Nutritional support in the cardiac intensive care unit

Optimal care of critically ill patients in the cardiac intensive care unit includes adequate nutritional support. This review highlights the high prevalence of malnutrition in acute heart failure, acute coronary syndrome, cardiogenic shock, and post-cardiac arrest and its adverse impact on prognosis. There is a lack of robust evidence regarding appropriate nutritional support in this patient population. Initiation of nutritional support with a comprehensive assessment of the patient's nutritional status is critical. High-risk cardiac patients who are not critically ill can receive oral nutrition adapted to individual risk factors or deficiencies, although overfeeding should be avoided in the acute phase. For critically ill patients at risk of or with malnutrition on admission, general principles include initiation of nutritional support within 48 h of admission, preference for enteral over parenteral nutrition, preference for hypocaloric nutrition in the first week of intensive care unit admission, and adequate micronutrient supplementation. Enteral nutrition in haemodynamically unstable patients carries a risk, albeit low, of intestinal ischaemia. In the case of malnutrition, the risk of refeeding syndrome should always be considered.

Lower respiratory tract single-cell RNA sequencing and neutrophil extracellular trap profiling of COVID-19-associated pulmonary aspergillosis: a single centre, retrospective, observational study

BACKGROUND

COVID-19-associated pulmonary aspergillosis (CAPA) is a severe superinfection with the fungus Aspergillus affecting patients who are critically ill with COVID-19. The pathophysiology and the role of neutrophil extracellular traps (NETs) in this infection are largely unknown. We aimed to characterise the immune profile, with a focus on neutrophils and NET concentrations, of critically ill patients with COVID-19, with or without CAPA.

METHODS

We conducted a single-centre, retrospective, observational study in two patient cohorts, both recruited at University Hospitals Leuven, Belgium. We included adults aged 18 years or older who were admitted to the intensive care unit because of COVID-19 between March 31, 2020, and May 18, 2021, and who were included in the previous Contagious trial (NCT04327570). We investigated the immune cellular landscape of CAPA versus COVID-19 only by performing single-cell RNA sequencing (scRNA-seq) on bronchoalveolar lavage fluid. Bronchoalveolar lavage immune cell fractions were compared between patients with CAPA and patients with COVID-19 only. Additionally, we determined lower respiratory tract NET concentrations using biochemical assays in patients aged 18 years and older who were admitted to the intensive care unit because of severe COVID-19 between March 15, 2020, and Dec 31, 2021, for whom bronchoalveolar lavage was available in the hospital biobank. Bronchoalveolar lavage NET concentrations were compared between patients with CAPA and patients with COVID-19 only and integrated with existing data on immune mediators in bronchoalveolar lavage and 90-day mortality.

FINDINGS

We performed scRNA-seq of bronchoalveolar lavage on 43 samples from 39 patients, of whom 36 patients (30 male and six female; 14 with CAPA) were included in downstream analyses. We performed bronchoalveolar lavage NET analyses in 59 patients (46 male and 13 female), of whom 26 had CAPA. By scRNA-seq, patients with CAPA had significantly lower neutrophil fractions than patients with COVID-19 only (16% vs 33%; p=0·0020). The remaining neutrophils in patients with CAPA preferentially followed a hybrid maturation trajectory characterised by expression of genes linked to antigen presentation, with enhanced transcription of antifungal effector pathways. Patients with CAPA also showed depletion of mucosal-associated invariant T cells, reduced T helper 1 and T helper 17 differentiation, and transcriptional defects in specific aspects of antifungal immunity in macrophages and monocytes. We observed increased formation of NETs in patients with CAPA compared with patients with COVID-19 only (DNA complexed with citrullinated histone H3 median 15 898 ng/mL [IQR 4588-86 419] vs 7062 ng/mL [775-14 088]; p=0·042), thereby explaining decreased neutrophil fractions by scRNA-seq. Low bronchoalveolar lavage NET concentrations were associated with increased 90-day mortality in patients with CAPA.

INTERPRETATION

Qualitative and quantitative disturbances in monocyte, macrophage, B-cell, and T-cell populations could predispose patients with severe COVID-19 to develop CAPA. Hybrid neutrophils form a specialised response to CAPA, and an adequate neutrophil response to CAPA is a major determinant for survival in these patients. Therefore, measuring bronchoalveolar lavage NETs could have diagnostic and prognostic value in patients with CAPA. Clinicians should be wary of aspergillosis when using immunomodulatory therapy that might inhibit NETosis to treat patients with severe COVID-19.

FUNDING

Research Foundation Flanders, KU Leuven, UZ Leuven, VIB, the Fundação para a Ciência e a Tecnologia, the European Regional Development Fund, la Caixa Foundation, the Flemish Government, and Horizon 2020.

High Burden of COVID-19-Associated Pulmonary Aspergillosis in Severely Immunocompromised Patients Requiring Mechanical Ventilation

BACKGROUND

Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is a frequent superinfection in critically ill patients with COVID-19 and is associated with increased mortality rates. The increasing proportion of severely immunocompromised patients with COVID-19 who require mechanical ventilation warrants research into the incidence and impact of CAPA during the vaccination era.

METHODS

We performed a retrospective, monocentric, observational study. We collected data from adult patients with severe COVID-19 requiring mechanical ventilation who were admitted to the intensive care unit (ICU) of University Hospitals Leuven, a tertiary referral center, between 1 March 2020 and 14 November 2022. Probable or proven CAPA was diagnosed according to the 2020 European Confederation for Medical Mycology/International Society for Human and Animal Mycology (ECMM/ISHAM) criteria.

RESULTS

We included 335 patients. Bronchoalveolar lavage sampling was performed in 300 (90%), and CAPA was diagnosed in 112 (33%). The incidence of CAPA was 62% (50 of 81 patients) in European Organisation for Research and Treatment of Cancer (EORTC)/Mycosis Study Group Education and Research Consortium (MSGERC) host factor-positive patients, compared with 24% (62 of 254) in host factor-negative patients. The incidence of CAPA was significantly higher in the vaccination era, increasing from 24% (57 of 241) in patients admitted to the ICU before October 2021 to 59% (55 of 94) in those admitted since then. Both EORTC/MSGERC host factors and ICU admission in the vaccination era were independently associated with CAPA development. CAPA remained an independent risk factor associated with mortality risk during the vaccination era.

CONCLUSIONS

The presence of EORTC/MSGERC host factors for invasive mold disease is associated with increased CAPA incidence and worse outcome parameters, and it is the main driver for the significantly higher incidence of CAPA in the vaccination era. Our findings warrant investigation of antifungal prophylaxis in critically ill patients with COVID-19.

