A double-blind clinical trial for treatment of Crohn's disease by oral administration of Alequel, a mixture of autologous colon-extracted proteins: a patient-tailored approach

Low-Dose Colchicine Attenuates Sepsis-Induced Liver Injury: A Novel Method for Alleviating Systemic Inflammation

Sepsis is a significant public health challenge. The immune system underlies the pathogenesis of the disease. The liver is both an active player and a target organ in sepsis. Targeting the gut immune system using low-dose colchicine is an attractive method for alleviating systemic inflammation in sepsis without inducing immunosuppression. The present study aimed to determine the use of low-dose colchicine in LPS-induced sepsis in mice. C67B mice were injected intraperitoneal with LPS to induce sepsis. The treatment group received 0.02 mg/kg colchicine daily by gavage. Short and extended models were performed, lasting 3 and 5 days, respectively. We followed the mice for biochemical markers of end-organ injury, blood counts, cytokine levels, and liver pathology and conducted proteomic studies on liver samples. Targeting the gut immune system using low-dose colchicine improved mice's well-being measured by the murine sepsis score. Treatment alleviated the liver injury in septic mice, manifested by a significant decrease in their liver enzyme levels, including ALT, AST, and LDH. Treatment exerted a trend to reduce creatinine levels. Low-dose colchicine improved liver pathology, reduced inflammation, and reduced the pro-inflammatory cytokine TNFα and IL1-β levels. A liver proteomic analysis revealed low-dose colchicine down-regulated sepsis-related proteins, alpha-1 antitrypsin, and serine dehydratase. Targeting the gut immune system using low-dose colchicine attenuated liver injury in LPS-induced sepsis, reducing the pro-inflammatory cytokine levels. Low-dose colchicine provides a safe method for immunomodulation for multiple inflammatory disorders.

Oral administration of human carbonic anhydrase I suppresses colitis in a murine inflammatory bowel disease model

The incidence of inflammatory bowel disease (IBD) is increasing; hence, effective treatments are warranted. The therapeutic effect of human carbonic anhydrase I (hCA I) in IBD remains unknown. Therefore, we investigated whether oral tolerization to hCA I would induce antigen-specific protection from intestinal inflammation in vivo. Severe combined immunodeficient mice received hCA I, keyhole limpet hemocyanin (KLH), or phosphate-buffered saline (PBS) orally for 7 days. Colons and mesenteric lymph nodes (MLNs) were collected 4 weeks after cell transfer. Additionally, the mechanisms underlying the therapeutic effects were investigated. The comparison between the effects of well-established drugs and hCA I oral administration was investigated. Oral administration of hCA I ameliorated colitis remarkably. hCA I reached the cecum and ameliorated colitis more effectively than mesalazine and similarly to prednisolone. Compared with PBS treatment, hCA I treatment reduced interleukin (IL)-17a, IL-6, and retinoic acid-related orphan receptor gamma t (RORγt) expression in the colon or MLNs; moreover, hCA I markedly reduced IL-6, IL-17, and interferon-gamma (IFN-γ) levels in the MLN. Oral administration of hCA I induced immune tolerance and suppressed colitis in vivo. Thus, hCA I administration could be proposed as a new treatment option for IBD.

Controlling Gut Inflammation by Restoring Anti-Inflammatory Pathways in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is caused by a dysregulated immune response against normal components of the intestinal microflora combined with defective functioning of anti-inflammatory pathways. Currently, all therapies approved for IBD manipulate the immune system by inhibiting pro-inflammatory mechanisms, such as tumor necrosis factor-α, gut-homing α4β7 integrin, interleukin-12/interleukin-23, and Janus kinases. However, some IBD patients are non-responders to these drugs, which are also associated with serious side effects. Thus, it has been hypothesized that therapies aimed at restoring anti-inflammatory signals, by exploiting the tolerogenic potential of cytokines (interleukin-10, transforming growth factor-β, granulocyte macrophage colony-stimulating factor), immune cells (regulatory T cells, tolerogenic dendritic cells), or mesenchymal stem cells, might offer promising results in terms of clinical efficacy with fewer side effects. In this review, we provide new insights into putative novel treatments aimed at restoring anti-inflammatory signaling pathways in IBD.

