Comparing the outcomes and costs of cardiac monitoring with implantable loop recorders and mobile cardiac outpatient telemetry following stroke using real-world evidence

Aim: Patients with ischemic stroke (IS) commonly undergo monitoring to identify atrial fibrillation with mobile cardiac outpatient telemetry (MCOT) or implantable loop recorders (ILRs). The authors compared readmission, healthcare cost and survival in patients monitored post-stroke with either MCOT or ILR. Materials & methods: The authors used claims data from Optum's de-identified Clinformatics® Data Mart Database to identify patients with IS hospitalized from January 2017 to December 2020 who were prescribed ambulatory cardiac monitoring via MCOT or ILR. They compared the costs associated with the initial inpatient visit as well as the rate and causes of readmission, survival and healthcare costs over the following 18 months. Datasets were balanced using patient baseline and hospitalization characteristics. Multivariable generalized linear gamma regression was used for cost comparisons. Cox proportional hazard regression was used for survival and readmission analysis. Sub-cohorts were analyzed based on the severity of the index IS. Results: In 2244 patients, readmissions were significantly lower in the MCOT monitored group (30.2%) compared with the ILR group (35.4%) (hazard ratio [HR] 1.23; 95% CI: 1.04-1.46). Average cost over 18 months starting with the index IS was $27,429 (USD) lower in the MCOT group (95% CI: $22,353-$32,633). Survival difference bordered on statistical significance and trended to lower mortality in MCOT (8.9%) versus ILR (11.3%) (HR 1.30; 95% CI: 1:00-1.69), led by significance in patients with complications or comorbidities with the index event (MCOT 7.5%, ILR 11.5%; HR 1.62; 95% CI: 1.11-2.36). Conclusion: The use of MCOT versus ILR as the primary monitor following IS was associated with significant decreases in readmission, lower costs for the initial IS and total care over the next 18 months, significantly lower mortality for patients with complications and comorbidities at the index stroke, and a trend toward improved survival across all patients.

Renal vein thrombosis in a patient secondary to high-grade rhabdoid renal cell carcinoma: a case report and review of literature

Introduction

Renal cell carcinoma, a common kidney tumour which is often incidentally discovered on imaging, can manifest with atypical symptoms. Renal cell carcinoma with rhabdoid features is a rare occurrence and even rarer in case of adults. Renal cell carcinoma has the tendency to form thrombus that can migrate to renal vein, inferior vena cava and even right atrium.

Case presentation

The authors report a case of an 81-year-old male with rhabdoid renal cell carcinoma presenting with persistent cough for 6-7 months. with tumour thrombus extending into the renal vein and hepatic inferior vena cava. The patient was found feeble for the surgery and hence was treated on anticancer drugs pembrolizumab and axitinib.

Conclusion

Renal cell carcinoma has the tendency to form tumour thrombus in renal vein and inferior vena cava. Prognosis without surgical intervention in these conditions is very poor.

Longer and better lives for patients with atrial fibrillation: the 9th AFNET/EHRA consensus conference

AIMS

Recent trial data demonstrate beneficial effects of active rhythm management in patients with atrial fibrillation (AF) and support the concept that a low arrhythmia burden is associated with a low risk of AF-related complications. The aim of this document is to summarize the key outcomes of the 9th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA).

METHODS AND RESULTS

Eighty-three international experts met in Münster for 2 days in September 2023. Key findings are as follows: (i) Active rhythm management should be part of the default initial treatment for all suitable patients with AF. (ii) Patients with device-detected AF have a low burden of AF and a low risk of stroke. Anticoagulation prevents some strokes and also increases major but non-lethal bleeding. (iii) More research is needed to improve stroke risk prediction in patients with AF, especially in those with a low AF burden. Biomolecules, genetics, and imaging can support this. (iv) The presence of AF should trigger systematic workup and comprehensive treatment of concomitant cardiovascular conditions. (v) Machine learning algorithms have been used to improve detection or likely development of AF. Cooperation between clinicians and data scientists is needed to leverage the potential of data science applications for patients with AF.

CONCLUSIONS

Patients with AF and a low arrhythmia burden have a lower risk of stroke and other cardiovascular events than those with a high arrhythmia burden. Combining active rhythm control, anticoagulation, rate control, and therapy of concomitant cardiovascular conditions can improve the lives of patients with AF.

