Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal disorder arising after solid organ transplant (SOT) or hematopoietic stem cell transplant (HSCT). Iatrogenically impaired ...immune surveillance and Epstein-Barr virus (EBV) primary infection/reactivation are key factors in the pathogenesis. However, current knowledge on all aspects of PTLD is limited due to its rarity, morphologic heterogeneity, and the lack of prospective trials. Furthermore, the broad spectrum of underlying immune disorders and the type of graft represent important confounding factors. Despite these limitations, several reviews have been written aimed at offering a guide for pathologists and clinicians in diagnosing and treating PTLD. Rather than providing another classical review on PTLD, this “How I Treat” article, based on 2 case reports, focuses on specific challenges, different perspectives, and novel insights regarding the pathogenesis, diagnosis, and treatment of PTLD. These challenges include the wide variety of PTLD presentation (making treatment optimization difficult), the impact of EBV on pathogenesis and clinical behavior, and the controversial treatment of Burkitt lymphoma (BL)-PTLD.
Plasma extracellular vesicles (EVs), especially exosome-like vesicles (ELVs), are being increasingly explored as a source of potential noninvasive disease biomarkers. The discovery of blood-based ...biomarkers associated with ELVs requires methods that isolate high yields of these EVs without significant contamination with highly abundant plasma proteins and lipoproteins. The rising interest in blood-based EV-associated biomarkers has led to the rapid development of novel EV isolation methods. However, the field suffers from a lack of standardization and often, new techniques are used without critical evaluation. Size exclusion chromatography (SEC) has become the method of choice for rapid isolation of relatively pure EVs from plasma, yet it has technical limitations for certain downstream applications. The recently released exoEasy kit (Qiagen) is a new membrane affinity spin column method for the isolation of highly pure EVs from biofluids with the potential to overcome most of the limitations of SEC.
By using multiple complementary techniques we assessed the performance of the exoEasy kit in isolating ELVs from 2 ml of human plasma and compared it with the SEC qEV column (Izon Science).
Our data show that exoEasy kit isolates a heterogenous mixture of particles with a larger median diameter, broader size range and a higher yield than the SEC qEV column. The exclusive presence of small RNAs in the particles and the total RNA yield were comparable to the SEC qEV column. Despite being less prone to low density lipoprotein contamination than the SEC qEV column, the overall purity of exoEasy kit EV preparations was suboptimal. The low particle-protein ratio, significant amount of albumin, very low levels of exosome-associated proteins and propensity to triglyceride-rich lipoprotein contamination suggest isolation of mainly non-ELVs and co-isolation of plasma proteins and certain lipoproteins by the exoEasy kit.
We demonstrate that performance of exoEasy kit for the isolation of ELVs for biomarker discovery is inferior to the SEC qEV column. This comprehensive evaluation of a novel EV isolation method contributes to the acceleration of the discovery of EV-associated biomarkers and the development of EV-based diagnostics.
Primary central nervous system lymphoma (PCNSL) is a rare type of non-Hodgkin lymphoma with an aggressive clinical course. To investigate the potential of immune-checkpoint therapy, we ...retrospectively studied the tumor microenvironment (TME) using high-plex immunohistochemistry in 22 PCNSL and compared to 7 secondary CNS lymphomas (SCNSL) and 7 “other” CNSL lymphomas with the presence of the Epstein–Barr virus and/or compromised immunity. The TME in PCNSL was predominantly composed of CD8+ cytotoxic T cells and CD163+ phagocytes. Despite molecular differences between PCNSL and SCNSL, the cellular composition and the functional spectrum of cytotoxic T cells were similar. But cytotoxic T cell activation was significantly influenced by pre-biopsy corticosteroids intake, tumor expression of PD-L1 and the presence of EBV. The presence of low numbers of CD8+ T cells and geographic-type necrosis each predicted inferior outcome in PCNSL. Both M1-like (CD68 + CD163
low
) and M2-like (CD68 + CD163
high
) phagocytes were identified, and an increased ratio of M1-like/M2-like phagocytes was associated with a better survival. PD-L1 was expressed in lymphoma cells in 28% of cases, while PD1 was expressed in only 0.4% of all CD8+ T cells. TIM-3, a marker for T cell exhaustion, was significantly more expressed in CD8
pos
PD-1
pos
T cells compared to CD8
pos
PD-1
neg
T cells, and a similar increased expression was observed in M2-like pro-tumoral phagocytes. In conclusion, the clinical impact of TME composition supports the use of immune-checkpoint therapies in PCNSL. Based on observed differences in immune-checkpoint expression, combinations that boost cytotoxic T cell activation (by blocking TIM-3 or TGFBR1) prior to the administration of PD-L1 inhibition could be of interest.
