Management of diarrhea induced by epidermal growth factor receptor tyrosine kinase inhibitors.

Treatment for non-small-cell lung cancer (nsclc) is moving away from traditional chemotherapy toward personalized medicine. The reversible tyrosine kinase inhibitors (tkis) erlotinib and gefitinib were developed to target the epidermal growth factor receptor (egfr). Afatinib, an irreversible ErbB family blocker, was developed to block egfr (ErbB1), human epidermal growth factor receptor 2 (ErbB2), and ErbB4 signalling, and transphosphorylation of ErbB3. All of the foregoing agents are efficacious in treating nsclc, and their adverse event profile is different from that of chemotherapy. Two of the most common adverse events with egfr tkis are rash and diarrhea. Here, we focus on diarrhea. The key to successful management of diarrhea is to treat early and aggressively using patient education, diet, and antidiarrheal medications such as loperamide. We also present strategies for the effective assessment and management of egfr tki-induced diarrhea.

Canadian Association of Gastroenterology Clinical Practice Guidelines: The use of tumour necrosis factor-alpha antagonist therapy in Crohn's disease.

BACKGROUND: Guidelines regarding the use of infliximab in Crohn's disease were previously published by the Canadian Association of Gastroenterology in 2004. However, recent clinical findings and drug developments warrant a review and update of these guidelines. OBJECTIVE: To review and update Canadian guidelines regarding the use of tumour necrosis factor-alpha antibody therapy in both luminal and fistulizing Crohn's disease. METHODS: A consensus group of 25 voting participants developed a series of recommendation statements that addressed pertinent clinical questions and gaps in existing knowledge. An iterative voting and feedback process was used in advance of the consensus meeting in conjunction with a systematic literature review to refine the voting statements. These statements were brought to a formal consensus meeting held in Montreal, Quebec (March 2008), wherein each statement underwent discussion, reformulation, voting and subsequent revision until group consensus was obtained (at least 80% agreement). OUTCOME: The 47 voting statements addressed three themes: induction therapy, maintenance therapy and safety issues. As a result of the iterative process, 23 statements achieved consensus and were submitted for publication. CONCLUSION: In the past five years, tumour necrosis factor-alpha antagonist therapy has become a cornerstone in the management of moderate-to-severe Crohn's disease refractory to conventional treatment algorithms. The evidentiary base supporting the use of these drugs in Crohn's disease is substantial and strengthened by results from longterm clinical and molecular studies. However, significant gaps in knowledge exist, particularly with regard to treatment failure. Confidence in the safety of these drugs is increasing, provided that therapy is administered in a clinical setting in which potential complications can be readily recognized and treated.

Nod2 influences microbial resilience and susceptibility to colitis following antibiotic exposure.

Inflammatory bowel disease (IBD) etiology involves genetic susceptibility, environmental triggers, and the gut microbiome. Antibiotic exposure is associated with IBD, both in early life and adulthood. Here, we investigated whether Nod2-deficiency influenced response of the gut microbiota to antibiotics and subsequent colitis susceptibility. Wild-type and Nod2-/- littermate mice were treated with amoxicillin as adults or neonates, and fecal samples were collected for 16S rRNA sequencing. Five weeks after antibiotic exposure, dextran sulfate sodium (DSS) colitis was induced. Antibiotic treatment altered the microbiota of adult WT and Nod2-/- mice, but recovery was delayed in Nod2-/- mice. Neonatal antibiotic treatment significantly changed the microbiota at weaning in WT and Nod2-/- littermates; however, Nod2-/- mice maintained reduced microbial diversity 14 days after cessation of antibiotics. Although treatment of adult mice did not influence susceptibility to colitis, neonatally treated Nod2-/- mice developed a more severe colitis. Moreover, the colitis phenotype was transferable through fecal transplantation into germ-free Nod2-/- recipients, and was associated with changes in intestinal T cells and the cytokine milieu following inflammation. These data demonstrate that neonatal antibiotic exposure has long-lasting influence on the microbiota and mucosal immunity, and may explain how NOD2 contributes to the risk of intestinal inflammation.

Review and clinical perspectives for the use of infliximab in ulcerative colitis.