Randomised, siteless study to compare systematic atrial fibrillation screening using enrichment by a risk prediction model with standard care in a Swedish population aged ≥ 65 years: CONSIDERING-AF study design

INTRODUCTION

Atrial fibrillation (AF) is the most common arrhythmia and confers an increased risk of mortality, stroke, heart failure and cognitive decline. There is growing interest in AF screening; however, the most suitable population and device for AF detection remains to be elucidated. Here, we present the design of the CONSIDERING-AF (deteCtiON and Stroke preventIon by moDEl scRreenING for Atrial Fibrillation) study.

METHODS AND ANALYSIS

CONSIDERING-AF is a randomised, controlled, siteless, non-blinded diagnostic superiority trial with four parallel groups and a primary endpoint of identifying AF during a 6-month study period set in Region Halland, Sweden. In each group, 740 individuals aged≥65 years will be included. The primary objective is to compare the intervention of AF screening enrichment using a risk prediction model (RPM), followed by 14 days of a continuous ECG patch, with no intervention (standard care). Primary outcome is defined as the incident AF recorded in the Region Halland Information Database after 6 months as compared with standard care. Secondary endpoints include the difference in incident AF between groups enriched or not by the RPM, with and without an invitation to 14 days of continuous ECG recording, and the proportions of oral anticoagulation treatment in the four groups.

ETHICS AND DISSEMINATION

This study has ethical approval from the Swedish Ethical Review Authority. Results will be published in peer-reviewed international journals.

TRIAL REGISTRATION NUMBER

NCT05838781.

Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars

The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater's sedimentary delta, finding the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Fe-Mg carbonates along grain boundaries indicate reactions with CO₂-rich water, under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks were stored aboard Perseverance for potential return to Earth.

Costs and outcomes of mobile cardiac outpatient telemetry monitoring post-transcatheter aortic valve replacement

Aim: To estimate the costs and outcomes of transcatheter aortic valve replacement (TAVR) recipients based on the use of mobile cardiac outpatient telemetry (MCOT) monitoring. Materials & methods: A retrospective database study was conducted to estimate costs, contribution margins (CMs), pacemaker insertions, and other outcomes for patients undergoing TAVR procedures with MCOT monitoring post-procedure versus non-MCOT monitoring. Results: A total of 4164 patients were identified (283 MCOT monitoring and 3881 non-MCOT monitoring). The rate of pacemaker insertion following hospital discharge was higher in the MCOT cohort (6.6 MCOT vs 2.1% non-MCOT; p = 0.007). MCOT use was associated with lower costs and improved CMs of the index TAVR admission (costs: US$40,569 MCOT vs $43,289 non-MCOT; p = 0.003; CMs: US$7087 MCOT vs $5177 non-MCOT; p = 0.047) with no difference through the subsequent 60-day period following discharge. Conclusion: MCOT for ambulatory cardiac monitoring post-TAVR discharge is associated with higher rates of pacemaker insertion, at no overall greater costs.

Wearables, telemedicine, and artificial intelligence in arrhythmias and heart failure: Proceedings of the European Society of Cardiology: Cardiovascular Round Table

Digital technology is now an integral part of medicine. Tools for detecting, screening, diagnosis, and monitoring health-related parameters have improved patient care and enabled individuals to identify issues leading to better management of their own health. Wearable technologies have integrated sensors and can measure physical activity, heart rate and rhythm, and glucose and electrolytes. For individuals at risk, wearables or other devices may be useful for early detection of atrial fibrillation or sub-clinical states of cardiovascular disease, disease management of cardiovascular diseases such as hypertension and heart failure, and lifestyle modification. Health data are available from a multitude of sources, namely clinical, laboratory and imaging data, genetic profiles, wearables, implantable devices, patient-generated measurements, and social and environmental data. Artificial intelligence is needed to efficiently extract value from this constantly increasing volume and variety of data and to help in its interpretation. Indeed, it is not the acquisition of digital information, but rather the smart handling and analysis that is challenging. There are multiple stakeholder groups involved in the development and effective implementation of digital tools. While the needs of these groups may vary, they also have many commonalities, including the following: a desire for data privacy and security; the need for understandable, trustworthy, and transparent systems; standardized processes for regulatory and reimbursement assessments; and better ways of rapidly assessing value.

