Adipose-derived mesenchymal stem cell-secreted exosome alleviates dextran sulfate sodium-induced acute colitis by Treg cell induction and inflammatory cytokine reduction

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is an inflammatory condition that results in gastrointestinal tract damage. Various factors, including environmental and genetic agents, disrupt the function of the intestinal immune system that can lead to IBD. Mesenchymal stem cells (MSCs) display an immunoregulatory function and demonstrate regenerative potential by paracrine action. In this study, we evaluated the immunomodulatory effects of MSCs' derived exosomes in the acute form of dextran sulfate sodium (DSS)-induced colitis. Exosomes were isolated from adipose-derived MSCs. Acute colitis was induced by DSS. The exosome was used by intraperitoneal injection into mice with acute colitis. Stool consistency, body weight changes, bleeding severity, colon length, and weight were examined. At the experimental endpoint (Day 7), the changes in the colon tissue were evaluated. The level of cytokines of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), IL-4, IL-12, transforming growth factor-β (TGF-β) and, IL-10, and Treg cells percentage were assayed. Results showed that exosome administration diminished colon shortening, bodyweight loss, bleeding, and colon injury. The levels of IFN-γ, TNF-α, IL-12, and IL-17 were decreased, and the level of TGF-β, IL-4, and IL-10 were increased in lymph node and spleen of mice treated with exosome.  Percentages of CD4+ CD25+ Foxp3+ Treg cells were grown in the lymph node and spleen of mice treated with exosomes. Overall, current data suggest that MSC-derived exosome could regulate the Treg population and improves inflammation in DSS-induced acute colitis.

PLGA microspheres encapsulating siRNA anti-TNFalpha: efficient RNAi-mediated treatment of arthritic joints

The aim of this study was to investigate potentialities of poly(dl-lactide-co-glycolide) (PLGA) microspheres for the delivery of small interfering RNAs (siRNAs) against tumor necrosis factor α (TNF-α) to achieve prolonged and efficient inhibition of TNF-α for the treatment of rheumatoid arthritis (RA). PLGA microspheres were prepared by a modified multiple emulsion-solvent evaporation method. The formulations were characterized in terms of morphology, mean diameter and siRNAs distribution, encapsulation efficiency, and in vitro release kinetics. The efficiency of this system was then evaluated both in vitro and in vivo using the murine monocytic cell line J774 and a pre-clinical model of RA, respectively. siRNA-encapsulating PLGA microspheres were characterized by a high encapsulation efficiency and a slow and prolonged anti-TNF-α siRNAs. Our results provide evidence that, upon intra-articular administration, PLGA microspheres slowly releasing siRNAs effectively inhibited the expression of TNF-α in arthritic joints. Our system might represent an alternative strategy for the design of novel anti-rheumatic therapies based on the use of RNA interference in RA.

Germline VH/VL pairing in antibodies

Antibodies are key molecules of the adaptive immune response and are now a major class of biopharmaceuticals. Pairing of heavy and light chains is one of the ways of generating antibody diversity and, while little is known about mechanisms governing V(H)/V(L) pairing, previous studies have suggested that the germline source from which chains are paired is random. By selecting paired antibody protein sequences from human and mouse antibodies from the KabatMan database and mapping them onto their corresponding germline sequences, we find that pairing preferences do exist in the germline, but only for a small proportion of germline gene segments; others are much more promiscuous showing no preferences. The closest equivalent human and mouse gene families were identified and pairing preferences compared. This work may impact on the ability to generate more stable antibodies for use as biopharmaceuticals.

Surgical resection in Crohn's disease: is immunosuppressive medication associated with higher postoperative infection rates?

AIM

The aim of this study was to analyse postoperative infection in patients undergoing surgery for Crohn's disease (CD) according to the use of preoperative immunosuppressants, including infliximab.

METHOD

With IRB approval, the records of all patients with CD who underwent abdominal surgery between 2001 and 2008 were reviewed for comorbidity, preoperative medication, type of surgery, stoma construction and postoperative complications. Patients were divided into three categories according to the preoperative medication within 90 days of surgery as follows: infliximab (IFX), other drugs including steroids and/or immunosuppressive agents (OD) and no drugs (ND).

RESULTS

Two hundred and twenty-five patients were identified. Preoperative comorbidity, surgical indication and type of surgery were not significantly different among the three groups. Ileocolic resection was the most common procedure [50.8%, IFX group; 61.2%, OD group; 41.3%, ND group (P = 0.09)]. Other procedures included total colectomy (16%), protectomy (15%) and others (18%). Laparoscopic surgery was performed in 47.7%, 45.9% and 29.3% of patients in the IFX, OD and ND groups, respectively (P = 0.04). There were no differences in postoperative rates of infection [pneumonia (P = 0.14), wound infection (P = 0.35), abscess (P = 0.34) or anastomotic leakage (P = 0.44)]. Reoperation was needed in 3.0%, 8.2% and 2.6% of patients in the IFX, OD and ND groups, respectively. Multiple logistic regression found no relationship between infliximab use and infection.

CONCLUSION

There was no difference in the rate of postoperative complications among the groups of patients undergoing surgery for CD pretreated with IFX or other immunosuppressive drugs.

The correlation between NF-κB inhibition and disease activity by coadministration of silibinin and ursodeoxycholic acid in experimental colitis

NF-κB is one of the most important nuclear factors responsible for overexpression of proinflammatory cytokines. This is demonstrated by increased NF-κB activity and other dependent immune factors in inflammatory bowel disease (IBD). Anti-inflammatory effects of silibinin and ursodeoxycholic acid (UDCA) along with their NF-κB inhibitory property are thought to be beneficial in colitis. Trinitrobenzene sulfonic acid was used to induce colitis rat models. After instillation, 48 rats were treated with oral silibinin, UDCA alone or a combination of both. Intraperitoneal dexamethasone was used in the control group. After 12 days of treatment, colonic samples were tested for the severity of mucosal damage macroscopically and microscopically. The levels of activated NF-κB, IL-1β, TNF-α, myeloperoxidase, thiobarbituric acid reactive substances (TBARS), protein carbonyl, and the antioxidant power of the bowel homogenates were determined. The results indicated a significant reduction in NF-κB activity as well as the levels of IL-1β, TNF-α, TBARS, protein carbonyl, myeloperoxidase activity, and an improvement in antioxidant power of colitis in treated rats. Combination therapy resulted in a more prominent improvement in bowel antioxidant power and myeloperoxidase activity. In conclusion, combination of silibinin and UDCA by inhibition of NF-κB and other relevant inflammatory factors of colitis is a good candidate for management of Crohn's disease.