Clinical and molecular epidemiological features of critically ill patients with invasive group A Streptococcus infections: a Belgian multicenter case-series

BACKGROUND

Recent alerts have highlighted an increase in group A streptococcal (GAS) infections since 2022 in Europe and the United States. Streptococcus pyogenes can cause limited skin or mucosal disease, but can also present as severe invasive disease necessitating critical care. We performed a multicenter retrospective study of patients with GAS infections recently admitted to Belgian intensive care units (ICUs) since January 2022. We describe patient characteristics and investigate the molecular epidemiology of the S. pyogenes strains involved.

RESULTS

Between January 2022 and May 2023, a total of 86 cases (56 adults, 30 children) with GAS disease were admitted to critical care in the university hospitals of Leuven, Antwerp and Liège. We noted a strikingly high incidence of severe community-acquired pneumonia (sCAP) (45% of adults, 77% of children) complicated with empyema in 45% and 83% of adult and pediatric cases, respectively. Two-thirds of patients with S. pyogenes pneumonia had viral co-infection, with influenza (13 adults, 5 children) predominating. Other disease presentations included necrotizing fasciitis (23% of adults), other severe skin/soft tissue infections (16% of adults, 13% of children) and ear/nose/throat infections (13% of adults, 13% of children). Cardiogenic shock was frequent (36% of adults, 20% of children). Fifty-six patients (65%) had toxic shock syndrome. Organ support requirements were high and included invasive mechanical ventilation (77% of adults, 50% of children), renal replacement therapy (29% of adults, 3% of children) and extracorporeal membrane oxygenation (20% of adults, 7% of children). Mortality was 21% in adults and 3% in children. Genomic analysis of S. pyogenes strains from 55 out of 86 patients showed a predominance of emm1 strains (73%), with a replacement of the M1global lineage by the toxigenic M1UK lineage (83% of emm1 strains were M1UK).

CONCLUSIONS

The recent rise of severe GAS infections (2022-23) is associated with introduction of the M1UK lineage in Belgium, but other factors may be at play-including intense circulation of respiratory viruses and potentially an immune debt after the COVID pandemic. Importantly, critical care physicians should include S. pyogenes as causative pathogen in the differential diagnosis of sCAP.

STEC colitis mimicking acute severe colitis with life-threatening consequences: a case report

Acute colitis is a common feature of infection with Shiga-toxin producing Escherichia coli (STEC) and can mimic acute severe ulcerative colitis. Early recognition is important as there is a risk of developing Shiga toxin-induced haemolytic uremic syndrome (STEC-HUS), defined by the triad of microangiopathic haemolytic anemia, thrombocytopenia and organ damage. In severe cases STEC-HUS can cause severe neurological complications and can be fatal. We present a patient with a medical history of refractory ulcerative colitis, where making the diagnosis of STEC-HUS was challenging since the initial clinical presentation was difficult to differentiate from a flare of ulcerative colitis. This case illustrates that STEC induced colitis can mimic acute severe ulcerative colitis. This finding is of utmost clinical importance because of the potential life-threatening complications of STEC-HUS. Therefore it should be excluded promptly in patients with acute severe ulcerative colitis by using multiplex-PCR assay on a faecal sample.

Biallelic mutations in the CFHR genes underlying atypical hemolytic uremic syndrome in a patient with catastrophic adult-onset Still's disease and recurrent macrophage activation syndrome: A case report

We report the fatal case of a 20-year-old woman with refractory adult-onset Still's disease (AOSD) accompanied by fulminant macrophage activation syndrome (MAS) and atypical hemolytic uremic syndrome (aHUS). Anakinra and tocilizumab temporarily controlled AOSD. In 2021, she presented to ICU with generalized tonic-clonic seizure, lymphocytic aseptic meningitis, and acute kidney injury. Despite hemodialysis and methylprednisolone, she developed another seizure, MAS, and disseminated intravascular coagulation (DIC). Following brief control, MAS flares -reflected by increased plasma CXCL9 and CXCL10- re-emerged and were controlled through dexamethasone, etoposide, cyclosporin and tofacitinib. No mutations were detected in haemophagocytic lymphohistiocytosis (HLH)-associated genes, nor in genes associated with periodic fever syndromes. Post-mortem genetic testing revealed loss-of-function biallelic deletions in complement factor H-related proteins (CFHR) genes, predisposing aHUS. This case underscores the importance of prompt genetic assessment of complement-encoding alleles, in addition to HLH-related genes, in patients with severe AOSD with recurrent MAS and features of thrombotic microangiopathy (TMA).

Peptidylarginine deiminase 4 and ADAMTS13 activity in Staphylococcus aureus bacteraemia

Staphylococcus aureus infection is associated with increased levels of neutrophil extracellular traps (NETs) and von Willebrand factor (VWF), and with reduced activity of ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motifs, member 13). Peptidylarginine deiminase 4 (PAD4) contributes to NET formation and inactivates ADAMTS13 in vitro. The role of PADs in the dynamics of NETs, VWF and ADAMTS13 has not yet been studied. We thus aimed to assess the longitudinal evolution of NETs, PADs, VWF and ADAMTS13 activity in S. aureus infection. Plasma samples from S. aureus bacteraemia patients were longitudinally collected and analysed for NETs, PAD4/PAD2, VWF and ADAMTS13 activity. Correlation analyses with clinical data were performed. Recombinant PAD4 and S. aureus were assessed in vitro for their potential to modulate ADAMTS13 activity. Sixty-seven patients were included. Plasma levels of NETs, VWF, PAD4 and PAD2 were increased and ADAMTS13 activity was decreased. Levels of PADs were negatively correlated with ADAMTS13 activity. NETs were positively correlated with PADs, and negatively with ADAMTS13 activity. In vitro, recombinant PAD4 but not S. aureus reduced ADAMTS13 activity in plasma. Levels of PAD4 and PAD2 correlate with reduced ADAMTS13 activity, with neutrophils as the likely source of PAD activity in S. aureus bacteraemia. This article is part of the Theo Murphy meeting issue 'The virtues and vices of protein citrullination'.