Systematic review: outcomes and adverse events from randomised trials in Crohn's disease

BACKGROUND

The suitability of disease activity indices has been challenged, with growing interest in objective measures of inflammation.

AIM

To undertake a systematic review of efficacy and safety outcomes in placebo-controlled randomised controlled trials (RCTs) of patients with Crohn's disease.

METHODS

MEDLINE, EMBASE, CINAHL and Cochrane Library were searched until November 2015, for RCTs of adult Crohn's disease patients treated with medical or surgical therapies. Data on efficacy and safety outcomes, end-point definitions, and measurement instruments were extracted and stratified by publication date (pre-2009 and 2009 onwards).

RESULTS

One hundred and eighty-one RCTs (110 induction and 71 maintenance) were identified, including 23 850 patients. About 92.3% reported clinical efficacy endpoints. The Crohn's Disease Activity Index (CDAI) dominated, defining clinical response or remission in 63.5% of trials (35 definitions of response or remission). CDAI < 150 was the commonest endpoint, but reporting reduced between periods (46.4%-41.1%), whilst use of CDAI100 increased (16.8%-30.4%). Fistula studies most commonly reported fistula closure (9, 90.0%). Reporting of biomarker, endoscopy and histology endpoints increased overall (33.3%-40.6%, 14.4%-30.4% and 3.2%-12.5%, respectively), but were heterogeneous and rarely reported in fistula trials. Patient-reported outcome measures were reported in 41.4% of trials and safety endpoints in 35.4%. Many of the common adverse events relate to disease exacerbation or treatment failure.

CONCLUSIONS

Trial endpoints vary across studies, over time and are distinct in fistula studies. Despite growth in reporting of objective measures of inflammation and in patient-reported outcome measures, there is a lack of standardisation. This confirms the need for a core outcome set for comparative effectiveness research in Crohn's disease.

Can We Target Endogenous Anti-inflammatory Responses as a Therapeutic Strategy for Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) describes chronic relapsing remitting inflammation of the gastrointestinal tract including ulcerative colitis and Crohn's disease. The prevalence of IBD is rising across the globe. Despite a growing therapeutic arsenal, current medical treatments are not universally effective, do not induce lasting remission in all, or are accompanied by short- and long-term adverse effects. Therefore, there is a clinical need for novel therapeutic strategies for IBD. Current treatments for IBD mainly manipulate the immune system for therapeutic gain by inhibiting pro-inflammatory activity. There is a robust endogenous immunoregulatory capacity within the repertoire of both innate and adaptive immune responses. An alternative treatment strategy for IBD is to hijack and bolster this endogenous capability for therapeutic gain. This review explores this hypothesis and presents current evidence for this therapeutic direction in immune cell function, cytokine biology, and alternative mechanisms of immunoregulation such as microRNA, oligonucleotides, and the endocannabinoid system.

An oral administration of a recombinant anti-TNF fusion protein is biologically active in the gut promoting regulatory T cells: Results of a phase I clinical trial using a novel oral anti-TNF alpha-based therapy

BACKGROUND

An orally administered BY-2 plant cell-expressed recombinant anti-TNF fusion protein (PRX-106) consists of the soluble form of the human TNF receptor (TNFR) fused to the Fc component of a human IgG1 domain. Aim This study aim at determining the safety and the immune modulatory effect of an oral administration of PRX-106 in humans.

METHODS

Three different doses (2, 8 or 16mg/day) of PRX-106 were orally administered for five consecutive days in 14 healthy volunteered participants. Subjects were followed for safety parameters and for an effect on T lymphocytes subsets and cytokine levels.

RESULTS

An oral administration of PRX-106 was safe and well tolerated. The PK study showed that PRX106 is not absorbed. No effect on white blood cells and lymphocytes counts were noted. A dose dependent effect was noted on systemic lymphocytes. The oral administration of all three dosages was associated with an increase in CD4+CD25+ and CD8+CD25+ subset of suppressor lymphocytes. A marked increase in CD4+CD25+FoxP3 regulatory T cells was noted in the 8mg treated group. In addition, NKT regulatory cells, CD3+CD69+ and CD4+CD62 lymphocyte subsets increased with treatment. No changes in serum TNF alpha were observed.

