Molecular characterization of Yersinia enterocolitica strains to evaluate virulence associated genes

INTRODUCTION

Yersinia enterocolitica (Ye) species is divided into 6 biotypes (BT), 1A, 1B, 2, 3, 4, 5 classified based on biochemical reactions and about 70 serotypes, classified based on the structure of the lipopolysaccharide O-antigen. The BT1A is considered non-pathogenic, while the BT 1B-5 are considered pathogenic.

METHODS

Evaluate the distribution of eleven chromosomal and plasmid virulence genes, ail, ystA, ystB, myfA, hreP, fes, fepD, ymoA, sat, virF and yadA, in 87 Ye strains isolated from food, animals and humans, using two SYBR Green real-time PCR platforms.

RESULTS

The main results showed the presence of the ail and ystA genes in all the pathogenic bioserotypes analyzed. The ystB, on the other hand, was identified in all non-pathogenic strains biotype 1A. The target fes, fepD, sat and hreP were found in both pathogenic biotypes and in BT1A strains. The myfA gene was found in all pathogenic biotype and in some Ye BT1A strains. The virF and yadA plasmid genes were mainly detected in bioserotype 4/O:3 and 2/O:9, while ymoA was identified in all strains.

CONCLUSIONS

The two molecular platforms could be used to better define some specific molecular targets for the characterization and rapid detection of Ye in different sources which important implications for food safety and animal and human health.

Evaluation of the Virulence Potential of Listeria monocytogenes through the Characterization of the Truncated Forms of Internalin A

Listeria monocytogenes is a widespread Gram-positive pathogenic bacterium that causes listeriosis, a rather rare but severe foodborne disease. Pregnant women, infants, the elderly, and immunocompromised individuals are considered particularly at risk. L. monocytogenes can contaminate food and food-processing environments. In particular, ready-to-eat (RTE) products are the most common source associated with listeriosis. L. monocytogenes virulence factors include internalin A (InlA), a surface protein known to facilitate bacterial uptake by human intestinal epithelial cells that express the E-cadherin receptor. Previous studies have demonstrated that the presence of premature stop codon (PMSC) mutations naturally occurring in inlA lead to the production of a truncated protein correlated with attenuate virulence. In this study, 849 L. monocytogenes isolates, collected from food, food-processing plants, and clinical cases in Italy, were typed and analyzed for the presence of PMSCs in the inlA gene using Sanger sequencing or whole-genome sequencing (WGS). PMSC mutations were found in 27% of the isolates, predominantly in those belonging to hypovirulent clones (ST9 and ST121). The presence of inlA PMSC mutations in food and environmental isolates was higher than that in clinical isolates. The results reveal the distribution of the virulence potential of L. monocytogenes circulating in Italy and could help to improve risk assessment approaches.

Newly Designed Primers for the Sequencing of the inlA Gene of Lineage I and II Listeria monocytogenes Isolates

Listeria monocytogenes is a major human foodborne pathogen responsible for listeriosis. The virulence factor Internalin A (inlA) has a key role in the invasion of L. monocytogenes into the human intestinal epithelium, and the presence of premature stop-codons (PMSC) mutations in the inlA gene sequence is correlated with attenuated virulence. The inlA sequencing process is carried out by dividing the gene into three sections which are then reassembled to obtain the full gene. The primers available however were only able to entirely amplify the lineage II isolates. In this study, we present a set of new primers which allow inlA sequencing of isolates belonging to both lineages, since lineage I isolates are the ones most frequently associated to clinical cases. Using newly designed primers, we assessed the presence of inlA PMSCs in food, food processing environments and clinical isolates.

Gluten quantification in gluten-free food for celiac people in Lombardy and Emilia Romagna - Italy

Background

In recent decades, the celiac disease showed a gradual increase in prevalence. Therefore, there was a raised demand of gluten-free products. EU Reg. 1169/2011 states that 20 mg.kg-1 (ppm) is the maximum gluten content in food for celiac people, and that “gluten-free” labelling must be put on compliant food packages. This work is a study on different food categories, aiming at verifying the safety of analyzed samples.

Methods

Totally, 4615 gluten-free-labelled specimens were collected from January 2019 to April 2022 (pasta, 2944; cured meat, 566; flours/bakery, 489; sweets, 125 and other matrices, 491). A commercially available E.L.I.S.A. kit, according to the AOAC 2012.01-2016 method, was used to quantify gluten.

Results

In 97% of samples (4475) the gluten content was <5 ppm (lower LOD), and in 2.4% (112) it was between 5 ppm and <20 ppm. In the remaining 0.6% (28), the gluten concentration was ≥20 ppm. Of these, 0.32% (15) were between 20 and <80 ppm (upper LOD), and 0.28% (13) ≥80 ppm.

Conclusions

The increased prevalence of celiac disease and the consumers’ perception that a gluten-free diet gives benefits, lead to a greater demand of gluten-free products. In this study, 99.4% of samples were compliant with the gluten-free labelling and safe for celiac consumers. The 0.32% had a gluten content between 20 and 80 ppm, still considered “compliant”, according to the EU Reg. 828/2014 that defines as very low gluten containing (thus edible for some celiac groups), those products with a gluten content <100 ppm. Only 0.28% of samples was non-compliant (≥80 ppm). However, the authors accounted irregular those foods with ≥20 ppm. Considering the importance of these products in the daily diet, and the increasing probability to get sick by individuals, the study of their compliance to the law limits results to be important.

Key messages

• A continuous surveillance of gluten-free-labelled food products is very important to prevent risks for celiac consumers.

• The foodstuffs distributed in the two considered regions are mainly safe for celiac patients.

Integrated monitoring of AMR and enterotoxins genes of S. aureus isolated in Lombardy

Background

S. aureus is a widespread pathogen responsible for mild to severe human and animals’ infections. The abuse of antimicrobials provides the potential for selection of resistant strains in livestock, which represents a public health concern. S. aureus can carry several virulence factors of which staphylococcal enterotoxins (SEs) play a key role during food poisoning in human populations. The aim of this study is to monitor the prevalence of antimicrobial resistance factors in S. aureus isolates and their ability to produce enterotoxins.

