Amantadine therapy in renal transplant patients with hepatitis C virus infection.

BACKGROUND: To date, there is no safe and efficient treatment of hepatitis C virus (HCV) infection after renal transplantation. Recently, there were encouraging reports after using amantadine in HCV-positive immunocompetent patients. OBJECTIVES: In an open pilot study, we evaluated the efficacy and the safety of amantadine monotherapy in 8 HCV positive renal-transplant patients with chronic active hepatitis and increased alanine aminotransferase (ALT) levels. RESULTS: After 6 months of amantadine therapy (200 mg per day), there were no decrease in HCV viremia (5.87 +/- 0.37 log copies/ml at M6 versus 5.71 +/- 0.5 log copies/ml at baseline; P > 0.05). However, we found a significant decrease in ALT activity (71 +/- 17 IU/l at M6 versus 100 +/- 9 IU/l at baseline; P = 0.04), whereas the decrease in aspartate aminotransferase activity did not reach statistical significance. There were no significant changes in liver histology. The clinical and biological tolerance was very good. Finally, there were a significant decrease in cyclosporine A whole blood trough levels during therapy. CONCLUSIONS: Our study is the first one to demonstrate that amantadine monotherapy lack of efficacy in HCV renal-transplant patients. It is able to improve liver enzymes but it has no impact neither upon HCV viremia nor upon liver histology.     

Fever-like thermal conditions regulate the activation of maturing dendritic cells

Fever is one of the most frequent clinical signs encountered in pathology, especially with respect to infectious diseases. It is currently thought that the role of fever on immunity is limited to activation of innate immunity; however, its relevance to activation of adaptive immunity remains unclear. Dendritic cells (DCs) that behave as sentinels of the immune system provide an important bridge between innate and adaptive immunity. To highlight the role of fever on adaptive immunity, we exposed murine bone marrow-derived lipopolysaccharide (LPS)- or live bacteria-maturing DCs over a 3-h period to 37 degrees C or to fever-like thermal conditions (39 degrees C or 40 degrees C). At these three temperatures, we measured the kinetics of cytokine production and the ability of DCs to induce an allogeneic mixed lymphocyte reaction. Our results show that short exposure of DCs to temperatures of 39 degrees C or 40 degrees C differentially increased the secretion of interleukin (IL)-12p70 and decreased the secretion of IL-10 and tumor necrosis factor alpha by maturing DCs. These fever-like conditions induced a regulation of cytokine production at the single-cell level. In addition, short-term exposed LPS-maturing DCs to 39 degrees C induced a stronger reaction with allogeneic CD4(+) T cells than maturing DCs incubated at 37 degrees C. These results provide evidence that temperature regulates cytokine secretion and DC functions, both of which are of particular importance in bacterial diseases.     

Artificial Circulation of the Liver: Machine Perfusion as a Preservation Method in Liver Transplantation

Due to the sharp increase in liver transplant candidates and the subsequent shortage of suitable donor livers, an extension of the current donor criteria is necessary. Simple cold storage, the current standard in organ preservation has proven to be insufficient to preserve extended criteria donor livers. Therefore a renewed interest grew toward alternative methods for liver preservation, such as hypothermic machine perfusion and normothermic machine perfusion. These “new” preservation methods were primarily assessed in rat models, and only a few clinically relevant large animal models have been described so far. This review will elaborate on these alternative preservation methods. Anat Rec, 291:735–740, 2008. © 2008 Wiley‐Liss, Inc.     