Uveitis: Mechanisms and recent advances in therapy

Uveitis is a sight threatening inflammatory disorder that affects all ages and remains a significant cause of visual loss. Animal models of autoimmune and inflammatory disease in the eye allow the scientist and clinician to study the basic mechanism of the disease, and serve as templates for the development of therapeutic approaches. The accumulating knowledge of the various steps that are involved in the pathogenesis make it possible to devise specific strategies that disrupt discrete stages in the process. Some of the strategies are in the process of being translated to the clinic. New technologies emerge, promising more specific and more easily applied therapies. In this review, we will concentrate specifically on mechanisms and recent advances in the therapy of uveitis.

Safety profile of IBD: lymphoma risks

This article describes the cancer risks of commonly used inflammatory bowel disease (IBD) medications, with an emphasis on hematologic malignancy risks. The increasing use of immunosuppressant therapies in the treatment of IBD has raised this question to an even greater importance. Studies evaluating these medications are complicated due to varying disease severity and concomitant use of other immunosuppressant medication. The potential risks of all therapies must be weighed against the benefits these therapies can offer these patients.

Safety profile of IBD: lymphoma risks

This article describes the cancer risks of commonly used inflammatory bowel disease (IBD) medications, with an emphasis on hematologic malignancy risks. The increasing use of immunosuppressant therapies in the treatment of IBD has raised this question to an even greater importance. Studies evaluating these medications are complicated due to varying disease severity and concomitant use of other immunosuppressant medication. The potential risks of all therapies must be weighed against the benefits these therapies can offer these patients.

Risk of lymphoma associated with combination anti-tumor necrosis factor and immunomodulator therapy for the treatment of Crohn's disease: a meta-analysis

BACKGROUND & AIMS

Although anti-tumor necrosis factor (TNF) therapy can effectively treat Crohn's disease (CD), there is concern that it might increase the risk of non-Hodgkin's lymphoma (NHL). A meta-analysis was performed to determine the rate of NHL in adult CD patients who have received anti-TNF therapy and to compare this rate with that of a population-based registry and a population of CD patients treated with immunomodulators.

METHODS

MEDLINE, EMBASE, Cochrane Collaboration, and Web of Science were searched. Inclusion criteria included randomized controlled trials, cohort studies, or case series reporting on anti-TNF therapy in adult CD patients. Standardized incidence ratios (SIR) were calculated by comparing the pooled rate of NHL with the expected rate of NHL derived from the Surveillance Epidemiology & End Results (SEER) database and a meta-analysis of CD patients treated with immunomodulators.

RESULTS

Twenty-six studies involving 8905 patients and 21,178 patient-years of follow-up were included. Among anti-TNF treated subjects, 13 cases of NHL were reported (6.1 per 10,000 patient-years). The majority of these patients had previous immunomodulator exposure. Compared with the expected rate of NHL in the SEER database (1.9 per 10,000 patient-years), anti-TNF treated subjects had a significantly elevated risk (SIR, 3.23; 95% confidence interval, 1.5-6.9). When compared with the NHL rate in CD patients treated with immunomodulators alone (4 per 10,000 patient-years), the SIR was 1.7 (95% confidence interval, 0.5-7.1).

CONCLUSIONS

The use of anti-TNF agents with immunomodulators is associated with an increased risk of NHL in adult CD patients, but the absolute rate of these events remains low and should be weighed against the substantial benefits associated with treatment.

Medical options for treating perianal Crohn's disease

Perianal Crohn's disease can cause significant morbidity for patients affected by the disease. However, diagnostic modalities and treatment options have progressed changing the goals of treatment from fistula "improvement" to complete cessation of drainage. Fistula closure and fibrosis of the fistula track is achieved in some patients. Furthermore, treatment has become a combined effort between medical physicians and surgeons. Simple disease can be treated with medical therapy alone consisting of antibiotics and immunomodulators. Infliximab should be added to refractory simple disease or simple disease with the presence of inflammation. If complex fistula disease is evident a surgical evaluation should also be done to determine if intervention is indicated. Complex disease should be treated with antibiotics, immunomodulators and biologic therapy from the onset. This review will summarise current data regarding medical options for treatment of fistulising Crohn's disease.

Do anti-tumor necrosis factors induce response and remission in patients with acute refractory Crohn's disease? A systematic meta-analysis of controlled clinical trials

To determine whether anti-tumor necrosis factors induce clinical response and remission in patients with Crohn's disease, PUBMED, OVID, and SCOPUS databases were searched for studies investigated the efficacy of anti-tumor necrosis factors on CD. Data were collected from 1966 to 2005 (up to 31 December). Types of outcome investigated were response (decrease in CDAI score >/=70 points) and remission (CDAI score </=150 points) 2 and 4 weeks after drug administration. The criteria for inclusion of studies in this analysis were exposure of patients with CD to any therapeutic dosage of any anti-tumor necrosis factors (infliximab, cetrolizumab, CDP870, CDP571, etanercept, onarcept). The results showed that anti-tumor necrosis factors have improved only clinical response 2 weeks after administration of these drugs statistically, but their effects on clinical remission after 2 weeks and response and remission after 4 weeks have not been significant. It seems that anti-tumor necrosis factors are not effective for induction of response and remission in patients with Crohn's disease.