CONCLUSION

An oral administration of the non-absorbable recombinant anti-TNF fusion protein, PRX-106, is safe, not associated with immune suppression, while inducing a favorable anti-inflammatory immune modulation. The PRX-106 may provide a safe orally administered effective anti-TNF alpha-based immune therapy for inflammatory bowel diseases and non-alcoholic steatohepatitis, as well as other autoimmune, TNF-mediated diseases.

Review article: novel methods for the treatment of non-alcoholic steatohepatitis - targeting the gut immune system to decrease the systemic inflammatory response without immune suppression

BACKGROUND

The systemic immune system plays a role in inflammation and fibrogenesis associated with non-alcoholic steatohepatitis (NASH) and has become a potential target for drug development. In particular, the gut immune system has been suggested as a means for generating signals that can target the systemic immune system.

AIM

To describe seven novel methods being developed for the treatment of NASH that target the gut immune system for alleviation of the systemic inflammatory response, including oral administration of fatty-liver-derived proteins, anti-CD3 antibodies, tumour necrosis factor fusion protein, anti-lipopolysaccharide antibodies, glucosylceramide, delayed-release mercaptopurine, and soy-derived extracts.

METHODS

A search for these methods for oral immunotherapy for NASH was conducted.

RESULTS

Oral administration of these compounds provides an opportunity for immune modulation without immune suppression, with the advantage of being independent of a single molecular/inflammatory pathway. These modes of oral immune therapy demonstrate superior safety profiles, such that the patient is not exposed to general immune suppression. Moreover, these approaches target the whole spectrum of the disease and may serve as adjuvants to other therapies, such that they provide a platform for treatment of concomitant disorders in patients with NASH, including diabetes and hyperlipidaemia. Most of the compounds reviewed are currently in phase II trials, and it is anticipated that the acquisition of more clinical data in the next few years will enable the use of this new class of drugs for the treatment of NASH.

CONCLUSION

Oral immunotherapy may provide a novel platform for the treatment of NASH.

Oral tolerance is inducible during active dextran sulfate sodium-induced colitis

AIM: To investigate whether oral tolerance is inducible during the active phase of dextran sulfate sodium (DSS)-induced colitis.

METHODS: Colitis was induced in 6- to 8-wk-old female BALB/c mice by the administration of 2% DSS. To induce oral tolerance, mice that received water with DSS [DSS (+)] and mice that received autoclaved water [DSS (-)] were intragastrically (i.g.) administered ovalbumin (OVA) as a tolerogen before systemic challenge with OVA. Following this, serum levels of OVA-specific IgE antibodies were measured. In mice with active colitis, CD4⁺CD25⁺Foxp3⁺ cell and B10 cell frequencies were evaluated using flow cytometry. Cytokine mRNA expression profiles were evaluated by reverse transcription real-time polymerase chain reaction.

RESULTS: Regardless of the presence of DSS colitis, OVA-specific immunoglobulin E concentrations were significantly reduced in mice that were i.g. administered OVA compared to mice that were i.g. administered PBS [DSS (+): 4.4 (4.2-9.5) ng/mL vs 83.9 (66.1-123.2) ng/mL, P < 0.01; DSS (-): 27.7 (0.1-54.5) ng/mL vs 116.5 (80.6-213.6) ng/mL, P < 0.01]. These results demonstrated that oral tolerance was induced in both the presence and absence of colitis. In the spleen and mesenteric lymph nodes (MLN), the frequencies of CD4⁺CD25⁺Foxp3⁺ cells and B10 cells, both of which are associated with oral tolerance, did not significantly change. In the spleen, interferon-γ mRNA expression significantly decreased in mice with colitis [DSS (+): 0.42 (0.31-0.53) vs DSS (-): 1.00 (0.84-1.39), P < 0.01]. The expression levels of other cytokines did not significantly change.

CONCLUSION: Oral tolerance is inducible during active DSS colitis. The stability of regulatory cell populations in the spleen and MLN in colitis might correlate with these results.