Methods

Within an ongoing monitoring plan for the assessment of antimicrobial resistance in S. aureus strains, a total of 83 isolates collected from food, and swine and dairy farms, between 2020-2022, were characterized using MLST and then screened for the presence of methicillin resistance and SEs genes. The isolates were tested for susceptibility to a panel of 14 antimicrobial agents using the disc agar diffusion method on Mueller-Hinton agar.

Results

Among 83 S. aureus isolates, 53% carried at least one SEs gene. Eighteen isolates were methicillin-resistant of which 17 were no-enterotoxigenic strains belonging to ST398, and one was a food origin ST8 strain and harbored SEs genes. Among the ST398 isolates, only one was a food origin strain, while the others were from swine farms. The antibiogram showed that a few isolates were susceptible to nalidixic acid, and 42% resulted multidrug-resistant.

Conclusions

Our results showed that more than half of S. aureus isolates were enterotoxigenic, the majority belonging to food industries. Numerous tested isolates resulted multidrug-resistant, confirming that antimicrobial resistance is a critical public health threat in a food safety perspective.

Key messages

• The antimicrobial resistance profiles of S. aureus isolates underlines the importance of monitoring plans with a One Health perspective.

• The prevalence of enterotoxins genes in S. aureus strains in Lombardy confirms the relevance of the microorganism as a foodborne pathogen.

Is SARS-CoV-2 a Concern for Food Safety? A Very Low Prevalence from a Food Survey during the COVID-19 Pandemic in Northern Italy

In 2019, SARS-CoV-2 was identified as the cause of an easily transmissible disease that was declared as a world pandemic. Foodborne transmission was never reported. However, early studies suggested that food could be involved in SARS-CoV-2 entry in the human gastrointestinal tract leading to possible infection, and highlighting the importance of further studies to inspect possible issues linked to food consumption. In this perspective, this work aimed at monitoring SARS-CoV-2 presence in some food and mains water samples in Northern Italy during the COVID-19 pandemic (2020–2022). A total of 1806 foods, 112 mains water samples, and 580 swabs on meat and dairy product surfaces were analyzed for SARS-CoV-2 RNA detection by Real-time PCR. All the analyzed samples were negative to viral RNA detection with the exception of one vegetable sample. Even if data on foodborne coronavirus transmission suggested a limited importance of this pathway, the impact of the current pandemic in Northern Italy deserved a rigorous investigation to rule out such possibility. Indeed, gaining insight on all SARS-CoV-2 possible transmission pathways, including the foodborne route, seemed of interest to maintain consumers’ confidence and trust in food safety, and for the effective management of the current, and future, possible pandemics.

Infant Botulism: Checklist for Timely Clinical Diagnosis and New Possible Risk Factors Originated from a Case Report and Literature Review

Infant botulism is a rare and underdiagnosed disease caused by BoNT-producing clostridia that can temporarily colonize the intestinal lumen of infants less than one year of age. The diagnosis may be challenging because of its rareness, especially in patients showing atypical presentations or concomitant coinfections. In this paper, we report the first infant botulism case associated with Cytomegalovirus coinfection and transient hypogammaglobulinemia and discuss the meaning of these associations in terms of risk factors. Intending to help physicians perform the diagnosis, we also propose a practical clinical and diagnostic criteria checklist based on the revision of the literature.

Rare internalin A premature stop codon on Listeria monocytogenes on Italian PDO cheeses isolates

Background

Listeria monocytogenes is a widespread foodborne pathogen that causes listeriosis, a human infection with low morbidity but high mortality. Internalin A (InlA), a L. monocytogenes virulence factor, has a key role in the invasion of human intestinal epithelium through the interaction with E-cadherin receptor. Truncated InlA caused by premature stop-codons (PMSC) have been correlated with attenuated virulence. To date, 29 mutations leading to a PMSC have been reported. In this study, we identified a rare PMSC mutation widespread in isolates from the production chain of the Gorgonzola and Taleggio PDO cheeses.

Methods

Within an ongoing monitoring plan for the characterization of L. monocytogenes, a total of 81 isolates collected in Lombardy (Northern Italy) from food, food processing environments, and clinical cases, between 2013-2021, were characterized using multilocus sequence tying (MLST) and then screened for the presence of PMSC by sequencing the 2400 pb inlA gene.

Results

A mutation leading to PMSC was identified on the position 277 (PMSC mutation type 26). To date, this mutation has been reported only on a CC7 strain from a clinical case. In our study, all isolates harbouring this mutation (n = 21) belong to ST325 (CC31, serotype 1/2a). Among these, 86% (n = 18) belong to the production chain of the Gorgonzola and Taleggio PDO cheeses.

Conclusions

To the best of our knowledge, this is the first report of PMSC mutation type 26 on food and environmental isolates. Although PMSC 26 is rarely found worldwide, our findings suggest that ST325 with this mutation is widespread in the production chain of the two PDO cheeses, and the presence of this PMSC may be correlated with the low incidence of ST325 clinical cases.

Key messages

A rare mutation leading to truncated InlA has been identified in a cluster of isolates correlated to the production chain of two PDO cheeses. Truncated inlA is suggestive of adaptation to the niche to the detriment of virulence.

A Listeria monocytogenes ST325 clone is widespread in the Lombardy Region dairy processing plants

Background

Listeria monocytogenes is a foodborne pathogen with low incidence but severe manifestations in at risk categories (up to 30% fatality rate in YOPI). L. monocytogenes can form biofilm and persist in food processing environments for decades. In the Lombardy Region up to 50% of listeriosis cases have been attributed to dairy products. This study aimed at investigating a L. monocytogenes clone widely present in one of the most important Italian cheese production chain.

