Mechanism for cotolerance in nonlethally conditioned mixed chimeras: negative selection of the Vbeta T-cell receptor repertoire by both host and donor bone marrow-derived cells

Bone marrow (BM) chimeras prepared by complete recipient ablation (A-- >B) exhibit donor-specific tolerance, yet survival is often limited by graft-versus-host disease (GVHD). Negative selection of potentially donor-reactive T cells, as assessed by relative T-cell receptor (TCR)- Vbeta expression, is dependent on donor BM-derived deleting ligands. Mixed chimerism and tolerance for both donor and host antigens can be achieved using partial recipient myeloablation with 500 cGy total-body irradiation (TBI) before transplantation followed by cyclophosphamide (CyP) on day +2. To examine the influence of residual host elements on negative selection, the peripheral TCR-Vbeta repertoire was analyzed in partially ablated C57BL/10SnJ (B10) recipients reconstituted with BM from major histocompatibility complex (MHC)-disparate B10.BR/SgSnJ or MHC, Hh-1 and Mls-disparate BALB/cByJ donors, which delete Vbeta5+ and 11+ or Vbeta3+, 5+, and 11+ TCR subsets, respectively. As in myeloblated recipients, donor-reactive subfamilies were deleted in B10.BR-->B10 and BALB/c-->B10 chimeras, suggesting that donor I-E and minor lymphocyte-stimulating (Mls) antigens contribute to the deleting ligands in the nonmyeloablated host. In striking contrast to completely ablated B10-->B10.BR chimeras, partially ablated recipients showed intramedullary I-E expression in the thymus and deleted host-reactive Vbeta5+ and Vbeta11+ subfamilies. These data demonstrate that efficient clonal deletion occurs after partial myeloablation and that both donor and host ligands contribute to TCR repertoire selection.     

X-sizer for thrombectomy in acute myocardial infarction improves ST-segment resolution: results of the X-sizer in AMI for negligible embolization and optimal ST resolution (X AMINE ST) trial

OBJECTIVES: We sought to compare, in a prospective randomized multicenter study, the effect of adjunctive thrombectomy using X-Sizer (eV3, White Bear Lake, Minnesota) before percutaneous coronary intervention (PCI) versus conventional PCI in patients with acute myocardial infarction (AMI) for <12 h and Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 to 1. The primary end point was the magnitude of ST-segment resolution after PCI. BACKGROUND: Despite a high rate of TIMI flow grade 3 achieved by PCI in patients with AMI, myocardial reperfusion remains relatively low. Distal embolization of thrombotic materials may play a major role in this setting. METHODS: We conducted a prospective, randomized, multicenter study in patients with AMI <12 h and initial TIMI flow grade 0 to 1 who were treated with primary PCI. The magnitude of ST-segment resolution 1 h after PCI was the primary end point. RESULTS: A total of 201 patients were included. Treatment groups were comparable by age (61 +/- 13 years), diabetes (22%), previous MI (8%), anterior MI (52%), onset-to-angiogram (258 +/- 173 min), and glycoprotein IIb/IIIa inhibitor use (59%). The magnitude of ST-segment resolution was greater in the X-Sizer group compared with the conventional group (7.5 vs. 4.9 mm, respectively; p = 0.033) as ST-segment resolution >50% (68% vs. 53%; p = 0.037). The occurrence of distal embolization was reduced (2% vs. 10%; p = 0.033) and TIMI flow grade 3 was obtained in 96% vs. 89%, respectively (p = 0.105). Myocardial blush grade 3 was similar (30% vs. 31%; p = NS). Six-month clinical outcome was comparable (death, 6% vs. 4% and major adverse cardiac and cerebral events, 13% vs. 13%, respectively). By multivariate analysis, independent predictors of ST-segment resolution >50% were: younger age, non-anterior MI, use of the X-Sizer, and a short time interval from symptom onset. CONCLUSIONS: Reducing thrombus burden with X-Sizer before stenting leads to better myocardial reperfusion, as illustrated by a reduced risk of distal embolization and better ST-segment resolution.     

Phenotyping of Intrahepatic and Peripheral Blood Lymphocytes in Patients with Chronic Hepatitis C

The host immune responses have been suggested toplay a role in liver injury occurring in patients withchronic hepatitis C. In order to explore therelationship between the relative proportions ofintrahepatic and peripheral blood lymphocytes (IHL, PBL),the levels of viremia, and the histological hepatitisactivity score, three-color fluorescence-activatedcytometric analysis was performed for 36 patients with chronic hepatitis C and six control subjectswithout chronic hepatitis. The liver biopsy wasperformed before any antiviral therapy. Each liverspecimen was divided into two parts: one forhistological examination and one for immunological analysis.Tricolor CD45 was used to improvelymphogating. Fluorescein isothiocyanate-or phycoerythrin-conjugated monoclonal antibodies withspecificity for CD3, CD4, CD8, and CD20 (lymphocyte subpopulations),for CD69 (activated lymphocytes), and for CD16/56(natural killer cells) were used. The livers of patientswith chronic hepatitis C contained a greater proportion of CD4⁺ lymphocytes that exhibitedmarked expression of CD69 than in control subjects (20.7± 7.3% vs 10.2 ± 4.6%, P = 0.027).Moreover, in patients with chronic hepatitis C, theproportion of CD4⁺ IHL correlated with the histological hepatitisactivity evaluated by the Knodell score (r = 0.48, P =0.004). No correlation was found between the percentageof CD4⁺ IHL and the level of viremia ortransaminase activities. Our findings clearly indicate thata cellular immune response does take place inHCV-infected livers and could thus contribute to theoutcome of hepatitis C virus infection.     