Oral immune therapy: targeting the systemic immune system via the gut immune system for the treatment of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are associated with an altered systemic immune response leading to inflammation-mediated damage to the gut and other organs. Oral immune therapy is a method of systemic immune modulation via alteration of the gut immune system. It uses the inherit ability of the innate system of the gut to redirect the systemic innate and adaptive immune responses. Oral immune therapy is an attractive clinical approach to treat autoimmune and inflammatory disorders. It can induce immune modulation without immune suppression, has minimal toxicity and is easily administered. Targeting the systemic immune system via the gut immune system can serve as an attractive novel therapeutic method for IBD. This review summarizes the current data and discusses several examples of oral immune therapeutic methods for using the gut immune system to generate signals to reset systemic immunity as a treatment for IBD.

Oral administration of non-absorbable delayed release 6-mercaptopurine is locally active in the gut, exerts a systemic immune effect and alleviates Crohn's disease with low rate of side effects: results of double blind Phase II clinical trial

Therapy for Crohn's disease (CD) with thiopurines is limited by systemic side effects. A novel formulation of fixed-dose, delayed-release 6-mercaptopurine (DR-6MP) was developed, with local effect on the gut immune system and minimal absorption. The aim of this study was to evaluate the safety and efficacy of DR-6MP in patients with moderately severe CD compared to systemically delivered 6-mercaptopurine (Purinethol). Seventy CD patients were enrolled into a 12-week, double-blind controlled trial. The primary end-point was the percentage of subjects with clinical remission [Crohn's Disease Activity Index (CDAI) < 150] or clinical response (100-point CDAI reduction). Twenty-six (56·5%) and 13 (54·2%) subjects from the DR-6MP and Purinethol cohorts, respectively, completed the study. DR-6MP had similar efficacy to Purinethol following 12 weeks of treatment. However, the time to maximal clinical response was 8 weeks for DR-6MP versus 12 weeks for Purinethol. A higher proportion of patients on DR-6MP showed clinical remission at week 8. A greater improvement in Inflammatory Bowel Disease Questionnaire (IBDQ) score was noted in the DR-6MP group. DR-6MP led to a decrease of CD62(+) expression on T cells, implying a reduction of lymphocyte adhesion to site of inflammation. DR-6MP was safer than Purinethol, with significantly fewer adverse events (AEs). There was no evidence of drug-induced leucopenia in the DR-6MP group; the proportion of subjects who developed hepatotoxicity was lower for the DR-6MP. Non-absorbable DR-6MP is safe and biologically active in the gut. It is clinically effective, exerting a systemic immune response with low systemic bioavailability and a low incidence of side effects.

Oral mixture of autologous colon-extracted proteins for the Crohn’s disease: A double-blind trial

AIM: To evaluate the safety and efficacy of oral administration of Alequel™, an autologous protein-containing colon extract.

METHODS: A total of 43 patients were enrolled in a randomized, placebo-controlled, double-blind trial. Patients were orally administered with autologous protein-containing colon extract three doses of autologous study drug per week for 15 wk, for a total of 45 doses. Patients were followed for safety parameters. Remission was defined as a Crohn’s disease activity index (CDAI) score of less than or equal to 150. All patients were followed for changes in subsets of T cells by fluorescence-activated cell sorting analysis.

RESULTS: Analysis was performed on a total number of evaluable patients of 14 in the study drug group and 15 in the placebo group. Treatment was well tolerated by all patients. No major treatment-related adverse events were reported or observed in any of the treated patients during the feeding or follow-up periods. Between weeks 6 and 9 of the study, six of the 14 (43%) evaluable subjects who received the study drug achieved a CDAI of 150 or lower. In contrast, five of the 15 (33%) evaluable subjects in the placebo group achieved remission. Between weeks 9 and 12, the remission rates were 50% and 33% for the drug group and placebo group, respectively. Among the drug-treated subjects who achieved remission, the effect of the drug was judged as stable in eight of the 14 subjects as measured by at least two CDAI scores indicating remission in the 15-wk treatment period. A decreased percentage of peripheral natural killer T regulatory cells (a decrease of 28% vs an increase of 16%) and an increased ratio of CD4⁺/CD8⁺ T lymphocytes (an increase of 11% vs a decrease of 9%) were noted in subjects with a significant clinical response.

CONCLUSION: Oral administration of the autologous colonic extract could be a safe and effective for the treatment of patients with moderate to severe Crohn’s disease.

