with UC showed augmented proliferation with increased numbers of CD19 and CD138 cells. The number of CD3 cells was not significantly increased, but the proportion of proliferating CD3 cells was increased. An increased proportion of Ki-67(+) cells in CD19 and CD138 cells represents proliferation of immature plasma cells in the appendix of patients with UC, and proliferation of such immature plasma cells was seen in both active- and remission-stage UC. Proliferation of immature plasma cells in the appendix of patients with UC suggests a primary role of humoral immune responses in the pathogenesis of UC.     

Mucosal-associated invariant T (MAIT) cells are activated in the gastrointestinal tissue of patients with combination ipilimumab and nivolumab therapy-related colitis in a pathology distinct from ulcerative colitis

The aim of this study was to investigate the pathogenesis of combination ipilimumab and nivolumab-associated colitis (IN-COL) by measuring gut-derived and peripheral blood mononuclear cell (GMNC; PBMC) profiles. We studied GMNC and PBMC from patients with IN-COL, IN-treated with no adverse-events (IN-NAE), ulcerative colitis (UC) and healthy volunteers using flow cytometry. In the gastrointestinal-derived cells we found high levels of activated CD8⁺ T cells and mucosal-associated invariant T (MAIT) cells in IN-COL, changes that were not evident in IN-NAE or UC. UC, but not IN-C, was associated with a high proportion of regulatory T cells (T_reg). We sought to determine if local tissue responses could be measured in peripheral blood. Peripherally, checkpoint inhibition instigated a rise in activated memory CD4⁺ and CD8⁺ T cells, regardless of colitis. Low circulating MAIT cells at baseline was associated with IN-COL patients compared with IN-NAE in one of two cohorts. UC, but not IN-COL, was associated with high levels of circulating plasmablasts. In summary, the alterations in T cell subsets measured in IN-COL-affected tissue, characterized by high levels of activated CD8⁺ T cells and MAIT cells and a low proportion of T_reg, reflected a pathology distinct from UC. These tissue changes differed from the periphery, where T cell activation was a widespread on-treatment effect, and circulating MAIT cell count was low but not reliably predictive of colitis.     

Activated T lymphocytes in the celiac lesion: Non-proliferative activation (CD25) of CD4+ α/β cells in the lamina propria but proliferation (Ki-67) of α/β and γ/δ cells in the epithelium

In order to identify any dominating subset of activated T cells in the celiac lesion, we examined CD3⁺, CD4⁺, CD8⁺ and T cell receptor (TcR) γ/δ⁺ Lymphocytes in jejunal cryosections from 25 patients with celiac disease and 10 controls by three-color immunofluorescence staining for expression of the nuclear proliferation marker detected by monoclonal antibody (mAb) Ki-67 and the p55 α chain of interleukin-2 receptor (CD25). mAb Ki-67⁺ intraepithelial lymphocytes (IEL) were exclusively observed in celiac patients. The median proportion of CD3⁺ IEL positive for Ki-67 increased from nil in controls to 4.5% in partly treated (range 0-19.0%; n = 10; p = 0.05) and 12.8% in untreated celiac disease (range 4.0-30.7%; n = 15; p 0.005). Only 1.5% of CD3⁺ subepithelial T cells expressed the Ki-67 marker in celiac disease (range 0-9.5%). Two- and three-color staining combining mAb to CD3 and Ki-67 with mAb to CD4, CD8 or TcR5 showed that both TcR α/β⁺ CD8⁺ and TcR γδ⁺ (but not CD4⁺) mucosal T cells proliferated in the epithelium. By contrast, CD25 were almost exclusively expressed on CD4⁺ T cells in the lamina propria. The percentage of CD25⁺ T cells increased significantly from 1.7% in controls (range 0-2.9%) to 7.5% in partly treated (range 0.8-17.8%, p 0.002), and to 14.65% in untreated celiac disease (range 3.9-21%, p 0.002). These results suggest that gluten ingestion in celiac disease induces proliferative activation of TcR α/β⁺ CD8⁺ and TcR γδ⁺ IEL but non-proliferative activation (lymphokine production?) of lamina propria CD4⁺ T cells.     

