Graft-derived cell-free DNA (GcfDNA), which is released into the blood stream by necrotic and apoptotic cells, is a promising noninvasive organ integrity biomarker. In liver transplantation (LTx), ...neither conventional liver function tests (LTFs) nor immunosuppressive drug monitoring are very effective for rejection monitoring. We therefore hypothesized that the quantitative measurement of donor-derived cell-free DNA (cfDNA) would have independent value for the assessment of graft integrity, including damage from acute rejection.
Traditional LFTs were performed and plasma GcfDNA was monitored in 115 adults post-LTx at three German transplant centers as part of a prospective, observational, multicenter cohort trial. GcfDNA percentage (graft cfDNA/total cfDNA) was measured using droplet digital PCR (ddPCR), based on a limited number of predefined single nucleotide polymorphisms, enabling same-day turn-around. The same method was used to quantify blood microchimerism. GcfDNA was increased >50% on day 1 post-LTx, presumably from ischemia/reperfusion damage, but rapidly declined in patients without graft injury within 7 to 10 d to a median <10%, where it remained for the 1-y observation period. Of 115 patients, 107 provided samples that met preestablished criteria. In 31 samples taken from 17 patients during biopsy-proven acute rejection episodes, the percentage of GcfDNA was elevated substantially (median 29.6%, 95% CI 23.6%-41.0%) compared with that in 282 samples from 88 patients during stable periods (median 3.3%, 95% CI 2.9%-3.7%; p < 0.001). Only slightly higher values (median 5.9%, 95% CI 4.4%-10.3%) were found in 68 samples from 17 hepatitis C virus (HCV)-positive, rejection-free patients. LFTs had low overall correlations (r = 0.28-0.62) with GcfDNA and showed greater overlap between patient subgroups, especially between acute rejection and HCV+ patients. Multivariable logistic regression modeling demonstrated that GcfDNA provided additional LFT-independent information on graft integrity. Diagnostic sensitivity and specificity were 90.3% (95% CI 74.2%-98.0%) and 92.9% (95% CI 89.3%-95.6%), respectively, for GcfDNA at a threshold value of 10%. The area under the receiver operator characteristic curve was higher for GcfDNA (97.1%, 95% CI 93.4%-100%) than for same-day conventional LFTs (AST: 95.7%; ALT: 95.2%; γ-GT: 94.5%; bilirubin: 82.6%). An evaluation of microchimerism revealed that the maximum donor DNA in circulating white blood cells was only 0.068%. GcfDNA percentage can be influenced by major changes in host cfDNA (e.g., due to leukopenia or leukocytosis). One limitation of our study is that exact time-matched GcfDNA and LFT samples were not available for all patient visits.
In this study, determination of GcfDNA in plasma by ddPCR allowed for earlier and more sensitive discrimination of acute rejection in LTx patients as compared with conventional LFTs. Potential blood microchimerism was quantitatively low and had no significant influence on GcfDNA value. Further research, which should ideally include protocol biopsies, will be needed to establish the practical value of GcfDNA measurements in the management of LTx patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The utility of autologous induced pluripotent stem cell (iPSC) therapies for tissue regeneration depends on reliable production of immunologically silent functional iPSC derivatives. However, ...rejection of autologous iPSC-derived cells has been reported, although the mechanism underlying rejection is largely unknown. We hypothesized that de novo mutations in mitochondrial DNA (mtDNA), which has far less reliable repair mechanisms than chromosomal DNA, might produce neoantigens capable of eliciting immune recognition and rejection. Here we present evidence in mice and humans that nonsynonymous mtDNA mutations can arise and become enriched during reprogramming to the iPSC stage, long-term culture and differentiation into target cells. These mtDNA mutations encode neoantigens that provoke an immune response that is highly specific and dependent on the host major histocompatibility complex genotype. Our results reveal that autologous iPSCs and their derivatives are not inherently immunologically inert for autologous transplantation and suggest that iPSC-derived products should be screened for mtDNA mutations.
Rovalpituzumab tesirine (Rova-T) is an antibody-drug conjugate targeting DLL3, a Notch pathway ligand highly expressed on SCLC cells. Rova-T was evaluated alone or in combination with platinum-based ...chemotherapy (cisplatin or carboplatin combined with etoposide CE) in frontline treatment of extensive-stage SCLC.