WHO informal consultation on revision of guidelines on evaluation of similar biotherapeutic products, virtual meeting, 30 June – 2 July 2021

The WHO informal consultation was held to promote the revision of WHO guidelines on evaluation of similar biotherapeutic products (SBPs) adopted by the Expert Committee on Biological Standardization (ECBS) in 2009. It was agreed in the past consultations that the evaluation principles in the guidelines are still valid, but a review was recommended to provide more clarity and case-by-case flexibility. The opportunity was therefore taken to review the experience and identify areas where the current guidance could be more permissive without compromising its basic principles, and where additional explanation could be provided regarding the possibility of reducing the amount of data needed for regulatory approval. The meeting participants applauded the leading role taken by the WHO in providing a much-needed streamlined approach for development and evaluation of SBPs which will provide efficient and cost-effective product development and increase patient access to treatments. It was recognized that the principles as currently described in the draft WHO guidelines are based on sound science and experience gained over the last fifteen years of biosimilar approvals. However, since these guidelines when finalised will constitute the global standard for biosimilar evaluation and assist national regulatory authorities in establishing revised guidance and regulatory practice in this complex area, it was felt that further revision and clarity on certain perspectives in specific areas was necessary to dispel uncertainties arising in the current revised version. This report describes the principles in the draft guidelines, including topics discussed and consensus reached.

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WHO guidelines serve as a basis for the development of national regulatory framework for biosimilars.

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Revision of guidelines is to provide more flexibility and clarification on data required for regulatory approval.

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Revised guidelines would contribute to improving consistency on regulatory decision and patient access to treatments.

Mobile Cardiac Outpatient Telemetry Patch vs Implantable Loop Recorder in Cryptogenic Stroke Patients in the US - Cost-Minimization Model

Purpose

The aim of this study was to compare costs and outcomes of mobile cardiac outpatient telemetry (MCOT) patch followed by implantable loop recorder (ILR) compared to ILR alone in cryptogenic stroke patients from the US health-care payors’ perspective.

Patients and Methods

A quantitative decision tree cost-minimization simulation model was developed. Eligible patients were 18 years of age or older and were diagnosed with having a cryptogenic stroke, without previously documented atrial fibrillation (AF). All patients were assigned first to one then to the alternative monitoring strategies. Following AF detection, patients were initiated on oral anticoagulants (OAC). The model assessed direct costs for one year attributed to MCOT patch followed by ILR or ILR alone using a monitoring duration of 30 days post-cryptogenic stroke.

Results

In the base case modeling, the MCOT patch arm detected 4.6 more patients with AFs compared to the ILR alone arm in a cohort of 1000 patients (209 vs 45 patients with detected AFs, respectively). Using MCOT patch followed by ILR in half of the patients initially undiagnosed with AF leads to significant cost savings of US$4,083,214 compared to ILR alone in a cohort of 1000 patients. Cost per patient with detected AF was significantly lower in the MCOT patch arm $29,598 vs $228,507 in the ILR only arm.

Conclusion

An initial strategy of 30-day electrocardiogram (ECG) monitoring with MCOT patch in diagnosis of AF in cryptogenic stroke patients realizes significant cost-savings compared to proceeding directly to ILR only. Almost 8 times lower costs were achieved with improved detection rates and reduction of secondary stroke risk due to new anticoagulant use in subjects with MCOT patch detected AF. These results strengthen emerging recommendations for prolonged ECG monitoring in secondary stroke prevention.

Oat Cell Carcinoma Lung Presenting as Chest Wall Swelling

Chest wall swelling originating from lung is an uncommon phenomenon that makes its diagnosis a challenging task. We present a case where an 82-year-old man, a lifetime smoker, presented with a chest swelling. The origin of the swelling was an extension of a peripherally located lung malignancy diagnosed with the help of contrast-enhanced CT chest and confirmed as oat(or anaplastic) cell carcinoma on histology. After complete workup it was diagnosed as metastatic small cell carcinoma lung. Patient was managed with palliative chemoradiotherapy.