Methods

Through a retrospective analysis of the Lombardy Region PFGE database a cluster comprising isolates from eight PDO Gorgonzola and Taleggio dairies (2013-2019) was identified. A representative subset of 33 isolates was typed with MLVA and MLST. All isolates were further typed with WGS and compared to all Lombardy clinical isolates (n = 9) that shared the same Sequence Type (ST). Genomic relationship among isolates were investigated with cgMLST and SNP analysis.

Results

All isolates had the same MVLA/MLST profile (ST325). cgMLST and SNP analysis divided the isolates in two clusters that however shared a very high similarity (99.4%). Interestingly, isolates collected from same production plants clustered separately. Conversely, isolates collected in different years and plants clustered together. By querying the L. monocytogenes MLVA database it was possible to identify isolates of the same production chain with identical profile back to the year 2005. ST325 clinical isolates represented 2% of all typed clinical isolates and have an incidence of 0.007 cases/100000 inhabitants. Due to the high genomic similarity, it was not possible to link any clinical isolate to a putative source.

Conclusions

Our data suggest a persistent contamination by a L. monocytogenes ST325 clone traced back to the year 2005 present in the dairy production chain of Lombardy. Given the high similarity among the isolates further analyses with a larger dataset and are needed to elucidate the epidemiology of this clone.

Key messages

A highly clonal contamination by L. monocytogenes is widespread in the Lombardy Region dairy production chain. The low incidence of ST325 among the population suggests a low pathogenicity of the strain, however the occurrence of an ongoing long-term outbreak cannot be excluded.

Second cancers in MPN: Survival analysis from an international study

One out of ten patients with Philadelphia-negative myeloproliferative neoplasms (MPN) develop a second cancer (SC): in such patients we aimed at assessing the survival impact of SC itself and of MPN-specific therapies. Data were therefore extracted from an international nested case-control study, recruiting 798 patients with SC diagnosed concurrently or after the MPN. Overall, 2995 person-years (PYs) were accumulated and mortality rate (MR) since SC diagnosis was 5.9 (5.1-6.9) deaths for every 100 PYs. A "poor prognosis" SC (stomach, esophagus, liver, pancreas, lung, ovary, head-and-neck or nervous system, osteosarcomas, multiple myeloma, aggressive lymphoma, acute leukemia) was reported in 26.3% of the patients and was the cause of death in 65% of them (MR 11.0/100 PYs). In contrast, patients with a "non-poor prognosis" SC (NPPSC) incurred a MR of 4.6/100 PYs: 31% of the deaths were attributed to SC and 15% to MPN evolution. At multivariable analysis, death after SC diagnosis was independently predicted (HR and 95% CI) by patient age greater than 70 years (2.68; 1.88-3.81), the SC prognostic group (2.57; 1.86-3.55), SC relapse (1.53; 10.6-2.21), MPN evolution (2.72; 1.84-4.02), anemia at SC diagnosis (2.32; 1.49-3.59), exposure to hydroxyurea (1.89; 1.26-2.85) and to ruxolitinib (3.63; 1.97-6.71). Aspirin was protective for patients with a NPPSC (0.60; 0.38-0.95). In conclusion, SC is a relevant cause of death competing with MPN evolution. Prospective data are awaited to confirm the role of cytoreductive and anti-platelet drugs in modulating patient survival after the occurrence of a SC.

Contamination of Poultry Meat with Salmonella infantis should be considered a Risk for Food Safety?

Issue/problem

EU Regulation regarding fresh poultry meat considers only S. enteritidis or S. typhimurium as Food Safety Criteria. On the contrary, the isolation of other Salmonella spp. in this food matrices is considered compliant. Several bibliographical sources indicate an increase in the isolation trend of S. infantis in the poultry industry and in derived products.

Description of the problem

Episodes of food poisoning caused by fresh chicken meat contaminated with S. infantis have been recently reported. According to CDC, last year in USA, an outbreak caused by a S. infantis strain, resistant to multiple antibiotics, ended with 129 sick people, 25 hospitalizations and a death. National Salmonellosis Control Plan for Poultry 2019-21 establishes in Italy the abatement conditions for poultry farms in case of positive isolation of S. enteritidis, S. typhimurium and S. infantis.

Results

In 2018, the National Health System disposed the analysis of batches of fresh chicken meat from Poland, sampled in a cold storage facility in Northern Italy. Food Control Dept. of IZSLER analysed 156 samples for a total of 780 sampling units (s.u.), for Salmonella spp.: 72 samples were positive (46,15%;corresponding to 222 s.u. - 28,46%). 42 strains were serotyped as S. enteritidis, 149 as S. infantis, 26 as S. newport, 4 as S. kentucky and 1 as S. mbandaka. According to EU Regulation, batches positive for S. enteritidis were indicated as not compliant, but batches positive to other Salmonella were considered regular.

Lessons

EU legislation allows the circulation of chicken meat contaminated with S. infantis. Chicken meat should be consumed after appropriate well cooking eliminating this hazard, but it does not protect the consumer from the risk of cross-contamination of tools and surfaces at the household level. It’s therefore fundamental the application of correct processing practices in order to prevent the spreading of Salmonella in home kitchens and limit dangerous episodes of infection.

Key messages

S. infantis trend of isolation in the poultry industry is increasing. application of GMPs in home cooking is fundamental to limit food outbreaks of infection.

Integrated veterinary-medical activity on characterization of shigatoxin producing Escherichia coli

Background

Shiga toxin-producing Escherichia coli (STEC) are an important public health concern as they cause severe conditions (bloody diarrhea and hemolytic uremic syndrome - HUS) and have epidemic potential. Cattle are the main reservoir for the highly virulent STEC O157 strain, and other HUS-associated non-O157 strains. This study aimed to characterize strains from animals and humans and to compare their molecular profiles. Animal isolates were tested for the presence of virulence factors correlated to their pathogenic potential.

Methods

74 STEC human isolates from 43 clinical cases (sporadic or epidemic) and 270 animal isolates from feces from 62 cattle farms were collected. Epidemiological investigation to collect environmental and suspected food samples was carried out for 22 cases. All isolates were typed with PFGE and their serotype was defined by Real-Time PCR. Animal isolates were also tested for the presence of subAB, saa, tia, cfk, adfO, hlyA, efaI1-lifA5’3’, and toxB virulence genes.