One cycle of CE pre-enrollment was permitted (later mandated). The following four cohorts were enrolled: Rova-T monotherapy (0.3 mg/kg, every 6 q6 wk × 2; cohort 1; n = 4); Rova-T induction (0.3 mg/kg, q6 wk × 2) followed by CE every 21 days (q21) × 4 (cohort 2; n = 5); Rova-T (0.1 or 0.2 mg/kg, q6 wk × 2) overlapping with CE q21 × 4 (cohort 3; n = 14); and Rova-T maintenance (0.3 mg/kg, q6 wk × 2) after CE q21 × 4 (cohort 4; n = 3).
A total of 26 patients were dosed (cohort 3: 14; cohorts 1, 2, and 4 combined: 12). Median age was 66 years, and 73% had Eastern Cooperative Oncology Group performance status of 1. In cohort 3, seven patients (50%) had confirmed objective responses, with a median progression-free survival of 5.2 months and median overall survival of 10.3 months. Compared with cohorts 1, 2, and 4 combined, cohort 3 had lower frequency of some Rova-T–related adverse events of special interest, such as pleural effusion (0 versus 33%), pericardial effusion (0 versus 17%), ascites (0 versus 8%), peripheral edema (36% versus 42%), generalized edema (0 versus 8%), pneumonia (7% versus 25%), and hypoalbuminemia (0 versus 17%).
Lower Rova-T doses may be associated with lower incidence of some Rova-T–related adverse events of special interest. Rova-T 0.2 mg/kg plus CE (cohort 3) was tolerable; however, there was no clear efficacy benefit of adding Rova-T to CE.
Metabolism is a critical basis for immune cell functionality. It was recently shown that NK cell subsets from peripheral blood modulate their expression of nutrient receptors following cytokine ...stimulation, demonstrating that NK cells can adjust to changes in metabolic requirements. As nutrient availability in blood and tissues can significantly differ, we examined NK cells isolated from paired blood-liver and blood-spleen samples and compared expression of the nutrient transporters Glut1, CD98 and CD71. CD56bright tissue-resident (CXCR6+) NK cells derived from livers and spleens expressed lower levels of Glut1 but higher levels of the amino acid transporter CD98 following stimulation than CD56bright NK cells from peripheral blood. In line with that, CD56dim NK cells, which constitute the main NK cell population in the peripheral blood, expressed higher levels of Glut1 and lower levels of CD98 and CD71 compared to liver CD56bright NK cells. Our results show that NK cells from peripheral blood differ from liver- and spleen-resident NK cells in the expression profile of nutrient transporters, consistent with a cell-adaptation to the different nutritional environment in these compartments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recurrence of cytomegalovirus reactivation remains a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation. Monitoring cytomegalovirus-specific cellular ...immunity using a standardized assay might improve the risk stratification of patients. A prospective multicenter study was conducted in 175 intermediate- and high-risk allogeneic hematopoietic stem cell transplant recipients under preemptive antiviral therapy. Cytomegalovirus-specific cellular immunity was measured using a standardized IFN-γ ELISpot assay (T-Track® CMV). Primary aim was to evaluate the suitability of measuring cytomegalovirus-specific immunity after end of treatment for a first cytomegalovirus reactivation to predict recurrent reactivation. 40/101 (39.6%) patients with a first cytomegalovirus reactivation experienced recurrent reactivations, mainly in the high-risk group (cytomegalovirus-seronegative donor/cytomegalovirus-seropositive recipient). The positive predictive value of T-Track® CMV (patients with a negative test after the first reactivation experienced at least one recurrent reactivation) was 84.2% in high-risk patients. Kaplan-Meier analysis revealed a higher probability of recurrent cytomegalovirus reactivation in high-risk patients with a negative test after the first reactivation (hazard ratio 2.73; p=0.007). Interestingly, a post-hoc analysis considering T-Track® CMV measurements at day 100 post-transplantation, a time point highly relevant for outpatient care, showed a positive predictive value of 90.0% in high-risk patients. Our results indicate that standardized cytomegalovirus-specific cellular immunity monitoring may allow improved risk stratification and management of recurrent cytomegalovirus reactivation after hematopoietic stem cell transplantation. This study was registered at www.clinicaltrials.gov as #NCT02156479.
The relevance of pre-existing HLA-antibodies (HLA-Ab) in liver transplantation (LTx) is controversial. While livers are allocated without HLA match or preoperative crossmatch testing, several studies ...point to an impact of donor specific antibodies (DSA) for acute rejection, bile duct complications or even graft loss.
To investigate the role of DSA in long term liver allograft survival we analysed 177 pre transplant sera of first LTx patients with Luminex single antigen technology defining a MFI of >1500 as positive. The analyses were done retrospectively, and the DSA results had no impact on graft acceptance or patients’ therapy. Three year follow up was available for all patients.
77% of our patients had any HLA-Ab pre transplantation, 55 patients were transplanted with DSA by chance.