Immune cell therapy in IBD

The therapeutic landscape of IBD has undergone a dramatic transformation since the advent of biologic therapies, especially TNF inhibitors. However, 30% of patients are primary nonresponders to biologic therapy and secondary failures are frequent. Due to substantial progress in our understanding of the biology of regulatory T cells (Tregs) and in the pathways of homing to the gastrointestinal tract, novel cell-based therapies for IBD have become possible. For example, although a reductionist view, one could envisage IBD as an imbalance between the proinflammatory effectors (such as Th17 cells) and the anti-inflammatory regulators (like Tregs). Here we focus on the development of ex vivo and in vivo approaches to enhance Tregs in the gastrointestinal tract. Specifically, herein we highlight a recently concluded phase 1/2a clinical trial that investigated the safety and efficacy of a single injection of escalating doses of autologous ovalbumin-specific Tregs in patients with active Crohn's disease refractory to conventional therapy. This therapy was well tolerated and demonstrated dose-related efficacy. We also discuss the potential of directing Tregs derived through intranasal as well as epicutaneous immunization to the gastrointestinal tract by enhancing their gut homing signature and their potential to decrease gastrointestinal inflammation. Finally, the strengths and pitfalls of these new therapeutic approaches are discussed as we move forward in this largely uncharted territory.

The therapeutic role of oral tolerance in dextran sulfate sodium-induced colitis via Th1-Th2 balance and γδ T cells

OBJECTIVE

To evaluate the state of oral tolerance and its therapeutic role in mice with dextran sulfate sodium (DSS)-induced colitis.

METHODS

Delayed-type hypersensitivity (DTH) was determined 7 and 14 days after DSS-induced colitis and control mice. Disease activity index (DAI) score and colonic histopathological score were measured 7 days after colonic extracted protein (CEP) or bovine serum albumin (BSA) (control) was administrated, with the evaluation of Th1-Th2 balance in the spleen, Peyer's patch and γδ T cells in intraepithelial lymphocytes and lamina proper lymphocytes in the intestine.

RESULTS

After fed with 250 μg ovalbumin oral tolerance was induced in 7 days in both DSS-induced colitis and control mice, while oral tolerance persisted in the control mice but vanished in DSS-induced colitis 14 days after ovalbumin challenge. DAI and colonic histopathological scores were decreased significantly after the ingestion of CEP (controlled by BSA) in DSS-induced colitis with significant reduction of Th1 and the ratio of Th1 to Th2 in Peyer's patch as well as the γδ T cells in lamina proper lymphocytes in the intestine. No significant difference in Th1-Th2 balance in the spleen and γδ T cells in intraepithelial lymphocytes in the intestine were observed.

CONCLUSIONS

There is a defect in oral tolerance at day 7 in DSS-induced colitis. If taken orally, CEP may have a protective role in DSS-induced colitis, which may be related to the deflection from Th1 to Th2 in Peyer's patch and the reduction of γδ T cells in lamina proper lymphocytes in the intestine.

Oral administration of carbonic anhydrase I ameliorates murine experimental colitis induced by Foxp3-CD4+CD25- T cells

IBDs are thought to involve uncontrolled innate and adaptive immunity against intestinal self-antigens and bacterial antigens. Mouse CA I is a major cecal bacterial antigen in fecal extracts and is implicated in the pathogenesis of IBD. We show here that oral tolerization to CA I induced antigen-specific protection from intestinal inflammation in a murine model. Oral administration of CA I but not irrelevant antigen (KLH) ameliorated CD4(+)CD25(-) T cell transfer murine colitis and DSS-induced murine colitis. Next, we investigated the mechanisms involved in the therapeutic effects of oral administration, such as induction of ALDH1a2, transcription factors, cytokines, CD103(+)CD11c(+) DCs, and generation of Tregs. Oral administration of CA I induced ALDH1a2 mRNA expression in the MLN and colon. When compared with PBS-treated mice, CA I-treated mice had higher Foxp3(+)CD4(+)CD25(+) Treg and CD103(+)CD11c(+) DC numbers in the MLN and colon; had higher TGF-β production in the MLN and colon; had lower RORγt mRNA expression in the MLN and colon; and had lower IL-17 mRNA expression and production in the MLN. These results demonstrate that oral administration of CA I induced antigen-specific immune tolerance by generating Foxp3(+)CD4(+)CD25(+) Tregs and inhibiting Th17 cells in a murine colitis model, thus suggesting that oral tolerization with CA I is an effective therapeutic strategy for IBD regulation.