Infliximab in fistulizing Crohn's disease

The treatment of fistulizing CD has evolved greatly in the last 15 years, largely caused by improvements in medical therapy. Tables 2 and 3 summarize all published controlled and uncontrolled trials of immunomodulator and biologic therapy for the treatment of Crohn's fistulae. The advent of immunomodulators and anti-TNF-alpha agents has transformed the treatment of Crohn's fistulae from almost exclusively surgical to placing a much larger emphasis on medical therapy, either as initial therapy alone, with surgery reserved for refractory cases, or in combination with surgery from the start. For this reason, surgeons and gastroenterologists must work in concert to provide the best care for each patient. Proper fistula management also relies heavily on accurate diagnosis, especially defining the anatomy of the fistula, ascertaining whether abscess formation is present, and determining the location and extent of intestinal inflammation.

The effect of acute psychologic stress on systemic and rectal mucosal measures of inflammation in ulcerative colitis

BACKGROUND & AIMS

Recent studies suggest that life events and chronic stress increase the risk of relapse in inflammatory bowel disease. Our aim was to study the effects of acute psychologic stress on systemic and rectal mucosal inflammatory responses in patients with inactive ulcerative colitis (UC).

METHODS

Twenty-five patients with inactive UC and 11 healthy volunteers (HV) underwent an experimental stress test. Ten patients with UC and 11 HV underwent a control procedure. Before and after each procedure, systemic inflammatory response was assessed by serum interleukin (IL)-6 and IL-13 concentrations, tumor necrosis factor (TNF)-alpha and IL-6 production by lipopolysaccharide (LPS)-stimulated whole blood, leukocyte count, natural killer (NK) cell numbers, platelet activation, and platelet-leukocyte aggregate (PLA) formation. In patients with UC, rectal mucosal inflammation was assessed by TNF-alpha, IL-13, histamine and substance P release, reactive oxygen metabolite (ROM) production, mucosal blood flow (RMBF) and histology.

RESULTS

Stress increased pulse (P < .0001) and systolic BP (P < .0001). In UC, stress increased LPS-stimulated TNF-alpha and IL-6 production by 54% (P = .004) and 11% (P = .04), respectively, leukocyte count by 16% (P = .01), NK cell count by 18% (P = .0008), platelet activation by 65% (P < .0001), PLA formation by 25% (P = .004), mucosal TNF-alpha release by 102% (P = .03), and ROM production by 475% (P = .001) and reduced rectal mucosal blood flow by 22% (P = .05). The control protocol did not change any of the variables measured. There were no differences between the responses of the patients with UC and HV.

CONCLUSIONS

Acute psychologic stress induces systemic and mucosal proinflammatory responses, which could contribute to exacerbations of UC in ordinary life.

Methods to characterize lymphoid apoptosis in a murine model of autoreactivity

The immune system is shaped by the random generation of lymphocytes followed by apoptosis of self-reactive cells, a process termed negative selection. The survival of these pathogenic cells in the periphery can elicit autoreactivity. We describe the development of a biomarker assay for the detection of pathogenic subpopulations of lymphoid cells in adult non-obese diabetic (NOD) mice based on disease-specific alterations in spontaneous or triggered cell death. Utilizing improved methods of cell separations, two distinct lymphoid cell subpopulations with increased susceptibility to apoptosis were identified and quantified. A subpopulation of CD8+ T cells that constitutes approximately 3-7% of the total CD8+ T cell population underwent apoptosis on exposure to low concentrations of TNF-alpha. Such cells were exclusively detected only in NOD mice with histologic signs of active autoreactivity. The non-T cell compartment of NOD immune system, although resistant to TNF-alpha-induced apoptosis, contained a subpopulation of B cells with spontaneous death by culture alone. The refined detection of small numbers of lymphoid cell subsets with quantifiable differences in apoptosis provides a possible immune biomarker for monitoring disease activity or treatment interventions.

Clinical and biological consequences of immunization to infliximab in pediatric Crohn's disease

Tumor necrosis factor (TNF)-alpha plays a critical role in the initiation and progression of Crohn's disease, a chronic inflammatory disorder of the gastrointestinal tract. Infliximab, a chimeric monoclonal antibody blocking TNF-alpha, has proven effective as an induction and maintenance therapy for refractory Crohn's disease in adult and pediatric patients. However, infliximab therapy induces the appearance of neutralizing anti-infliximab antibodies. In the pediatric cohort, we analyzed (n=28) sensitization occurred in 35.7% patients and was associated with a loss of response to maintenance infusions. In two patients presenting high titers of anti-infliximab antibodies, severe infusion reactions were observed, possibly IgE-mediated, precluding further use of the medication. Serum concentrations of TNF-alpha and infliximab were influenced by the presence of anti-infliximab antibodies. We propose that surveillance of circulating infliximab and/or TNF-alpha concentration during maintenance therapy represents an indirect but reliable method to monitor anti-infliximab immunization.

New cytokine therapeutics for inflammatory bowel disease

Conventional therapy for inflammatory bowel diseases rely on corticosteroids and 5-aminosalicylates combined with immunosuppressive agents for maintenance. These drugs are not always effective and may inflict serious side effects. Other therapies are therefore awaited. Infliximab, a monoclonal antibody against the pro-inflammatory cytokine TNF-alpha has been successfully applied as a treatment for Crohn's disease. The mechanism of action of this drug extends beyond the level of TNF-alpha scavenging and includes induction of apoptosis of effector cells. Numerous anti-TNF antibodies have been developed and are currently evaluated in clinical trials. Other targets for monoclonal antibodies include integrins and cytokines involved in T-cell differentiation and activation. Likewise recombinant proteins that moderate TNF bioactivity and lymphocyte function have been developed. The therapeutic effect of recombinant interleukin-10 seems to be dependent on local delivery of the protein. Antisense therapy targeting lymphocyte migration has also been tested in IBD. Finally, the conventional drug thalidomide and possibly MAP-kinase inhibitors may become novel treatment entities for IBD.