Acute rejections or ischemic type bile duct lesions (ITBL) were not higher in the DSA group, but ITBL was associated with a higher donor age. There was no difference in long term graft function or survival in patients without HLA-Ab, with non DSA or with DSA (p = 0.712).
We suggest that determination of pre-existing DSA in first LTx recipients is not appropriate and we conclude that pre-existing DSA in first LTx patients are not a contraindication for liver transplantation.
The recruitment and retention of Natural Killer (NK) cells in the liver are thought to play an important role during hepatotropic infections and liver cirrhosis. The aims of this study were to ...determine differences between liver-derived and peripheral blood-derived NK cells in the context of liver inflammation and cirrhosis. We conducted a prospective dual-center cross-sectional study in patients undergoing liver transplantation or tumor-free liver resections, in which both liver tissue and peripheral blood samples were obtained from each consenting study participants. Intrahepatic lymphocytes and PBMCs were stained, fixed and analyzed by flow cytometry. Our results showed that, within cirrhotic liver samples, intrahepatic NK cells were particularly enriched for CD49a+ NK cells when compared to tumor-free liver resection samples. CD49a+ liver-derived NK cells included populations of cells expressing CD25, CD34 and CXCR3. Moreover, CD49a+CD25+ liver-derived NK cells exhibited high proliferative capacity in vitro in response to low doses of IL-2. Our study identified a specific subset of CD49a+CD25+ NK cells in cirrhotic livers bearing functional features of proliferation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Immune responses show a high degree of tissue specificity shaped by factors influencing tissue egress and retention of immune cells. The transcription factor Hobit was recently shown to regulate ...tissue-residency in mice. Whether Hobit acts in a similar capacity in humans remains unknown. Our aim was to assess the expression and contribution of Hobit to tissue-residency of Natural Killer (NK) cells in the human liver. The human liver was enriched for CD56bright NK cells showing increased expression levels of the transcription factor Hobit. Hobitpos CD56bright NK cells in the liver exhibited high levels of CD49a, CXCR6 and CD69. Hobitpos CD56bright NK cells in the liver furthermore expressed a unique set of transcription factors with higher frequencies and levels of T-bet and Blimp-1 when compared to Hobitneg CD56bright NK cells. Taken together, we show that the transcription factor Hobit identifies a subset of NK cells in human livers that express a distinct set of adhesion molecules and chemokine receptors consistent with tissue residency. These data suggest that Hobit is involved in regulating tissue-residency of human intrahepatic CD56bright NK cells in a subset of NK cells in inflamed livers.
Mit dem 2013 in Kraft getretenen Kindes- und Erwachsenenschutzgesetz erlebte das Schweizer System der Kinder- und Jugendhilfe neben rechtlichen auch strukturelle und organisationale Veränderungen. ...Denn dieses Gesetz führte dazu, dass die Kantone und Gemeinden die Zuständigkeiten im Bereich des Kindes- und Erwachsenenschutzes neu regeln und sogenannte Kindes- und Erwachsenenschutzbehörden einrichten mussten. Im Zuge dieser Umgestaltungen wurden neue fachliche und organisationale Rollen und Selbstverständnisse etabliert, die nicht selten Widersprüche und Ambivalenzen erzeugten, welche mitunter bis heute anhalten und zum Teil symptomatisch für die sogenannte "street-level bureaucracy" (LIPSKY 2010 1980) sind. Anhand eines ethnografischen Fallbeispiels gehen wir in diesem Beitrag der Frage nach, wie das von uns untersuchte Jugendamt mit Anforderungen umgeht, die ihm aus unterschiedlichen institutionellen Logiken erwachsen. Mit dem Konzept der "institutional logics" (THORNTON & OCASIO 2008) stützen wir uns auf Überlegungen, die dem organisationssoziologischen Neoinstitutionalismus entstammen. Im untersuchten Jugendamt zeigten sich ambivalente oder gar konfligierende Logiken empirisch nicht nur als verstrickt, sondern gerade ihre Ununterscheidbarkeit eröffnete organisationale Handlungsspielräume. Diese Befunde lassen sich möglicherweise für andere street-level bureaucracies verallgemeinern.
Every patient with kidney failure requiring dialysis in Germany has the right to at least be evaluated for a transplantation. When an affected person can be considered for a transplantation, it must ...be clarified which allocation program is the right one for the person and whether a living organ donor can be considered. It should also be individually discussed with patients which type of donor organ should be accepted. Following a transplantation an individualized immunosuppression is relevant not only for the long-term survival of the transplant but also for the adherence of the patient.
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