Infliximab is a chimeric, monoclonal anti-tumour necrosis factor-alpha antibody. It has been previously demonstrated to be an effective treatment for patients with Crohn's disease who do not achieve the desired response with conventional treatments. Although the etiology of ulcerative colitis (UC) differs from that of Crohn's disease, randomized controlled trials have demonstrated that infliximab is also beneficial for the treatment of moderate to severe UC in patients who are either intolerant of or refractory to immunosuppressant agents or steroids, or those who are steroid-dependent. A review of the literature is followed by practical recommendations regarding infliximab that address the needs of clinicians and UC patients. Where there is a lack of evidence-based information, the expert panel provides its combined opinion derived from the members' clinical experiences.

CD40 expression by human peripheral blood eosinophils.

In this study, we have investigated CD40 expression in human peripheral blood eosinophils and in human chronically inflamed nasal tissues, i.e., nasal polyps. We show by both reverse transcriptase-PCR and Northern blot analysis that eosinophils from allergic subjects express human CD40 mRNA. We also show that constitutive CD40 mRNA expression in eosinophils could be upregulated by exposure to IgA immune complexes and downregulated by IL-10 and the synthetic steroid budesonide. In addition, we demonstrate that eosinophils express CD40 protein by flow cytometry. Such expression is biologically functional as cross-linking CD40 with CD40 mAbs enhances eosinophil survival in a dose-dependent fashion; in addition, CD40 ligation stimulates eosinophils to release GM-CSF. CD40-mediated eosinophil survival was largely inhibited by an anti-GM-CSF neutralizing antibody suggesting GM-CSF involvement in the survival enhancing mechanism. CD40 mRNA was also detected in total RNA extracted from nasal polyp tissues but not in RNA isolated from normal nasal mucosa (inferior turbinate); by immunohistochemistry, we were able to detect immunoreactive CD40 protein in a variety of cell types in the polyp stroma, but primarily in eosinophils. These observations suggest previously unforeseen interactions between eosinophils and cells expressing the CD40 ligand and, thus, novel pathways by which eosinophils may contribute to the regulation of airway inflammation.

Induction versus noninduction antiviral therapy for chronic hepatitis C virus in patients with congenital coagulation disorders: a Canadian multicentre trial.

BACKGROUND: Patients with congenital coagulation disorders and chronic hepatitis C virus (HCV) infection have multiple risk factors (ie, infection predominantly with genotype-1 HCV, long duration of the disease, HIV coinfection and male sex) for poor response to antiviral therapy. The present study compared induction therapy with interferon-alpha (IFN-alpha)-2b with standard IFN-alpha2b therapy. Pegylated IFN was not available at the time that the study was initiated. PATIENTS AND METHODS: A randomized study was performed comparing the efficacy of traditional IFN-alpha2b therapy (group A -- three million units, three times weekly for 24 to 48 weeks) and daily ribavirin (1.0 g to 1.2 g according to weight for 24 to 48 weeks), with induction IFN-alpha2b therapy (group B -- three million units, daily for eight weeks followed by the same dose administered three times a week for a further 16 to 40 weeks) and daily ribavirin (same dose as above) in IFN-naive patients with congenital coagulation disorders and chronic HCV infection. RESULTS: Between 2000 and 2003, 54 HIV-negative patients were recruited and randomly assigned to group A or B (n=27 each). Both groups were comparable in terms of age, sex, ethnicity, body mass index, baseline HCV RNA titre, viral genotype, liver fibrosis stage and type of coagulation disorder. Induction therapy did not significantly alter sustained virological response rates (group A 50%, group B 50%; P=1.0). Multiple logistic regression analysis indicated that induction therapy did not benefit individuals with difficult-to-treat infection (ie, those infected with genotypes 1 and 4, or those with high baseline viral loads). CONCLUSIONS: There was no benefit with induction antiviral therapy for HCV infection in individuals with congenital coagulation disorders.

Higher Adalimumab Drug Levels are Associated with Mucosal Healing in Patients with Crohn's Disease.

