[Recommendations of the S3 Guideline "Use of Extracorporeal Circulation (ECLS/ ECMO) for Cardiac and Circulatory Failure" of the Association of Scientific Medical Societies in Germany]. / Empfehlungen der S3-Leitlinie (AWMF) "Einsatz der extrakorporalen Zirkulation (ECLS/ECMO) bei Herz- und Kreislaufversagen".

In recent years, the use of mechanical support for patients with cardiac or circulatory failure has continuously increased, leading to 3,000 ECLS/ECMO (extracorporeal life support/extracorporeal membrane oxygenation) implantations annually in Germany. Due to the lack of guidelines, there is an urgent need for evidence-based recommendations addressing the central aspects of ECLS/ECMO therapy. In July 2015, the generation of a guideline level S3 according to the standards of the Association of the Scientific Medical Societies in Germany (AWMF) was announced by the German Society for Thoracic and Cardiovascular Surgery (GSTCVS). In a well-structured consensus process, involving experts from Germany, Austria and Switzerland, delegated by 16 scientific societies and the patients' representation, the guideline "Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure" was created under guidance of the GSTCVS, and published in February 2021. The guideline focuses on clinical aspects of initiation, continuation, weaning and aftercare, herein also addressing structural and economic issues. This article presents an overview on the methodology as well as the final recommendations.

Six-Month Survival After Extracorporeal Membrane Oxygenation for Severe COVID-19.

OBJECTIVES: The authors evaluated the outcome of adult patients with coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) requiring the use of extracorporeal membrane oxygenation (ECMO). DESIGN: Multicenter retrospective, observational study. SETTING: Ten tertiary referral university and community hospitals. PARTICIPANTS: Patients with confirmed severe COVID-19-related ARDS. INTERVENTIONS: Venovenous or venoarterial ECMO. MEASUREMENTS AND MAIN RESULTS: One hundred thirty-two patients (mean age 51.1 ± 9.7 years, female 17.4%) were treated with ECMO for confirmed severe COVID-19-related ARDS. Before ECMO, the mean Sequential Organ Failure Assessment score was 10.1 ± 4.4, mean pH was 7.23 ± 0.09, and mean PaO2/fraction of inspired oxygen ratio was 77 ± 50 mmHg. Venovenous ECMO was adopted in 122 patients (92.4%) and venoarterial ECMO in ten patients (7.6%) (mean duration, 14.6 ± 11.0 days). Sixty-three (47.7%) patients died on ECMO and 70 (53.0%) during the index hospitalization. Six-month all-cause mortality was 53.0%. Advanced age (per year, hazard ratio [HR] 1.026, 95% CI 1.000-1-052) and low arterial pH (per unit, HR 0.006, 95% CI 0.000-0.083) before ECMO were the only baseline variables associated with increased risk of six-month mortality. CONCLUSIONS: The present findings suggested that about half of adult patients with severe COVID-19-related ARDS can be managed successfully with ECMO with sustained results at six months. Decreased arterial pH before ECMO was associated significantly with early mortality. Therefore, the authors hypothesized that initiation of ECMO therapy before severe metabolic derangements subset may improve survival rates significantly in these patients. These results should be viewed in the light of a strict patient selection policy and may not be replicated in patients with advanced age or multiple comorbidities. CLINICAL TRIAL REGISTRATION: identifier, NCT04383678.

[Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure : Short version of the S3 guideline]. / Einsatz der extrakorporalen Zirkulation (ECLS/ECMO) bei Herz- und Kreislaufversagen : Kurzversion der AWMF-S3-Leitlinie.

In Germany, a remarkable increase regarding the usage of extracorporeal membrane oxygenation (ECMO) and extracorporeal life support (ECLS) systems has been observed in recent years with approximately 3000 ECLS/ECMO implantations annually since 2015. Despite the widespread use of ECLS/ECMO, evidence-based recommendations or guidelines are still lacking regarding indications, contraindications, limitations and management of ECMO/ECLS patients. Therefore in 2015, the German Society of Thoracic and Cardiovascular Surgery (GSTCVS) registered the multidisciplinary S3 guideline "Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure" to develop evidence-based recommendations for ECMO/ECLS systems according to the requirements of the Association of the Scientific Medical Societies in Germany (AWMF). Although the clinical application of ECMO/ECLS represents the main focus, the presented guideline also addresses structural and economic issues. Experts from 17 German, Austrian and Swiss scientific societies and a patients' organization, guided by the GSTCVS, completed the project in February 2021. In this report, we present a summary of the methodological concept and tables displaying the recommendations for each chapter of the guideline.

Physiologically based pharmacokinetic evaluation of cefuroxime in perioperative antibiotic prophylaxis.