Kinetics of gene expression in murine cutaneous graft-versus-host disease

The kinetics of gene expression associated with the development of cutaneous graft-versus-host disease (GVHD) were examined in a mouse model of MHC-matched allogeneic hematopoietic stem cell transplantation. Ear skin was obtained from recipient mice with or without GVHD between 7 and 40 days after transplantation for histopathological analysis and gene expression profiling. Gene expression patterns were consistent with early infiltration and activation of CD8(+) T and mast cells, followed by CD4(+) T, natural killer, and myeloid cells. The sequential infiltration and activation of effector cells correlated with the histopathological development of cutaneous GVHD and was accompanied by up-regulated expression of many chemokines and their receptors (CXCL-1, -2, -9, and -10; CCL-2, -5, -6, -7, -8, -9, -11, and -19; CCR-1 and CCR-5), adhesion molecules (ICAM-1, CD18, Ly69, PSGL-1, VCAM-1), molecules involved in antigen processing and presentation (TAP1 and TAP2, MHC class I and II, CD80), regulators of apoptosis (granzyme B, caspase 7, Bak1, Bax, and BclII), interferon-inducible genes (STAT1, IRF-1, IIGP, GTPI, IGTP, Ifi202A), stimulators of fibroblast proliferation and matrix synthesis (interleukin-1beta, transforming growth factor-beta1), and markers of keratinocyte proliferation (keratins 5 and 6), and differentiation (small proline-rich proteins 2E and 1B). Many acute-phase proteins were up-regulated early in murine cutaneous GVHD including serum amyloid A2 (SAA2), SAA3, serpins a3g and a3n, secretory leukocyte protease inhibitor, and metallothioneins 1 and 2. The kinetics of gene expression were consistent with the evolution of cutaneous pathology as well as with current models of disease progression during cutaneous GVHD.     

Phenotype delineation of ZNF462 related syndrome

Zinc finger protein 462 (ZNF462) is a relatively newly discovered vertebrate specific protein with known critical roles in embryonic development in animal models. Two case reports and a case series study have described the phenotype of 10 individuals with ZNF462 loss of function variants. Herein, we present 14 new individuals with loss of function variants to the previous studies to delineate the syndrome of loss of function in ZNF462. Collectively, these 24 individuals present with recurring phenotypes that define a multiple congenital anomaly syndrome. Most have some form of developmental delay (79%) and a minority has autism spectrum disorder (33%). Characteristic facial features include ptosis (83%), down slanting palpebral fissures (58%), exaggerated Cupid's bow/wide philtrum (54%), and arched eyebrows (50%). Metopic ridging or craniosynostosis was found in a third of study participants and feeding problems in half. Other phenotype characteristics include dysgenesis of the corpus callosum in 25% of individuals, hypotonia in half, and structural heart defects in 21%. Using facial analysis technology, a computer algorithm applying deep learning was able to accurately differentiate individuals with ZNF462 loss of function variants from individuals with Noonan syndrome and healthy controls. In summary, we describe a multiple congenital anomaly syndrome associated with haploinsufficiency of ZNF462 that has distinct clinical characteristics and facial features.     

Pre-B-cell colony-enhancing factor,whose expression is up-regulated in activated lymphocytes,is a nicotinamide phosphoribosyltransferase,a cytosolic enzyme involved in NAD biosynthesis

The murine homologue of the previously identified human "pre-B-cell colony-enhancing factor" (PBEF) gene coding for a putative cytokine has been identified by screening a subtractive library enriched in genes expressed in activated T lymphocytes. Unlike most cytokine genes known to date, the PBEF gene is ubiquitously expressed in lymphoid and non-lymphoid tissues and displays significant homology with genes from primitive metazoans (marine sponges) and prokaryotic organisms. Recently, a bacterial protein encoded by nadV, a gene from the prokaryote Haemophilus ducreyi displaying significant homology with PBEF, has been identified as a nicotinamide phosphoribosyltranferase (NAmPRTase), an enzyme involved in nicotinamide adenine dinucleotide (NAD) biosynthesis. Using a panel of antibodies to murine PBEF, we demonstrate in this work that, similarly to its microbial counterpart, the murine protein is a NAmPRTase, catalyzing the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to yield nicotinamide mononucleotide, an intermediate in the biosynthesis of NAD. The role of PBEF as a NAmPRTase was further confirmed by showing that the mouse gene was able to confer the ability to grow in the absence of NAD to a NAmPRTase-defective bacterial strain. The present findings are in keeping with the ubiquitous nature of this protein, and indicate that NAD biosynthesis may play an important role in lymphocyte activation.     