BACKGROUND AND AIMS: The current approach to managing the loss of response to anti-tumour necrosis factor (TNF) agents is generally empirical. Prior studies have suggested that adalimumab levels of >4.9 µg/mL are required to achieve clinical remission. Our aim was to identify an optimal adalimumab level to achieve endoscopic healing in Crohn's disease (CD). METHODS: A cohort of 60 CD patients treated with adalimumab between 2005 and 2013 were reviewed for the study. Demographic and clinical information was obtained from chart review and patient interview. Disease activity was determined using the Harvey-Bradshaw index (HBI), ileocolonoscopy reports and C-reactive protein (CRP) levels. Clinical remission was defined as HBI <5. Endoscopic remission/mucosal healing (MH) was defined as the absence of any ulceration in all ileocolonic segments. Trough adalimumab levels and adalimumab antibody levels were tested using a liquid-phase mobility shift assay. RESULTS: Lower median CRP was significantly associated with MH 1.2mg/dl vs no MH 14.4mg/dl (p = 6.93×10(-6)). Higher adalimumab trough level was significantly associated with MH (median 14.7 µg/mL in those with MH vs 3.4 µg/mL in those without, p = 6.25×10(-5)). Higher adalimumab trough level was also significantly associated with the combined outcome of clinical and endoscopic remission (median 13.0 vs 4.8 µg/mL, p = 5.36×10(-3)). A cut-off of 8.14 µg/ml best discriminated subjects with MH from those without MH, with sensitivity and specificity of 91.4 and 76.0%, respectively (positive and negative predictive values 84.2 and 86.4%, respectively). CONCLUSIONS: Higher adalimumab levels were significantly associated with MH. This study suggests that attaining MH alone or a combined outcome of clinical and endoscopic remission is more likely to occur in those patients who achieve an adalimumab trough level of at least 8.14 µg/mL.

MHC class I-mediated antigen presentation and induction of CD8+ cytotoxic T-cell responses in autoimmune diabetes-prone NOD mice.

The common class I alleles (e.g., Kd and Db) within the H2g7 major histocompatibility complex (MHC) clearly contribute to autoimmune IDDM in NOD mice, but the mechanism by which this occurs has been controversial. One laboratory has reported that the peptide transporter encoded by the Tap1 gene within H2g7 is defective, and this contributes to IDDM by impairing MHC class I-mediated antigen presentation. If true, defective MHC class I-mediated antigen presentation should segregate with the H2g7 haplotype. NOD mice, related congenic stocks, and other control strains were used to test this hypothesis. H2g7-positive strains did not differ from those expressing other MHC haplotypes in ability to present MHC class I-restricted H3aa or H3ab minor histocompatibility (H) antigens to cytotoxic T-lymphocytes (CTL). The H2g7 haplotype was found to have a reduced capacity to mediate MHC class I-restricted presentation of the H47a minor H antigen. However, MHC class I-restricted presentation of H47a was found to be Tap independent. NOD mice and control strains also did not differ in ability to activate adenovirus-specific MHC class I restricted CTL. Thus, the H2g7 haplotype is not characterized by a Tap gene defect that only impairs the inductive phase of the immune response. In addition, MHC class I-restricted presentation of either minor H or adenoviral antigens was equivalent in male and female NOD mice. Therefore, while the class I alleles of the H2g7 haplotype exert diabetogenic functions in NOD mice, this is not elicited through a Tap gene defect. The absence of female-specific Tap gene defects also indicates this cannot account for the reduced male incidence of IDDM in some NOD mouse colonies.

Immunomodulation of helicobacter infection.

Helicobacter pylori leads to a chronic infection in humans that is associated with gastric inflammation and a vigorous immune response. Despite the humoral and cellular responses that can be detected in both human and animal models of helicobacter infection, the immune response fails to eliminate the organism. Eradication failure may be due to the niche in which H pylori confines itself, well away from direct contact with elements of the immune system. Alternatively, the general tendency of the intestinal immune response to down- regulate reactivity to noninvasive luminal bacteria also may contribute to the failure to eliminate helicobacter infection. Results of vaccine studies in mouse models indicate that modulating the helper T cell response from a T helper cell type 1 to a T helper cell type 2 response likely is required for the prevention and elimination of helicobacter infection. Understanding the mechanisms by which the immune response controls bacterial infections will allow for the design of novel strategies of immune modulation and the development of vaccines for both the treatment and prevention of H pylori.

Characterisation of complementary and alternative medicine use and its impact on medication adherence in inflammatory bowel disease.

