Involvement of interleukin 18 in Crohn's disease: evidence from in vitro analysis of human gut inflammatory cells and from experimental colitis models

An imbalance of immunoregulatory factors and/or cells contributes to uncontrolled mucosal T cell activation and inflammation in Crohn's disease (CD). Bioactive interleukin (IL)-18 has been shown to be produced by macrophages in CD lesions. We report here that T cells freshly isolated from inflamed tissue of CD patients (and not T cells from control intestinal tissue) were responsive to IL-18. In the presence of IL-18, these T cells produced more interferon (IFN)-gamma and less IL-10. To analyse further the role of IL-18 in this disease, an acute and a chronic model of murine colitis were used. IL-18 mRNA was significantly enhanced in trinitrobenzene sulphonic acid (TNBS) induced colitis, and treatment with IL-18 binding protein (IL-18BPa), which neutralizes IL-18 bioactivity, significantly reduced the severity of colitis. However, IL-18BPa did not affect the course of chronic colitis in CD45RBhighCD4+ T cell reconstituted SCID mice. Production of IFN-gamma in lamina propria mononuclear cell cultures from IL-18BPa-treated SCID mice was decreased, but at the same time fewer lamina propria CD4+ T cells harvested from IL-18BPa-treated mice compared to non-treated mice were in apoptosis. We conclude that IL-18 clearly has a modulatory role in the inflammatory cascade of CD and experimental colitis by affecting IFN-gamma and IL-10 production, and apoptosis. In view of the divergent effects of IL-18 neutralization in the two different murine colitis models, it is unlikely that IL-18 is at the top of this cascade.     

Familial translocation t(10;14) (q26.1;q32.3): report of three offspring with 10q deletion and 14q duplication

We describe two brothers and a cousin with common clinical features, including mild mental retardation, motor delays, hypotonia with truncal ataxia, esotropia, and mild facial and hand dysmorphia. The initial routine chromosome study failed to detect any abnormality in the proband. Based on a high index of clinical suspicion, high-resolution chromosome studies were performed on the proband's parents. A small reciprocal translocation t(10;14) (q26.1;q32.3) was detected in the father. The breakpoint on the derivative chromosome 14 was further placed telomeric to the immunoglobulin heavy-chain gene cluster at the band q32.33 by fluorescence in situ hybridization. Studies of the proband and two affected paternal cousins revealed that each had inherited the same derivative chromosome 10 from their carrier parents. This unbalanced karyotype resulted from an adjacent-1 segregation of the 10;14 translocation.     

Increased Mycobacterium tuberculosis growth in HIV-1-infected human macrophages: role of tumour necrosis factor-alpha

Synergism between Mycobacterium tuberculosis (M. tuberculosis) and HIV-1 infections was demonstrated in several in vitro models and clinical studies. Here, we investigated their reciprocal effects on growth in chronically HIV-1-infected promonocytic U1 cells and in acutely infected monocyte-derived macrophages (MDM). Phagocytosis of M. tuberculosis induced HIV-1 expression in U1 cells, together with increased TNF-alpha production. M. tuberculosis growth, evaluated by competitive PCR, was greater in HIV-1-infected MDM compared to uninfected cells. M. tuberculosis phagocytosis induced greater TNF-alpha and IL-10 production in HIV-1-infected MDM than in uninfected cells. In uninfected MDM, addition of TNF-alpha and IFN-gamma decreased, whereas IL-10 increased M. tuberculosis growth. On the contrary, in HIV-1-infected MDM, addition of TNF-alpha and IFN-gamma increased, whereas IL-10 has no effect on M. tuberculosis growth. TNF-alpha seems to play a pivotal role in the enhanced M. tuberculosis growth observed in HIV-1-infected MDM, being unable to exert its physiological antimycobacterial activity. Here, for the first time we demonstrated an enhanced M. tuberculosis growth in HIV-1-infected MDM, in line with the observed clinical synergism between the two infections.     