TNF pathophysiology in murine models of chronic inflammation and autoimmunity

Experimental work in animal models is providing important clues on the specific function of tumor necrosis factor (TNF) and its receptors in disease, especially on the molecular and cellular pathways through which TNF mediates beneficial and deleterious responses. Emerging data on the posttranscriptional regulatory processes, secretion, and postreceptor actions of TNF indicate a variety of mechanisms that may be causative of disease. More recent evidence in murine disease models has indicated heterogeneity of TNF receptor usage in autoimmune disease suppression versus inflammatory tissue damage, suggesting that selective TNF receptor inhibition may be advantageous to anti-TNF treatments in combating chronic inflammatory disease.

Infliximab as rescue therapy in severe to moderately severe ulcerative colitis: a randomized, placebo-controlled study

BACKGROUND & AIMS

Despite treatment with corticosteroids, severe to moderately severe attacks of ulcerative colitis have a high colectomy rate. We intended to find a rescue therapy other than cyclosporin A, which imposes a high risk of side effects and cyclosporine-related mortality.

METHODS

This was a randomized double-blind trial of infliximab or placebo in severe to moderately severe ulcerative colitis not responding to conventional treatment. Patients were randomized to infliximab/placebo either on day 4 after the initiation of corticosteroid treatment if they fulfilled the index criteria for fulminant ulcerative colitis on day 3 or on day 6-8 if they fulfilled index criteria on day 5-7 for a severe or moderately severe acute attack of ulcerative colitis. Results were analyzed according to the intention-to-treat principle. The primary end point was colectomy or death 3 months after randomization. Secondary end points were clinical and endoscopic remission at that time in patients who did not undergo operation.

RESULTS

Forty-five patients were included (24 infliximab and 21 placebo). No patient died. Seven patients in the infliximab group and 14 in the placebo group had a colectomy (P = .017; odds ratio, 4.9; 95% confidence interval, 1.4-17) within 3 months after randomization. No serious side effects occurred. Three patients in the placebo group required operation for septic complications.

CONCLUSIONS

Infliximab 4-5 mg/kg is an effective and safe rescue therapy in patients experiencing an acute severe or moderately severe attack of ulcerative colitis not responding to conventional treatment.

Aggressive cutaneous T-cell lymphomas after TNFalpha blockade

Pharmacologic blockade of TNFalpha has been a highly effective approach to treating several immunologically mediated diseases, including rheumatoid arthritis, Crohn's disease, and psoriatic arthritis. 1,2,3 Both etanercept, the recombinant extracellular domain of the tumor necrosis factor receptor 2 (TNFR2), and infliximab, a humanized murine antibody, bind TNFalpha and block its interaction with cell surface receptors. Recently, it has become clear that blockade of TNFalpha action is profoundly immunosuppressive, and may result in reactivation of tuberculosis and histoplasmosis, as well as the emergence of B-cell lymphomas. 4,5,6 In this report, we describe two cases of cutaneous and systemic T-cell lymphoma that progressed rapidly in the setting of TNFalpha blockade. Both cases were characterized by rapid onset, a fulminant clinical course with extensive cutaneous and systemic involvement, and death within months of diagnosis.

Functional significance of gastrin gene expression in human cancer cells

The gastrointestinal peptide, gastrin, stimulates the growth of human pancreatic cancer. A receptor for gastrin activity, the cholecystokinin-C (CCK-C) receptor, has been identified in binding assays, cloned and sequenced, and is a splice variant of the CCK-B receptor. The relationship of gastrin and the CCK-C receptor to the growth of cancer cells was examined in vitro and in vivo. Stable transfection of the sense cDNA of gastrin into human MDA Amp-7 ampullary cancer cells, which normally lack gastrin gene expression but possess CCK-C receptors, increased cell growth up to 10-fold over wild type (WT) and vector-transfected (VT) cells. MDA Amp-7 tumors of gastrin-transfected cells reduced latency time for a visible tumor by 35%, decreased the timetable of tumor incidence, and increased tumor size by at least 2-fold in comparison to WT and VT groups. Transfection of human BxPC-3 pancreatic cancer cells, which normally express gastrin and possess CCK-C receptors, with the antisense cDNA to human gastrin decreased cell number by 30% in culture and tumor size by 53% compared to the WT and VT groups. Transfection of sense gastrin cDNA to monkey COS-1 cells, which normally lack both the gastrin and the CCK-C receptor genes, had no effect on growth. These studies demonstrate that gastrin and the CCK-C receptor form an autocrine loop in human pancreatic cancer that plays a role in regulating growth.

Emerging fungal diseases: the importance of the host

More yeasts and molds are now recognized to cause more human disease than ever before. This development is not due to a change in the virulence of these fungi, but rather to changes in the human host. These changes include immunosuppression secondary to the pandemic of HIV, the use of life-saving advances in chemotherapy and organ transplantation, and the use of corticosteroids and other immunosuppressive agents to treat a variety of diseases. Fungi that were once considered common saprophytes are now recognized as potential pathogens in these patients. This situation necessitates better communication than ever between the clinician, pathologist, and clinical mycologist to ensure the prompt and accurate determination of the cause of fungal diseases.

Treatment of fistulizing Crohn's disease

The primary goals of the clinician in the treatment of fistulizing Crohn's disease (CD) include (1) defining the anatomy of the fistula, (2) draining any associated infectious material, (3) eradicating the fistulous tract through medical or surgical therapies, and (4) preventing recurrence of fistulas. Evaluation and therapeutic decisions require close collaboration between the gastroenterologist and surgeon. Appropriate evaluation should include identification of septic complications, delineation of the fistulous tract including the origin and terminus of the fistula, and determination of the extent of bowel involvement with active CD. Drainage of abscesses and control of septic complications through the placement of drains or setons is essential. Conservative therapy with avoidance of sphincter muscle-cutting procedures is the standard approach. The appropriate approach to asymptomatic patients is uncertain because there are little data to indicate if treatment alters the natural course of disease.