Results

O157 was detected in 44% of human cases, other relevant serogroups O26, O111, O103, O145 in 21, 9, 5 and 5% of cases, respectively. The source of infection was identified in one case (cheese contaminated by a O157 strain). Among animal isolates 2, 0.7, 0.7 and 0.3% were identified as O157, O11, O113, and O145, respectively. PFGE highlighted a high heterogeneicity among animal strains, however no pulsotype common to cattle and clinical isolates was found. adfO, cfk, efaI1-lifA5’3’ and toxB were found significantly correlated to eae (intimin).

Conclusions

Human and cattle strains were not correlated, however STEC diversity in cattle was very high and included some strains potentially pathogenic to humans. For this reason, upholding an integrated surveillance is very important.

Key messages

Serotypes relevant to human health were found in cattle in a small but not negligible frequence. No direct correlation was found between animal and clinical isolates.

Addressing and proposing solutions for unmet clinical needs in the management of myeloproliferative neoplasm-associated thrombosis: A consensus-based position paper

This article presents the results of a group discussion among an ad hoc constituted Panel of experts aimed at highlighting unmet clinical needs (UCNs) in the management of thrombotic risk and thrombotic events associated with Philadelphia-negative myeloproliferative neoplasms (Ph-neg MPNs). With the Delphi technique, the challenges in Ph-neg MPN-associated thrombosis were selected. The most clinically relevant UCNs resulted in: (1) providing evidence of the benefits and risks of direct oral anticoagulants, (2) providing evidence of the benefits and risks of cytoreduction in patients with splanchnic vein thrombosis without hypercythemia, (3) improving knowledge of the role of the mutated endothelium in the pathogenesis of thrombosis, (4) improving aspirin dosing regimens in essential thrombocythemia, (5) improving antithrombotic management of Ph-neg MPN-associated pregnancy, (6) providing evidence for the optimal duration of anticoagulation for prophylaxis of recurrent VTE, (7) improving knowledge of the association between somatic gene mutations and risk factors for thrombosis, and (8) improving the grading system of thrombosis risk in polycythemia vera. For each of these issues, proposals for advancement in research and clinical practice were addressed. Hopefully, this comprehensive overview will serve to inform the design and implementation of new studies in the field.

Second cancer in Philadelphia negative myeloproliferative neoplasms (MPN-K). A nested case-control study

We conducted a large international nested case-control study including 1881 patients with Philadelphia-negative myeloproliferative neoplasms (MPN). Cases (n = 647) were patients with second cancer (SC: carcinoma, non-melanoma skin cancer, hematological second cancer, and melanoma) and controls (n = 1234) were patients without SC, matched with cases for sex, age at MPN diagnosis, date of MPN diagnosis, and MPN disease duration. The aim was to evaluate the risk of SC after exposure to cytoreductive drugs. Patients exposed to hydroxyurea (HU) (median: 3 years) had a risk of SC similar to unexposed patients (OR = 1.06, 95% CI 0.82-1.38). In contrast, in cancer-specific stratified multivariable analysis, HU had two-fold higher risk of non-melanoma (NM) skin cancer (OR = 2.28, 95% CI 1.15-4.51). A significantly higher risk of NM-skin cancer was also documented for pipobroman (OR = 3.74, 95% CI 1.00-14.01), ruxolitinib (OR = 3.87, 95% CI 1.18-12.75), and for drug combination (OR = 3.47, 95% CI 1.55-7.75). These three drugs did not show excess risk of carcinoma and hematological second cancer compared with unexposed patients. Exposure to interferon, busulfan, and anagrelide did not increase the risk. In summary, while it is reassuring that no excess of carcinoma was documented, a careful dermatologic active surveillance before and during the course of treatments is recommended.

Clinical outcomes under hydroxyurea treatment in polycythemia vera: a systematic review and meta-analysis

Hydroxyurea is the standard treatment in high-risk patients with polycythemia vera. However, estimates of its effect in terms of clinical outcomes (thrombosis, bleeding, hematologic transformations and mortality) are lacking. We performed a meta-analysis to determine the absolute risk of events in recent cases of patients under hydroxyurea treatment. We searched for relevant articles or abstracts in the following databases: Medline, EMBASE, clinicaltrials.gov, WHO International Clinical Trials Registry, LILACS. Sixteen studies published from 2008 to 2018 reporting number of events using World Health Organization diagnosis for polycythemia vera were selected. Through a random effect logistic model, incidences, study heterogeneity and confounder effects were estimated for each outcome at different follow ups. Overall, 3,236 patients were analyzed. While incidences of thrombosis and acute myeloid leukemia were stable over time, mortality and myelofibrosis varied depending on follow-up duration. Thrombosis rates were 1.9%, 3.6% and 6.8% persons/year at median ages 60, 70 and 80 years, respectively. Higher incidence of arterial events was predicted by previous cardiovascular complication. Leukemic transformation incidence was 0.4% persons/year. Incidence of transformation to myelofibrosis and mortality were significantly dependent on age and follow-up duration. For myelofibrosis, rates were 5.0 at five years and 33.7% at ten years; overall mortality was 12.6% and 56.2% at five and ten years, respectively. In conclusion, we provide reliable risk estimates for the main outcomes in polycythemia vera patients under hydroxyurea treatment. These findings can help design comparative clinical trials with new cytoreductive drugs and prove the feasibility of using critical end points for efficacy, such as major thrombosis.

