Access and use of immunoglobulins in supportive cancer care: A thematic analysis of a systematic review data set.

Background: Secondary immunodeficiency (SID) disorders are known to occur in patients with haematological malignancies (HM) due to immunosuppressive treatments. Recurring infections causing subsequent morbidity and mortality commonly occur in this patient cohort. Immunoglobulin replacement therapy (IgRT) benefits patients with primary antibody deficiencies. However, evidence supporting their therapeutic role is not as explicit in SID-associated antibody deficiencies, which raises the questions regarding its use in SID and the knock-on effects of this use on its access and availability more generally. Objectives: This study aimed to learn about the use of immunoglobulins in SID, identify themes concerning its use and access and suggest methods for improving access. Design: This study included a thematic analysis of a published data set of 43 articles concerning immunoglobulin use and access in SID. Data Sources and Methods: The data set used to perform the thematic analysis is based on research articles identified from Excerpta Medica Database (EMBASE) and PubMed databases, published as part of a systematic review and part 1 of this two-part publication series. Results: A thematic synthesis was conducted to identify recurrent themes. The three primary themes included (1) the context for IgRT prescription, which included patient characteristics and cost burden of IgRT administration, and its use in different countries; (2) factors contributing to inappropriate IgRT use, including health care professionals' awareness of IgRT, disparity between guidelines and actual clinical practice, and the effect of shortages on prescription and chemotherapy-induced hypogammaglobulinemia (HGG); and (3) measures identified to improve IgRT use and access, which included multidisciplinary involvement, improved diagnostic tools and safer withdrawal and stewardship protocols. Conclusions: IgRT use is increasing in HM as a supportive therapy but without comprehensive clinical guidelines and appropriate prescribing recommendations, medication wastage may occur with consequences for immunoglobulin access.

Access and Use of Immunoglobulins in Supportive Cancer Care: A Thematic Analysis of a Systematic Review Data Set This study covers the use of immunoglobulins in SID, identifies themes concerning its use and access and suggests ways for improving both using a thematic analysis approach. The study identified that IgRT use is increasing in haematological malignancies as a supportive therapy but without comprehensive clinical guidelines and appropriate prescribing recommendations, medication wastage may occur with consequences for immunoglobulin access.

Access and use of immunoglobulins in secondary supportive cancer care: A systematic literature review.

Background: Immunoglobulin replacement therapy (IgRT) benefits patients with primary immuno deficiency (PID) originating from the innate or polygenic defects in the immune system. However, evidence supporting their therapeutic role is not as explicit in secondary immuno deficiency (SID) resulting from the treatment of haematological malignancies. Objectives: This study aimed to (1) create a dataset of relevant research papers, which explore the use of IgRT in SID for analysis, (2) assess the risk of bias within this dataset and (3) study the characteristics of these papers. Design: This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. In addition to the risk of bias, the study characteristics explored in this article included study design, study geographical location and year of publication. Data Sources and Methods: To identify studies relevant to the research question, EMBASE and PubMed databases were searched. The Population, Intervention, Comparison and Outcome (PICO) framework was used to assess study quality. Risk of bias and quality of studies were assessed in accordance with the study design. As one model was not appropriate to assess bias in all articles, several tools were used. Results: A total of 43 studies were identified from the literature search as relevant to the research objective. The most common study design was a retrospective case-control cohort study (n = 16/43), and randomised trials were among the least commonly used approaches (n = 1). Research in this area is occurring around the globe including the United States (n = 7), Italy (n = 7), China, India, Japan and throughout Europe. The annual number of papers in this area has varied from 2012 (n = 1) to 2021 (n = 7). The studies in this article demonstrated a varied risk of bias, with 9 of the 20 cohort studies scoring less than 5 out of 9 stars. Conclusions: Randomised controlled trials are less frequently used to assess access and use of immunoglobulins. More commonly, a retrospective case-control cohort study was used which correlates with the higher risk of bias seen in the studies in this article. Most of the research concerning immunoglobulin use and access occurs in higher-income countries.