Crohn's-associated chronic recurrent multifocal osteomyelitis responsive to infliximab

We report a case of chronic recurrent clavicular osteomyelitis in association with Crohn disease. Steroid therapy resulted in partial remission; however, intractable shoulder pain and an enlarging clavicular mass subsequently recurred. Infliximab therapy resulted in significant improvement in the degree of bone pain and resolution of the large sclerotic clavicular lesion.

A novel targeted T-cell modulator, efalizumab, for plaque psoriasis

BACKGROUND

Interactions between leukocyte-function-associated antigen type 1 (LFA-1) and intercellular adhesion molecules are important in the pathogenesis of psoriasis. Efalizumab, a humanized monoclonal antibody, binds to the alpha subunit (CD11a) of LFA-1 and inhibits the activation of T cells.

METHODS

In a phase 3, multicenter, randomized, placebo-controlled, double-blind study, we assign 597 subjects with psoriasis to receive subcutaneous efalizumab (1 or 2 mg per kilogram of body weight per week) or placebo for 12 weeks. Depending on the response after 12 weeks, subjects received an additional 12 weeks of treatment with efalizumab or placebo. Study treatments were discontinued at week 24, and subjects were followed for an additional 12 weeks.

RESULTS

At week 12, there was an improvement of 75 percent or more in the psoriasis area-and-severity index in 22 percent of the subjects who had received 1 mg of efalizumab per kilogram per week and 28 percent of those who had received 2 mg of efalizumab per kilogram per week, as compared with 5 percent of the subjects in the placebo group (P<0.001 for both comparisons). Efalizumab-treated subjects had greater improvement than those in the placebo group as early as week 4 (P<0.001). Among the efalizumab-treated subjects who had an improvement of 75 percent or more at week 12, improvement was maintained through week 24 in 77 percent of those who continued to receive efalizumab, as compared with 20 percent of those who were switched to placebo (P<0.001 for both comparisons). After the discontinuation of efalizumab at week 24, an improvement of 50 percent or more in the psoriasis area-and-severity index was maintained in approximately 30 percent of subjects during the 12 weeks of follow-up. Efalizumab was well tolerated, and adverse events were generally mild to moderate.

CONCLUSIONS

Efalizumab therapy resulted in significant improvements in plaque psoriasis in subjects with moderate-to-severe disease. Extending treatment from 12 to 24 weeks resulted in both maintenance and improvement of responses.

Biologic therapies in the spondyloarthritis: new opportunities, new challenges

Therapeutic options for patients suffering from the more severe forms of spondyloarthritis have been rather limited in the last decades. There is now accumulating evidence that antitumor necrosis factor therapy is highly effective in spondyloarthritis, especially in ankylosing spondylitis and psoriatic arthritis. Based on the data recently published on more than 500 patients with ankylosing spondylitis and psoriatic arthritis, this treatment seems to be even more effective than in rheumatoid arthritis. The antitumor necrosis factor-alpha agents currently available, infliximab (Remicade), etanercept (Enbrel), and adalimumab (Humira), are approved for the treatment of rheumatoid arthritis in the United States and partly in Europe. The situation in spondyloarthritis is different from that of rheumatoid arthritis because there is an unmet medical need, especially in ankylosing spondylitis: no therapies with disease-modifying antirheumatic drugs are available for severely affected patients, especially with spinal disease. Thus, tumor necrosis factor blockers may even be considered a first-line treatment in a patient with active ankylosing spondylitis and psoriatic arthritis whose condition is not sufficiently controlled with nonsteroidal antiinflammatory drugs in the case of axial disease, and sulfasalazine or methotrexate in the case of peripheral arthritis. For infliximab, a dose of 5 mg/kg was required, and intervals between 6 and 12 weeks were necessary to suppress disease activity constantly-also a major aim for long-term treatment. The standard dosage of etanercept is 2 x 25 mg subcutaneously per week. There are no studies yet on adalimumab (standard rheumatoid arthritis dose, 20-40 mg subcutaneously every 1-2 weeks) in spondyloarthritis. Infliximab was very recently approved for AS in Europe. The efficacy of etanercept was first demonstrated in psoriatic arthritis, and it is now approved for this indication. A double-blind study has also been performed in ankylosing spondylitis, with similarly clear efficacy. There is preliminary evidence that both agents do also work in other spondyloarthritis, such as undifferentiated spondyloarthritis. Ideally, both agents will be approved soon for the short-term treatment of severe, uncontrolled spondyloarthritis. In parallel, studies should be performed to document the long-term efficacy of this treatment. There is hope that ankylosis may be preventable, but it remains to be shown whether patients benefit from long-term antitumor necrosis factor therapy and whether radiologic progression and ankylosis can be stopped. Severe adverse events have remained rare. Complicated infections including tuberculosis have been reported. These can be largely prevented by appropriate screening. At it stands now, the benefits of antitumor necrosis factor therapy in ankylosing spondylitis seem to outweigh these shortcomings.

Infliximab but not etanercept induces apoptosis in lamina propria T-lymphocytes from patients with Crohn's disease

BACKGROUND & AIMS

Steroid-refractory Crohn's disease responds to therapy with the chimeric anti-tumor necrosis factor (TNF)-alpha antibody infliximab. Etanercept, a recombinant TNF receptor/immunoglobulin G fusion protein, is highly effective in rheumatoid arthritis but not in Crohn's disease. Because both infliximab and etanercept are TNF-alpha-neutralizing drugs, we investigated the differences in TNF-alpha-neutralizing capacity and human lymphocyte binding and apoptosis-inducing capacity of both molecules.

