Phase 3 immunogenicity and safety study of a tick-borne encephalitis vaccine in healthy Japanese participants 1 year of age and older

BACKGROUND

Tick-borne encephalitis (TBE) virus infects the central nervous system and may lead to severe neurological complications or death. This study assessed immunogenicity, safety, and tolerability of TBE vaccine in Japanese participants 1 year of age and older.

METHODS

This phase 3, multicenter, single-arm, open-label study was conducted in Japanese adult (≥ 16 years) and pediatric (1-< 16 years) populations. Participants received a single 0.5-mL (adult) or 0.25-mL (pediatric) dose of TBE vaccine at each of 3 visits. The primary endpoint was the proportion of participants who were seropositive (neutralization test [NT] titer ≥ 1:10) 4 weeks after Dose 3. Secondary and exploratory endpoints included NT seropositivity rates 4 weeks after Dose 2, immunoglobulin G (IgG) seropositivity 4 weeks after Doses 2 and 3, NT geometric mean titers (GMTs), IgG geometric mean concentrations (GMCs), and geometric mean fold rises. Primary safety endpoints were frequencies of local reactions, systemic events, adverse events (AEs), and serious AEs.

RESULTS

Among 100 adult and 65 pediatric participants, 99.0 % and 100.0 % completed the study, respectively. NT seropositivity was achieved in 98.0 % adult and 100.0 % pediatric participants after Dose 3; seropositivity after Dose 2 was 93.0 % and 92.3 %, respectively. In both age groups, IgG seropositivity was ≥ 90.0 % and ≥ 96.0 % after Doses 2 and 3, respectively; GMTs and GMCs were highest 4 weeks after Dose 3. Reactogenicity events were generally mild to moderate in severity and short-lived. AEs were reported by 15.0 % (adult) and 43.1 % (pediatric) of participants. No life-threatening AEs, AEs leading to discontinuation, immediate AEs, related AEs, or deaths were reported. No serious AEs were considered related to TBE vaccine.

CONCLUSIONS

TBE vaccine elicited robust immune responses in Japanese participants 1 year of age and older. The 3-dose regimen was safe and well tolerated, and findings were consistent with the known safety profile of this TBE vaccine.

CLINICALTRIALS

gov: NCT04648241.

First evidence of tick-borne encephalitis (TBE) outside of Hokkaido Island in Japan

Tick-borne encephalitis (TBE) is an infection of the central nervous system caused by the tick-borne encephalitis virus (TBEV). TBE is endemic in parts of Europe and Asia. TBEV is transmitted to humans primarily by Ixodes ticks. There have been 5 TBE cases identified in Japan, all on the northern island of Hokkaido. Rodents with TBEV antibodies and Ixodes ticks have been identified throughout Japan, indicating that TBEV infection might be undiagnosed in Japan. Residual serum and cerebrospinal fluid (CSF) collected in 2010-2021 from 520 patients ≥1 year-of-age previously hospitalized with encephalitis or meningitis of unknown etiology at 15 hospitals (including 13 hospitals outside of Hokkaido) were screened by ELISA for TBEV IgG and IgM antibodies; TBEV infection was confirmed by the gold standard neutralization test. Residual serum was available from 331 (63.6%) patients and CSF from 430 (82.6%) patients; both serum and CSF were available from 189 (36.3%). Two patients were TBE cases: a female aged 61 years hospitalized for 104 days in Oita (2000 km south of Hokkaido) and a male aged 24 years hospitalized for 11 days in Tokyo (1200 km south of Hokkaido). Retrospective testing also identified a previous TBEV infection in a female aged 45 years hospitalized for 12 days in Okayama (1700 km south of Hokkaido). TBEV infection should be considered as a potential cause of encephalitis or meningitis in Japan. TBE cases are likely undiagnosed in Japan, including outside of Hokkaido, due to limited clinical awareness and lack of availability of TBE diagnostic tests.