Oral tolerance

The gut-associated lymphoid tissue is the largest immune organ in the body and is the primary route by which we are exposed to antigens. Tolerance induction is the default immune pathway in the gut, and the type of tolerance induced relates to the dose of antigen fed: anergy/deletion (high dose) or regulatory T-cell (Treg) induction (low dose). Conditioning of gut dendritic cells (DCs) by gut epithelial cells and the gut flora, which itself has a major influence on gut immunity, induces CD103(+) retinoic acid-dependent DC that induces Tregs. A number of Tregs are induced at mucosal surfaces. Th3 type Tregs are transforming growth factor-β dependent and express latency-associated peptide (LAP) on their surface and were discovered in the context of oral tolerance. Tr1 type Tregs (interleukin-10 dependent) are induced by nasal antigen and forkhead box protein 3(+) iTregs are induced by oral antigen and by oral administration of aryl hydrocarbon receptor ligands. Oral or nasal antigen ameliorates autoimmune and inflammatory diseases in animal models by inducing Tregs. Furthermore, anti-CD3 monoclonal antibody is active at mucosal surfaces and oral or nasal anti-CD3 monoclonal antibody induces LAP(+) Tregs that suppresses animal models (experimental autoimmune encephalitis, type 1 and type 2 diabetes, lupus, arthritis, atherosclerosis) and is being tested in humans. Although there is a large literature on treatment of animal models by mucosal tolerance and some positive results in humans, this approach has yet to be translated to the clinic. The successful translation will require defining responsive patient populations, validating biomarkers to measure immunologic effects, and using combination therapy and immune adjuvants to enhance Treg induction. A major avenue being investigated for the treatment of autoimmunity is the induction of Tregs and mucosal tolerance represents a non-toxic, physiologic approach to reach this goal.

Effects of appendectomy and oral tolerance on dextran sulfate sodium colitis

AIM: To evaluate the concomitant effects of appendectomy and oral tolerance on colitis.

METHODS: Delayed-type hypersensitivity (DTH) was investigated at a 7-d interval after ovalbumin (OVA) administration and immunization under normal and colitis conditions in appendectomized or sham-operated mice. Pathological scores for the colon were graded after ingestion of colon-extracted protein (CEP) and induction of dextran sulfate sodium (DSS) colitis in appendectomized or sham-operated mice. Thereafter, Th1 and Th2 in Peyer’s patches and spleen lymphocytes were detected in CEP-treated and bovine serum albumin (BSA)-treated control mice.

RESULTS: In appendectomized mice, DTH was not inhibited at day 7 after OVA administration and at the initial phase of DSS colitis, whereas it was inhibited at day 14 and day 21. However, in sham-operated mice, it was inhibited during the whole procedure and the onset of DSS colitis. The protective role of CEP against DSS colitis was present in sham-operated mice, with predominant improvement of colonic pathological changes, while vanished in the appendectomized mice. A shift from Th1 to Th2 in Peyer’s patches resulted from a decrease of Th1 cells with the ingestion of CEP. Compared with BSA in the sham-operated group, no predominant changes were observed in the appendectomized mice.

CONCLUSION: Appendectomy interferes with the protective role of CEP in DSS colitis via a shift from Th2 to Th1 during oral tolerance induction.

The protective effect of oral colitis-derived proteins in a murine model of inflammatory bowel disease is associated with an increase in gammadelta T cells in large intestinal mucosa

BACKGROUNDS AND AIMS

Oral tolerance has previously been shown effective in preventing several immune-mediated disorders in animal models. The aims of this study were to investigate the effect of oral colitis-extracted proteins (CEP) on dextran sulfate sodium (DSS)-induced colitis in BALB/c mice and to explore the relative role of the intestinal mucosal gammadelta T cells.

METHODS

The effect of five low oral doses of CEP on colitis was evaluated by clinical manifestation and histological lesions. Serum cytokines were measured by enzyme-linked immunosorbent assay. The percentages of the intestinal mucosal gammadelta T cells were evaluated by flow cytometry.