Abstract
Peripheral T-cell lymphoma (PTCL) is a heterogeneous group of non-Hodgkin lymphomas with poor prognosis. Up to 30% of PTCL lack distinctive features and are classified as PTCL, not otherwise ...specified (PTCL-NOS). To further improve our understanding of the genetic landscape and biology of PTCL-NOS, we perform RNA-sequencing of 18 cases and validate results in an independent cohort of 37 PTCL cases. We identify
FYN-TRAF3IP2
,
KHDRBS1-LCK
and
SIN3A-FOXO1
as new in-frame fusion transcripts, with
FYN-TRAF3IP2
as a recurrent fusion detected in 8 of 55 cases. Using ex vivo and in vivo experiments, we demonstrate that
FYN-TRAF3IP2
and
KHDRBS1-LCK
activate signaling pathways downstream of the T cell receptor (TCR) complex and confer therapeutic vulnerability to clinically available drugs.
Liver transplantation has emerged as a life-saving treatment for several patients with acute liver failure, end stage liver disease and primary hepatic malignancies. However, long term ...immunosuppressive therapy aiming to reduce the risk of transplant rejection increases the incidence of several com-plications including malignancies. This is illustrated by the observation of a high ratio between observed and expected cases of lymphoproliferative disorders following liver transplantation. Despite a huge heterogeneity in morphological appearance of these disorders ranging from reactive-like lesions to real lymphomas, they are collectively termed posttransplant lymphoproliferative disorders. In this review we will provide an overview of this rare but challenging disorder as a complication of liver transplantation.
Abstract Thrombotic microangiopathy (TMA) is a rare but serious complication of organ transplantation. This article presents the first literature review on TMA following non-renal solid organ ...transplantation (SOT). Ischemia–reperfusion, immunosuppressive drugs, acute interfering disease and a relative deficiency of the von Willebrand factor (vWF) cleaving protease (ADAMTS13) appear to play a major role in its pathogenesis. De novo TMA occurs in 4.0% of liver and 2.3% of lung transplant recipients, whereas the incidence remains unknown after intestinal transplantation. The median time of onset is 2, 37 and 8 weeks after liver, lung and intestinal transplantations respectively, with a three month survival of about 70%. In heart transplantation TMA is rare, occurrence is late and prognosis is poor. In TMA early after liver transplantation an elevated vWF/ADAMTS13 ratio may show diagnostic value. Early withdrawal of calcineurin inhibitors (CNI) proves to be lifesaving. Conversion to another CNI and rechallenge after resolution are generally safe, except after heart transplantation. The value of plasma exchange therapy remains controversial.
The incidence of hematologic malignancies during pregnancy is 0.02%. However, this figure is increasing, as women delay conception until a later age. Systemic symptoms attributed to the development ...of a hematologic cancer may overlap with physiologic changes of pregnancy. A favorable prognosis is contingent upon early diagnosis and treatment. Therefore, a high index of suspicion is required by health care providers. Although timely, accurate diagnosis followed by appropriate staging is essential and should not be delayed due to pregnancy, management guidelines are lacking due to insufficient evidence-based research. Consequently, treatment is delayed, posing significant risks to maternal and fetal health, and potential pregnancy termination. This report provides guidelines for clinical management of hematologic cancers during the perinatal period, which were developed by a multidisciplinary team including an experienced hematologist/oncologist, a high-risk obstetrics specialist, a neonatologist, and experienced nurses, social workers, and psychologists.
These guidelines were developed by experts in the field during the first International Consensus Meeting of Prenatal Hematologic Malignancies, which took place in Leuven, Belgium, on May 23, 2014.
This consensus summary equips health care professionals with novel diagnostic and treatment methodologies that aim for optimal treatment of the mother, while protecting fetal and pediatric health.
Noninvasive prenatal testing (NIPT) for fetal aneuploidy by scanning cell-free fetal DNA in maternal plasma is rapidly becoming a major prenatal genetic test. Similar to placental DNA, tumor DNA can ...be detected in the plasma, and analysis of cell-free tumor DNA can be used to characterize and monitor cancers. We show that plasma DNA profiling allows for presymptomatic detection of tumors in pregnant women undergoing routine NIPT.
During NIPT in over 4000 prospective pregnancies by parallel sequencing of maternal plasma cell-free DNA, 3 aberrant genome representation (GR) profiles were observed that could not be attributed to the maternal or fetal genomic constitution. A maternal cancer was suspected, and those 3 patients were referred for whole-body diffusion-weighted magnetic resonance imaging, which uncovered an ovarian carcinoma, a follicular lymphoma, and a Hodgkin lymphoma, each confirmed by subsequent pathologic and genetic investigations. The copy number variations in the subsequent tumor biopsies were concordant with the NIPT plasma GR profiles.
We show that maternal plasma cell-free DNA sequencing for noninvasive prenatal testing also may enable accurate presymptomatic detection of maternal tumors and treatment during pregnancy.
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