Changes in cellular prion protein expression, processing and localisation during differentiation of the neuronal cell line CAD 5.

BACKGROUND INFORMATION: Cellular prion protein (PrPC ) is infamous for its role in prion diseases. The physiological function of PrPC remains enigmatic, but several studies point to its involvement in cell differentiation processes. To test this possibility, we monitored PrPC changes during the differentiation of prion-susceptible CAD 5 cells, and then we analysed the effect of PrPC ablation on the differentiation process. RESULTS: Neuronal CAD 5 cells differentiate within 5 days of serum withdrawal, with the majority of the cells developing long neurites. This process is accompanied by an up to sixfold increase in PrPC expression and enhanced N-terminal ß-cleavage of the protein, which suggests a role for the PrPC in the differentiation process. Moreover, the majority of PrPC in differentiated cells is inside the cell, and a large proportion of the protein does not associate with membrane lipid rafts. In contrast, PrPC in proliferating cells is found mostly on the cytoplasmic membrane and is predominantly associated with lipid rafts. To determine the importance of PrPC in cell differentiation, a CAD 5 PrP-/- cell line with ablated PrPC expression was created using the CRISPR/Cas9 system. We observed no considerable difference in morphology, proliferation rate or expression of molecular markers between CAD 5 and CAD 5 PrP-/- cells during the differentiation initiated by serum withdrawal. CONCLUSIONS: PrPC characteristics, such as cell localisation, level of expression and posttranslational modifications, change during CAD 5 cell differentiation, but PrPC ablation does not change the course of the differentiation process. SIGNIFICANCE: Ablation of PrPC expression does not affect CAD 5 cell differentiation, although we observed many intriguing changes in PrPC features during the process. Our study does not support the concept that PrPC is important for neuronal cell differentiation, at least in simple in vitro conditions.

Are prions transported by plasma exosomes?

Blood has been shown to contain disease-associated misfolded prion protein (PrP(TSE)) in animals naturally and experimentally infected with various transmissible spongiform encephalopathy (TSE) agents, and in humans infected with variant Creutzfeldt-Jakob disease (vCJD). Recently, we have demonstrated PrP(TSE) in extracellular vesicle preparations (EVs) containing exosomes from plasma of mice infected with mouse-adapted vCJD by Protein Misfolding Cyclic Amplification (PMCA). Here we report the detection of PrP(TSE) by PMCA in EVs from plasma of mice infected with Fukuoka-1 (FU), an isolate from a Gerstmann-Sträussler-Scheinker disease patient. We used Tga20 transgenic mice that over-express mouse cellular prion protein, to assay by intracranial injections the level of infectivity in a FU-infected brain homogenate from wild-type mice (FU-BH), and in blood cellular components (BCC), consisting of red blood cells, white blood cells and platelets, plasma EVs, and plasma EVs subjected to multiple rounds of PMCA. Only FU-BH and plasma EVs from FU-infected mice subjected to PMCA that contained PrP(TSE) transmitted disease to Tga20 mice. Plasma EVs not subjected to PMCA and BCC from FU-infected mice failed to transmit disease. These findings confirm the high sensitivity of PMCA for PrP(TSE) detection in plasma EVs and the efficiency of this in vitro method to produce highly infectious prions. The results of our study encourage further research to define the role of EVs and, more specifically exosomes, as blood-borne carriers of PrP(TSE).

Mechanisms of prion-induced neurodegeneration.

Transmissible spongiform encephalopathies (TSEs), or prion diseases, are fatal neurodegenerative disorders characterised by long incubation period, short clinical duration, and transmissibility to susceptible species. Neuronal loss, spongiform changes, gliosis and the accumulation in the brain of the misfolded version of a membrane-bound cellular prion protein (PrP(C)), termed PrP(TSE), are diagnostic markers of these diseases. Compelling evidence links protein misfolding and its accumulation with neurodegenerative changes. Accordingly, several mechanisms of prion-mediated neurotoxicity have been proposed. In this paper, we provide an overview of the recent knowledge on the mechanisms of neuropathogenesis, the neurotoxic PrP species and the possible therapeutic approaches to treat these devastating disorders.