Effectiveness of Tick-borne Encephalitis Vaccines in Children, Latvia, 2018-2020

BACKGROUND

Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) with symptoms of central nervous system inflammation. TBE is endemic in Latvia and other parts of Europe. TBE vaccination is recommended for children in Latvia. TBE vaccine effectiveness (VE) was estimated in Latvia, a country with high TBE incidence, providing the first VE estimates against a range of TBEV infection outcomes in children 1-15 years-of-age.

METHODS

Rīga Stradinš University conducted nationwide surveillance for suspected TBE cases. Serum and cerebrospinal fluid were ELISA tested for TBEV-specific IgG and IgM antibodies. A fully vaccinated child was an individual who had received the 3-dose primary series and appropriately timed boosters. The proportion of laboratory-confirmed TBE cases fully vaccinated (PCV) was determined from interviews and medical records. The proportion of the general population fully vaccinated (PPV) was determined from national surveys conducted in 2019 and 2020. TBE VE in children 1-15 years-of-age was estimated using the screening method: VE = 1 - [PCV/(1 - PCV)/PPV/(1 - PPV)].

RESULTS

From 2018 to 2020, surveillance identified 36 TBE cases in children 1-15 years-of-age; all were hospitalized, 5 (13.9%) for >12 days. Of the TBE cases, 94.4% (34/36) were unvaccinated compared with 43.8% of children in the general population. VE against TBE hospitalization in children 1-15 years-of-age was 94.9% (95% confidence interval 63.1-99.3). In 2018-2020, vaccination in children 1-15 years-of-age averted 39 hospitalized TBE cases.

CONCLUSION

Pediatric TBE vaccines were highly effective in preventing TBE in children. Increasing TBE vaccine uptake in children is essential to maximize the public health impact of TBE vaccination.

Effectiveness of tick-borne encephalitis vaccination in Latvia, 2018-2020: an observational study

OBJECTIVES

Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) that results in symptoms of central nervous system inflammation. TBE is endemic in Latvia and other European countries. TBE vaccines are commonly used in Latvia, but vaccine effectiveness estimates are limited.

METHODS

Study staff at Rīga Stradinš University conducted nationwide active surveillance for TBEV infections. Serum and cerebrospinal fluid were ELISA-tested for TBEV-specific IgG and IgM antibodies. Vaccination history was collected by interview and medical record review. Utilising data from surveillance and population surveys, vaccine effectiveness (with 95% confidence intervals) and cases averted were estimated using the screening method.

RESULTS

There were 587 laboratory-identified TBE cases from 2018-2020; 98.1% (576/587) were unvaccinated, 1.5% (9/587) were unknown or partially-vaccinated, and 0.3% (2/587) were fully-vaccinated (three-dose primary series and appropriately timed boosters). TBE resulted in the death of 1.7% (10/587) of TBE cases. TBE vaccine history was ascertained from 92.0% (13,247/14,399) people from the general population: 38.6% (5113/13,247) were unvaccinated, 26.3% (3484/13,247) were fully-vaccinated, and 35.1% (4650/13,247) were partially-vaccinated. TBE vaccine effectiveness was 99.5% (98.0-99.9) against TBE, 99.5% (97.9-99.9) against TBE hospitalisation, 99.3% (94.8-99.9) against moderate/severe TBE, and 99.2% (94.4-99.9) against TBE hospitalisation >12 days. From 2018-2020, vaccination averted 906 TBE cases, including 20 deaths.

CONCLUSIONS

TBE vaccine was highly effective in preventing TBE, moderate and severe disease, and prolonged hospitalisation. To prevent life-threatening TBE, TBE vaccine uptake and compliance should be increased in Latvia and other European regions where TBE is endemic.

Vaccine uptake in 20 countries in Europe 2020: Focus on tick-borne encephalitis (TBE)

