Efficiency of curative and prophylactic treatment with rituximab in ADAMTS13-deficient thrombotic thrombocytopenic purpura: a study of 11 cases

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease that occurs mainly in young adults. Acquired cases are usually a result of antibodies directed against ADAMTS13 (a disintegrin-like and metalloprotease [reprolysin type] with thrombospondin type 1 motif 13), a protease that cleaves the von Willebrand factor multimers. Prognosis has been improved by plasma therapy, but some acute severe forms are refractory to this treatment and achieving a sustained remission is still a challenge in chronic relapsing forms. We therefore conducted a multicentric open-label prospective trial to test the efficacy of rituximab, an anti-B-cell monoclonal antibody, as a curative and prophylactic treatment in patients with TTP as a result of anti-ADAMTS13 antibodies. Six patients were included during an acute refractory TTP episode. Five patients with severe relapsing TTP and persistent anti-ADAMTS13 antibodies were prophylactically treated during remission. All patients received 4 weekly infusions of rituximab. The target of treatment was to restore a significant ADAMTS13 plasma activity (> 10%). Treatment with rituximab led to clinical remission in all cases of acute refractory TTP. In all patients, anti-ADAMTS13 antibodies disappeared, and a significant (18%-75%) plasma ADAMTS13 activity was detected following treatment. Tolerance of rituximab was good. Rituximab is a promising first-line immunosuppressive treatment in patients with acute refractory and severe relapsing TTP related to anti-ADAMTS13 antibodies.     

ALK activation by the CLTC-ALK fusion is a recurrent event in large B-cell lymphoma

We present 3 cases of large B-cell lymphoma (LBCL) with a granular cytoplasmic staining for anaplastic lymphoma kinase (ALK). All of the cases showed striking similarities in morphology and immunohistochemical profile characterized by a massive monomorphic proliferation of CD20-/CD138+ plasmablast-like cells. In one of the cases, initially diagnosed as a null-type anaplastic large cell lymphoma (ALCL), the B-cell phenotype became evident only at recurrence. Fluorescent in situ hybridization (FISH) and molecular studies led to the detection of a CLTC-ALK rearrangement in all 3 cases, without any evidence of full-length ALK receptor expression. The associated t(2;17)(p23;q23) was demonstrated in the karyotype of 2 cases. Although a similar CLTC-ALK aberration was previously identified in ALK-positive T-/null cell ALCL and inflammatory myofibroblastic tumor, its association with ALK-positive LBCL seems to be specific and intriguing.     

Bacteriocin from epidemic Listeria strains alters the host intestinal microbiota to favor infection

Listeria monocytogenes is responsible for gastroenteritis in healthy individuals and for a severe invasive disease in immunocompromised patients. Among the three identified L. monocytogenes evolutionary lineages, lineage I strains are overrepresented in epidemic listeriosis outbreaks, but the mechanisms underlying the higher virulence potential of strains of this lineage remain elusive. Here, we demonstrate that Listeriolysin S (LLS), a virulence factor only present in a subset of lineage I strains, is a bacteriocin highly expressed in the intestine of orally infected mice that alters the host intestinal microbiota and promotes intestinal colonization by L. monocytogenes, as well as deeper organ infection. To our knowledge, these results therefore identify LLS as the first bacteriocin described in L. monocytogenes and associate modulation of host microbiota by L. monocytogenes epidemic strains to increased virulence.The gram-positive bacterium Listeria monocytogenes is a facultative intracellular pathogen that causes foodborne infections in humans and animals. Upon consumption of contaminated food, L. monocytogenes reaches the intestinal lumen, crosses the intestinal barrier, and disseminates within the host. The clinical manifestations of listeriosis vary from a mild, self-limiting gastroenteritis to severe intestinal and systemic infections, with a fatality rate estimated to 20–30% of infected individuals (1). Host gut microbiota plays a critical role in resistance against colonization by invading pathogens within the intestine (2). The mechanisms of L. monocytogenes to compete with the host microbiota to survive in the intestine remain unknown.During the last decades, the majority of Listeria studies in bacterial pathophysiology, cell biology, and immunology compared three pathogenic strains from lineage II: EGD, EGD-e, and 10403S (3). Interestingly, major listeriosis epidemics have been preferentially associated to L. monocytogenes clonal groups belonging to the evolutionary lineage I and, more specifically, to serotype 4b (4, 5), but the molecular mechanisms that contribute to the higher virulence potential of these bacterial strains have not been identified yet.Bacteriocins are bacterially synthesized proteinaceous substances that target and inhibit the growth of closely related bacteria, allowing competition in diverse ecological niches, including the digestive tract (6, 7). Production of these antimicrobial peptides is widespread among bacterial species, and such production is made possible by biosynthetic machineries present in the genome, plasmids, or conjugative transposons (7). A conserved biosynthetic gene cluster for the production of bacteriocins displaying thiazole and oxazole heterocycles was discovered in 2008 in six microbial phyla (8). These gene clusters encode a toxin precursor and all indispensable proteins for toxin maturation in a mode similar to that associated with the bacteriocin microcin B17 (8). This gene cluster in L .monocytogenes was only present in a subset of lineage I strains responsible for the majority of Listeria epidemics (9). This L. monocytogenes toxin was designated Listeriolysin S (LLS) and was shown to produce a hemolytic and cytotoxic factor necessary for virulence in a murine intraperitoneal (i.p.) infection model (9).The aim of the present work was to understand where LLS is produced in a murine oral infection model, as well as to investigate the function of this virulence factor. Interestingly, to our knowledge, we show that LLS is the first bacteriocin described in L. monocytogenes. This toxin that is specifically expressed in the intestine augments host colonization.     