A Pathology-based Case Series of Influenza- and COVID-19-associated Pulmonary Aspergillosis: The Proof Is in the Tissue

Rationale: Invasive pulmonary aspergillosis has emerged as a frequent coinfection in severe coronavirus disease (COVID-19), similarly to influenza, yet the clinical invasiveness is more debated. Objectives: We investigated the invasive nature of pulmonary aspergillosis in histology specimens of influenza and COVID-19 ICU fatalities in a tertiary care center. Methods: In this monocentric, descriptive, retrospective case series, we included adult ICU patients with PCR-proven influenza/COVID-19 respiratory failure who underwent postmortem examination and/or tracheobronchial biopsy during ICU admission from September 2009 until June 2021. Diagnosis of probable/proven viral-associated pulmonary aspergillosis (VAPA) was made based on the Intensive Care Medicine influenza-associated pulmonary aspergillosis and the European Confederation of Medical Mycology (ECMM) and the International Society for Human and Animal Mycology (ISHAM) COVID-19-associated pulmonary aspergillosis consensus criteria. All respiratory tissues were independently reviewed by two experienced pathologists. Measurements and Main Results: In the 44 patients of the autopsy-verified cohort, 6 proven influenza-associated and 6 proven COVID-19-associated pulmonary aspergillosis diagnoses were identified. Fungal disease was identified as a missed diagnosis upon autopsy in 8% of proven cases (n = 1/12), yet it was most frequently found as confirmation of a probable antemortem diagnosis (n = 11/21, 52%) despite receiving antifungal treatment. Bronchoalveolar lavage galactomannan testing showed the highest sensitivity for VAPA diagnosis. Among both viral entities, an impeded fungal growth was the predominant histologic pattern of pulmonary aspergillosis. Fungal tracheobronchitis was histologically indistinguishable in influenza (n = 3) and COVID-19 (n = 3) cases, yet macroscopically more extensive at bronchoscopy in influenza setting. Conclusions: A proven invasive pulmonary aspergillosis diagnosis was found regularly and with a similar histological pattern in influenza and in COVID-19 ICU case fatalities. Our findings highlight an important need for VAPA awareness, with an emphasis on mycological bronchoscopic work-up.

External Validation of the Augmented Renal Clearance Predictor in Critically Ill COVID-19 Patients

The ARC predictor is a prediction model for augmented renal clearance (ARC) on the next intensive care unit (ICU) day that showed good performance in a general ICU setting. In this study, we performed a retrospective external validation of the ARC predictor in critically ill coronavirus disease 19 (COVID-19) patients admitted to the ICU of the University Hospitals Leuven from February 2020 to January 2021. All patient-days that had serum creatinine levels available and measured creatinine clearance on the next ICU day were enrolled. The performance of the ARC predictor was evaluated using discrimination, calibration, and decision curves. A total of 120 patients (1064 patient-days) were included, and ARC was found in 57 (47.5%) patients, corresponding to 246 (23.1%) patient-days. The ARC predictor demonstrated good discrimination and calibration (AUROC of 0.86, calibration slope of 1.18, and calibration-in-the-large of 0.14) and a wide clinical-usefulness range. At the default classification threshold of 20% in the original study, the sensitivity and specificity were 72% and 81%, respectively. The ARC predictor is able to accurately predict ARC in critically ill COVID-19 patients. These results support the potential of the ARC predictor to optimize renally cleared drug dosages in this specific ICU population. Investigation of dosing regimen improvement was not included in this study and remains a challenge for future studies.

Visualizing in deceased COVID-19 patients how SARS-CoV-2 attacks the respiratory and olfactory mucosae but spares the olfactory bulb

Anosmia, the loss of smell, is a common and often the sole symptom of COVID-19. The onset of the sequence of pathobiological events leading to olfactory dysfunction remains obscure. Here, we have developed a postmortem bedside surgical procedure to harvest endoscopically samples of respiratory and olfactory mucosae and whole olfactory bulbs. Our cohort of 85 cases included COVID-19 patients who died a few days after infection with SARS-CoV-2, enabling us to catch the virus while it was still replicating. We found that sustentacular cells are the major target cell type in the olfactory mucosa. We failed to find evidence for infection of olfactory sensory neurons, and the parenchyma of the olfactory bulb is spared as well. Thus, SARS-CoV-2 does not appear to be a neurotropic virus. We postulate that transient insufficient support from sustentacular cells triggers transient olfactory dysfunction in COVID-19. Olfactory sensory neurons would become affected without getting infected.

Internal jugular vein valves complicating central venous catheter placement: a case report

Placement of central venous catheters in the internal jugular vein is a frequently performed procedure. We present the case of a patient with venous valves causing an unexpected anatomic hindrance in the placement of a central venous catheter in the internal jugular vein. Venous valves are common in the internal jugular vein and can hinder cannulation. Ultrasound can be of use in the proper placement of a central venous line in a patient where cannulation is complicated by venous valves.

Extracorporeal membrane oxygenation in a patient with newly diagnosed acute myeloblastic leukaemia presenting with severe respiratory failure

Veno-venous extracorporeal membrane oxygenation (ECMO) is typically instituted in severe respiratory failure, defined by Lung Injury Score, and caused either by pulmonary or extra-pulmonary reversible disease processes. These processes will have led to acute worsening of oxygenation and/or respiratory acidosis together with an inability to provide safe, lung protective, mechanical ventilation. Patients with underlying chronic immunosuppression or haematological malignancies treated with ECMO for severe respiratory failure have poor short- and long-term functional and survival outcomes. Consequently, in many centres, a diagnosis of haematological malignancy is considered a contraindication to provision of ECMO support for severe respiratory failure. We present a case of a 51-year-old female who attended her local hospital with symptoms suggestive of community-acquired pneumonia. Within a few days, there was progression to severe respiratory failure, initially managed with invasive mechanical ventilation but rapidly deteriorating respiratory failure triggered referral for ECMO support. Initial investigations on ECMO demonstrated features of acute myeloblastic leukaemia with a superimposed community-acquired pneumonia. This was successfully managed with supportive treatment alongside mechanical respiratory therapy and targeted chemotherapy, achieving complete remission and full functional recovery.

Staphylococcus aureus endocarditis: distinct mechanisms of bacterial adhesion to damaged and inflamed heart valves

AIMS

The pathogenesis of endocarditis is not well understood resulting in unsuccessful attempts at prevention. Clinical observations suggest that Staphylococcus aureus infects either damaged or inflamed heart valves. Using a newly developed endocarditis mouse model, we therefore studied the initial adhesion of S. aureus in both risk states.