3020insC insertion in NOD2/CARD15 gene, a prevalent variant associated with anti-Saccharomyces cerevisiae antibodies and ileal location of Crohn’s disease in Tunisian population

Objective:  Our aim is to investigate the relation between CARD15 3020insC mutation, anti-Saccharomyces cerevisiae antibodies (ASCA) and disease phenotype, in Tunisian inflammatory bowel disease (IBD) patients. Materials:  A hundred Tunisian patients with IBD (75 Crohn’s disease CD and 25 ulcerative colitis UC) and 60 matched healthy controls were studied. Methods:  CARD15 mutation was analysed by using an allele-specific polymerase chain reaction and sequencing. Assessment of ASCA in serum was performed by ELISA. Results:  The frequency of the mutation was significantly higher in Crohn’s disease than in control (p = 0,0005; OR = 20.45; CI 95% = 2.86–413.85) and did not differ statistically in UC group (p = 0, 05) from control. ASCAs were present in 60% of CD and 20, 8% of UC Conclusion:  This study suggests that in northen Tunisian population, 3020insC mutation in NOD2/CARD15 gene is a prevalent mutation leading to the typical Crohn’s disease including ileal location, stricturing and penetrating clinical types and ASCA expression. Received 24 June 2008; returned for revision 30 July 2008; received from final revision 13 October 2008; accepted by M. Parnham 21October 2008 K. Bougatef, A. Moussa, S. Ouerhani; The authors have collaborated on the same level.     

Human cytomegalovirus-specific CD8+ T-cell expansions contain long-lived cells that retain functional capacity in both young and elderly subjects

The immune response to human cytomegalovirus (HCMV) infection is characterized by the accumulation of HCMV-specific CD8⁺ T cells, particularly in the elderly; such expansions may impair immune responses to other pathogens. We investigated mechanisms underlying HCMV-specific expansions in 12 young and 21 old healthy subjects (although not all analyses were performed on all subjects). Phenotypically, HCMV-pentamer⁺ CD8⁺ T cells were characterized by marked Vβ restriction, advanced differentiation (being predominantly CD27⁻ CD28⁻), and variable CD45RO/RA expression. Although more common and larger in older subjects, expansions had similar phenotypic characteristics in the young. In one old subject, repeated studies demonstrated stability in size and Vβ distribution of pentamer⁺ populations over 6 years. We tested whether HCMV-specific CD8⁺ T-cell expansions arose from accelerated proliferation or extended lifespan by in vivo labelling with deuterated glucose and ex vivo Ki-67 expression. Uptake of deuterated glucose was lower in pentamer⁺ cells than in pentamer^– CD8⁺ CD45RO⁺ or CD8⁺ CD45RA⁺ cells in three old subjects, consistent with reduced proliferation and extended lifespan. Similarly Ki-67 labelling showed no evidence for increased proliferation in HCMV-specific CD8⁺ expansions in older subjects, although pentamer^– CD45RA⁺ cells from young donors expressed very little Ki-67. We investigated Bcl-2 and CD95 as possible anti-apoptotic mediators, but neither was associated with pentamer-positivity. To investigate whether expansion represents a compensatory response to impaired functionality, we performed two tests of functionality, peptide-stimulated proliferation and CD107 expression; both were intact in pentamer⁺ cells. Our data suggest that HCMV-specific CD8⁺ expansions in older subjects accumulate by extended lifespan, rather than accelerated proliferation.     