Protein misfolding cyclic amplification (PMCA): Current status and future directions.

Transmissible spongiform encephalopathies (TSEs) most commonly known as prion diseases are invariably fatal neurological disorders that affect humans and animals. These disorders differ from other neurodegenerative conformational diseases caused by the accumulation in the brain of misfolded proteins, sometimes with amyloid properties, in their ability to infect susceptible species by various routes. While the infectious properties of amyloidogenic proteins, other than misfolded prion protein (PrP(TSE)), are currently under scrutiny, their potential to transmit from cell to cell, one of the intrinsic properties of the prion, has been recently shown in vitro and in vivo. Over the decades, various cell culture and laboratory animal models have been developed to study TSEs. These assays have been widely used in a variety of applications but showed to be time consuming and entailed elevated costs. Novel economic and fast alternatives became available with the development of in vitro assays that are based on the property of conformationally abnormal PrP(TSE) to recruit normal cellular PrP(C) to misfold. These include the cell-free conversion assay, protein misfolding cyclic amplification (PMCA) and quaking induced conversion assay (QuIC), of which the PMCA has been the only technology shown to generate infectious prions. Moreover, it allows indefinite amplification of PrP(TSE) with strain-specific biochemical and biological properties of the original molecules and under certain conditions may give rise to new spontaneously generated prions. The method also allows addressing the species barrier phenomena and assessing possible risks of animal-to-animal and animal-to-human transmission. Additionally, its unprecedented sensitivity has made possible the detection of as little as one infectious dose of PrP(TSE) and the biochemical identification of this protein in different tissues and biological fluids, including blood, cerebral spinal fluid (CSF), semen, milk, urine and saliva during the pre-clinical and clinical phases of the disease. The mechanistic similarities between TSEs and other conformational disorders have resulted in the adaptation of the PMCA to the amplification and detection of various amyloidogenic proteins. Here we provide a compelling discussion of the different applications of this technology to the study of TSEs and other neurodegenerative diseases.

First demonstration of transmissible spongiform encephalopathy-associated prion protein (PrPTSE) in extracellular vesicles from plasma of mice infected with mouse-adapted variant Creutzfeldt-Jakob disease by in vitro amplification.

The development of variant Creutzfeldt-Jakob disease (vCJD) in three recipients of non-leukoreduced red blood cells from asymptomatic donors who subsequently developed the disease has confirmed existing concerns about the possible spread of transmissible spongiform encephalopathies (TSEs) via blood products. In addition, the presence of disease-associated misfolded prion protein (PrP(TSE)), generally associated with infectivity, has been demonstrated in the blood of vCJD patients. However, its origin and distribution in this biological fluid are still unknown. Various studies have identified cellular prion protein (PrP(C)) among the protein cargo in human blood-circulating extracellular vesicles released from endothelial cells and platelets, and exosomes isolated from the conditioned media of TSE-infected cells have caused the disease when injected into experimental mice. In this study, we demonstrate the detection of PrP(TSE) in extracellular vesicles isolated from plasma samples collected during the preclinical and clinical phases of the disease from mice infected with mouse-adapted vCJD and confirm the presence of the exosomal marker Hsp70 in these preparations.

Candidate cell substrates, vaccine production, and transmissible spongiform encephalopathies.

Transmissible spongiform encephalopathy (TSE) agents have contaminated human tissue-derived medical products, human blood components, and animal vaccines. The objective of this study was to determine the potential susceptibility to infection of 5 cell lines used or proposed for manufacture of biological products, as well as other lines. Cell lines were exposed to the infectious agents of sporadic and variant Creutzfeldt-Jakob disease and bovine spongiform encephalopathy (BSE). Exposed cultures were tested for TSE-associated prion protein (PrP(TSE)) and TSE infectivity by assay in rodents and nonhuman primates. No PrP(TSE) or infectivity has been detected in any exposed cell line under study so far. Animals inoculated with BSE brain homogenate developed typical spongiform encephalopathy. In contrast, animals inoculated with cells exposed to the BSE agent remained asymptomatic. All cell lines we studied resisted infection with 3 TSE agents, including the BSE agent.