METHODS

We used a nuclear factor kappaB reporter assay and a cytotoxicity bioassay to study TNF-alpha neutralization by infliximab and etanercept. Lymphocyte binding and apoptosis-inducing capacity was investigated using fluorescence-activated cell sorter analysis, annexin V staining, and cleaved caspase-3 immunoblotting using mixed lymphocyte reaction-stimulated peripheral blood lymphocytes (PBL) from healthy volunteers and lamina propria T cells from patients with Crohn's disease.

RESULTS

Both infliximab and etanercept neutralized TNF-alpha effectively. Infliximab bound to activated PBL and lamina propria T cells, whereas binding of etanercept was equal to a nonspecific control antibody. Infliximab but not etanercept induced peripheral and lamina propria lymphocyte apoptosis when compared with a control antibody. Infliximab activated caspase 3 in a time-dependent manner, whereas etanercept did not.

CONCLUSIONS

Although both infliximab and etanercept showed powerful TNF-alpha neutralization, only infliximab was able to bind to PBL and lamina propria T cells and subsequently to induce apoptosis of activated lymphocytes. These data may provide a biological basis for the difference in efficacy of the 2 TNF-alpha-neutralizing drugs.

Development of antinuclear antibodies and its clinical impact in patients with Crohn's disease treated with chimeric monoclonal anti-TNFalpha antibodies (infliximab)

BACKGROUND

Although the efficacy of infliximab in Crohn's disease (CD) has been demonstrated, its safety profile has yet to be established. Autoimmune adverse events such as human anti-chimeric antibodies and the development of antinuclear antibodies (ANAs) have been notified, but the true incidence and clinical relevance of the latter is still unknown.

OBJECTIVE

To evaluate the changes in ANA status in CD patients treated with infliximab and the clinical evolution of those who are ANA positive.

METHODS

The ANA status of 36 CD patients treated with infliximab was determined at baseline and 6 weeks after the initial infliximab infusion. Patients were followed up monthly. In the case of infliximab re-treatment, ANA status was again evaluated. Twenty-eight patients (78%) were treated concomitantly with immunosuppressants.

RESULTS

Eight patients (22%) were ANA positive at baseline; none developed anti-double-stranded DNA antibodies (aDNAds) at week 6. Three of them were re-treated: there were increasing ANA titres in all cases and developing aDNAds in two. Only six of 28 patients who were ANA negative at baseline changed their ANA status at week 6, but none developed aDNAds. One of them was retreated showing a further increase in ANA titre and developing aDNAds at high titre. No patient presented lupus-like syndrome.

CONCLUSIONS

Only a few CD patients treated with infliximab and immunosuppressants develop ANAs. This condition is not associated with aDNAds and/or lupus-like syndrome in the majority of cases.

Role of TNF/TNFR in autoimmunity: specific TNF receptor blockade may be advantageous to anti-TNF treatments

Deregulated TNF production, be it low or high, characterizes many autoimmune diseases. Recent evidence supports a dualistic, pro-inflammatory and immune- or disease-suppressive role for TNF in these conditions. Blocking TNF in autoimmune-prone chronic inflammatory diseases may, therefore, lead to unpredictable outcomes, depending on timing and duration of treatment. Indeed, blockade of TNF in human rheumatoid arthritis or inflammatory bowel disease patients, although so far impressively beneficial for the majority of patients, it has also led to a significant incidence of drug induced anti-dsDNA production or even in manifestations of lupus and neuro-inflammatory disease. Notably, anti-TNF treatment of multiple sclerosis patients has led almost exclusively to immune activation and disease exacerbation. We discuss here recent evidence in murine disease models, indicating an heterogeneity of TNF receptor usage in autoimmune suppression versus inflammatory tissue damage, and put forward a rationale for a predictably beneficial effect of 'anti-TNFR' instead of 'anti-TNF' treatment in human chronic inflammatory and autoimmune conditions.

Medical treatment of Crohn's disease

Crohn's disease is not medically (and is rarely surgically) curable. Patients do, however, live a normal life span. The goal of therapy is to optimize the quality of life, minimize disease activity and disease-related complications, and avoid therapeutic toxicity.

Biological and novel therapies for inflammatory bowel disease in children

During the past decade, a tremendous wealth of information regarding the pathogenesis, genetics, and therapy of IBD has been discovered. Judging by the number of new publications published every month in scientific journals and the great enthusiasm at scientific meetings, this outstanding pace surely will continue. In the near future, clinicians may be able to classify IBD into several subtypes depending on patients' cytokine and gene profiles. For example, two groups of researchers recently have identified mutation in the NOD2 gene, which is associated with susceptibility to CD. This identification may allow the clinician to better predict outcome and response to medical therapy. At the same time, several promising new therapies are being investigated. Technologic advances will continue to result in the development of potent and specific agents that will control and possibly correct the abnormal inflammatory processes responsible for pediatric IBD.

Targeting tumor necrosis factor alpha. New drugs used to modulate inflammatory diseases

Since its discovery, the understanding of the roles for TNF-alpha in human biology and disease has grown. Receptors for TNF are found on virtually all cell types, and many physiologic processes seem to be altered by TNF-alpha. The understanding of how TNF-alpha is involved in the pathophysiology of diseases, such as inflammatory diseases, has allowed the development of new drugs that can interfere with excess TNF-alpha and thus has allowed novel therapies for rheumatoid arthritis and Crohn's disease. As the role of TNF-alpha in other diseases becomes better understood, such TNF-alpha-modulating drugs may find further applications. In the skin, TNF-alpha is prominent cytokine that seems to be important in allergic and irritant contact dermatitis and inflammatory skin conditions. Modulating TNF-alpha activity in the skin may provide therapeutic benefits for a variety of skin conditions (Table 4). Tumor necrosis factor-alpha levels are elevated in skin lesions of psoriasis. A few reports have already suggested that etanercept and infliximab may offer a therapeutic effect in patients with psoriasis. Clinical studies evaluating the true efficacy of these drugs in psoriasis are under way. Specifically, the authors and others are involved in a double-blind, placebo-controlled study to assess the efficacy of etanercept for psoriasis. Thalidomide has been used off-label with some success to treat a number of dermatologic diseases, including several inflammatory skin conditions. Etanercept and infliximab might perhaps prove efficacious for inflammatory skin conditions as well. Finally, it is possible that drugs targeting TNF-alpha may have yet-unrecognized serious side effects. Because TNF-alpha seems to be a central cytokine in UVR-induced apoptosis, the chronic use of TNF-alpha-altering drugs might increase the risk for skin cancers. Tumor necrosis factor-alpha also plays some role in cutaneous wound healing; the effect these drugs might have on this process is also unknown at this time. Certainly, much is already [table: see text] known about TNF-alpha and how it plays many central roles. This understanding has allowed the development of useful new drugs for intractable disease. As the understanding of TNF-alpha and other cytokine biology increases, so will the number of potential therapeutic agents.