Blunt Abdominal Trauma With Hollow Viscus and Mesenteric Injury: A Prospective Study of 50 Cases

Introduction Hollow viscus injury following blunt abdominal trauma is an infrequent diagnosis. Blunt hollow viscus and mesenteric injury (HVMI) is not only an uncommon finding but its timely diagnosis is also difficult. Due to its less frequency, this injury has not been studied in detail prospectively. Aims and objectives The aim of this study is to determine the causes, pattern, management, and outcome of HVMI following blunt abdominal trauma. Methodology This study was conducted from January 2015 to June 2016 in a high-volume tertiary care trauma center and teaching hospital in North India. All patients with blunt HVMI admitted during this period were included in this study. Data were collected regarding medical history, physical findings, demographics, injury dates and times, laboratory results, diagnostic tests, delay in surgical intervention, type of surgical procedure performed, site of injury, complications, and mortality. Results Out of a total of 6,570 trauma admissions, 465 blunt abdominal injuries were identified, and HVMI was found only in 50 patients. The small bowel was the most common injury, with the jejunum being the most commonly involved segment. All patients were managed surgically. The mean time to operative intervention after hospital admission was 4.5 hours (IQR: 2-8 hours). Primary repair was performed in 54% of patients. Mortality rate was high in patients with HVMI (22% patients). Septic shock was the most common cause of death. Conclusion Hollow viscus injury in blunt abdominal trauma is not so common finding. Early diagnosis and treatment is an important but difficult task. Prognosis depends on age, associated injuries, co-morbid conditions, and delay in operative intervention.

Magnesium isotopes of the bulk solar wind from Genesis diamond-like carbon films

NASA's Genesis Mission returned solar wind (SW) to the Earth for analysis to derive the composition of the solar photosphere from solar material. SW analyses control the precision of the derived solar compositions, but their ultimate accuracy is limited by the theoretical or empirical models of fractionation due to SW formation. Mg isotopes are "ground truth" for these models since, except for CAIs, planetary materials have a uniform Mg isotopic composition (within ≤1‰) so any significant isotopic fractionation of SW Mg is primarily that of SW formation and subsequent acceleration through the corona. This study analyzed Mg isotopes in a bulk SW diamond-like carbon (DLC) film on silicon collector returned by the Genesis Mission. A novel data reduction technique was required to account for variable ion yield and instrumental mass fractionation (IMF) in the DLC. The resulting SW Mg fractionation relative to the DSM-3 laboratory standard was (-14.4‰, -30.2‰) ± (4.1‰, 5.5‰), where the uncertainty is 2ơ SE of the data combined with a 2.5‰ (total) error in the IMF determination. Two of the SW fractionation models considered generally agreed with our data. Their possible ramifications are discussed for O isotopes based on the CAI nebular composition of McKeegan et al. (2011).

Collaborative study for the establishment of Etanercept Biological Reference Preparation Batch 1

Three preparations of the human tumour necrosis factor (TNF) receptor II Fc fusion protein (TNFR II-Fc) Etanercept were formulated and lyophilised at the National Institute for Biological Standards & Control (NIBSC) prior to evaluation in a collaborative study for their suitability to serve as a World Health Organization (WHO) International Standard (IS)/European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for the potency assay of Etanercept. Seven laboratories tested the preparations using an in vitro cell-based bioassay (TNF-α neutralisation) prescribed by the Ph. Eur. monograph on Etanercept (2895). The results of this study indicated that the candidate preparation, coded 13/204, established as the first IS for Etanercept with an assigned potency for TNF neutralisation activity of 10 000 IU per ampoule was also suitable to serve as Ph. Eur. BRP batch 1. The results were compared to those obtained with different cell-based neutralisation assays that were used by further laboratories in the context of establishing the 1st WHO IS for Etanercept. Based on these analyses, preparation 13/204 was adopted by the Ph. Eur. Commission as Etanercept BRP batch 1 with an assigned potency of 10 000 IU per ampoule.

Collaborative study for the establishment of Infliximab Biological Reference Preparation Batch 1