Vaccination as a highly effective measure to protect against tick-borne encephalitis (TBE) comes into new focus as known risk areas are expanding across Europe and Asia. Here we present an online household survey conducted in 20 European countries spanning endemic and non-endemic regions of TBE in 2020. With a comprehensive and standardized list of questions, this survey provided a unique opportunity to compare TBE/TBE vaccine awareness, TBE severity perception, vaccine uptake, vaccination completeness/compliance and motivators/barriers for vaccination across Europe. Among the 51,478 participants, tetanus- (72-92%), influenza- (83-98%), and measles-awareness (79-96%) were highest, but awareness was low for Lyme borreliosis, bacterial meningitis and pneumococcal pneumonia. Awareness towards TBE and a TBE vaccine was 74% and 56% in endemic countries, respectively, compared to 30% and 12% in non-endemic countries. Vaccine uptake defined as at least one TBE vaccination was found to be highly heterogenous across both endemic (range 7-81%) and non-endemic countries (range 1-8%). Compliance with the recommended vaccination schedule was 21% for the primary vaccination series and dropped to 7% for the first booster vaccination in endemic countries. The percentage of participants protected against TBE by vaccination at the time of the survey ranged from 21% in Slovakia to 69% in Lithuania. The perception of personal risk or lack thereof was found to be the most influencing factor for and against TBE vaccination. Overall, these data indicate highly heterogenous responses in different European countries regarding not only awareness towards a TBE vaccine, but also regarding TBE vaccine uptake and compliance. Regionally focused strategies to increase diagnostic completeness as well as TBE vaccination are needed across Europe.

Recommendations to Improve Tick-Borne Encephalitis Surveillance and Vaccine Uptake in Europe

There has been an increase in reported TBE cases in Europe since 2015, reaching a peak in some countries in 2020, highlighting the need for better management of TBE risk in Europe. TBE surveillance is currently limited, in part, due to varying diagnostic guidelines, access to testing, and awareness of TBE. Consequently, TBE prevalence is underestimated and vaccination recommendations inadequate. TBE vaccine uptake is unsatisfactory in many TBE-endemic European countries. This review summarizes the findings of a scientific workshop of experts to improve TBE surveillance and vaccine uptake in Europe. Strategies to improve TBE surveillance and vaccine uptake should focus on: aligning diagnostic criteria and testing across Europe; expanding current vaccine recommendations and reducing their complexity; and increasing public education of the potential risks posed by TBEV infection.

Effectiveness of two doses of tick-borne encephalitis (TBE) vaccine

Vaccine effectiveness (VE) was consistently high following two doses (94.6–97.4%) and three doses (96.1%) of the tick-borne encephalitis (TBE) vaccine. These data support the public health value of providing two doses of the TBE vaccine to a traveller to an endemic area presenting with insufficient time to complete the full three-dose primary series.

Effectiveness of TBE vaccination in southern Germany and Latvia

BACKGROUND

Tick-borne encephalitis (TBE) is a vaccine-preventable disease which may cause long-term sequelae and even death. The data on the long-term effectiveness of TBE vaccines are limited. Additionally, the vaccination schedule is complex which in part contributes towards sub-optimal uptake in TBE-endemic areas. The current ecological study measures vaccine effectiveness (VE) in two European countries.

METHODS

TBE VE was measured from 2007 to 2018 in Latvia and Southern German states by age group, vaccination history, and schedule compliance. TBE cases and vaccination history were obtained from the public health agencies for Latvia and the southern German federal states of Bavaria and Baden-Wuerttemberg. Cases were "within schedule" if a TBE infection was diagnosed within the time interval preceding the next scheduled dose and "outside schedule" if the diagnosis occurred after the next scheduled dose. Vaccine uptake was estimated via representative nationwide surveys.

RESULTS

VE after 2, 3, and ≥4 doses was high in both countries at 97.2%, 95.0%, and 95.4% for southern Germany, and 98.1%, 99.4%, and 98.8% for Latvia while within- schedule, and only showed marginal differences outside schedule at 90.6%, 89.9%, and 95.6% for southern Germany, and 97.4%, 98.4%, and 99.0% for Latvia regardless of age groups.

CONCLUSIONS

In both countries, VE after two and three primary doses within-schedule was very high in all age groups. Once receiving booster doses, high VE continued to be observed even in persons with extended intervals since the last dose received, suggesting that longer and more flexible booster intervals may be considered for sustainable long-term protection.

TBE Vaccination Breakthrough Cases-Does Age Matter?