METHODS AND RESULTS

Using 3D confocal microscopy, we examined the adhesion of fluorescent S. aureus to murine aortic valves. To mimic different risk states we either damaged the valves with a surgically placed catheter or simulated valve inflammation by local endothelium activation. We used von Willebrand factor (VWF) gene-deficient mice, induced platelet and fibrinogen depletion and used several S. aureus mutant strains to investigate the contribution of both host and bacterial factors in early bacterial adhesion. Both cardiac valve damage and inflammation predisposed to endocarditis, but by distinct mechanisms. Following valve damage, S. aureus adhered directly to VWF and fibrin, deposited on the damaged valve. This was mediated by Sortase A-dependent adhesins such as VWF-binding protein and Clumping factor A. Platelets did not contribute. In contrast, upon cardiac valve inflammation, widespread endothelial activation led to endothelial cell-bound VWF release. This recruited large amounts of platelets, capturing S. aureus to the valve surface. Here, neither fibrinogen, nor Sortase A were essential.

CONCLUSION

Cardiac valve damage and inflammation predispose to S. aureus endocarditis via distinct mechanisms. These findings may have important implications for the development of new preventive strategies, as some interventions might be effective in one risk state, but not in the other.

Use of Intravenous Immunoglobulins in Patients with Suspected Toxin-Mediated Shock Requiring Extracorporeal Membrane Oxygenation

BACKGROUND

Toxin-producing, gram-positive bacteria can lead to severe and refractory septic shock with high attributable mortality. Adjunctive therapies such as intravenous immunoglobulins (IVIG) have been proposed for these patients. However, at presentation the presence of a toxin-producing organism is most often unknown. As IVIG is a potentially valuable but also limited resource, we investigated the use of IVIG in our critically ill patients requiring extracorporeal membrane oxygenation (ECMO).

MATERIALS AND METHODS

Retrospective cohort study (April 2016 to March 2018) of adult patients with clinically suspected toxin-mediated shock requiring ECMO and who received IVIG in our regional severe respiratory failure (SRF)/ECMO center.

RESULTS

In 44% (15/34) of the patients, group A Streptococcus or Panton-Valentine Leukocidin producing S aureus was isolated. IVIG use in these patients was safe. The mortality was 30%, lower than the predicted mortality of >90% based on the SOFA scores.

CONCLUSION

IVIG administration can be considered in a selected group of patients presenting with acute and very severe septic shock.

Von Willebrand factor and ADAMTS13 impact on the outcome of Staphylococcus aureus sepsis

BACKGROUND

Previous clinical evidence correlates levels of von Willebrand factor (VWF) and its cleaving protease ADAMTS13 with outcome in septic patients. No previous studies addressed if VWF and ADAMTS13 affected the outcome of Staphylococcus aureus sepsis.

OBJECTIVES

We studied the role of VWF and ADAMTS13 in S. aureus sepsis both in patients and in mice.

METHODS

VWF levels and ADAMTS13 activity levels were measured in plasma samples from 89 S. aureus bacteremia patients by chemiluminescent assays and were correlated with clinical sepsis outcome parameters. In wild-type mice and mice deficient in VWF and ADAMTS13, we investigated the outcome of S. aureus sepsis and quantified bacterial clearance and organ microthrombi.

RESULTS

In patients with S. aureus bloodstream infections, high VWF levels and low ADAMTS13 activity levels correlated with disease severity and with parameters of inflammation and disseminated intravascular coagulation. In septic mice, VWF deficiency attenuated mortality, whereas ADAMTS13 deficiency increased mortality. Bacterial clearance was enhanced in VWF-deficient mice. The differences in mortality for the studied genotypes were associated with differential loads of organ microthrombi in both liver and kidneys.

CONCLUSIONS

In conclusion, this study reports the consistent relation of VWF, ADAMTS13 and their ratio to disease severity in patients and mice with S. aureus sepsis. Targeting VWF multimers and/or the relative ADAMTS13 deficiency that occurs in sepsis should be explored as a potential new therapeutic target in S. aureus endovascular infections.

Necrotizing skin and soft-tissue infections in the intensive care unit

BACKGROUND

Necrotizing skin and soft-tissue infections (NSTI) are rare but potentially life-threatening and disabling infections that often require intensive care unit admission.

OBJECTIVES

To review all aspects of care for a critically ill individual with NSTI.

SOURCES

Literature search using Medline and Cochrane library, multidisciplinary panel of experts.

CONTENT

The initial presentation of a patient with NSTI can be misleading, as features of severe systemic toxicity can obscure sometimes less impressive skin findings. The infection can spread rapidly, and delayed surgery worsens prognosis, hence there is a limited role for additional imaging in the critically ill patient. Also, the utility of clinical scores is contested. Prompt surgery with aggressive debridement of necrotic tissue is required for source control and allows for microbiological sampling. Also, prompt administration of broad-spectrum antimicrobial therapy is warranted, with the addition of clindamycin for its effect on toxin production, both in empirical therapy, and in targeted therapy for monomicrobial group A streptococcal and clostridial NSTI. The role of immunoglobulins and hyperbaric oxygen therapy remains controversial.

IMPLICATIONS

Close collaboration between intensive care, surgery, microbiology and infectious diseases, and centralization of care is fundamental in the approach to the severely ill patient with NSTI. As many aspects of management of these rare infections are supported by low-quality data only, multicentre trials are urgently needed.

Targeting Coagulase Activity in Staphylococcus aureus Bacteraemia: A Randomized Controlled Single-Centre Trial of Staphylothrombin Inhibition

BACKGROUND

Staphylococcus aureus (S. aureus) bacteraemia is frequent and carries a high morbidity and mortality. Coagulases secreted by S. aureus initiate blood coagulation by directly activating prothrombin. This pathogen-activated coagulation is insensitive to most antithrombotic drugs, with the exception of small molecule direct thrombin inhibitors (DTIs). DTIs inhibit the coagulase-prothrombin complex, or staphylothrombin, and improve outcome in preclinical models of S. aureus infection.

OBJECTIVE

A single-centre, randomized, controlled feasibility and safety trial of staphylothrombin inhibition with DTIs in patients with S. aureus bacteraemia.

PATIENTS AND METHODS

Consecutive eligible adult patients with S. aureus positive blood cultures in the University Hospitals Leuven (Belgium) were randomized 1:1 to DTI (oral dabigatran 110 mg twice daily or intravenous argatroban according to activated partial thromboplastin time [aPTT]) for 7 to 10 days, or subcutaneous enoxaparin 40 mg once daily. Primary outcomes were feasibility and safety of DTI in patients with S. aureus bacteraemia. Secondary outcomes include D-dimer evolution (day 0-4) as marker of coagulation activation; inflammatory and microbiological parameters; and clinical outcomes including metastatic infections.