Two preparations of the chimeric anti-Tumour Necrosis Factor (TNF) monoclonal antibody Infliximab were formulated and lyophilised at the National Institute for Biological Standards & Control (NIBSC) prior to evaluation in a collaborative study for their suitability to serve as a World Health Organization (WHO) International Standard (IS)/European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for the potency assay of Infliximab. Twenty-six laboratories tested the preparations using different in vitro cell-based bioassays (TNF-α neutralisation, antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity) and binding assays. Amongst them, 19 laboratories performed cell-based bioassays. The results of this study indicated that the candidate preparation coded 16/170 was suitable to serve as an International Standard for Infliximab based on the data obtained for biological activity. This candidate standard was established in 2017 as the first International Standard for Infliximab with an assigned potency for TNF neutralisation activity of 500 IU per ampoule. In the same study, the suitability of preparation 16/170 of Infliximab to serve as the European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for the Infliximab potency assay as described in the Ph. Eur. monograph on Infliximab concentrated solution (2928) was also evaluated. The corresponding analysis, based on the measurement of the inhibitory action of anti-human TNF (Infliximab) on the cytotoxic activity of TNF-alpha, was performed using data from a subset of 9 laboratories using the TNF-alpha-sensitive fibrosarcoma cell line WEHI-164. The results obtained were compared to those obtained from different cell-based neutralisation assays that were used by other laboratories in the context of establishing the 1st World Health Organization (WHO) International Standard (IS) for Infliximab. Based on the analyses, preparation 16/170 was adopted by the Ph. Eur. Commission in June 2018 as Infliximab BRP batch 1 with an assigned potency of 500 IU per ampoule.

A genetic screen for increasing metabolic flux in the isoprenoid pathway of Saccharomyces cerevisiae: Isolation of SPT15 mutants using the screen

A genetic screen to identify mutants that can increase flux in the isoprenoid pathway of yeast has been lacking. We describe a carotenoid-based visual screen built with the core carotenogenic enzymes from the red yeast Rhodosporidium toruloides. Enzymes from this yeast displayed the required, higher capacity in the carotenoid pathway. The development also included the identification of the metabolic bottlenecks, primarily phytoene dehydrogenase, that was subjected to a directed evolution strategy to yield more active mutants. To further limit phytoene pools, a less efficient version of GGPP synthase was employed. The screen was validated with a known flux increasing gene, tHMG1. New mutants in the TATA binding protein SPT15 were isolated using this screen that increased the yield of carotenoids, and an alternate isoprenoid, α-Farnesene confirming increase in overall flux. The findings indicate the presence of previously unknown links to the isoprenoid pathway that can be uncovered using this screen.

Basal Cell Adenoma with Perplexity in Diagnosis - A Case Report

Every salivary gland tumour irrespective of its benign or malignant nature or occurrence, exhibits certain unique and overlapping histopathologic features. Basal Cell Adenoma (BCA) is a rare salivary gland tumour and hence it becomes our responsibility to report every case with unique histopathologic features so that it can add to our present knowledge of this lesion. Often, the pathologists experience difficulty while diagnosing lesions like BCA which contain basaloid cells due to its similarity with other lesions of similar histological appearance. Hence, this paper discusses a case of BCA with rare histopathologic features along with the possible differential diagnosis.

Wastes to worth: value added products from fruit and vegetable wastes

Abstract

The concentrations of phenolics and other phytochemicals present in the peels, pulp/pomace and seeds of many fruits and vegetables namely citrus, apples, peaches, pears, banana, pomegranate, berries, mangoes, onions, potatoes, tomatoes and sugar beet are generally substantially higher than in their respective edible tissues, suggesting these wastes and residues to be the potential sources for isolating bio-active compounds. The antioxidants (polyphenolic and other phytochemicals) and other bio-active compounds from these sources exhibit anti-cancer, anti-microbial (pathogens), anti-oxidative and immune-modulatory effects. In addition they reduce incidence of cardiovascular diseases and capillary fragility, inhibit platelet aggregation and prevent thrombosis, oxidative stress, osteoporosis and diabetes in vertebrates. Specifically, the phenolics and flavonoids present in apple, date pit, rambutan (Nephelium lappaceum) peel, tomato peel extracts strongly inhibit tumour-cell proliferation. Penta-O-galloyl-glucoside (PGG) present in mango seed kernel extract and mango peel is used in pharmaceutical industries as it possesses anti-tumor, antioxidant, anti-cardiovascular and hepato-protective effects. The terpenoid and flavonoids in banana foliage exhibit anthelmintic properties. Pomace of apple, pear, orange, peach, blackcurrant, cherry, artichoke, asparagus, onion, raspberry, tomato and carrot, durian seeds (gelling and thickening agents), mango peels, date pits, cauliflower trimmings, empty pea pods and okara are used as dietary fibre supplements and as a functional ingredient in processed food products due to the presence of pectins and carotenoids and bound antioxidants. Some of the fruit and vegetable wastes are excellent source of biopigments; examples being betalains in beet root pulp and carotenoid in carrot pulp. Tomato seeds, banana peel, rambutan and mango seed kernel, passion fruit seed, black currant, date pits are good sources of edible oil rich in polyunsaturated fatty acids. Many fruit and vegetable wastes are used as a substrate for the production of organic acids (citric, lactic and ferulic acids), single cell protein, essential oils, exogenous enzymes, bio-ethanol/methanol, bio-pesticides, bio-sorbants, bio-degradable plastic, bio-fertilizers, bio-preservatives and edible mushrooms. Some have potential to decrease the emission of enteric methane.