Tick-borne encephalitis (TBE) vaccines are highly effective in preventing TBE and vaccine failures (VF) are rare events. In this study, we compared the age distribution of TBE cases and TBE VF in three endemic countries: Sweden, Southern Germany, and Latvia. While the age distribution of TBE cases was similar for those <50 years versus those ≥50 years in all three countries, in Sweden, a higher proportion of VF cases was ≥50 years, whereas most VF cases in Latvia were <50 years of age and more evenly distributed between those <50 years versus those ≥50 in Southern Germany. Here, theoretical explanations were provided, including differences in diagnostic practices, vaccine uptake between age groups, behavioral patterns and underlying medical conditions, as to why VF were generally older in Sweden than the other countries. There is no scientific rationale to give an extra priming dose of TBE vaccine to subjects ≥50 years of age.

Can the booster interval for the tick-borne encephalitis (TBE) vaccine 'FSME-IMMUN' be prolonged? - A systematic review

Tick-borne encephalitis (TBE) vaccines are effective and well tolerated. However, their acceptance and use by the public in endemic areas are suboptimal. To some extent this is due to the complicated dosing schedule requiring frequent boosters at variable intervals that even change with age. Simplification of the dosing schedule has failed so far as it is debated if the persistence of TBE virus (TBEV) antibodies is the only relevant factor for protection or if immune memory plays a decisive role as well. The objective here is to present the available evidence to determine the need for boosters and their interval after a primary series of three doses of FSME-IMMUN. A systematic literature review was conducted with a focus on serology, particularly seropersistence, immune memory, effectiveness, and vaccine breakthroughs (VB) of FSME-IMMUN. While after a 3-dose primary series seropositivity persisted for more than 10 years in >90% of younger subjects, it dropped to 37.5% in those 60 years or older. In contrast, field effectiveness of FSME-IMMUN remains high in irregularly vaccinated subjects and thus does not correlate well with the percentage of subjects achieving an arbitrarily defined threshold of persisting antibodies. FSME-IMMUN booster doses led to increases in antibody responses within 7 days. VB are rare and remain poorly understood. VB did not increase, and vaccine effectiveness did not significantly decrease with time since completion of the primary vaccination series or with the time since administration of the last vaccine dose. For all these reasons, data identified from this systematic review suggest that seropersistence alone does not explain the high effectiveness of FSME-IMMUN irrespective of the time since the last vaccine dose was administered. Induction of immunological memory characterized by a rapid and sustained secondary immune response is proving to be an alternative mechanism of action for protection against TBE. In this context Switzerland and Finland have adopted a longer booster interval (i.e., 10 years) following the three-dose primary immunization schedule without any evidence of harm at a population level. Longer booster intervals will likely drive up vaccine uptake. There is a lack of data to base an interval recommendation beyond 10 years.

758. Epidemiology of Tick-Borne Encephalitis (TBE): A Traveler′s Perspective

Background

Tick-borne Encephalitis (TBE) is a CNS infection caused by the TBE virus (TBEV), transmitted by ticks or by ingestions of unpasteurized dairy products. Persisting sequelae occur in up to 50% of patients and case fatality rates are 0.4-6% (up to 20% in Russia). There is no specific treatment, but prevention exists. New areas of TBEV circulation were recently identified. Here the current distribution of the TBEV by the end of 2019 is summarized.

Methods

Data were obtained from solicitation of local expert data from countries in Europe and Asia on TBEV isolation, type of surveillance/reporting, past/current case counts, and vaccine uptake, supplemented by literature searches. Countries were classified as suggested by the European Centers for Disease Prevention and Control (ECDC) as TBE- “predisposed” (competent ticks present), “imperiled” (TBEV isolated), “affected” (sporadic autochthonous cases) or “endemic” (annually autochthonous cases).

Results

TBE has now been diagnosed in Eurasia from the United Kingdom, Norway and France in the west, northern Italy in the south, central/eastern Europe, Russia, China on to Japan in the east. “New endemic” countries in the last five years include the United Kingdom, the Netherlands, as well as “new endemic regions”, e.g. in France, Norway, Germany, Finland and Poland. Six countries are considered as predisposed only, three as imperiled, five as affected and 29 as endemic. Misclassification is likely as some countries have no testing (no test), incomplete testing and/or underreporting.