Fukuoka-1 strain of transmissible spongiform encephalopathy agent infects murine bone marrow-derived cells with features of mesenchymal stem cells.

BACKGROUND: The possible risk of iatrogenic transmissible spongiform encephalopathies (TSEs, prion diseases) from transplantation of marrow-derived mesenchymal stem cells (MSCs) is uncertain. While most cell lines resist infection, a few propagate TSE agents. STUDY DESIGN AND METHODS: We generated MSC-like (MSC-L) cell cultures from bone marrow (BM) of mice inoculated with the human-derived Fukuoka-1 (Fu) strain of TSE agent. Cultured cells were characterized for various markers and cellular prion protein (PrP(C) ) by fluorescence-activated cell sorting and for PrP(C) and its pathologic TSE-associated form (PrP(TSE) ) by Western blotting (WB). Cell cultures were tested for their susceptibility to infection with Fu in vitro. The infectivity of one Fu-infected cell culture was assayed in mice. RESULTS: BM cells from Fu-infected mice expressed neither PrP(C) nor PrP(TSE) after 3 days in culture as demonstrated by WB. Cells adherent to plastic and maintained under two different culture conditions became spontaneously immortalized and began to express PrP(C) at about the same time. One culture became transformed shortly after exposure to Fu in vitro and remained persistently infected, continuously generating PrP(TSE) through multiple passages; the infectivity of cultured cells was confirmed by intracerebral inoculation of lysates into mice. Both persistently TSE-infected and uninfected cells expressed a number of typical MSC markers. CONCLUSION: BM-derived MSC-L cells of mice became persistently infected with the Fu agent under certain conditions in culture-conditions that differ substantially from those currently used to develop investigational human stem cell therapies.

Susceptibilities of nonhuman primates to chronic wasting disease.

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy, or prion disease, that affects deer, elk, and moose. Human susceptibility to CWD remains unproven despite likely exposure to CWD-infected cervids. We used 2 nonhuman primate species, cynomolgus macaques and squirrel monkeys, as human models for CWD susceptibility. CWD was inoculated into these 2 species by intracerebral and oral routes. After intracerebral inoculation of squirrel monkeys, 7 of 8 CWD isolates induced a clinical wasting syndrome within 33-53 months. The monkeys' brains showed spongiform encephalopathy and protease-resistant prion protein (PrPres) diagnostic of prion disease. After oral exposure, 2 squirrel monkeys had PrPres in brain, spleen, and lymph nodes at 69 months postinfection. In contrast, cynomolgus macaques have not shown evidence of clinical disease as of 70 months postinfection. Thus, these 2 species differed in susceptibility to CWD. Because humans are evolutionarily closer to macaques than to squirrel monkeys, they may also be resistant to CWD.

Murine bone marrow stromal cell culture with features of mesenchymal stem cells susceptible to mouse-adapted human TSE agent, Fukuoka-1.

Transmission of transmissible spongiform encephalopathies (TSEs)/prion diseases through transplantation of bone marrow (BM) has never been reported in humans. However, the use of fetal bovine serum in current protocols for generating mesenchymal stem cells (MSCs) carries the risk of iatrogenic spread. We developed a cell model from murine BM-derived MSCs and tested its susceptibility to Fukuoka-1 (Fu) strain of TSEs. The adherent cells expressed significant levels of normal prion protein, PrPC, at the time when they became immortalized. The cell culture underwent spontaneous transformation following inoculation with Fu-infected brain homogenate and became persistently infected after reinoculation with Fu agent. Extensive analysis of the original and two Fu-exposed cell cultures revealed a phenotype characteristic of MSCs with a majority of cells being positive for stem cell antigen, Sca-1. Taken together, our results demonstrate that BM-derived MSCs can be infected with TSE agents under certain conditions ex vivo. Comprehensive studies should be undertaken to address the safety of cell-based therapies in regard to iatrogenic transmission of TSEs. BM-derived cell cultures can be used for studies of molecular mechanisms underlying the cells' susceptibility to various strains of TSEs, their propagation ex vivo, and for screening of potential anti-TSEs therapeutics.