Monoclonal antibody TGN1412 trial failure explained by species differences in CD28 expression on CD4+ effector memory T-cells

BACKGROUND AND PURPOSE

In 2006, a life-threatening 'cytokine storm', not predicted by pre-clinical safety testing, rapidly occurred in all six healthy volunteers during the phase I clinical trial of the CD28 superagonist monoclonal antibody (mAb) TGN1412. To date, no unequivocal explanation for the failure of TGN1412 to stimulate profound cytokine release in vitro or in vivo in species used for pre-clinical safety testing has been established. Here, we have identified a species difference almost certainly responsible for this disparate immunopharmacology.

EXPERIMENTAL APPROACH

Polychromatic flow cytometry and intracellular cytokine staining were employed to dissect the in vitro immunopharmacology of TGN1412 and other therapeutic mAbs at the cellular level to identify differences between humans and species used for pre-clinical safety testing.

KEY RESULTS

In vitro IL-2 and IFN-γ release from CD4+ effector memory T-cells were key indicators of a TGN1412-type response. This mechanism of cytokine release differed from that of other therapeutic mAbs, which can cause adverse reactions, because these other mAbs stimulate cytokine release primarily from natural killer cells. In contrast to humans, CD28 is not expressed on the CD4+ effector memory T-cells of all species used for pre-clinical safety testing, so cannot be stimulated by TGN1412.

CONCLUSIONS AND IMPLICATIONS

It is likely that activation of CD4+ effector memory T-cells by TGN1412 was responsible for the cytokine storm. Lack of CD28 expression on the CD4+ effector memory T-cells of species used for pre-clinical safety testing of TGN1412 offers an explanation for the failure to predict a 'cytokine storm' in humans.

Immune responses in advanced colorectal cancer following repeated intradermal vaccination with the anti-CEA murine monoclonal antibody, PR1A3: results of a phase I study

BACKGROUND AND AIMS

The aim was to determine the toxicity, clinical and immune responses to the murine monoclonal anti-carcinoembryonic antigen (CEA) antibody, PR1A3, in patients with advanced colorectal cancer.

MATERIALS AND METHODS

Fifteen patients with advanced colorectal cancer received either 0.5-, 1.0- or 5.0-mg doses of PR1A3 mixed with 10% w/v Alum adjuvant (Superfos Biosector, Denmark) intradermally at 4-week intervals for 3 months. Patient serum was assessed for anti-idiotypic (Ab2), anti-anti-idiotypic (Ab3) and human anti-mouse antibody (HAMA) reactivity. Peripheral blood mononuclear cell (PBMC) proliferation with phytohaemagglutinin (PHA), CEA and PR1A3, stimulated IL-2, IL-4 and IFN-gamma levels and PR1A3-stimulated IL-2 receptor expression during immunotherapy were determined. Comparisons were made with 16 age-matched controls without malignant disease.

RESULTS

Hyperimmune sera from 12 of the 15 patients showed Ab2 reactivity with no detectable Ab3 responses. Strong HAMA reactivity was recorded in 7 of the 15 cases with no adverse clinical effect. Delayed-type hypersensitivity (DTH) responses developed in 12 of the 15 patients. Pre-treatment PBMC proliferation with PHA was subnormal in each patient compared with controls, becoming normal (or supranormal) in all patients during immunisation (P<0.001). PBMC proliferation with CEA and PR1A3 increased during immunotherapy (P<0.001) along with stimulated production of IL-2, IFN-gamma and IL-2 receptor expression. Progressive disease was observed in 14 of the 15 patients with minimal toxicity.

CONCLUSION

PR1A3 generated limited idiotypic responses but robust DTH reactivity in most patients. In vitro PBMC proliferation with mitogens and recall antigens is greatly increased during the course of immunisation, with a shift in stimulated cytokine profile.