Conclusion

The main considerations of TBEV risk for oversea travelers to Eurasia are: 1) the exact region and terrain within a country; 2) the planned type of (outdoor) activity; 3) the reliability of within country TBEV surveillance. TBE incidences per region may fluctuate log-fold over just a few years and low reported case counts may reflect a lack of testing, and/or preventive measures including vaccine uptake, and underreporting. As the incidence of TBE is unpredictable, prevention measures should be considered for any person traveling or residing in a recognized TBE “risk area”.

Disclosures

Sarah Pugh, PhD, Pfizer (Employee, Shareholder) Wilhelm Erber, PhD, Pfizer (Employee, Shareholder) Andreas Pilz, PhD, Pfizer (Employee, Shareholder) Heinz-Josef Schmitt, MD, Pfizer (Employee, Shareholder)

Seropersistence and booster response following vaccination with FSME-IMMUN in children, adolescents, and young adults

BACKGROUND

Tick-borne encephalitis (TBE) is a viral disease that can have a severe clinical course and considerable long-term morbidity. As no curative treatment exists, vaccination is the primary means of prevention. Long-term antibody seropersistence 2-5 years after the 3-dose primary immunization and 3-10 years after first booster was evaluated, as well as booster responses in children, adolescents and young adults.

METHODS

Subjects who participated in these phase 4 prospective, open-label follow-up studies received all vaccinations with FSME-IMMUN. After 3-dose primary immunization, subjects were followed for 2-5 years. Overall, 205 out of 358 subjects (57%) received the first booster and 179 of these subjects (87%) enrolled in a further 10-year follow-up. Antibody seropersistence was assessed annually. Subjects with a TBE antibody titer below a pre-specified cut-off at the yearly blood draw received a booster. Seropositivity rates and geometric mean fold rises (GMFRs) were assessed.

RESULTS

In children who received their 3-dose primary immunization between 1 and 15 years of age, the seropositivity rate 5 years after the 3rd dose was 84.9% by NT and 72.0% by ELISA. One month post-first booster, all subjects were seropositive by NT and 98.5% by ELISA. Response to first booster by GMFR ranged from 3.7 to 11.4. At 5 years post-first booster, seropositivity was 99.4% by NT and 97.5% by ELISA, and at 10 years, was 90.3% by NT and 87.7% by ELISA. Although seropositivity rates differed between age groups, all subjects (100%) who received a second booster responded with a robust increase of TBEV antibodies.

DISCUSSION

Long-lasting seropersistence of TBEV antibodies after the 3-dose primary immunization and first booster was demonstrated as well as a competent immune memory response in those who received a first or second booster at any time during the 15-year follow-up. Therefore, an extension of FSME-IMMUN booster interval up to 10 years after the 3-dose primary immunization seems warranted. ClinicalTrials.gov Identifier: NCT00894686.

The Effect of Adjunctive Fresh Frozen Plasma Administration on Coagulation Parameters and Survival in a Canine Model of Antivenom-treated Brown Snake Envenoming

This study aimed to assess the effects of dugite envenoming on blood coagulation and platelet count in a canine model, and the efficacy of fresh frozen plasma (FFP) in reversing the clotting disorder after both adequate and inadequate venom neutralization. Following initial dosing and administration studies, an intravenous venom dose of 1μg/kg was administered to eleven dogs. This was followed 30 minutes later by antivenom in either adequate or inadequate doses. A further 30 minutes later, the animals were given either two units of their own FFP or saline. Fibrinogen, aPTT and platelet levels were monitored for eight hours.

Of the six study dogs given antivenom plus FFP, two died at around 60 to 90 minutes post envenoming, at the end of the FFP infusions, and all but one of the survivors had persistent afibrinogenaemia. Of the five study dogs given antivenom and no FFP, all but one had return of detectable fibrinogen at eight hours after envenoming. The platelet count fell in all animals with recovery independent of antivenom dose, administration of FFP, or regeneration of fibrinogen. Post mortem examinations of dogs that died during dosage and administration studies showed massive intracardiac clots.