The rational design of TAP inhibitors using peptide substrate modifications and peptidomimetics

The major histocompatibility complex (MHC)-encoded transporter associated with antigen processing (TAP) translocates peptides from the cytosol into the lumen of the endoplasmic reticulum. This step precedes the binding of peptides to MHC class I molecules and is essential for cell surface expression of the MHC class I/peptide complex. TAP has a broad sequence specificity and a preference for peptides of around 9 amino acids. To synthesize inhibitors for TAP, we studied various alterations of the peptide substrate. The results indicate that TAP is stereospecific and that peptide bonds engineered into isosteric structures can improve translocation of the peptide. Furthermore, TAP is able to translocate peptides with large side chains that correspond to a peptide of ～ 21 amino acids in extended conformation. Peptides with longer side chains compete for the peptide binding site of TAP but fail to be translocated. Therefore, they represent the first rationally designed inhibitors of TAP.     

Identification of a new cluster of T-cell receptor delta recombining elements

Within the human T-cell receptor delta (TCRD) gene we have identified a new cluster of seven delta recombining elements (deltaRec2.1-2.7), located 2.6-5.2 kilobases downstream of the Vdelta2 gene segment. The deltaRec2 elements are isolated recombining signal sequences (RSS), which were shown to rearrange with the Ddelta3 and Jdelta1 segments of the TCRD gene as well as with the psiJalpha of the TCRA gene. Rearrangements involving the deltaRec2 elements were found in all peripheral blood (PB) samples from 10 healthy individuals, although their frequency was about 100-fold lower than that of classical deltaRec rearrangements. The total frequency of deltaRec2 rearrangements was lower in PB T lymphocytes, as compared with thymocytes, suggesting that they are deleted during T-cell development. The decrease of the frequency of the deltaRec2-Ddelta3 rearrangements was most prominent: 11 times lower in PB T lymphocytes than in thymocytes. Since the deltaRec2-Jdelta1 rearrangements contained the Ddelta3 segment in the junctional region, we assume that they are derived from the deltaRec2-Ddelta3 rearrangements. In contrast, the majority of deltaRec2-psiJalpha rearrangements did not contain the Ddelta3 segment, indicating that they are single step rearrangements. The deltaRec2-Jdelta1 and deltaRec2-psiJalpha rearrangements seem to be T-lineage specific, but the deltaRec2-Ddelta3 rearrangements were also found at very low frequencies in B lymphocytes and natural killer cells. Our results suggest that deltaRec2 rearrangements are transient steps in the recombinatorial process of the TCRAD locus and are probably deleted by subsequent Valpha-Jalpha rearrangements. We hypothesize, that in a similar manner to the classical deltaRec rearrangements, the deltaRec2 rearrangements might also contribute to T-cell differentiation towards the TCR-alphabeta lineage.     

Impairment of intramacrophagic Brucella suis multiplication by human natural killer cells through a contact-dependent mechanism

Brucella spp. are facultative intracellular bacteria that can establish themselves and cause chronic disease in humans and animals. NK cells play a key role in host defense. They are implicated in an early immune response to a variety of pathogens. However, it was shown that they do not control Brucella infection in mice. On the other hand, NK cell activity is impaired in patients with acute brucellosis, and recently it was demonstrated that human NK cells mediate the killing of intramacrophagic Mycobacterium tuberculosis in in vitro infection. Therefore, we have analyzed the behavior of Brucella suis infecting isolated human macrophages in the presence of syngeneic NK cells. We show that (i) NK cells impair the intramacrophagic development of B. suis, a phenomenon enhanced by NK cell activators, such as interleukin-2; (ii) NK cells cultured in the presence of infected macrophages are highly activated and secrete gamma interferon and tumor necrosis factor alpha; (iii) impairment of bacterial multiplication inside infected cells is marginally associated with the cytokines produced during the early phase of macrophage-NK cell cocultures; (iv) direct cell-to-cell contact is required for NK cells to mediate the inhibition of B. suis development; and (v) inhibition of B. suis development results from an induction of NK cell cytotoxicity against infected macrophages. Altogether, these findings show that NK cells could participate early in controlling the intramacrophagic development of B. suis in humans. It seems thus reasonable to hypothesize a role for NK cells in the control of human brucellosis. However, by impairing the activity of these cells in the acute phase of the illness, the pathogen should avoid this control.