RESULTS

Thirty-one percent (94/303) of screened patients were enrolled. Dabigatran plasma levels inhibited staphylothrombin. Clinically relevant bleeding (5/47 vs. 5/47) and thrombotic (7/47 vs. 7/47) complications were similar in both groups. Coagulase inhibition with DTIs was associated with a trend towards faster D-dimer decrease at day 4 (-662 ± 249 ng/mL vs. -40 ± 213 ng/mL for DTI-treated patients vs. control; p = 0.06) and a numerically lower number of persistently positive blood cultures. No differences in inflammatory parameters or other clinical outcomes were observed.

CONCLUSION

Targeting staphylothrombin with DTIs is feasible in a subset of S. aureus bacteraemic patients, with comparable safety to standard thromboprophylaxis. In future studies of staphylothrombin inhibition, feasibility can be further improved by rapid diagnostics and by strategies without concomitant anticoagulant effect.

An open conformation of ADAMTS-13 is a hallmark of acute acquired thrombotic thrombocytopenic purpura

Essentials Conformational changes in ADAMTS-13 are part of its mode-of-action. The murine anti-ADAMTS-13 antibody 1C4 discriminates between folded and open ADAMTS-13. ADAMTS-13 conformation is open in acute acquired thrombotic thrombocytopenic purpura (TTP). Our study forms an important basis to fully elucidate the pathophysiology of TTP.

SUMMARY

Background Acquired thrombotic thrombocytopenic purpura (aTTP) is an autoimmune disorder characterized by absent ADAMTS-13 activity and the presence of anti-ADAMTS-13 autoantibodies. Recently, it was shown that ADAMTS-13 adopts a folded or an open conformation. Objectives As conformational changes in self-antigens play a role in the pathophysiology of different autoimmune diseases, we hypothesized that the conformation of ADAMTS-13 changes during acute aTTP. Methods Antibodies recognizing cryptic epitopes in the spacer domain were generated. Next, the conformation of ADAMTS-13 in 40 healthy donors (HDs), 99 aTTP patients (63 in the acute phase versus 36 in remission), 12 hemolytic-uremic syndrome (HUS) patients and 63 sepsis patients was determined with ELISA. Results The antibody 1C4 recognizes a cryptic epitope in ADAMTS-13. Therefore, we were able to discriminate between a folded and an open ADAMTS-13 conformation. We showed that ADAMTS-13 in HDs does not bind to 1C4, indicating that ADAMTS-13 circulates in a folded conformation. Similar results were obtained for HUS and sepsis patients. In contrast, ADAMTS-13 of acute aTTP patients bound to 1C4 in 92% of the cases, whereas, in most cases, this binding was abolished during remission, showing that the conformation of ADAMTS-13 is open during an acute aTTP episode. Conclusions Our study shows that, besides absent ADAMTS-13 activity and the presence of anti-ADAMTS-13 autoantibodies, an open ADAMTS-13 conformation is also a hallmark of acute aTTP. Demonstrating this altered ADAMTS-13 conformation in acute aTTP will help to further unravel the pathophysiology of aTTP and lead to improved therapy and diagnosis.

Clumping factor A, von Willebrand factor-binding protein and von Willebrand factor anchor Staphylococcus aureus to the vessel wall

Essentials Staphylococcus aureus (S. aureus) binds to endothelium via von Willebrand factor (VWF). Secreted VWF-binding protein (vWbp) mediates S. aureus adhesion to VWF under shear stress. vWbp interacts with VWF and the Sortase A-dependent surface protein Clumping factor A (ClfA). VWF-vWbp-ClfA anchor S. aureus to vascular endothelium under shear stress.

SUMMARY

Objective When establishing endovascular infections, Staphylococcus aureus (S. aureus) overcomes shear forces of flowing blood by binding to von Willebrand factor (VWF). Staphylococcal VWF-binding protein (vWbp) interacts with VWF, but it is unknown how this secreted protein binds to the bacterial cell wall. We hypothesized that vWbp interacts with a staphylococcal surface protein, mediating the adhesion of S. aureus to VWF and vascular endothelium under shear stress. Methods We studied the binding of S. aureus to vWbp, VWF and endothelial cells in a micro-parallel flow chamber using various mutants deficient in Sortase A (SrtA) and SrtA-dependent surface proteins, and Lactococcus lactis expressing single staphylococcal surface proteins. In vivo adhesion of bacteria was evaluated in the murine mesenteric circulation using real-time intravital vascular microscopy. Results vWbp bridges the bacterial cell wall and VWF, allowing shear-resistant binding of S. aureus to inflamed or damaged endothelium. Absence of SrtA and Clumping factor A (ClfA) reduced adhesion of S. aureus to vWbp, VWF and activated endothelial cells. ADAMTS-13 and an anti-VWF A1 domain antibody, when combined, reduced S. aureus adhesion to activated endothelial cells by 90%. Selective overexpression of ClfA in the membrane of Lactococcus lactis enabled these bacteria to bind to VWF and activated endothelial cells but only in the presence of vWbp. Absence of ClfA abolished bacterial adhesion to the activated murine vessel wall. Conclusions vWbp interacts with VWF and with the SrtA-dependent staphylococcal surface protein ClfA. The complex formed by VWF, secreted vWbp and bacterial ClfA anchors S. aureus to vascular endothelium under shear stress.

Shear-Resistant Binding to von Willebrand Factor Allows Staphylococcus lugdunensis to Adhere to the Cardiac Valves and Initiate Endocarditis

BACKGROUND

Staphylococcus lugdunensis is an emerging cause of endocarditis. To cause endovascular infections, S. lugdunensis requires mechanisms to overcome shear stress. We investigated whether platelets and von Willebrand factor (VWF) mediate bacterial adhesion to the vessel wall and the cardiac valves under flow.

METHODS

S. lugdunensis binding to VWF, collagen, and endothelial cells was studied in a parallel flow chamber in the absence and presence of platelets. In vivo adhesion of S. lugdunensis was evaluated in a mouse microvasculature perfusion model and a new mouse model of endocarditis.

RESULTS

Contrary to other coagulase-negative staphylococci, S. lugdunensis bound to VWF under flow, thus enabling its adhesion to endothelial cells and to the subendothelial matrix. In inflamed vessels of the mesenteric circulation, VWF recruited S. lugdunensis to the vessel wall. In a novel endocarditis mouse model, local inflammation and the resulting release of VWF enabled S. lugdunensis to bind and colonize the heart valves.