BACKGROUND: Complementary and alternative medicine (CAM) use among inflammatory bowel disease (IBD) patients is common. We characterised CAM utilisation and assessed its impact on medical adherence in the IBD population. AIM: To characterise CAM utilisation and assess its impact on medical adherence in the IBD population. METHODS: Inflammatory bowel disease patients recruited from an out-patient clinic at a tertiary centre were asked to complete a questionnaire on CAM utilisation, conventional IBD therapy, demographics and communication with their gastroenterologist. Adherence was measured using the self-reported Morisky scale. Demographics, clinical characteristics and self-reported adherence among CAM and non-CAM users were compared. RESULTS: We recruited prospectively 380 IBD subjects (57% Crohn's disease; 35% ulcerative colitis, and 8% indeterminate colitis). The prevalence of CAM use was 56% and did not significantly vary by type of IBD. The most common reason cited for using CAM was ineffectiveness of conventional IBD therapy (40%). The most popular form of CAM was probiotics (53%). CAM users were younger than non-CAM users at diagnosis (21.2 vs. 26.2, P < 0.0001) and more likely than non-CAM users to have a University-level education or higher (75% vs. 62% P = 0.006). There was no overall difference in adherence between CAM and non-CAM users (Morisky score: 1.0 vs. 0.9, P = 0.26). CONCLUSIONS: The use of complementary and alternative medicine is widely prevalent among IBD patients, and is more frequent among those with experience of adverse effects of conventional medications. From this cross-sectional analysis, complementary and alternative medicine use does not appear to be associated with reduced overall adherence to medical therapy.

Infections in the immunopathogenesis of chronic inflammatory bowel disease.

In chronic inflammatory bowel disease, self-destructive, exaggerated inflammation seems to occur in the absence of a well defined pathogen. However, epidemiological data strongly suggests that development of disease does not depend on endogenous factors alone. In this review, we summarize how a possible role for microbial factors can be reconciled with the current understanding of etiology and pathogenesis of IBD. The data presented does not support that IBD is an infectious disease nor that it is a self-antigen-specific autoimmune disease, however, recent findings increasingly suggest that tissue damage might be caused by a non-specific autoaggressive inflammation which is driven by common, ubiquitous microbial agents derived from the bacterial flora in the intestinal lumen.

TH1/TH2,3 imbalance due to cytokine-producing NK, gammadelta T and NK-gammadelta T cells in murine pregnancy decidua in success or failure of pregnancy.

PROBLEM: Recurrent spontaneous abortion in DBA/2-mated CBA/J mice has been attributed to the production of Th1 cytokines (tumor necrosis factor [TNF]-alpha and interferon [IFN]-gamma) by asialoGM1+ natural killer (NK) cells and Vgamma1.1delta6.3+ T cells that infiltrate decidua by day 6.5, during the peri-implantation period. Abortions can be prevented by a second population of Vgamma1.1delta6.3 cells, which infiltrate on day 8.5 of gestation, and produce the Th2 cytokine interleukin (IL)-10 and Th3 cytokine transforming growth factor (TGF)-beta2. In low abortion rate immunocompetent mice, most of the TGF-beta2 is derived from gammadelta T cells. However, TGF-beta2-producing cells are present in the decidua of pregnant severe combined immune deficient (SCID) mice, which lack gammadelta T cells. METHODS: The cells in day 13.5 decidua of CBA x DBA/2 matings and SCID x SCID matings were identified using flow cytometry and combined surface staining for gammadelta and/or asialoGM1, and intracellular cytokine staining for TNF-alpha, IFN-gamma, and TGF-beta2,3. RESULTS: TGF-beta2 and TNF-alpha were found in asialoGM1+ NK cells in SCID mouse decidua. In CBA x DBA/2 mated mice, two major and one minor subsets of cytokine-positive cells were identified: -gammadelta-only T cells, double positive asialoGM1+ gammadelta+ (NK-gammadelta T) cells, and a small number of asialoGM1 +gammadelta- NK-only cells. The NK-only and NK-gammadelta T subsets showed a greater Th1/Th2,3 pattern of intracellular staining compared with the gammadelta-only subset. In the CBA x DBA/2 and SCID x SCID systems, Th1/Th2,3 ratios could not predict actual observed abortion rates but did correlate with susceptibility to abortions (if exposed to an additional stimulus such as stress). The known effect of in vivo administration of anti-asialoGM1 antibody on abortion rates within groups of mice exposed to such stresses could also be predicted. CONCLUSION: gammadelta+ cells in decidua (e.g. Vgamma1+ cells which can recognize trophoblasts) differ based on the presence or absence of the NK marker-asialo-GM1. NK-gammadelta T cells may be quite important in the Th1 response in early pregnancy that predisposes to abortions in CBA x DBA/2 matings, whereas gammadelta T-only cells appear to be protective. In pregnant SCID mice, the TNF-alpha+/TGF-beta2+ NK population is greatly expanded. An activating stimulus (such as stress or endotoxin) appears to be as important in triggering abortions, as is the Th1/Th2,3 ratio at the feto maternal interface.