The role of mucosal T lymphocytes in regulating intestinal inflammation

Suppression of chronic intestinal inflammation by different subtypes of T cells has been described in recent years. In particular, naturally arising CD4⁺CD25⁺ regulatory T cells and IL-10-producing regulatory T cell type 1 CD4⁺ T lymphocytes have been implicated in the regulation of intestinal inflammation. Here we focus on the ability of CD4⁺CD25⁺ regulatory T cells to suppress innate and T-cell responses and discuss implications for immunoregulation in human inflammatory bowel disease. Besides the modulation of lymphoproliferation, a role for CD4⁺CD25⁺ T cells in down-modulation of innate immune responses is emerging and the immunoregulatory activities of regulatory T cells in vivo may be mediated via effects on dendritic cells. Considering the extraordinary regenerative potential of the intestinal mucosa, the ability to impede pathogenic T-cell responses by active regulation might be of particular therapeutic benefit for the treatment of chronic intestinal inflammatory diseases such as Crohns disease and ulcerative colitis.     

Intensity of Proliferative Processes and Degree of Oxidative Stress in the Mucosa of the Ileum in Crohn’s Disease

The intensity of proliferative processes (estimated from Ki-67 expression) and degree oxidative stress (chemiluminescence assay) in biopsy specimens from the terminal portion of the ileal mucosa were studied in patients with Crohn’s disease. Crohn’s disease is characterized by hyper-regenerative processes in the ileal mucosa. The labeling index (Ki-67 expression) in biopsy specimens from the intact ileal mucosa in patients with the irritable bowel syndrome (reference group) was 10.64 ± 0.62%. The corresponding values in patients receiving monotherapy with mesalazine (group 1) and combination therapy with mesalazine and dalargin (group 2) were 24.05 ± 1.17 and 22.90 ± 0.92%, respectively. Analysis of free radical oxidation showed that this state is accompanied oxidative stress. Spontaneous and H₂O₂-induced luminol-dependent chemiluminescence in biopsy specimens from the ileal mucosa was 1.8-2.3-fold higher compared to the reference group. After therapy, the labeling index in groups 1 and 2 decreased to 18.60 ± 1.18 and 14.38 ± 0.81%, respectively. Histologically, normalization of the disease symptoms was more pronounced after combination therapy. The decrease in free radical oxidation in this group of patients was more pronounced than after mesalazine monotherapy. Our results suggest that oxidative stress plays a role in the hyper-regenerative reaction.     

Immunohistologic demonstration of abnormal colonic crypt cell kinetics in ulcerative colitis

A monoclonal antibody, Ki-67, that reacts with cells in the proliferative phases (G1, G2, S, and M) of the cell cycle was used in an immunohistochemical labeling reaction to examine the colonic crypt epithelium in active ulcerative colitis, inactive ulcerative colitis, and normal mucosa. The proportions of labeled cells in the lower two thirds (proliferative zone) and in the upper quarter of the crypt were determined. The proportions of Ki-67-positive crypt epithelial cells in both the proliferative zone and the upper crypt were higher in biopsy specimens from patients with active ulcerative colitis than from patients with normal mucosa or with inactive ulcerative colitis. In inactive ulcerative colitis the proportion of Ki-67-positive epithelial cells in the proliferative zone of the crypt was higher than in normal mucosa. These results are similar to those obtained in studies using tritiated thymidine to determine the proportion of cells in the DNA-synthesizing thymidine to determine the proportion of cells in the DNA-synthesizing phase of the cell cycle and suggest that immuno-histochemical staining with Ki-67 may be a practical method for measuring the proliferative activity of epithelial cells in patients with ulcerative colitis and other disorders of the gastrointestinal tract.     