CONCLUSIONS

S. lugdunensis binds directly to VWF, which proved to be vital for withstanding shear forces and for its adhesion to the vessel wall and cardiac valves. This mechanism explains why S. lugdunensis causes more-aggressive infections, including endocarditis, compared with other coagulase-negative staphylococci.

The addition of idarucizumab to plasma samples containing dabigatran allows the use of routine coagulation assays for the diagnosis of hemostasis disorders

BACKGROUND

The anticoagulant effect of dabigatran can be approximated by its prolongation of routine coagulation assays. Consequently, dabigatran also interferes with thrombophilia screening or with diagnosing hemostasis disorders that have developed after the initiation of anticoagulant treatment, such as vitamin K deficiency or acquired hemophilia A.

OBJECTIVES

This study was carried out to determine whether idarucizumab, a humanized antibody fragment that binds dabigatran, could fully neutralize dabigatran in routine diagnostic coagulation assays conducted in vitro, thereby preventing false-positive or false-negative diagnostic readouts.

METHODS

Preliminary experiments identified coagulation assays that were sensitive to dabigatran, and identified a concentration of idarucizumab that neutralized the effects of dabigatran. These assays were then carried out with patient and control plasma samples spiked with dabigatran, with or without a molar excess of idarucizumab.

RESULTS

Dabigatran altered the prothrombin time, activated partial thromboplastin time and thrombin time, and the measurement of intrinsic and extrinsic factor levels. Screening and confirmation tests used for lupus anticoagulant detection were prolonged by dabigatran, falsely suggesting the presence of lupus anticoagulant. Conversely, the addition of dabigatran falsely corrected an abnormal activated protein C resistance ratio. Addition of idarucizumab completely normalized these measurements, and allowed the correct identification of normal and abnormal samples with these assays.

CONCLUSIONS

In vitro addition of idarucizumab to plasma samples containing dabigatran fully neutralizes the drug, and facilitates the use of routine coagulation assays to allow the diagnosis of hemostasis disorders that may be concurrently present in patients taking dabigatran.

Bacterial pathogens activate plasminogen to breach tissue barriers and escape from innate immunity

Both coagulation and fibrinolysis are tightly connected with the innate immune system. Infection and inflammation cause profound alterations in the otherwise well-controlled balance between coagulation and fibrinolysis. Many pathogenic bacteria directly exploit the host's hemostatic system to increase their virulence. Here, we review the capacity of bacteria to activate plasminogen. The resulting proteolytic activity allows them to breach tissue barriers and evade innate immune defense, thus promoting bacterial spreading. Yersinia pestis, streptococci of group A, C and G and Staphylococcus aureus produce a specific bacterial plasminogen activator. Moreover, surface plasminogen receptors play an established role in pneumococcal, borrelial and group B streptococcal infections. This review summarizes the mechanisms of bacterial activation of host plasminogen and the role of the fibrinolytic system in infections caused by these pathogens.

Abnormal uterine bleeding in VTE patients treated with rivaroxaban compared to vitamin K antagonists

INTRODUCTION

Rivaroxaban is a convenient oral anticoagulant for patients with venous thromboembolism (VTE). The impact of rivaroxaban and vitamin K antagonists (VKAs) on abnormal uterine bleeding (AUB) in real life has not been previously explored.

MATERIALS AND METHODS

We performed a single-center retrospective study on AUB in female VTE patients of reproductive age who were treated with either rivaroxaban or VKAs.

RESULTS

Questionnaire results were available for 52 patients in each treatment group. Approximately two thirds of all women reported AUB after initiation of anticoagulant therapy. Patients using rivaroxaban were more likely to experience prolonged (>8days) menstrual bleeding (27 % vs. 8.3%, P=0.017). Rivaroxaban treatment increased the duration of menstrual bleeding from median 5 (IQR 3.5-6.0) days before start of treatment to 6 (IQR 4.1-8.9) days (P<0.001). VKA treatment did not lead to significant prolongation of the menstrual period. Patients on rivaroxaban more frequently reported an unscheduled contact with a physician for AUB than women using VKAs (41% vs. 25%, P=0.096). They also reported increased need for menorrhagia-related medical or surgical intervention (25% vs. 7.7%, P=0.032) and had more adaptations of anticoagulant therapy (15% vs. 1.9%, P=0.031).

CONCLUSION

AUB is frequent after initiation of anticoagulant therapy for acute symptomatic VTE. Compared to VKAs, rivaroxaban was associated with prolonged menstrual bleeding and more medical interventions and adaptation of anticoagulant treatment for AUB. These data can guide proactive discussion with patients starting anticoagulant therapy.

Staphylokinase Control of Staphylococcus aureus Biofilm Formation and Detachment Through Host Plasminogen Activation

Staphylococcus aureus biofilms, a leading cause of persistent infections, are highly resistant to immune defenses and antimicrobial therapies. In the present study, we investigated the contribution of fibrin and staphylokinase (Sak) to biofilm formation. In both clinical S. aureus isolates and laboratory strains, high Sak-producing strains formed less biofilm than strains that lacked Sak, suggesting that Sak prevents biofilm formation. In addition, Sak induced detachment of mature biofilms. This effect depended on plasminogen activation by Sak. Host-derived fibrin, the main substrate cleaved by Sak-activated plasminogen, was a major component of biofilm matrix, and dissolution of this fibrin scaffold greatly increased susceptibility of biofilms to antibiotics and neutrophil phagocytosis. Sak also attenuated biofilm-associated catheter infections in mouse models. In conclusion, our results reveal a novel role for Sak-induced plasminogen activation that prevents S. aureus biofilm formation and induces detachment of existing biofilms through proteolytic cleavage of biofilm matrix components.

In Vitro and In Vivo Model to Study Bacterial Adhesion to the Vessel Wall Under Flow Conditions

In order to cause endovascular infections and infective endocarditis, bacteria need to be able to adhere to the vessel wall while being exposed to the shear stress of flowing blood.

To identify the bacterial and host factors that contribute to vascular adhesion of microorganisms, appropriate models that study these interactions under physiological shear conditions are needed. Here, we describe an in vitro flow chamber model that allows to investigate bacterial adhesion to different components of the extracellular matrix or to endothelial cells, and an intravital microscopy model that was developed to directly visualize the initial adhesion of bacteria to the splanchnic circulation in vivo. These methods can be used to identify the bacterial and host factors required for the adhesion of bacteria under flow. We illustrate the relevance of shear stress and the role of von Willebrand factor for the adhesion of Staphylococcus aureus using both the in vitro and in vivo model.