We conclude that early death from Brown Snake envenoming may be due to massive intravascular clotting. FFP administration was associated with persistent afibrinogenaemia regardless of antivenom dose. In the absence of any evidence for its efficacy, this study suggests that the role of FFP after Brown Snake envenoming should be reconsidered.

Tick-borne encephalitis: A 43-year summary of epidemiological and clinical data from Latvia (1973 to 2016)

Background

The incidence of tick-borne encephalitis (TBE) varies significantly over time. To better understand the annual incidence of all TBE cases in Latvia we investigated the disease burden in the country from 1973–2016 using several available sources and case definitions.

Methods

We identified cases of TBE from an electronic database (maintained by the Centre for Disease Prevention and Control of Latvia [CDPC]) by the use of ICD-10 diagnosis codes for TBE (A84; A84.0; A84.1; A84.8; A84.9). In addition, previously unreported TBE cases were found by review of TBE diagnoses according to ICD-10 codes in four hospital databases.

Results

From 1973 to 2016 a total of 15,193 TBE cases were reported to the CDPC, 2,819 of which were reported from January 2007 through December 2016, additionally for this time period, 104 cases were identified via hospital survey. From all 2,923 reported cases (2007–2016), 1,973 met TBE case definition criteria and were included in the TBE study analysis. The highest average 10 year incidence was observed from 1990–1999 (27.9 cases per 100,000; range 4.6–53.0), however, the average 10-year incidence from 2007–2016 using officially adopted TBE case definition was 9.6 cases per 100,000 (range 5.8–14.6). For this 10-year time period most cases were adults (95.1%) and male (52.2%). The most common clinical form of TBE was meningitis (90.6%). A tick bite prior to TBE onset was reported in 60.6% of TBE cases and 98.2% of cases were not vaccinated against TBE.

Conclusion

The data demonstrate that the incidence of TBE varies by about one third based on the case definition used. TBE occurs almost entirely in the unvaccinated population. Regular TBE awareness campaigns could encourage the population in Latvia to use protective measures to further control TBE in the country, either via vaccination or tick avoidance.

Genetic characterisation of molecular targets in carcinoma of unknown primary

BACKGROUND

Carcinoma of unknown primary (CUP) is a metastatic epithelial malignancy in the absence of an identifiable primary tumour. Prognosis for patients with CUP is poor because treatment options are generally limited to broad spectrum chemotherapy. A shift towards personalised cancer management based on mutation profiling offers the possibility of new treatment paradigms. This study has explored whether actionable, oncogenic driver mutations are present in CUP that have potential to better inform treatment decisions.

METHODS

Carcinoma of unknown primary cases (n = 21) were selected and DNA was isolated from formalin-fixed paraffin embedded sections prior to amplification and sequencing. Two distinct yet complementary targeted gene panels were used to assess variants in up to 76 known cancer-related genes for the identification of biologically relevant and actionable mutations.

RESULTS

Variants were detected in 17/21 cases (81%) of which 11 (52%) were potentially actionable with drugs currently approved for use in known primary cancer types or undergoing clinical trials. The most common variants detected were in TP53 (47%), KRAS (12%), MET (12%) and MYC (12%). Differences at the molecular level were seen between common CUP histological subtypes. CUP adenocarcinomas and poorly differentiated carcinomas harboured the highest frequency of variants in genes involved in signal transduction pathways (e.g. MET, EGFR, HRAS, KRAS, and BRAF). In contrast, squamous cell carcinoma exhibited a higher frequency of variants in cell cycle control and DNA repair genes (e.g. TP53, CDKN2A and MLH1).

CONCLUSION

Taken together, mutations in biologically relevant genes were detected in the vast majority of CUP tumours, of which half provided a potentially novel treatment option not generally considered in CUP.