RESULTS

CEP-fed colitis mice showed less severe symptoms and histological injury than bovine serum albumin (BSA)-fed control mice. Tolerized mice developed an increase in TGF-beta1 and no change in IFN-gamma serum levels. Increases in TCRgammadelta(+) T cells and CD8alpha(+)TCRgammadelta(+) T cells in small intestinal mucosal lymphocytes and no quantitative change in large intestinal mucosal lymphocytes were demonstrated in colitis mice compared to untreated mice. The proportions of TCRgammadelta(+) T cells and CD8alpha(+)TCRgammadelta(+) T cells in large intestinal mucosal lymphocytes from CEP-fed colitis mice were significantly higher compared to BSA-fed controls. The disease activity index negatively correlated with the percentages of large intestinal mucosal gammadelta T cells. Furthermore, mucosal repair in repair-period mice was also accompanied by increases in TCRgammadelta(+) T cells and CD8alpha(+)TCRgammadelta(+) T cells in large intestinal mucosal lymphocytes.

CONCLUSION

Improvement of DSS-induced colitis that resulted from oral administration of colitis-extracted proteins is associated with an increase in gammadelta T cells in large intestinal mucosa.

Oral administration of Alequel, a mixture of autologous colon-extracted proteins for the treatment of Crohn's disease

The pathogenesis of Crohn's disease involves an immune-mediated damage to the gut mucosa. Current developed therapies are based on the use of immunosuppressive drugs that can lead to significant drug-related adverse responses. There is a need for a therapeutic strategy that is more specific and less global in its effect on the immune system. Oral tolerance is an active process wherein oral administration of antigens is associated with the induction of regulatory cells and the suppression of effector cells directed toward specific and nonspecific antigens. Studies in animal models of experimental colitis suggest that oral administration of proteins extracted from the gut can induce tolerance and alleviate the disease symptoms. Recent clinical trials showed that oral administration of Alequel, an autologous protein-containing colon extract, to patients with Crohn's disease is safe and may be effective as a therapeutic modality for treating the disease. This treatment was associated with disease-associated antigen alterations of the immune response in the patients. Oral administration of Alequel could provide a patient-tailored approach that is side-effect-free for the treatment of patients with Crohn's disease.

Oral tolerance: can we make it work?

Mucosal tolerance remains an attractive approach for the treatment of autoimmune and inflammatory diseases. The agents used in these treatments lack toxicity, can be easily administered, and enable the promotion of antigen-specific immune responses. The limited success of clinical trials over the past 2 decades has led to the fear that the beneficial effect observed in animal models cannot be repeated in humans. Successful application of mucosal tolerance for the treatment of human diseases will depend on strategies that target the correct cells in the gut-liver axis, improve antigen presentation, alter the administered dose and formulations, utilize potent mucosal adjuvants, develop immune biomarkers enabling follow-up of the effect, utilize combination therapies with other immune modulatory agents, and target the right patient populations. Here, we discuss 12 of the major questions related to oral tolerance and its clinical application to humans with immune-mediated disorders.

Crohn's disease: beyond antagonists of tumour necrosis factor

In the past few years, antagonists of tumour necrosis factor have resulted in unforetold therapeutic benefits in Crohn's disease, but the magnitude and duration of responses are variable. New agents are therefore needed. Their development has benefited from advances in the understanding of the pathophysiology of this disease. Uncontrolled activation of the acquired immune system has an important role, and lymphocytes, cytokines, and adhesion molecules are broadly targeted for therapeutic intervention. With increasing evidence of an implication of the innate immune system and the intestinal epithelium, the therapeutic paradigm is also shifting from mere immunosuppression to the reinforcement of the intestinal barrier. We review mechanisms of actions of new drugs and the efficacy and adverse events from data from clinical trials. We discuss future directions, including new strategies with optimum endpoints.

Intrahepatic CD8+ lymphocyte trapping during tolerance induction using mushroom derived formulations: A possible role for liver in tolerance induction

AIM: To determine the immunomodulatory effect of Shiitake (a mushroom extract), we tested its effect on liver-mediated immune regulation in a model of immune-mediated colitis.