Human antibodies as next generation therapeutics

Antibodies and antibody derivatives constitute twenty five percent of therapeutics currently in development, and a number of therapeutic monoclonal antibodies have recently reached the market. All antibodies approved by the US Food and Drug Administration, however, contain mouse protein sequences. These partially murine antibodies, therefore, have the potential to elicit allergic or other complications when used in human patients. Recent developments aim to reduce or eliminate murine components, and fully human antibodies are rapidly becoming the norm. A number of technologies exist which enable the development of 100% human antibodies.

New treatment options in spondyloarthropathies: increasing evidence for significant efficacy of anti-tumor necrosis factor therapy

Tumor necrosis factor-alpha is a major effector and regulatory cytokine, which seems to have an outstanding position in rheumatic and other inflammatory states. Because TNF-alpha has been detected in the inflamed gut and sacroiliac joints of patients with chronic inflammatory bowel diseases and spondyloarthritides, like ankylosing spondylitis, there was need for studies of the efficacy of the modern biologic anti-TNF agents infliximab and etanercept in these diseases. Infliximab is approved for the treatment of Crohn disease. In addition, there are now also positive data for infliximab in the treatment of ankylosing spondylitis and for etanercept and infliximab in the treatment of psoriatic arthritis.

Evolving treatment strategies for inflammatory bowel disease

Crohn's disease and ulcerative colitis are idiopathic inflammatory bowel diseases characterized by dysregulated intestinal immune responses in genetically susceptible hosts. Conventional approaches to the medical therapy of ulcerative colitis and Crohn's disease can now be directed at either induction or maintenance of remission to improve therapeutic efficacy while minimizing complications. Newer approaches have expanded the utility of conventional therapies by improving both safety and efficacy and highlight the importance of specific targets along the immunoinflammatory pathways. The combination of conventional and novel approaches now offers the potential of modifying the natural history of these diseases.

Medical therapy for Crohn's disease: the state of the art

Various medications are used to control the symptoms of Crohn's disease. This article reviews the traditional medical therapies of Crohn's disease, including aminosalicylates and corticosteroids, and the broad armamentarium of immune modulators and biologic agents that are becoming increasingly important in the management of Crohn's disease.

Pediatric Inflammatory Bowel Disease

The combination of an unprecedented number of new therapeutic options (Fig. 1), along with new insights in how to optimize currently available therapies and advances in our understanding of disease pathogenesis, present many exciting new aspects to the management of patients with inflammatory bowel disease (IBD). Clinical management paradigms must evolve in parallel to keep pace with these advances. Traditional pediatric IBD regimens have underutilized combination therapies (Fig. 2) and immunomodulatory agents. Increased appreciation for steroid side effects is leading to a shift away from their inclusion in maintenance regimens. Immunomodulators are being introduced earlier in the course of disease for maintenance of remission and growth promotion. Recognition that the sole signs of active disease in children and adolescents may be growth and maturational delay, despite a relative lack of gastrointestinal symptoms, should prompt earlier, more aggressive interventions. When more potent, rapidly acting interventions such as infliximab, cyclosporine (CSA), or tacrolimus are considered, they should generally be co-administered with agents such as 6-mercaptopurine (6-MP) or azathioprine (AZA) for longer-term disease suppression.

Advances in inflammatory bowel disease

Optimal management of patients with IBD requires a multidisciplinary approach involving primary care physicians, gastroenterologists, surgeons, radiologists, and nutritionists. The rapidly evolving medical armamentarium promises better quality of life for patients afflicted with these complex, chronic diseases. It is expected that future development of biologic agents will add to the therapeutic options, although it may complicate treatment algorithms. Surgical advancements, particularly in ileoanal anastomosis and bowel preservation by strictureplasty, have improved outcome dramatically. The focus on development of new therapies and refinement of older ones demands a constant attention to the latest peer-reviewed literature and that the clinician keep abreast of the various advancements that have been summarized here.

An immunoadsorption strategy to produce specific antisera against analogs of human proteins: development of sensitive and specific radioimmunoassays for two analogs of human leptin

Immunoassay technology is routinely used to measure concentrations of proteins and polypeptides in biological matrices. Increasingly, research efforts have sought to create analogs of human proteins with the aim of improving efficacy or pharmaceutical properties relative to the native protein. Pharmacokinetic assessment of these polypeptide analogs, however, can be greatly confounded by the presence of endogenous native protein. This report describes an immunization and immunoabsorption strategy that was used to create monospecific polyclonal antibodies against analogs of human leptin (LY355101 and LY396623, one and two amino acid changes relative to native human leptin, respectively). Rabbits were immunized with either LY355101 or LY396623. Antisera were screened to determine if any showed increased specificity for the analog relative to native human leptin. Antisera showing increased specificity for the leptin analog were then treated by immunoabsorption against native human leptin, thus depleting human leptin cross-reactivity. The antibodies developed in this process were used in radioimmunoassays. which were validated for use in clinical studies. Both assays proved to be highly specific for LY355101 or LY396623 in the presence of native human leptin. Use of this procedure permitted the measurement of LY355101 and LY396623 pharmacokinetics that were not confounded by the high levels of endogenous human leptin found in obese subjects. This technique has the potential for broad application in the development of assays capable of specifically measuring protein analogs without cross-reactivity to an endogenous substance.