Hydroxyurea prevents arterial and late venous thrombotic recurrences in patients with myeloproliferative neoplasms but fails in the splanchnic venous district. Pooled analysis of 1500 cases

We collected 1500 patients with myeloproliferative neoplasms (MPN) and arterial or venous thrombosis (935/565), pooling three independent cohorts previously reported. Long-term treatment with antiplatelet drugs or vitamin K-antagonists (VKA) was given to 1391 (92.7%) patients; 975 (65%) patients received hydroxyurea (HU). We recorded 348 recurrences (venous in 142 cases) over 6075 patient-years, with an incidence rate of 5.7 per 100 pt-years (95% CI 5.1-6.4). The site of the first thrombosis predicted the site of recurrence. Independent factors influencing the rate of novel arterial thrombosis were HU (HR 0.67, 95% CI 0.46-0.98), antiplatelet treatment (HR 0.54, 95% CI 0.35-0.82), and VKA (HR 0.58, 95% CI 0.35-0.96). On the contrary, the recurrence of venous thromboses was significantly diminished only by VKA (HR 0.60, 95% CI 0.37-0.95), while HU prevented late but not early recurrences after venous thrombosis at common sites. Of note, we failed to demonstrate a positive effect of HU in the prevention of recurrent splanchnic vein thrombosis. In conclusion, in MPN patients, HU plays a role in the prevention of arterial thrombosis, together with aspirin and VKA, whereas its action in the prevention of recurrent venous thrombosis is uncertain. Such findings call for future studies to optimize and personalize secondary prophylaxis after MPN-related thrombosis.

Thrombosis in Cancer Patients Treated with Hematopoietic Growth Factors - A Meta-Analysis

Hematopoietic colony-stimulating factors (CSFs) are largely used in patients with cancer undergoing cytotoxic treatment to accelerate neutrophil recovery and decrease the incidence of febrile neutropenia. Clinical practice guidelines for their use have been recently established (1), taking into account clinical benefit, but also cost and toxicity. Vascular occlusions have been recently reported among the severe reactions associated with the use of CSFs, in anedoctal case reports (2, 3), consecutive case series (4) and randomized clinical trial (5, 6). However, the role of CSFs in the pathogenesis of thrombotic complications is difficult to ascertain, because pertinent data are scanty and widely distributed over a number of heterogenous investigations. We report here a systematic review of relevant articles, with the aims to estimate the prevalence of thrombosis associated with the use of CSFs and to assess if this rate is significantly higher than that observed in cancer patients not receiving CSFs.

Clinical Manifestations and Management of Inherited Thrombophilia: Retrospective Analysis and Follow-up after Diagnosis of 238 Patients with Congenital Deficiency of Antithrombin III, Protein C, Protein S

The clinical history of 238 patients with inherited thrombophilia (AT III = 94, PC = 103, PS = 41) was analyzed retrospectively at diagnosis and in the follow-up period after diagnosis. At diagnosis 129 patients (54%) had suffered from thrombosis, with a recurrence rate of 48%. The most frequent onset manifestation was deep vein thrombosis of lower limbs (58%). Thrombotic history started before 40 in 80% of the cases. Forty-nine percent of the venous thromboses were preceded by a triggering event, in most cases pregnancy (17%) and surgery (12%). After diagnosis, follow-up lasted a total of 1,113 pt-years. A policy of short-term prophylaxis during risk situations for all patients and long-term prophylaxis in symptomatic patients failed to prevent venous thrombotic episodes (diagnosed by objective methods) in 4 previously asymptomatic subjects and recurrence in 7 previously symptomatic subjects. After knowledge of the patients’ diagnosis the incidence of venous thrombosis/100 pt-years was reduced as compared before diagnosis as total episodes (onset + recurrencies) (1.0 vs 1.9), onset episodes (0.7 vs 1.3) and recurrent episodes (1.3 vs 4.8), even though the differences were not statistically significant. However most of the venous thromboses occurred at a more advanced age (67% after 40 years) and without any apparent cause (83%), at significant variance with the period preceding the diagnosis; in particular the incidence of venous thrombotic onset in patients younger than 40 passed from 1.3/100 pt-years to 0.2/100 pt-years. In 6 recurrences after diagnosis a poor compliance for antithrombotic treatment was recognized. We conclude that a policy based on knowledge of diagnosis and on the implementation of antithrombotic treatment during risk situations appears to modify the clinical outcome of deficiencies of natural anticoagulants even in the absence of long-term antithrombotic prophylaxis; in particular morbidity of young patients is significantly reduced.

Fibrinogen Bergamo I (Aα16Arg → Cys): Susceptibility Towards Thrombin Following Aminoethylation, Methylation or Carboxamidomethylation of Cysteine Residues

An abnormal fibrinogen, denoted as “fibrinogen Bergamo I”, has been characterized. Its defect consists in an exchange of arginine by cysteine in position 16 of the Aα-chain, thus corresponding to that found in a number of other fibrinogen variants. The abnormal fibrinopeptide A cannot be split off by thrombin from intact fibrinogen Bergamo I. We describe three different chemical modifications of the cysteine Aαl6, i.e. aminoethylation, methylation and carboxamidomethylation, and their effects on the susceptibility of fibrinogen Bergamo I towards thrombin attack. S-aminoethylation of the Aαl6Cys renders the peptide bond Aαl6–17 cleavable by thrombin. Following methylation or carboxamidomethylation, the Aαl9-arginyl bond becomes accessible for thrombin. The chemically modified extended fibrinopeptide A can be readily separated from the normal fibrinopeptide A by HPLC. The latter two modifications are suitable alternative procedures for detecting the molecular defect Aαl6Arg → Cys of fibrinogen.

Different Incidence of Venous Thrombosis in Patients with Inherited Deficiencies of Antithrombin III, Protein C and Protein S

A cohort study was undertaken to compare the incidence of thrombosis in patients with inherited deficiency of Antithrombin III (n = 9), Protein C (n = 36) and Protein S (n = 36). The patients were stratified for schedule of antithrombotic prophylaxis and followed for a total period of 160 patient-years. Seven venous thrombosis were observed for a total incidence of 4.3% pts.-ys. The incidence of thrombosis was not significantly different in patients of different age, sex and schedule of prophylaxis, although there was a trend to a lower incidence in young individuals and in those receiving long-term oral anticoagulation. Patients with AT III deficiency had an higher incidence of thrombosis than patients with Protein C or Protein S deficiency (12 vs. 2.8 vs. 3.3% pts.-ys., p <0.05), despite the fact that they were, on average, younger and more prophylaxed. This study suggests that congenital Antithrombin III deficiency constitutes a greater risk of thrombosis than congenital deficiences of Protein C and Protein S.