Abstract P2-01-05: Sensitive blood-based monitoring of breast cancer

Breast cancer is the leading cause of cancer in women worldwide. Although there have been significant advances in the clinical management of breast cancer over the past few decades, women continue to die from this disease. Current methods for detection and monitoring of breast cancer progression, metastasis, and late recurrences lack sensitivity and have not yet been proven to significantly extend overall survival. Current research is focused on identifying novel monitoring methods, with a particular focus on blood-based tumour markers. Monitoring of circulating tumor cells improves detection, but the methods are complex and not applicable to routine practice. A new more sensitive method based on detection of circulating cell free tumor DNA has shown to be more sensitive for women known to have late stage disease. This is a great advance but has not been shown to be a valuable prospective monitoring tool. Tumor derived exosomes (TEX) represent an alternative blood-based method. These are small membrane vesicles that are secreted into the blood and harbor a molecular signature that are directly representative of their 'parent cell'. Emerging evidence suggests that TEX are a veritable 'treasure chest' from which an abundance of stable biomarkers can be isolated and applied to disease monitoring. We hypothesized that: (1) TEX harbor patient-specific DNA mutations similar to those of the patient's tumor; and (2) determining the number and genomic profile of TEX has the capacity for earlier identification of recurrent or progressive disease. To investigate this in a pilot study, TEX were isolated from the plasma of breast cancer patients (n=11) by ultracentrifugation. Western blotting and electron microscopy were performed to validate TEX isolation. DNA was extracted from TEX, patient-matched breast tumor tissue and buccal swabs. Next generation sequencing was performed using the Ion Torrent platform and the Cancer Hotspot Panel v2 (Life Technologies). Despite the small cohort size, there was a statistically significant association (p=0.028) between exosome protein yield and clinical disease stage. TEX protein levels were higher among patients with axillary lymph node involvement (mean 4.8µg per µl of plasma) compared to those with localized disease (mean 3.5µg per µl of plasma). In keeping with other studies the TEX contained low levels of double-stranded DNA that spanned the majority of the genome. Validation of the variants detected in the TEX is currently underway to confirm whether exosomal DNA contains the same genetic variants present in the primary neoplastic tissue. The early detection of breast cancer recurrence and progression represents an unmet challenge that needs to be overcome. This study demonstrates that with continued exploration, TEX may represent a novel approach for disease monitoring that has the potential to improve clinical management and survival.

Citation Format: Meehan K, Ruhen O, Myna K, Mirzai B, Erber W. Sensitive blood-based monitoring of breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-01-05.

ICSH recommendations for identification, diagnostic value, and quantitation of schistocytes

Schistocytes are fragments of red blood cells (RBCs) produced by extrinsic mechanical damage within the circulation. The detection of schistocytes is an important morphological clue to the diagnosis of thrombotic microangiopathic anemia (TMA). Reporting criteria between different laboratories, however, are not uniform, owing to variability of shape and nature of fragments, as well as subjectivity and heterogeneity in their morphological assessment. Lack of standardization may lead to inconsistency or misdiagnosis, thereby affecting treatment and clinical outcome. The Schistocyte Working Group of the International Council for Standardization in Haematology (ICSH) has prepared specific recommendations to standardize schistocyte identification, enumeration, and reporting. They deal with the type of smear, method of counting, morphological description based on positive criteria (helmet cells, small, irregular triangular, or crescent-shaped cells, pointed projections, and lack of central pallor). A schistocyte count has a definite clinical value for the diagnosis of TMA in the absence of additional severe red cell shape abnormalities, with a confident threshold value of 1%. Automated counting of RBC fragments is also recommended by the ICSH Working Group as a useful complement to the microscope, according to the high predictive value of negative results, but worthy of further research and with limits in quantitation.

VS38: a new monoclonal antibody for detecting plasma cell differentiation in routine sections

AIMS

To characterise a new mouse monoclonal antibody, VS38, which recognises an intracytoplasmic antigen of 64 kilodaltons present in normal and neoplastic plasma cells; and to establish its value as a diagnostic reagent for routine pathological practice.

METHODS

A range of normal and neoplastic tissue sections, both frozen and routinely fixed, were immunostained, using the microwave method of antigen retrieval for routinely fixed specimens. The antibody was also tested on blood and bone marrow specimens and a range of human cell lines. The molecular weight of the antigen recognised by the antibody was obtained by western blot analysis. FACS analysis was used to demonstrate the cellular location of the antigen and its presence on tonsil cell suspensions and myeloma cases.