METHODS: Four groups of mice were studied. Colitis was induced by intracolonic instillation of TNBS in groups A and B. Groups A and C were treated daily with Shiitake extract, while groups B and D received bovine serum albumin. Mice were evaluated for development of macroscopic and microscopic. The immune effects of Shiitake were determined by FACS analysis of intra-hepatic and intrasplenic lymphocytes and IFN-γ ELISPOT assay.

RESULTS: Administration of Shiitake resulted in marked alleviation of colitis, manifested by significant improvement in the macroscopic and microscopic scores, and by reduction in IFN-γ-producing colonies in group A, compared to group B mice (1.5 pfu/mL vs 3.7 pfu/mL, respectively). This beneficial effect was associated with a significant increase in the intra-hepatic CD8⁺ lymphocyte trapping, demonstrated by an increased intrasplenic/intrahepatic CD4/CD8 lymphocyte ratio. These effects were accompanied by a 17% increase in the number of intrahepatic natural killer T (NKT) cells. A similar effect was observed when Shiitake was administered to animals without disease induction.

CONCLUSION: Shiitake extract affected liver-mediated immune regulation by altering the NKT lymphocyte distribution and increasing intrahepatic CD8⁺ T lymphocyte trapping, thereby leading to alleviation of immune-mediated colitis.

Antigen-specific therapy of rheumatoid arthritis

BACKGROUND

Immunotherapy offers the promise of antigen-specific suppression of pathological immune responses in conditions such as autoimmunity and organ transplantation. Substantial advances have been made in recent years in terms of understanding basic immunological mechanisms of autoreactivity, as well as clinically implementing immune-based therapies that are antigen nonspecific.

OBJECTIVE

To provide an integrated overview of the current state of the art in terms of antigen-specific tolerance induction, as well as to predict future directions for the field.

METHODS

Examples of successes and failures of antigen-specific immunotherapy were sought. Particular attention was paid to the well-established collagen II-induced model of arthritis.

RESULTS/CONCLUSIONS

Previous failures of antigen-specific immunotherapy were associated with lack of identification of clinically relevant antigens, as well as inappropriate tolerogenic methodologies. The advances in proteomics combined with novel gene-specific immune modulatory techniques place today's translational researchers in a unique position to tackle the problem of antigen-specific immunotherapeutic protocols.

Oral tolerance

Multiple mechanisms of tolerance are induced by oral antigen. Low doses favor active suppression, whereas higher doses favor clonal anergy/deletion. Oral antigen induces T-helper 2 [interleukin (IL)-4/IL-10] and Th3 [transforming growth factor (TGF)-beta] T cells plus CD4+CD25+ regulatory cells and latency-associated peptide+ T cells. Induction of oral tolerance is enhanced by IL-4, IL-10, anti-IL-12, TGF-beta, cholera toxin B subunit, Flt-3 ligand, and anti-CD40 ligand. Oral (and nasal) antigen administration suppresses animal models of autoimmune diseases including experimental autoimmune encephalitis, uveitis, thyroiditis, myasthenia, arthritis, and diabetes in the non-obese diabetic (NOD) mouse, plus non-autoimmune diseases such as asthma, atherosclerosis, graft rejection, allergy, colitis, stroke, and models of Alzheimer's disease. Oral tolerance has been tested in human autoimmune diseases including multiple sclerosis (MS), arthritis, uveitis, and diabetes and in allergy, contact sensitivity to dinitrochlorobenzene (DNCB), and nickel allergy. Although positive results have been observed in phase II trials, no effect was observed in phase III trials of CII in rheumatoid arthritis or oral myelin and glatiramer acetate (GA) in MS. Large placebo effects were observed, and new trials of oral GA are underway. Oral insulin has recently been shown to delay onset of diabetes in at-risk populations, and confirmatory trials of oral insulin are being planned. Mucosal tolerance is an attractive approach for treatment of autoimmune and inflammatory diseases because of lack of toxicity, ease of administration over time, and antigen-specific mechanisms of action. The successful application of oral tolerance for the treatment of human diseases will depend on dose, developing immune markers to assess immunologic effects, route (nasal versus oral), formulation, mucosal adjuvants, combination therapy, and early therapy.