Recombinant Versus High-sensitivity Conventional Thromboplastin: A Randomized Clinical Study in Patients on Oral Anticoagulation

A prospective, randomized, double-blind clinical trial was carried out in a single center to compare the clinical and laboratory quality of oral anticoagulant therapy monitored with recombinant tissue factor (RTF) or with a sensitive, human-derived, conventional thromboplastin (CT) in the PT test. Seven hundred and fifty-seven consecutive patients receiving oral anticoagulation for various indications were randomized to RTF (n = 379) or CT (n = 368) for 6 months. Total follow-up was 167 and 153 patient-years for RTF and TP groups respectively. Fifty-six bleeding events were observed: 31 in the RTF group and 25 in the TP group. The incidence of bleeding was 18.5 and 16.5% pt-yrs for RTF and TP patients respectively (n.s.). The event-free follow-up curves were not significantly different between the two groups. The laboratory quality of oral anticoagulation was evaluated with the “last check in file” method: therapeutic INR was found in the same propor-tipn of RTF and TP patients (70.2% vs 68.8%). Our study shows that RTF is as effective as a sensitive, conventional thromboplastin for monitoring oral anticoagulation.

Thrombotic and Hemorrhagic Complications in Patients with Mechanical Heart Valve Prosthesis Attending an Anticoagulation Clinic

This study evaluated the advantage of an anticoagulation clinic in terms of the improvement of the clinical quality of oral anticoagulation (i.e. prevention of thromboembolism and low rate of hemorrhagic complications). The incidence of thromboembolic events and major hemorrhagic complications was assessed in a series of 271 patients on oral anticoagulation for mechanical heart valve prosthesis before and after their enrollment in our anticoagulation clinic from January 1987 to December 1990. Risk factors for hemostatic events were also analyzed. The incidence of major hemostatic complications was significantly lower when patients attended the clinic: 1.0 vs 4.9%/pt-yr for hemorrhage and 0.6 vs 6.6%/pt-yr for thrombosis. This depended on three main factors: better dose regulation of warfarin, continuous patient education and early identification of clinical conditions potentially at risk for thrombosis and hemorrhage. Only previous hemorrhagic or thromboembolic events were recognized as major risk factors for hemostatic complications.

In conclusion, our study shows that an anticoagulation clinic offers a real advantage to patients with mechanical heart valve prosthesis in terms of prevention of thromboembolic events and hemorrhagic complications.

Markers of Procoagulant Imbalance in Patients with Inherited Thrombophilic Syndromes

In 107 asymptomatic and untreated patients with inherited syndromes associated with thrombophilia (antithrombin III, protein C and protein S deficiencies), we compared in parallel two plasma peptides which reflect activation of the common coagulation pathway: the prothrombin fragment 1 + 2 (F1+2) and fibrinopeptide A (FPA). Both F1+2 and FPA were measured with simple, commercially available ELISA methods. High levels of F1+2 or FPA were found in about one fourth of the patients as a whole. When patients were divided according to the type of inherited thrombophilie syndrome, it appeared that F1+2 was more frequently elevated in protein C and protein S deficiencies than in antithrombin deficiency; and that, in general, it was no more frequently elevated than FPA. Although our data confirm the existence of a procoagulant imbalance in inherited thrombophilie syndromes due to defects of natural anticoagulant proteins, they do not confirm that such imbalance can be more frequently diagnosed by measuring F1+2 levels, particularly in patients with antithrombin deficiency.

Antithrombotic therapy for venous thromboembolism in myeloproliferative neoplasms

In myeloproliferative neoplasms (MPNs) the incidence of venous thromboembolism (VTE) is 0.6–1.0 per 100 pt-years, and the rate of recurrence after VTE is 6.0–6.5 per 100 pt-yrs. Vitamin K-antagonists (VKA) reduces the risk of recurrence after VTE at usual sites (i.e., deep venous thrombosis (DVT) of the legs and pulmonary embolism (PE)) by 48–69%, with a rate of recurrent thrombosis per 100 pt-yrs of 3.4–4.7 on VKA and 8.9–9.6 off VKA; VKA discontinuation produces a 2.2-fold increased risk of novel thrombotic events with respect to continuation. However, the rate of both recurrent thrombosis and major bleeding on VKA is higher in MPN patients than in non-MPN patients, and the risk-benefit balance of long-term VKA treatment is challenging. In the absence of strong evidence, the tailored management of MPN-related VTE should operatively consider the risk categories for recurrence and bleed well established in the non-MPN setting. In summary, MPN patients with VTE are candidates for life-long VKA treatment, especially after unprovoked proximal DVT and PE. Aspirin can offer a moderate benefit in those patients who stop anticoagulation. The use of direct oral anticoagulants should be explored aiming to ameliorate the rate of bleeding.

Splanchnic vein thrombosis in myeloproliferative neoplasms: treatment algorithm 2018

Myeloproliferative neoplasms (MPNs) are a leading cause of splanchnic vein thrombosis (SVT). SVT is observed in all MPNs and frequently affects young patients. Therapy should be addressed to three main goals: preventing thrombosis recurrence, managing the underlying MPN, and supporting liver dysfunction. Life-long oral anticoagulation with vitamin K antagonists is the cornerstone of the antithrombotic treatment. However, recurrences of SVT or other thrombosis may occur in 15-20% of patients. Direct oral anticoagulants can represent an alternative and preliminary data encourage comparative studies. Survival of patients with SVT in MPN is primarily influenced by the natural history of the underlying neoplasms, rather than the SVT event. An aggressive management is recommended and a treatment algorithm based on the different MPN subtypes is proposed. Hydroxyurea is the cytoreductive drug of choice in polycythemia vera and essential thrombocythemia, whereas ruxolitinib is indicated in intermediate and high-risk patients with myelofibrosis and in PV patients resistant or intolerant to hydroxyurea. The management of SVT in MPNs requires a multidisciplinary approach that may include a hematologist, a gastroenterologist, an interventional radiologist, and a surgeon. In the case of clinical deterioration despite pharmacological therapy, patients with SVT should be considered for invasive procedures or liver transplantation.