Prostaglandin E2 synergistically with interleukin-23 favors human Th17 expansion

Microenvironment molecular cues direct T helper (Th) cell differentiation; however, Th17 fate determination is still imprecisely understood in humans. To assess the role of prostaglandin E(2) (PGE(2)) in Th expansion, we activated peripheral blood mononuclear cells by CD3 cross-linking. In the presence of exogenous PGE(2), peripheral blood mononuclear cells produced higher interleukin-17 (IL-17), C-C chemokine ligand 20 (CCL20)/macrophage inflammatory protein 3alpha (MIP-3alpha), CXC chemokine ligand 8 (CXCL8)/IL-8, and lower interferon-gamma and IL-22 levels than in control cultures. Exogenous PGE(2) and IL-23 synergized in inducing IL-17, whereas indomethacin and IL-23 blockade drastically reduced IL-17 but not interferon-gamma production. Furthermore, IL-1 but not tumor necrosis factor was absolutely required for IL-17 production. PGE(2) doubled the frequency of CD4+ T cells producing IL-17 and within the CD4+ subset enhanced C-C chemokine receptor 6 (CCR6) and CCR4 while decreasing CXC chemokine receptor 3 (CXCR3) expression. Furthermore, in CD4+ T-cell lines, the production of IL-17 segregated with the CCR6+ subset. In the presence of CCR6+ compared with CXCR3+ Th cells, monocytes/macrophages produced much higher levels of matrix metalloproteinase-1, -3, and -9 but similar levels of CXCL10 and IL-1beta. These results identify PGE(2) and IL-23 as participating in the expansion of CD4+ T cells endowed with high IL-17 production capacity, which in turn favors monocyte production of mediators important for host defense and tissue destruction.     

Immortalization of a primate bipotent epithelial liver stem cell

Liver regeneration after partial hepatectomy results primarily from the simple division of mature hepatocytes. However, during embryonic and fetal development or in circumstances under which postnatal hepatocytes are injured, organ regeneration is believed to occur from a compartment of epithelial liver stem or progenitor cells with biliary and hepatocytic bipotentiality. The ability to identify, isolate, and transplant epithelial liver stem cells from fetal liver would greatly facilitate the treatment of hepatic diseases currently requiring orthotopic liver transplantation. Here we report the identification and immortalization by retrovirus-mediated transfer of the simian virus 40 large T antigen gene of primate fetal epithelial liver cells with a dual hepatocytic biliary phenotype. These cells grow indefinitely in vitro and express the liver epithelial cell markers cytokeratins 8/18, the hepatocyte-specific markers albumin and alpha-fetoprotein, and the biliary-specific markers cytokeratins 7 and 19. Bipotentiality of gene expression was confirmed by clonal analysis initiated from single cells. Endogenous telomerase also is expressed constitutively. After orthotopic transplantation via the portal vein, approximately 50% of the injected cells integrated into the liver parenchyma of athymic mice without tumorigenicity. Three weeks after transplantation, cells having seeded in the liver parenchyma expressed both albumin and alpha-fetoprotein but had lost expression of cytokeratin 19. These results provide strong evidence for the existence of a bipotent epithelial liver stem cell in nonhuman primates. This unlimited source of donor cells also should enable the establishment of a model of allogenic liver cell transplantation in a large animal closely related to humans and shed light on important questions related to liver organogenesis and differentiation.     

Age-related alterations in prolactin binding sites in the female rat

Aging is associated with various neuroendocrine alterations, including in the rat a hypersecretion of PRL with maintained ovulations (repetitive pseudo-pregnancy) and a reduced activity of the hypothalamic dopaminergic neurons with loss of the neuron responsiveness to PRL, suggestive of age-related alterations in PRL receptors. In this study we have investigated PRL binding sites in the hypothalamus as well as in the mammary glands, the ovaries and the liver of young and old nulliparous female rats. The old rats (26-28 months) displayed spontaneous repetitive pseudopregnancies and they were compared with young (4-6 months) pseudopregnant rats; the binding studies were performed by saturation analysis using 125I-oPRL as ligand and particulate membrane preparations. In the hypothalamus, a negligible binding of PRL was observed in all fragments studied, mediobasal hypothalamus, median eminence, in both young and old rats and no characterization of the binding sites could be achieved. In the mammary glands, the number of PRL binding sites was appreciable in spite of the nulliparity of the rats, but it was smaller in the old than in the young rats (9.0 +/- 1.4 vs 14.9 +/- 1.2 fmol/mg protein; mean +/- SEM; p less than 0.02). In the ovaries, the density of PRL binding sites was similar in the old and young rats (112.6 +/- 9.7 vs 115.0 +/- 8.9 fmol/mg protein), illustrative of a maintained luteotropic effect of PRL with age in the rat. In contrast, in the liver a greater number of binding sites was found in the old than in the young rats (261.9 +/- 36.6 vs 63.6 +/- 5.8 fmol/mg protein; p less than 0.001), supportive of the ability of PRL to induce its own receptors in that tissue. The affinity constant of PRL binding was not altered with age in the tissues studied. These results are illustrative of tissue-specific modifications in the number of PRL binding sites with age and they are suggestive of a sustained biological activity of PRL in the old rats.     