Plasminogen activation by staphylokinase enhances local spreading of S. aureus in skin infections

BACKGROUND

Staphylococcus aureus (S. aureus) is a frequent cause of skin and soft tissue infections. A unique feature of S. aureus is the combined presence of coagulases that trigger fibrin formation and of the plasminogen activator staphylokinase (SAK). Whereas the importance of fibrin generation for S. aureus virulence has been established, the role of SAK remains unclear. We studied the role of plasminogen activation by SAK in a skin infection model in mice and evaluated the impact of alpha-2-antiplasmin (α2AP) deficiency on the spreading and proteolytic activity of S. aureus skin infections. The species-selectivity of SAK was overcome by adenoviral expression of human plasminogen. Bacterial spread and density was assessed non-invasively by imaging the bioluminescence of S. aureus Xen36.

RESULTS

SAK-mediated plasmin activity increased the local invasiveness of S. aureus, leading to larger lesions with skin disruption as well as decreased bacterial clearance by the host. Even though fibrin and bacterial surfaces protected SAK-mediated plasmin activity from inhibition by α2AP, the deficiency of α2AP resulted in increased bacterial spreading. SAK-mediated plasmin also induced secondary activation of gelatinases, shown both in vitro and in lesions from the in vivo model.

CONCLUSION

SAK contributes to the phenotype of S. aureus skin infections by enhancing bacterial spreading as a result of fibrinolytic and proteolytic activation.

Active PAI-1 as marker for venous thromboembolism: case-control study using a comprehensive panel of PAI-1 and TAFI assays

BACKGROUND

Both activated Thrombin Activatable Fibrinolysis Inhibitor (TAFI) and active Plasminogen Activator Inhibitor-1 (PAI-1) attenuate fibrinolysis and may therefore contribute to the pathophysiology of Venous ThromboEmbolism (VTE). Whether increased TAFI and/or PAI-1 concentrations are associated with VTE is unclear.

OBJECTIVE

To study an association of impaired fibrinolysis and VTE using a comprehensive panel of in-house developed assays measuring intact TAFI, activation peptide of TAFI (AP-TAFI), PAI-1 antigen, endogenous PAI-1:t-PA complex (PAI-1:t-PA) and active PAI-1 levels in 102 VTE patients and in 113 healthy controls (HC).

RESULTS

Active PAI-1 was significantly higher in VTE patients compared to HC (20.9 [9.6-37.8] ng/ml vs. 6.2 [3.5-9.7] ng/ml, respectively). Active PAI-1 was the best discriminator with an area under the ROC curve and 95% confidence interval (AUROC [95%CI]) of 0.84 [0.79-0.90] compared to 0.75 [0.68-0.72] for PAI-1:t-PA, 0.65 [0.58-0.73] for PAI-1 antigen, 0.62 [0.54-0.69] for AP-TAFI and 0.51 [0.44-0.59] for intact TAFI. Using ROC analysis, we defined an optimal cut-off of 12.8 ng/ml for active PAI-1, with corresponding sensitivity of 71 [61-79] % and specificity of 89 [82-94] %. A lack of association with the time between VTE event and sample collection or with the intake of anticoagulant treatment suggests that active PAI-1 levels are sustainable high in VTE patients.

CONCLUSIONS

This case-control study emphasizes the clinical importance of measuring active PAI-1 instead of PAI-1 antigen and identifies active PAI-1 as a potential marker of VTE. Prognostic studies will need to address the clinical significance of active PAI-1 as biomarker.

The role of staphylothrombin-mediated fibrin deposition in catheter-related Staphylococcus aureus infections

Staphylococcus aureus (S. aureus) is a frequent cause of catheter-related infections. S. aureus secretes the coagulases staphylocoagulase and von Willebrand factor-binding protein, both of which form a staphylothrombin complex upon binding to prothrombin. Although fibrinogen and fibrin facilitate the adhesion of S. aureus to catheters, the contribution of staphylothrombin-mediated fibrin has not been examined. In this study, we use a S. aureus mutant lacking both coagulases (Δcoa/vwb) and dabigatran, a pharmacological inhibitor of both staphylothrombin and thrombin, to address this question. Genetic absence or chemical inhibition of pathogen-driven coagulation reduced both fibrin deposition and the retention of S. aureus on catheters in vitro. In a mouse model of jugular vein catheter infection, dabigatran reduced bacterial load on jugular vein catheters, as well as metastatic kidney infection. Importantly, inhibition of staphylothrombin improved the efficacy of vancomycin treatment both in vitro and in the mouse model.

Itraconazole versus amphotericin B plus nystatin in the prophylaxis of fungal infections in neutropenic cancer patients

The efficacy and safety of itraconazole oral solution and a combination of amphotericin B capsules plus nystatin oral suspension were compared in the prophylaxis of fungal infections in neutropenic patients. In an open, randomized, multicentre trial, 144 patients received itraconazole oral solution 100 mg bd, and 133 patients received amphotericin B 500 mg tds plus nystatin 2 MU qds. Overall, 65% of itraconazole-treated patients were considered to have had successful prophylaxis, compared with 53% in the polyene group. Proven deep fungal infections occurred in 5% of patients in each group. Fewer patients receiving itraconazole than amphotericin plus nystatin had superficial infections (3 versus 8%; P = 0.066). This trend in favour of itraconazole was seen in patients with profound neutropenia (neutrophil count <0.1 x 10(9) cells/L at least once) or prolonged neutropenia (neutrophil count <1.0 x 10(9) cells/L for >14 days). The median time to prophylactic failure was longer in the itraconazole group (37 days) than in the polyene group (34 days). The number of patients with fungal colonization (nose, sputum, stool) changed more favourably from baseline to endpoint in the itraconazole group than in the polyene group. Both treatments were safe and well tolerated; however, patients receiving amphotericin plus nystatin had a higher incidence of nausea and rash. In conclusion, itraconazole oral solution at doses of 100 mg bd and oral amphotericin B plus nystatin have similar prophylactic efficacy against fungal infections in neutropenic patients. On the basis of reduced incidence of superficial fungal infections, fungal colonization and specific adverse events, itraconazole may be the preferred treatment.