Persistent propagation of variant Creutzfeldt-Jakob disease agent in murine spleen stromal cell culture with features of mesenchymal stem cells.

The transmission of variant Creutzfeldt-Jakob disease (vCJD) through blood transfusions has created new concerns about the iatrogenic spread of transmissible spongiform encephalopathies (TSEs)/prion diseases through blood and plasma-derived products and has increased the need to develop efficient methods for detection of the agent in biologics. Here, we report the first successful generation of spleen-derived murine stromal cell cultures that persistently propagate two mouse-adapted isolates of human TSE agents, mouse-adapted vCJD, and Fukuoka 1. These new cell cultures can be used efficiently for studies of the pathogenesis of the disease, for development of diagnostics and therapeutics, and as a rapid ex vivo assay for TSE inactivation/removal procedures.

Detection of misfolded prion protein in blood with conformationally sensitive peptides.

BACKGROUND: The long-standing goal of a preclinical diagnostic test for transmissible spongiform encephalopathy (TSE) has recently become urgent because of the discovery that humans with variant Creutzfeldt-Jakob disease can transmit disease via blood transfusions. STUDY DESIGN AND METHODS: The misfolded protein diagnostic (MPD) assay employs a pyrene-labeled palindromic sequence of prion peptides that undergoes a cascade of coil to beta-sheet conversion in the presence of the misfolded prion protein (PrP(TSE)). The ability of the assay to detect PrP(TSE) in brain, serum, and plasma was tested. The basic protocol involved a several-hour incubation of 200-microL sample volumes with the peptide reagent in 96-well plates, after which fluorescence was monitored by a fluorescence plate reader with an excitation wavelength of 350 nm and emission scanning wavelength range of 365 to 600 nm. RESULTS: Target specificity for PrP(TSE) was documented by correlation of assay signal with Western blot signals in brain tissue from TSE-infected, normal, and knockout mice and negative assay signals by use of reagents with different peptide sequences. When applied to plasma or serum, the assay discriminated between samples from a variety of experimental and natural TSE infections compared to uninfected controls, with a sensitivity threshold of approximately 1 infectious dose per mL in pooled plasma from TSE-infected mice. CONCLUSIONS: The MPD assay is a sensitive and specific test for the detection of PrP(TSE) that may be useful in both preclinical and clinical diagnosis of TSE diseases of animals and humans.

Gerstmann-Sträussler-Scheinker: a new phenotype with 'curly' PrP deposits.

Gerstmann-Sträussler-Scheinker (GSS) is a hereditary prion disease typically associated with prion protein (PrP)-containing plaques. The protease-resistant, scrapie PrP (PrPSc) is represented by internal fragments, whereas the C-terminal fragments associated with the other prion diseases are generally underrepresented. Different histopathologic and PrPSc features associated with at least 13 PrP gene (PRNP) mutations have been described in GSS. We report the histopathology and PrP characteristics in a father and son carrying a mutation at PRNP codon 187 that substitutes histidine (H) with arginine (R) and is coupled with valine (V) at position 129 (H187R-129V). The PrP plaques were present in both cases but with different structure and topography and minimal spongiform degeneration. A distinctive, "curly" PrP immunostaining was prominent in one case. The protease-resistant PrPSc differed in amount in the 2 cases, possibly depending on whether plaques or the curly immunostain was present. Two protease-resistant PrP fragments of 14 kDa and 7 kDa with, in at least one case, N-terminus between residues 90-99 and 82-90, respectively, codistributed with the plaques, whereas only very small amounts of the PK-resistant PrP were present in the curly staining regions. PK-resistant PrP recovered from the plaque and curly staining regions appeared to be full length.