Leukocytes in the intestinal epithelium: an unusual immunological compartment revisited.

Intraepithelial lymphocytes (IEL) are characterized by significant heterogeneity in morphology, surface antigen expression, and function. Although IEL can express T cell markers including the T cell receptor (TcR), their relationship to peripheral T cells is not clear. The finding of IEL in athymic nude mice first suggested that a number of IEL may be thymic-independent. The identification of the gamma/delta TcR heterodimer on IEL further suggested that these cells are part of a distinct population of epithelial-associated lymphocytes, many of which express the gamma/delta TcR. We review the nature of the V gamma gene usage in IEL and highlight the differences between different gamma/delta T cell populations. The thymic independent nature of these gamma/delta cells is discussed and compared to that of the alpha/beta TcR expressing IEL. The finding that some alpha/beta IEL can develop independent of thymic processing suggests that IEL are characterized by a unique collection of T cells that may undergo differentiation within the intestinal compartment. The ability to distinguish T-dependent from T-independent IEL raises the possibility of identifying the functional nature of these two IEL lineages. We propose that the ability of IEL to potentially undergo repertoire selection in the intestine could allow for the development of mucosal T cells uniquely adapted to function in this environment.

Intestinal epithelial cell line induction of T cell differentiation from bone marrow precursors.

The mechanism whereby the intestinal microenvironment promotes T cell development in the absence of the thymus is unknown. We show that the murine intestine-derived epithelial cell line, MODE-K, can induce T cell differentiation marker expression in vitro on bone marrow (BM) T cell precursors. Three-color flow cytometry analysis of T-cell-depleted C3H BM mononuclear cells (MNC) after 4 days of coculture on monolayers of MODE-K indicated that approximately 25% of MNC expressed CD3 and TCR alpha beta. Of these CD3+ cells, 36% were CD3loCD4-CD8- double negative (DN), 34% were CD3loCD4+CD8 alpha beta+ double positive (DP), and the remainder were CD3hiCD4+CD8- or CD3hiCD4-CD8 alpha beta+ single positive (SP). In addition, the T cells which developed in coculture with MODE-K expressed the early T cell differentiation marker CD24 (heat-stable antigen). These T cells subsets did not develop when BM was cocultured with the LTA fibroblast cell line or in medium alone. Interestingly, preventing cell contact between MODE-K and BM by culturing in Transwell plates did not interfere with the development of T cells expressing the DN, DP, or SP phenotypes. Double-positive T cells did not develop if splenic MNC were cocultured with MODE-K. These results suggest that the intestinal epithelial environment can induce and support the T cell development from bone marrow precursors.

Phenotypic and functional assessment of intraepithelial lymphocytes bearing a 'forbidden' alpha beta TCR.

Differences in the surface antigen phenotype, such as the expression CD8 as an alpha alpha homodimer or the lack of Thy-1, on intestinal intraepithelial lymphocytes (IEL) are related, in part, to alternative differentiation pathways. The relationship of IEL lacking the pan-T cell marker CD5 to these IEL, their TCR repertoire and function has not been examined directly. We explored the TCR repertoire and function of the CD5- IEL subset in relation to the expression of the 'autospecific' V beta 6 TCR in MIs-1a mice and to gamma delta TCR. The results indicate that CD5 expression was absent on the majority of TCR gamma delta IEL (96.9%) and on a significant proportion of TCR alpha beta IEL (25.0%). Virtually all IEL in DBA/2 (MIs-1a) mice that expressed the 'autospecific' V beta 6 TCR were CD5-, and this correlated with the expression of CD8 alpha alpha. To assess the functional capacity of this subset of IEL, we examined proliferation and IL-2 production in response to TCR activation. Although CD5- IEL proliferated in response to anti-CD3, IEL bearing TCR V beta 6, in MIs-1a mice, were not responsive to TCR-mediated activation. Similarly, TCR gamma delta IEL were not responsive to stimulation by anti-TCR gamma delta antibodies. The addition of exogenous IL-2, however, reconstituted the proliferative response of both TCR gamma delta IEL and the TCR V beta 6 expressing IEL. We conclude that the lack of CD5 defines a unique subset of intraepithelial T cells expressing either TCR gamma delta or alpha beta that include potentially autoreactive cells that remain anergic in the absence of IL-2.