Complement inhibitors: a resurgent concept in anti-inflammatory therapeutics

In addition to its essential role in immune defense, the complement system contributes to tissue damage in many clinical conditions. Thus, there is a pressing need to develop therapeutically effective complement inhibitors to prevent these adverse effects. This concept, though old, received little scientific attention until recently. Data from animal models of diseases that have been produced using complement-deficient, knockout, and transgenic animals, as well as data demonstrating that complement proteins are produced in many important tissue sites (including the brain) have attracted the interest of many basic research scientists and applied scientists from the biotechnology field and larger pharmaceutical firms. This resurgence of interest has generated a wealth of new information in the field of complement inhibition. In this article, we comprehensively review up-to-date information in the field of complement inhibitors.

Clinical trials of antibody therapy

Much of the 25 years since Kohler and Milstein first described making monoclonal antibodies (mAbs) has been spent trying to develop these reagents to treat human disease. Until recently, progress has been frustratingly slow and by 1994 only one mAb, anti-CD3 (OKT3), had been licensed for clinical use. In the past five years, however, the situation has changed dramatically, with numerous mAbs now showing clinical potential, and a further seven approved for human treatment. Furthermore, all indications are that this upward trend will continue, with a quarter of all new biological products currently undergoing clinical development being antibody based.

Humanization of a mouse monoclonal antibody neutralizing TNF-alpha by guided selection

With the advent of phage display antibody libraries, humanization of murine antibodies can be achieved by epitope guided selection. In present study, guided selection was applied to the humanization of the mouse mAb Z8 that is directed to human TNF-alpha and can neutralize the cytotoxicity of TNF-alpha. First, the Z8 Fd gene was paired as a template with a repertoire of human kappa chains, and displayed on the filamentous phage, forming a hybrid phage antibody library. Selected by four rounds of panning against TNF-alpha, hybrid antibody fragments that bound to TNF-alpha and contained human kappa chains were obtained. Meanwhile human Fd genes were selected by pairing the human Fd repertoire with the Z8 kappa chain and performing the same procedure of panning. One of the isolated human Fd genes (huFd2), which showed the strongest reactivity, was chosen to pair with 12 of selected human kappa chains. Two of the resulting human Fabs (huFd2-hukappa1 and huFd2-hukappa2), with same Fd and different kappa chains, bound to TNF-alpha specifically. Their human origin was proved by ELISA and sequencing analysis. The human Fabs competitive ELISA and in vitro TNF-alpha neutralization assay demonstrated that the human Fabs resembled its parental mouse mAb Z8 in that they both recognized the same epitope and neutralized the cytotoxicity of TNF-alpha. These results suggest that guided selection is a promising strategy in murine mAb humanization.

Therapy for Crohn disease

Medical therapy for Crohn disease has advanced incrementally: Small, non-definitive controlled trials of mesalamine continue to be reported, but the results are not sufficient to change the conclusion of a large meta-analysis that shows only marginal benefit of mesalamine in Crohn disease. Low-dose, controlled ileal-release budesonide is not effective for preventing postoperative recurrence of Crohn disease. A loading dose of intravenous azathioprine does not accelerate the time to response in patients with steroid-treated Crohn disease; however, standard azathioprine may work more quickly than previously reported. Mycophenolate mofetil may be therapeutically equivalent to azathioprine for active Crohn disease. There is a trend toward benefit of oral methotrexate (15 mg/wk) for active Crohn disease, and there is no significant difference in the blood concentrations of methotrexate in patients with inflammatory bowel disease who receive methotrexate (15 or 25 mg weekly) administered subcutaneously. Results in a pilot study suggest that tacrolimus may close perianal fistulas in patients with Crohn disease. The anti-tumor necrosis factor antibody infliximab is effective in closing perianal and enterocutaneous fistulas and in maintaining remission in patients with Crohn disease. Infliximab also leads to endoscopic and histologic remission. There is a trend toward benefit of subcutaneous recombinant interleukin-11 for active Crohn disease. Two pilot studies have shown that thalidomide may be of benefit in patients with refractory Crohn disease.

A preliminary study of growth hormone therapy for Crohn's disease

BACKGROUND

Crohn's disease is a chronic inflammatory disorder of the bowel. In a preliminary study, we evaluated whether the administration of growth hormone (somatropin) as well as a high-protein diet would ameliorate the symptoms of the disease.

METHODS

We randomly assigned 37 adults with moderate-to-severe active Crohn's disease to four months of self-administered injections of growth hormone (loading dose, 5 mg per day subcutaneously for one week, followed by a maintenance dose of 1.5 mg per day) or placebo. We instructed all patients to increase their protein intake to at least 2 g per kilogram of body weight per day. Patients continued to be treated by their usual physicians and to receive other medications for Crohn's disease. The primary end point was the change in scores on the Crohn's Disease Activity Index from base line to month 4. Scores can range from 0 to 600, with higher scores indicating more disease activity.

RESULTS

At base line, the mean (+/-SD) score on the Crohn's Disease Activity Index was somewhat higher among the 19 patients in the growth hormone group than among the 18 patients in the placebo group (287+/-134 vs. 213+/-120, P=0.09). Three patients in the placebo group withdrew before their first follow-up visit and were not included in the data analysis. At four months, the Crohn's Disease Activity Index score had decreased by a mean of 143+/-144 points in the growth hormone group, as compared with a decrease of 19+/-63 points in the placebo group (P=0.004). Side effects in the growth hormone group included edema (in 10 patients) and headache (in 5) and usually resolved within the first month of treatment.

CONCLUSIONS

Our preliminary study suggests that growth hormone may be a beneficial treatment for patients with Crohn's disease.