RESULTS

VS38 recognised normal and neoplastic plasma cells in all of the tissues, including all routinely fixed plasma cell neoplasms tested. The antibody also weakly stained epithelial elements within the tissue but was absent from haemopoietic cells of other lineages.

CONCLUSION

Antibody VS38 is of potential value in identifying myeloma or plasmacytoma in bone marrow or other tissues. It differentiates lymphoplasmacytoid lymphoma from lymphocytic and follicular lymphoma. It also subdivides large cell lymphomas into two groups which may be a more reliable method of separating these tumours than morphology alone.

Very early analysis of graft establishment after allogeneic bone marrow transplantation using the polymerase chain reaction

We have used minisatellite polymorphisms flanking the apolipoprotein B locus and PCR to demonstrate the emergence of donor specific alleles in peripheral blood at 3-7 d post allogeneic bone marrow transplantation (BMT). This technique affords a very early indication of the establishment of stable engraftment, and may identify patients at risk of graft failure or leukaemic relapse. Patterns of T-cell chimaerism in the first 7-14 d following transplantation may be closely associated with the development of graft-versus-host disease (GVHD), the graft versus leukaemia (GVL) effect and graft rejection and future application of this technique to the investigation of early T-cell chimaerism may give further insights into these immunologically mediated events.

Separation of polysaccharide-specific human immunoglobulin G subclasses using a protein A superose column with a pH gradient elution system

Protein A Superose was employed to separate affinity-purified anticarbohydrate antibodies according to immunoglobulin G (IgG) subclass. Separation was achieved with a novel buffer system (disodium phosphate-sodium acetate-sodium chloride-glycine), which allowed the generation of a linear pH gradient from pH 8 to 3. Protein A-bound anti-carbohydrate antibodies were eluted as three peaks, two of them mainly containing IgG2 and one consisting of highly enriched IgG1. The enriched antibody preparations retained their functional activity. This separation procedure can be considered as an alternative to the preparation of IgG subclasses with subclass-specific monoclonal antibodies and could be employed whenever contamination with immune complexes has to be avoided.

Acute transformation of essential thrombocythaemia: report of two cases

Two cases of leukaemic transformation are reported, one to acute lymphoblastic leukaemia associated with a 14q+ marker chromosome and the other to acute monocytic leukaemia, occurring 20 and 30 years, respectively, after the original diagnosis was made.

Megakaryoblastic leukaemia and myelofibrosis complicating Fanconi anaemia

A 9-yr-old boy with a 2-yr history of Fanconi anaemia developed worsening pancytopenia that was unresponsive to oxymetholone therapy. Bone marrow was difficult to aspirate but showed the presence of megakaryoblasts. Bone marrow trephine was hypercellular with large clusters of abnormal megakaryocytes and a small population of megakaryoblasts, giving a diagnosis of megakaryoblastic leukaemia.

The differential diagnosis of hairy cell leukemia with a panel of monoclonal antibodies

A panel of monoclonal antibodies reactive with normal human lymphoid cells and with hairy cells has been applied to the immunocytochemical analysis of hairy cell leukemia. Staining was performed by immunoenzymatic methods on frozen sections of bone marrow trephines and extramedullary tissues and on cell smears. Hairy cells reacted with antibodies against HLA-DR, leukocyte common antigen, B-cell antigens (antibodies To15 and B1) and with three anti-hairy cell monoclonal antibodies (S-HCL3, HC1, and HC2). Neoplastic cells in other B-cell lymphoproliferative disorders also expressed HLA-DR, leukocyte common, and B-cell antigens but were consistently negative for the antigen detected by monoclonal antibody S-HCL3. Furthermore, hairy cells differed from other neoplastic B-cells in that they were unreactive with monoclonal antibodies against C3b receptors, anti-Leu-1, Tü1, Tü33, and lacked a meshwork of dendritic reticulum cells. These findings establish a distinctive antigenic phenotype for hairy cell leukemia and indicate that it may be diagnosed reliably by immunoenzymatic labeling of tissue sections or cell smears.