Pentostatin (Nipent) in T-cell malignancies. Leukemia Cooperative Group and the European Organization for Research and Treatment of Cancer

Within this phase II trial of the European Organization for Research and Treatment of Cancer, we have investigated the safety and efficacy of pentostatin (Nipent; SuperGen, San Ramon, CA) in refractory lymphoid malignancies. Pentostatin was administered at a dosage of 4 mg/m2 every week for the first 3 weeks, then every 14 days, followed by maintenance therapy of 4 mg/m2 monthly for a maximum of 6 months. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia, and hairy cell leukemia This report focuses on the outcome in T-cell malignancies: T-cell chronic lymphocytic leukemia, Sézary syndrome, mycosis fungoides, and T-zone lymphoma. Of 92 patients with these diagnoses enrolled, 76 were evaluable for response and toxicity, ie, 25 of 28 with T-cell chronic lymphocytic leukemia, 21 of 26 with Sézary syndrome, 22 of 26 with mycosis fungoides, and eight of 12 with T-zone lymphoma. All patients had progressive and advanced disease. Sixteen patients (21%) died during the first 9 weeks of treatment: 12 of progressive disease, two of infectious complications thought to be unrelated to treatment, one of myocardial infarction, and one of renal failure related to administration of intravenous contrast. Major toxicity (grades 3 and 4) included infection in 10.5% of patients, nausea/vomiting in 5%, and hepatotoxicity in 3%. One patient (1.3%) achieved a complete remission and 15 (19.7%) a partial remission. Better results were achieved in patients with Sézary syndrome or mycosis fungoides (complete remission + partial remission = 33.4% and 22.7%, respectively) than in patients with T-cell chronic lymphocytic leukemia (8%) or T-zone lymphoma (25%). We conclude that pentostatin is active in low-grade T-cell malignancies. Toxicities are mild to moderate at the dose schedule administered. Severe hematologic toxicity has not been observed. The efficacy at the present dose level is moderate. A higher dose might be necessary for some T-cell malignancies.

Pentostatin in T-cell malignancies--a phase II trial of the EORTC. Leukemia Cooperative Group

PURPOSE

Within this phase II EORTC trial, we have investigated the safety and efficacy of pentostatin in lymphoid malignancies. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia. This report focuses on the outcome in T-cell malignancies: T-CLL, Sézary syndrome (Sézary), mycosis fungoides (MF) and T-zone lymphoma (TZL).

PATIENTS AND METHODS

Of the 92 patients with these diagnoses enrolled, 76 were evaluable for response and toxicity, i.e., 25 of 28 with T-CLL, 21 of 26 with Sézary, 22 of 26 with MF, and 8 of 12 with TZL. All patients had progressive and advanced disease. Pentostatin was administered at a dosage of 4 mg/m2 every week for the first 3 weeks, then 4 mg/m2 every 14 days for another 6 weeks, followed by maintenance therapy of 4 mg/m2 monthly for a maximum of 6 months.

RESULTS

Response rates (complete and partial responses) in patients with Sézary (n = 22) or MF (n = 21) were 33% and 23%, respectively, and in patients with T-CLL (n = 21) or TZL (n = 8) 8% and 25%, respectively. Sixteen (21%) patients died during the first ten weeks of treatment: twelve of progressive disease, two of infectious complications with progressive disease, one of myocard infarction and one of renal failure related to administration of i.v. contrast. Major toxicity (grade 3-4) included infection in 11% of patients, nausea/vomiting in 4%, diarrhea in 3%. Hematologic toxicity was mild to non-existent.

CONCLUSIONS

We conclude that pentostatin is active in Sézary and MF but showed marginal activity in T-CLL or TZL. Toxicities are mild to moderate at the dose schedule administered. Due to its relatively specific lympholytic effect and its favorable toxicity spectrum, pentostatin might be especially useful for the palliative treatment of T-cell malignancies.

Quality of life in patients with acute myelogenous leukemia in prolonged first complete remission after bone marrow transplantation (allogeneic or autologous) or chemotherapy: a cross-sectional study of the EORTC-GIMEMA AML 8A trial

A cross-sectional study of quality of life (QOL) was performed in 98 patients in continued first complete remission (CR) for 1-7.4 years, after inclusion in the AML 8A trial which prospectively compared allogeneic bone marrow transplantation (AlloBMT), autologous BMT (ABMT) and intensive consolidation chemotherapy. Several significant differences between the three treatment groups were observed, on the basis of patient self-reports, with regard to somatic symptoms (mouth sores, cough, hair loss, headache), repeated acute medical problems, physical functioning, role functioning, leisure activities and, above all, sexual functioning. There were also significant differences for overall physical condition, and overall quality of life. For all these parameters, the ranking was uniformly AlloBMT lower than ABMT lower than chemotherapy. These differences remain significant after adjustment for time interval between CR and QOL evaluation, sex or age. These results, confirming a higher risk of permanent impairment of QOL after BMT, may have an impact on medical decisions and warrant further studies.

Granulocyte-macrophage colony-stimulating factor associated with induction treatment of acute myelogenous leukemia: a randomized trial by the European Organization for Research and Treatment of Cancer Leukemia Cooperative Group

PURPOSE

To assess the value of granulocyte-macrophage colony-stimulating factor (GM-CSF) for induction treatment of acute myeloid leukemia (AML), both for priming of leukemic cells and for acceleration of hematopoietic recovery.

PATIENTS AND METHODS

GM-CSF was administered 5 micrograms/kg/d by continuous intravenous (i.v.) infusion during induction therapy with daunorubicin (DNR) (days 1 to 3) and cytarabine (ARA-C) (days 1 to 7). A total of 102 patients were randomized onto four arms, as follows: (1) GM-CSF 24 hours before and during chemotherapy (arm +/-); (2) GM-CSF after chemotherapy until day 28 or recovery of polymorphonuclear leukocytes (PMNs) (arm -/+);(3) GM-CSF before, during, and after chemotherapy (arm +/+); or (4) no GM-CSF (arm -/-). Stopping rules were applied in case of an initial WBC count greater than 30 x 10(9)/L or a secondary increase of circulating blast cells. Analyses were performed according to the intention-to-treat principle.

RESULTS

The complete remission (CR) rates were 77% (arm -/-), 72% (arm +/-), 48% (arm -/+), and 46% (arm +/+). Patients randomized to receive GM-CSF after induction (arms -/+ and +/+) had a significantly lower CR rate (P = .008) and a trend toward accelerated recovery of neutrophils, but no fewer infections or induction deaths. The lower CR rate appeared to be related to an increased resistance rate, with persistent leukemia. The main side effects of GM-CSF were fluid retention and hypotension.

CONCLUSION

GM-CSF administered during induction treatment of AML with a DNR/Ara-C combination did not provide any clinical benefit. Furthermore, there was a significant decrease in the CR rate with more persistent leukemia when GM-CSF was administered during the hypoplastic phase after the chemotherapy courses.