Differential risk factors for early and later hospital readmission of older patients

BACKGROUND AND AIMS: This study aimed at analyzing rates and factors associated with early and later readmission (0-1 month and 2-3 months after discharge, respectively) of older people after index hospitalization. METHODS: This prospective observational study was conducted in two teaching hospitals. People 70 years and over were interviewed within 48 h of emergency admission. Socio-demographic and medical factors were collected, together with functional factors including Activities of Daily Living (basis and instrumental), cognitive state, and geriatric syndromes. Medical diagnosis, length of stay, and destination were collected at discharge, and patients were followed up by phone 1 and 3 months after discharge. During these interviews, outcomes on readmission, institutionalization, need for help, and death were evaluated. RESULTS: The population of 625 patients had a mean age of 80.0 years. The rate of early readmission (01 month) was 10. 7% and the overall rate within 3 months was 23.1%. Logistic regression analysis showed that variables predicting early readmission were previous hospitalization within 3 months, a longer length of stay, and a discharge diagnosis in chapter 8 (respiratory system) and chapter 10 (genito-urinary system) of the ICD-9-CM. Variables predicting later readmission were previous hospitalization within 3 months, a discharge diagnosis in chapter 7 (circulatory system) of the ICD-9-CM, and a poor pre-admission IADL score. CONCLUSIONS: In a medicalized population of older people, several risk factors may be identified for 0-1 month and 2-3 month readmission. Besides severe morbidities at discharge, diagnoses and previous hospitalization, pre-admission IADL was an independent risk factor for 2-3 month readmission.     

Peanut‐based ready‐to‐use therapeutic food: how acceptable and tolerated is it among malnourished pregnant and lactating women in Bangladesh?

Within a Medecins Sans Frontieres's nutrition programme in Kamrangirchar slum, Dhaka, Bangladesh this study was conducted to assess the acceptability of a peanut‐based ready‐to‐use therapeutic food (RUTF) – Plumpy'nut^® (PPN) among malnourished pregnant and lactating women (PLW). This was a cross‐sectional survey using semi‐structure questionnaire that included all PLW admitted in the nutrition programme, who were either malnourished or at risk of malnutrition and who had received PPN for at least 4 weeks. A total of 248 women were interviewed of whom 99.6% were at risk of malnutrition. Overall, 212 (85%) perceived a therapeutic benefit. Despite this finding, 193 (78%) women found PPN unacceptable, of whom 12 (5%) completely rejected it after 4 weeks of intake. Reasons for unacceptability included undesirable taste (60%) and unwelcome smell (43%) – more than half of the latter was due to the peanut‐based smell. Overall, 39% attributed side effects to PPN intake including nausea, vomiting, diarrhoea, abdominal distension and pain. Nearly 80% of women felt a need to improve PPN – 82% desiring a change in taste and 48% desiring a change in smell. Overall, only 146 (59%) understood the illustrated instructions on the package. Despite a perceived beneficial therapeutic effect, only two in 10 women found PPN acceptable for nutritional rehabilitation. We urge nutritional agencies and manufacturers to intensify their efforts towards developing more RUTF alternatives that have improved palatability and smell for adults and that have adequate therapeutic contents for treating malnourished PLW in Bangladesh.     

Whole‐body muscle magnetic resonance imaging in SEPN1‐related myopathy shows a homogeneous and recognizable pattern

Introduction: The aim of this study was to delineate the spectrum of muscle involvement in patients with a myopathy due to mutations in SEPN1 (SEPN1‐RM). Methods: Whole‐body magnetic resonance imaging (WBMRI) was used in 9 patients using T1‐weighted turbo spin–echo (T1‐TSE) sequences and short tau inversion recovery (STIR) in 5 patients. Results: Analysis of signal and volume abnormalities by T1‐TSE sequences in 109 muscles showed a homogeneous pattern characterized by a recognizable combination of atrophy and signal abnormalities in selected muscles of the neck, trunk, pelvic girdle, and lower limbs. Severe wasting of sternocleidomastoid muscle and atrophy of semimembranosus were detected. Selective paraspinal, gluteus maximus, and thigh muscle involvement was also observed. The lower leg was less constantly affected. Conclusions: WBMRI scoring of altered signal and atrophy in muscle can be represented by heatmaps and is associated with a homogeneous, recognizable pattern in SEPN1‐RM, distinct from other genetic muscle diseases. Muscle Nerve 52 : 728–735, 2015