Unusual cutaneous manifestations of miliary tuberculosis.

Cutaneous manifestations of miliary tuberculosis are extremely rare. We describe a 62-year-old woman with leukopenia who developed infiltrated dermal-hypodermal and ulcerative cutaneous lesions during the course of miliary tuberculosis. Miliary tuberculosis was diagnosed when Mycobacterium tuberculosis bacilli were isolated by cultures of the bronchoalveolar lavage fluid and blood and when acid-fast bacilli were detected on histopathologic examination of hepatic, pulmonary, and cutaneous biopsy specimens. With the increasing incidence of immunocompromised patients, unusual presentations of tuberculosis may be observed more often. Acute miliary tuberculosis of the skin is an exceptional manifestation that is due to acute hematogenous dissemination of M. tuberculosis to the skin. We describe a patient who had unusual cutaneous manifestations of miliary tuberculosis.     

Eimeria tenella: quantitative in vitro and in vivo studies on the effects of mouse polyclonal and monoclonal antibodies on sporozoites

Murine, polyclonal and monoclonal antibodies, raised against sporozoites of Eimeria tenella, were tested for their ability to neutralize sporozoite infectivity in vitro and in vivo. Neutralization was effected via three mechanisms. Firstly, sporozoites fixed complement, at low titres, and lysis occurred by the alternative pathway of complement activation. Secondly, in the absence of complement activity, the murine heat-inactivated, hyperimmune antiserum neutralized sporozoites at relatively low titres. At high titres, even though sporozoites were agglutinated, neither the heat-inactivated hyperimmune antiserum nor the monoclonal antibody neutralized sporozoites. Finally, in the presence of complement and specific antibodies, at titres which by themselves would not neutralize sporozoites, neutralization was effected due to lysis via the classical pathway of complement activation.     

Plasma thyroid hormone pattern in king penguin chicks: a semi-altricial bird with an extended posthatching developmental period

Plasma concentrations of thyroid hormones (TH) were investigated during the extended posthatching developmental period (approximately 11 months) of a semi-altricial bird species, the king penguin (Aptenodytes patagonicus). The first period of growth in summer was marked by a progressive rise in plasma T4 concentration that paralleled rapid increases in body mass and in structural and down growth. By contrast, plasma T3 concentration had already reached adult levels in newly hatched chicks and did not change thereafter. Circulating TH of king penguin chicks thus follow an original pattern when comparing to altricial and precocial species. During the austral winter, the long period of undernutrition of king penguin chicks was characterized by a decrease in circulating TH that can be related to a seasonal stop in growth and energy saving mechanisms. Plasma TH concentrations increased again during the second growth phase in spring, and they reached their highest levels at the end of the fledging period, slightly before juveniles initiated their first foraging trip at sea. As expected, plasma T4 levels were elevated when chicks moulted, developing a true-adult type waterproof plumage. The data also suggest that T4 plays a major role in skeletal development and pectoral muscle maturation in anticipation of marine life. Plasma T3 was at its highest during the period when juveniles improved resistance to cold waters by going back and forth to the sea, suggesting a role for circulating T3 in cold acclimatization occurring at that time.     

Certification of donor apheresis nurses: Keys to develop an effective training program

Within Sanquin Blood Supply, a training program to train apheresis nurses was developed. The parts of the work for which qualification should be necessary was analysed. Based on this analysis, a modular program with theoretical and practical information and knowledge was developed. The modular program consists of two sections: a theoretical and technical / practical. The theoretical section consists of by the project group identified themes including basic hematology (e.g. the characteristics, kinetics, physiology and function of blood cells), basic apheresis physiology, indications for apheresis procedures, criteria for donors apheresis, difficulties and risks of procedures as well as the actions to be taken in case of side effects, and introduction to the apheresis machine available, including the mechanism of the machine. The program for the technical / practical section consists of machine and procedure knowledge (in theory and practise) and troubleshooting. To conclude each individual module, tests in theory and capability to perform procedures are taken. Each trainee needs to demonstrate to have sufficient insight and skill to master all the relevant critical features of the work. Also a text-book for the trainee was written. This educational program provides an approach to educate and test apheresis donor nurses. The combination of theoretical and practical components and monitoring of the progression are an important basis.