Protein phosphatase PP1 is required for normal DNA methylation in Neurospora

Covalent modifications of histones integrate intracellular and extracellular cues to regulate the genome. H3 Lys 9 methylation (H3K9me) can direct heterochromatin formation and DNA methylation, while phosphorylation of H3 Ser 10 (H3S10p) drives gene activation and chromosome condensation. To examine the relationship between H3S10p, H3K9me, and DNA methylation in Neurospora crassa, we built and tested mutants of the putative H3S10 phosphatase, PP1. A PP1-impaired mutant showed increased H3S10p and selective reduction of methylation of H3K9 and DNA. Similarly, amino acid substitutions of H3S10 abolished methylation of H3K9 and DNA. Thus, H3S10 dephosphorylation by PP1 is required for DNA methylation of some loci.     

The pattern and frequency of t(14;18) translocation and immunophenotype in Asian follicular lymphoma

AIMS: Follicular lymphoma is frequently associated with t(14;18)(q32;q21) translocation. This study was undertaken to determine the pattern of Bcl-2, CD10 and Bcl-6 expression in relation to t(14;18) translocation in follicular lymphoma from a cohort of a multi-ethnic Asian population. METHODS AND RESULTS: Sixty-two cases of follicular lymphoma were retrieved for immunohistochemistry, and t(14;18) translocation analysis by polymerase chain reaction and fluorescent in-situ hybridization techniques. Bcl-2 expression was present in 74% of the cases. CD10 expression was also relatively low (61%), with decreasing frequency of expression in high-grade tumours. Bcl-6 protein was expressed in most of the tumours (88%) regardless of the tumour grade. The t(14;18) translocation was detected in 46 cases (74%) with an extremely high rate of t(14;18) translocation in ethnic Indian cases (100%). CONCLUSION: The frequency of t(14;18) translocation in this series of follicular lymphomas was higher when compared with previous Asian reports, but in accordance with European and North American findings. CD10 expression is strongly associated with a t(14;18) translocation event, but the overall CD10 expression was relatively low, possibly due to the high proportion of high-grade tumours in the series. t(14;18) translocation was not associated with Bcl-2 or Bcl-6 expression.     

Activation of invariant NK T cells protects against experimental rheumatoid arthritis by an IL-10-dependent pathway

Invariant natural killer T (iNKT) cells are a unique lymphocyte subtype implicated in the regulation of autoimmunity and a good source of protective Th2 cytokines. Agonist alpha-galactosylceramide (alpha-GalCer) of iNKT cells exert a therapeutical effect in type 1 diabetes. We investigated whether iNKT activation with alpha-GalCer was protective in collagen-induced arthritis (CIA) in DBA/1 mice, a standard model of rheumatoid arthritis. Here, we have shown that in vivo iNKT cell function was altered in DBA/1 mice since stimulation with alpha-GalCer led to decreased IL-4 and IFN-gamma levels in sera, as compared with C57BL/6 mice. alpha-GalCer induced a clear-cut diminution of clinical and histological arthritides. An anti-IL-10 receptor antibody abrogated the protective effect of alpha-GalCer, suggesting a key role for IL-10 in the protection against CIA by activated iNKT cells. Confirming these data, disease protection conferred by alpha-GalCer correlated with the ability of LN CD4+ cells to secrete larger amounts of IL-10. These findings suggest that in CIA susceptibility to autoimmunity is associated with dysfunctions of iNKT cells. Our demonstration that iNKT cell activation by alpha-GalCer remains efficient in CIA-prone DBA/1 mice to provide protective IL-10 suggests that this could be used therapeutically to treat autoimmune arthritis.     