Benefit-risk profile of cytoreductive drugs along with antiplatelet and antithrombotic therapy after transient ischemic attack or ischemic stroke in myeloproliferative neoplasms

We analyzed 597 patients with myeloproliferative neoplasms (MPN) who presented transient ischemic attacks (TIA, n = 270) or ischemic stroke (IS, n = 327). Treatment included aspirin, oral anticoagulants, and cytoreductive drugs. The composite incidence of recurrent TIA and IS, acute myocardial infarction (AMI), and cardiovascular (CV) death was 4.21 and 19.2%, respectively at one and five years after the index event, an estimate unexpectedly lower than reported in the general population. Patients tended to replicate the first clinical manifestation (hazard ratio, HR: 2.41 and 4.41 for recurrent TIA and IS, respectively); additional factors for recurrent TIA were previous TIA (HR: 3.40) and microvascular disturbances (HR: 2.30); for recurrent IS arterial hypertension (HR: 4.24) and IS occurrence after MPN diagnosis (HR: 4.47). CV mortality was predicted by age over 60 years (HR: 3.98), an index IS (HR: 3.61), and the occurrence of index events after MPN diagnosis (HR: 2.62). Cytoreductive therapy was a strong protective factor (HR: 0.24). The rate of major bleeding was similar to the general population (0.90 per 100 patient-years). In conclusion, the long-term clinical outcome after TIA and IS in MPN appears even more favorable than in the general population, suggesting an advantageous benefit-risk profile of antithrombotic and cytoreductive treatment.

The Risk of Thrombosis in Patients with Lupus Anticoagulants Is Predicted by their Specific Coagulation Profile

Lupus anticoagulants belong to the family of antiphospholipid antibodies. They include two phospholipid-dependent inhibitors of coagulation that may be distinguished on the basis of specific coagulation profiles generated from the comparison of the ratios of the Kaolin Clotting Time (KCT) and the dilute Russell’s Viper Venom Time (dRVVT): when the ratio of the KCT exceeds that of the dRVVT, the plasma is allocated to the “KCT” coagulation profile, when the opposite occurs, the plasma is defined to belong to the “dRVVT” coagulation profile group. We prospectively followed-up a historical cohort of 100 consecutive patients with lupus anticoagulants referred to our Institution between January 1988 and October 1997 to investigate the relationship between their coagulation profile at diagnosis and the development of thrombosis during a median follow-up time of 37.5 months (range 1-115 months). Fifty-six patients were allocated to the “dRVVT” coagulation profile, whereas the other 44 displayed the “KCT” profile. Lupus anticoagulants were transient in 17 patients, without differences between the two groups. None of these patients developed clinical events before disappearance of the phospholipid-dependent inhibitors of coagulation. The 83 cases with persistent lupus anticoagulants consistently displayed the same coagulation profile they had been allocated to at entry. Fourteen patients developed 18 thromboembolic events during the follow-up, with an overall rate of thrombosis of 4.2% patients-year. Twelve of them belonged to the “dRVVT” coagulation profile, whereas the other 2 to the “KCT” profile (p = 0.03). The “dRVVT” coagulation profile gave an odds ratio of thrombosis of 5.25 (95% confidence interval [C.I.]: 1.17-23.50). Ten of the 14 patients who developed thrombosis during follow-up had already experienced thrombosis: a previous thrombotic event caused an odds ratio of recurrency of 2.72 (95% C.I.: 0.85-8.73) (p = 0.09). By multivariate analysis, the “dRVVT” coagulation profile was still associated with a trend to a higher risk of thrombosis, but the difference did not reach statistical significance. Increased levels of anticardiolipin antibodies (> 40 GPL and/or MPL units) were found in all the 14 patients (p = 0.0064). The “KCT” coagulation profile was significantly associated (p = 0.005) with moderate thrombocytopenia (platelets 50-150 × 109/l). Neither profile was found to represent a risk factor for the development of recurrent miscarriages, neoplastic diseases and death. In conclusion, the “dRVVT” profile appears to have predictive value with respect to the thrombotic complications suffered by patients with antiphospholipid antibodies.

Congenital Resistance to Activated Protein C in Patients with Lupus Anticoagulants: Evaluation of Two Functional Assays

The R506Q mutation (“Factor V Leiden”) is responsible for the resistance to activated Protein C (aPCR), that is evaluated by coagulation tests. Such tests cannot be used in patients with lupus anticoagulants (LAs), due to the interfering effect exerted by these antibodies on “in vitro” phospholipid-dependent coagulation tests. For this reason, assays have been developed to evaluate aPCR that are insensitive to the presence of LA antibodies. We evaluated two such coagulation tests in the plasma of 82 consecutive patients with LAs. By polymerase chain reaction 3 patients (3.6%) were found heterozygous for the R506Q mutation. aPCR was evaluated by two clotting assays, proposed to be “insensitive” to the presence of LAs: 1. aPCR-tissue factor-based assay, using Factor V deficient plasma and 1:40 diluted test plasma; 2. aPCR-dRVVT-based assay with highly concentrated phospholipids. Their interassay coefficient of variation was 28% and 6.2%, respectively. Compared to the polymerase chain reaction analysis, the 2 tests displayed the following characteristics: sensitivity 67% vs 100%, specificity 92% vs 96%, positive predictive value 25% vs 50%, negative predictive value 99% vs 100%, respectively. Among LA patients without the R506Q mutation, 5 scored positive in the aPCR-tissue factor-based assay, 2 in the aPCR-dRVVT-based assay and another one in both assays. Our findings suggest that the aPCRdRVVT-based test is more reliable and sensitive than the aPCR-tissue factor-based one to the R506Q mutation in patients with LAs. Both assays, when negative, make unlikely the presence of the R506Q mutation. Polymerase chain reaction analysis remains, however, to be performed when either test is positive.