Enhanced peripheral blood T-cell cytotoxicity in inflammatory bowel disease

Monoclonal antibodies to the CD3 component of the T-cell antigen receptor can trigger antigen-specific cytotoxic T cells to elicit nonantigen-specific cytotoxicity, possibly by mimicking or bypassing the requirement for antigen triggering. We have used this technique to investigate the possible presence ofin vivo primed cytotoxic T cells, of unknown antigen specificity, in peripheral blood of patients with inflammatory bowel disease. Peripheral blood lymphocytes, which were depleted of background natural killer (NK) activity (CD16^–), from patients with Crohn's disease exhibited significantly enhanced levels of anti-CD3-triggered T-cell cytotoxicity compared with lymphocytes from normal subjects. Enhanced lytic activity was also found in some patients with ulcerative colitis and in patients with ulcerative colitis postcolectomy. These results were not influenced by treatment or disease activity. There was no correlation between the anti-CD3-triggered T lytic activity and the NK activity in normal subjects or in patients with inflammatory bowel disease. The surface antigen phenotype of the anti-CD3-triggered T killer cell was CD3⁺, CD8⁺, CD16^–, and Leu 7⁺. The results provide indirect evidence for increased activity of a subpopulation of cytotoxic T cells, of unknown antigen specificity, in inflammatory bowel disease. Increased activity in patients with ulcerative colitis postcolectomy suggests that this might reflect a fundamental immunological disturbance.     

Proportions of several types of plasma and urine microparticles are increased in patients with rheumatoid arthritis with active disease

We analysed the proportions of different microparticles (MPs) in plasma from patients with rheumatoid arthritis (RA), and assessed their relationship with disease activity/therapy and their in‐vitro effect on proinflammatory cytokine release. Blood and urine samples were obtained from 55 patients with RA (24 untreated and 31 under conventional therapy) and 20 healthy subjects. Fourteen patients with systemic lupus erythematosus (SLE) were also studied. The proportions of CD3⁺, CD14⁺, CD19⁺, CD41⁺ and CD62E⁺ MPs were determined by flow cytometry analysis. The in‐vitro effect of plasma MPs on the release of interleukin (IL)‐1, IL‐6, IL‐17 and tumour necrosis factor (TNF)‐α was also analysed. We detected that the proportions of different types of annexin‐V⁺ MPs were enhanced in plasma (CD3⁺, CD14⁺, CD19⁺, CD41⁺ and CD62E⁺ MPs) and urine (CD14⁺, CD3⁺ and CD19⁺ MPs) from RA patients with high disease activity (DAS28 index > 5·1). Accordingly, a significant positive correlation was observed between the levels of MPs and DAS28 score, and these levels diminished significantly at week 4 of immunosuppressive therapy. Finally, MPs isolated from patients with high disease activity induced, in vitro, an enhanced release of IL‐1, IL‐17 and TNF‐α. In SLE, enhanced levels of different types of plasma MPs were also detected, with a tight correlation with disease activity. Our data further support that MPs have a relevant role in the pathogenesis of RA and suggest that the analysis of the proportions of these microvesicles in plasma could be useful to monitor disease activity and therapy response in patients with RA.     

Expansion of T cells negative for CD28 expression in hiv infection. Relation to activation markers and cell adhesion molecules,and correlation with prognostic markers

  CD28 is a transmembrane glycoprotein that provides T cells with an essential co-stimulatory signal during antigen presentation. Using flow cytometry, we document here an expansion of CD28^– T cells in HIV infection. Whereas the percentage of CD4⁺CD28⁺ T cells among total lymphocytes was decreased, a small increase of the percentage of CD4⁺CD28^– T cells was observed. In the CD8⁺ subset, there was a marked expansion of CD8⁺CD28^– T cells. An increased percentage of CD8⁺ T cells positive for HLA-DR was found in both CD28⁺ and CD28^– cells. Results were similar for CD38 expression. HIV infection was also distinguished by a shift from LFA-1^lowCD28^low to LFA-1^highCD28^high and LFA-1^high-CD28^neg expression pattern on CD8⁺ T cells. Negative correlations were found between percentage and absolute number of CD8⁺CD28⁺ T cells and several serum parameters usually associated with poor prognosis (IgA, IgE, β2-microglobulin and HIV-1 p24 antigen). Thus, HIV infection is characterized by a marked expansion of CD28^– T cells with an abnormal expression of activation markers and cell adhesion molecules. In addition, CD8⁺CD28⁺, but not CD8⁺CD28^– or total CD8⁺ T cell numbers, correlated with the levels of established serological markers of disease severity or progression and may, therefore, have predictive value. Received: 1 November 1995