Type 1 and type 2 tumor infiltrating effector cell subpopulations in progressive breast cancer

Effector T cells fall into two subpopulations based on cytokine-secretion. Type 1 cells secrete IFN-gamma, whereas type 2 cells secrete IL-4, IL-10, and GM-CSF. NKT cells represent a third subpopulation that secretes similar cytokines and have been associated with immunoregulation. Using the TS/A adenocarcinoma, we assessed the phenotype and kinetics of tumor-infiltrating lymphocytes (TIL) in mice challenged subcutaneously in the mammary region. Flow cytometric analysis shows that T cells do not infiltrate the primary tumor site until days 7-14 following tumor challenge. Both CD4 and CD8 TILs were predominantly CD44(High) and expressed CD25, CD69, and CD95 cell surface activation markers. Activated CD4/CD44(High) TIL numbers reached peak levels at day 21 that precipitously decreased by day 28 whereas corresponding CD8 cell numbers progressively increased, however, at lower levels and with later kinetics. Intracellular cytokine staining showed that greater numbers of IL-4-producing Th2 cells were elicited and with earlier kinetics than that of IFN-gamma-producing Th1 cells. T cells co-expressing DX5 (CD3(+)/DX5(+)) emerged (>21 days), suggesting a recruitment of NK-like T cells at later stages of tumor progression. Moreover, tumors selectively up-regulated TGF-beta, MIF, and IP-10 gene expression at times as early as day 4, with peak levels at day 7 in vivo. Such gene expression remained elevated and correlated with a continued progression in tumor growth suggesting that preferential effector cell recruitment and production of select factors during different stages of tumor maturation may aid in regulating effective endogenous antitumor responses in progressive breast cancer.     

Anti-proliferative effects of phosphodiester oligodeoxynucleotides

The immunostimulatory effects of cytosine-phosphate-guanosine (CpG)-containing oligodeoxynucleotides (ODNs) have been extensively documented. In this paper, we describe the inhibitory effects of ODNs that contain natural phosphodiester backbones (O-ODNs) on the immunostimulation caused by CpG-containing phosphorothioated ODNs (CpG-S). CpG-S stimulation of mouse splenocyte proliferation was reduced by the addition of O-ODNs that contained or lacked the CpG-motif (CpG-containing phosphodiester oligodeoxynucleotide, CpG-O or GpC-O). The total number of cultured splenocytes was up-regulated by CpG-S, whereas repetitive addition of O-ODNs to the cell cultures inhibited this effect. The frequency of T2-like B cells was found to be increased by CpG-S. The culture supernatants of CpG-S-treated splenocytes contained elevated levels of IL-10 and IL-6. However, IL-10 and IL-6 production was down-regulated significantly by the combination of CpG-S and either CpG-O or GpC-O. The O-ODN mediated inhibition of proliferation was less pronounced in IL-10-/- mice. Thus, the O-ODNs, irrespective of CpG content, exerted inhibitory activities on the proliferation of B cells. These anti-proliferative effects appear to be mediated both by the down-regulation of IL-10 production and increased apoptosis.     

Infrared spectroscopy: A new diagnostic tool in Alzheimer disease

Biological markers play an evolving role in the diagnosis of Alzheimer disease (AD). We compare conventional measurements of cerebrospinal fluid (CSF) tau and β-amyloid_1–42 proteins to a novel approach – Fourier transformed infrared (FT-IR) spectroscopy – a simple technique derived from chemical and physical sciences that characterizes intramolecular bonds. For automatic diagnostic analysis, we developed an artificial neural network (ANN). We examined 71 patients with a clinical diagnosis of AD and 66 controls. β-Amyloid_1–42 was decreased (sensitivity 80% and specificity 78%); tau was elevated (sensitivity 76% and specificity 88%) in CSF of AD patients. The combined tau/β-amyloid_1–42 quotient was able to distinguish healthy from diseased subjects with 99% sensitivity and 86% specificity. The ANN could separate FT-IR spectroscopy data with 88.5% sensitivity and 80% specificity. FT-IR spectroscopy proved to be cost-effective and simple to perform. Diagnostic sensitivity and specificity is in the range of CSF tau and β-amyloid_1–42 protein analysis. Larger sample numbers for ANN training and validation could increase diagnostic accuracy and thus prove to be a useful screening tool.