A reappraisal of the benefit-risk profile of hydroxyurea in polycythemia vera: A propensity-matched study

The use of hydroxyurea (HU) as first line therapy in polycythemia vera (PV) has been criticized because no solid demonstration that this drug prevents thrombosis or prolongs survival has been so far produced. Here we present the outcomes of a large cohort of patients with PV included in the European Collaborative Low-dose Aspirin (ECLAP) study. We selected 1,042 patients who, during the follow-up, had received only phlebotomy (PHL) or HU to maintain the hematocrit level < 45%. To assure comparability, we conducted a propensity score matching analysis. The two groups (PHL n = 342 and HU n = 681) were well balanced for the parameters included in the propensity score (overall balance: χ²  = 2.44, P = 0.964). Over a comparable period of follow-up (PHL = 29.9 vs. HU = 34.7 months), we documented an advantage of HU over PHL consistently significant with respect to the incidence of fatal/non-fatal cardiovascular (CV) events (5.8 vs. 3.0 per 100 person-years in PHL vs. HU group, P = 0.002) and myelofibrosis transformation that was only experienced by patients of PHL group. Evolution to acute leukemia was registered in three patients (two in PHL and one in HU group). The excess of mortality and total CV events in the PHL patients was restricted to the high-risk group, and, compared with HU cases, was significant higher in the PHL patients who failed to reach the hematocrit target < 0.45% (P = 0.000). In conclusion, this analysis provides reliable and qualified estimates of the therapeutic profile of HU and PHL treatments for future experimental studies and for the management of PV in clinical practice.

Safety and efficacy of ruxolitinib in splanchnic vein thrombosis associated with myeloproliferative neoplasms

Splanchnic vein thrombosis (SVT) is one of the vascular complications of myeloproliferative neoplasms (MPN). We designed a phase 2 clinical trial to evaluate safety and efficacy of ruxolitinib in reducing splenomegaly and improving disease-related symptoms in patients with MPN-associated SVT. Patients diagnosed with myelofibrosis (12 cases), polycythemia vera (5 cases) and essential thrombocythemia (4 cases) received ruxolitinib for 24 weeks in the core study period. Spleen volume was assessed by magnetic resonance imaging (MRI) and splanchnic vein circulation by echo-Doppler analysis. Nineteen patients carried JAK2V617F, one had MPLW515L, and one CALRL367fs*46 mutation. Eighteen patients had spleno-portal-mesenteric thrombosis, two had Budd-Chiari syndrome, and one had both sites involved; 16 patients had esophageal varices. Ruxolitinib was well tolerated with hematological toxicities consistent with those of patients without SVT and no hemorrhagic adverse events were recorded. After 24 weeks of treatment, spleen volume reduction ≥35% by MRI was achieved by 6/21 (29%) patients, and a ≥50% spleen length reduction by palpation at any time up to week 24 was obtained by 13/21 (62%) patients. At week 72, 8 of the 13 (62%) patients maintained the spleen response by palpation. No significant effect of treatment on esophageal varices or in splanchnic circulation was observed. MPN-related symptoms, evaluated by MPN-symptom assessment form (SAF) TSS questionnaire, improved significantly during the first 4 weeks and remained stable up to week 24. In conclusion, this trial shows that ruxolitinib is safe in patients with MPN-associated SVT, and effective in reducing spleen size and disease-related symptoms.

The potential role of hematocrit control on symptom burden among polycythemia vera patients: Insights from the CYTO-PV and MPN-SAF patient cohorts

Current guidelines suggest that polycythemia vera (PV) patients maintain a strict hematocrit less than 45%. However, to date, little is known about the relationship between HCT control and PV- related symptom burden. In this study, PV patient data was analyzed from the CYTO PV trial (n = 224) and the MPN-SAF study cohort (n = 645). No significant differences in symptom burden were seen at the 6 and 12 month follow-up when evaluating prospective hematocrit control in the CYTO PV cohort. Patients in the MPN-SAF cohort with a worst item score of greater than 5/10 on the Myeloproliferative Neoplasm Symptom Total Symptom Score had a significantly lower mean hematocrit (p = .0376). These findings suggest a relationship between traditional aggressive therapy for PV and increased symptom burden with prolonged therapy. Thus, symptom burden should be considered when contemplating the choice of therapy in the second-line setting for PV.

Splanchnic vein thrombosis in myeloproliferative neoplasms: risk factors for recurrences in a cohort of 181 patients

We retrospectively studied 181 patients with polycythaemia vera (n=67), essential thrombocythaemia (n=67) or primary myelofibrosis (n=47), who presented a first episode of splanchnic vein thrombosis (SVT). Budd–Chiari syndrome (BCS) and portal vein thrombosis were diagnosed in 31 (17.1%) and 109 (60.3%) patients, respectively; isolated thrombosis of the mesenteric or splenic veins was detected in 18 and 23 cases, respectively. After this index event, the patients were followed for 735 patient years (pt-years) and experienced 31 recurrences corresponding to an incidence rate of 4.2 per 100 pt-years. Factors associated with a significantly higher risk of recurrence were BCS (hazard ratio (HR): 3.03), history of previous thrombosis (HR: 3.62), splenomegaly (HR: 2.66) and leukocytosis (HR: 2.8). Vitamin K-antagonists (VKA) were prescribed in 85% of patients and the recurrence rate was 3.9 per 100 pt-years, whereas in the small fraction (15%) not receiving VKA more recurrences (7.2 per 100 pt-years) were reported. Intracranial and extracranial major bleeding was recorded mainly in patients on VKA and the corresponding rate was 2.0 per 100 pt-years. In conclusion, despite anticoagulation treatment, the recurrence rate after SVT in myeloproliferative neoplasms is high and suggests the exploration of new avenues of secondary prophylaxis with new antithrombotic drugs and JAK-2 inhibitors.