Protease-resistant prion protein in lymphoreticular tumors of variant Creutzfeldt-Jakob disease mice.

We report protease-resistant prion protein (PrPres) in spontaneous lymphoreticular tumors of mice infected with the agent of variant Creutzfeldt-Jakob disease (vCJD). PrPres may accumulate in lymphoreticular system tumors of asymptomatic persons with vCJD. The statistical power of estimates of vCJD prevalence might be increased by expanding screening to include samples of lymphoreticular neoplasms.

Effect of protease treatment on plasma infectivity in variant Creutzfeldt-Jakob disease mice.

BACKGROUND: The emergence of variant Creutzfeldt-Jakob disease (vCJD) and of a probable transmission of the disease through blood transfusion from a presymptomatic case has underlined the need for a reliable, sensitive, and specific screening test. This study was initiated to explain why attempts to identify protease-resistant prion protein (PrPres) following treatment with proteinase K (PK) in blood or blood components have so far failed. STUDY DESIGN AND METHODS: RIII mice were inoculated intracerebrally (i.c.) with vCJD agent. As soon as some mice became ill, blood from all mice was collected, pooled, and separated into components. Aliquots of plasma were treated with either 100 and 500 microg per mL PK or left untreated. Samples were analyzed for total protein and for PrPres by Western blot with 6H4 antibodies. Infectivity in PK-treated and untreated samples was bioassayed by i.c. inoculation into healthy mice. RESULTS: Estimated infectivity in untreated control plasma was 20.6 IU per mL. Treatment of plasma with 100 or 500 microg per mL PK resulted in estimated infectivity levels of 8.4 and 5.2 IU per mL, respectively. Coomassie staining revealed substantial changes in the protein profile after PK treatment, with massive degradation of proteins at 500 microg per mL PK. No PrPres was detected in plasma samples by Western blotting. CONCLUSION: Infectivity in plasma of vCJD-infected mice showed a trend toward reduction following enzymatic treatment with increasing doses of PK, possibly because of activity against proteolysis-sensitive isoforms of abnormal prion protein. It is concluded that the use of PK in protocols for the detection of PrPres may decrease the sensitivity of blood-based assays.

Advances in screening test development for transmissible spongiform encephalopathies.

The blood of patients with transmissible spongiform encephalopathy or prion disease can no longer be considered free of infectivity. There have been two recent reports of highly probable transfusion-associated iatrogenic variant Creutzfeldt-Jakob disease infections, and there is supporting experimental evidence of scrapie transmission by the transfusion of blood from sheep with naturally occurring disease. In the absence of a preclinical diagnostic test for transmissible spongiform encephalopathy, the main precautionary measures undertaken by blood agencies employ donor exclusion criteria, ensuring that the number of any further iatrogenic cases will be small. The development of a sensitive, specific and reliable diagnostic test is urgently needed for early identification of infected individuals in order to ensure the safety of blood supplies. During the past 5 years, significant progress has been made in improving the sensitivity and specificity of tests using brain and lymphoreticular tissues to identify Creutzfeldt-Jakob disease-infected individuals. However, the quest for a blood test is still in its infancy and requires extensive further research.

The modern landscape of transfusion-related iatrogenic Creutzfeldt-Jakob disease and blood screening tests.

The idea that blood in naturally occurring transmissible spongiform encephalopathies is not infectious has imploded in the face of recent transmissions from the blood of naturally occurring scrapie in sheep and of variant Creutzfeldt-Jakob disease in humans. Although donor exclusion criteria ensure that the number of any further iatrogenic cases will be small, the risk of future blood-borne disease transmissions could be entirely eliminated by a diagnostic preclinical screening test. A variety of methodological approaches to blood testing are under development, with different levels of success, but no method has yet achieved the critical goal of discriminating transmissible spongiform encephalopathy-infected from healthy uninfected humans.