AIMS: Adequate plasma concentrations of antibiotics during surgery are essential for the prevention of surgical site infections. We examined the pharmacokinetics of 1.5 g cefuroxime administered during induction of anaesthesia with follow-up doses every 2.5 hours until the end of surgery. We built a physiologically based pharmacokinetic model with the aim to ensure adequate antibiotic plasma concentrations in a heterogeneous population. METHODS: A physiologically based pharmacokinetic model (PK-Sim® /MoBi® ) was developed to investigate unbound plasma concentrations of cefuroxime. Blood samples from 25 thoracic surgical patients were analysed with high-performance liquid chromatography. To evaluate optimized dosing regimens, physiologically based pharmacokinetic model simulations were conducted. RESULTS: Dosing simulations revealed that a standard dosing regimen of 1.5 g every 2.5 hours reached the pharmacokinetic/pharmacodynamic target for Staphylococcus aureus. However, for Escherichia coli, >50% of the study participants did not reach predefined targets. Effectiveness of cefuroxime against E. coli can be improved by administering a 1.5 g bolus immediately followed by a continuous infusion of 3 g cefuroxime over 3 hours. CONCLUSION: The use of cefuroxime for perioperative antibiotic prophylaxis to prevent staphylococcal surgical site infections appears to be effective with standard dosing of 1.5 g preoperatively and follow-up doses every 2.5 hours. In contrast, if E. coli is relevant in surgeries, this dosing regimen appears insufficient. With our derived dose recommendations, we provide a solution for this issue.

[Extracorporeal Membrane Oxygenation in Thoracic Surgery: Establishing Functional and Technical Operability]. / Extrakorporale Membranoxygenierung in der Thoraxchirurgie: Etablierung funktioneller und technischer Operabilität.

Functional and technical operability has to be evaluated and defined prior to thoracic surgical procedures. Sometimes patients assigned to thoracic surgery procedures have to be declared inoperable due to functional und technical limitations. Extracorporeal lung support is an important tool to establish functional and technical operability in patients undergoing thoracic surgical procedures. This ensures perioperative safety and minimises the risk during extended lung resection.

Impact of the Interdisciplinary Tumor Board of the Cooperative Ewing Sarcoma Study Group on local therapy and overall survival of Ewing sarcoma patients after induction therapy.

BACKGROUND: The Interdisciplinary Tumor Board (ITB) of the Cooperative Ewing Sarcoma Study (CESS) Group was investigated to assess its impact on the overall survival (OAS) of Ewing sarcoma (EwS) patients. The ITB functions as a reference center for the international institutions participating in the clinical trials of the CESS group, but is also available internationally to patients who have not been treated within an appropriate clinical trial. The value of tumor boards in terms of benefit for the patients and the health care system in general is not well documented and is also the subject of controversial discussions. A review of the representative literature is included. METHODS: Data were analyzed from 481 patients who had been registered into the European Ewing Tumor Working Initiative of National Groups (EURO E.W.I.N.G.-99) clinical trial via the CESS data center between 2006 and 2009; this included 331 patients with localized disease and another 150 individuals with metastases at diagnosis. Median follow-up time was 3.2 years. RESULTS: Improved OAS was observed for patients with metastases who had received recommendations from the ITB compared with those who had not received recommendations. In patients with localized disease, a recommendation from the ITB had no influence on OAS. CONCLUSION: As a reference center for a rare disease, recommendations from our ITB impacted local therapy and led to higher OAS in patients with metastatic disease. To our knowledge, this is the first analysis that examines the value of a reference tumor board on a rare disease.

Thoracic Wall Reconstruction with Acellular Porcine Dermal Collagen Matrix.

BACKGROUND: Major thoracic wall resections require the implantation of foreign materials for reconstruction and stabilization. Recently, biological collagen matrixes have emerged as an alternative to the routinely used synthetic materials. MATERIALS AND METHODS: Retrospectively, we analyzed our initial experience of chest wall reconstruction on large defects using a cross-linked porcine dermal acellular collagen matrix mesh with a thickness of 1.5 mm. RESULTS: Six sarcoma patients with a mean age of 46 (22-66) years underwent chest wall resections. Complete thoracic wall defects (mean area 149 cm2) ranged from 8 × 10 to 15 × 20 cm in size. In the majority of cases, only mobilized subcutaneous tissue and skin were used for soft-tissue coverage of the implanted porcine collagen matrix patches. Implantation and postoperative courses were uneventful in all patients. No local infections or wound healing problems occurred. The collagen material resulted in durable and good to excellent chest wall stability in clinical follow-ups, and on computed tomography scans spanning over 3.5 years. Histological examination showed integration, neovascularization, and long-term persistence of the collagen matrix on late reoperation of one patient. CONCLUSION: Acellular porcine dermal collagen matrix is a feasible and reliable biological patch material for reconstruction of the thoracic wall. Excellent wound healing and long-term stability are achieved even in large defects or complete sternal replacements.

Local control in Ewing sarcoma of the chest wall: results of the EURO-EWING 99 trial.

BACKGROUND: Primary Ewing sarcoma (ES) can sometimes present as a chest-wall tumor. Multidisciplinary management, including chemotherapy and local treatment consisting of surgery, radiotherapy (RT), or both, has improved the survival of patients with localized ES; however, the best approach to achieving local control remains controversial. METHODS: We retrospectively analyzed data from 198 patients with non-metastatic ES of the chest wall, who were registered in the database of the German Society of Pediatric Hematology and Oncology between July 1998 and April 2009. The majority of patients (n = 130) presented with rib tumors; 7 patients received RT only, 85 patients underwent surgery alone, and 106 patients were treated with a combination of surgery and RT. RESULTS: Overall survival in all patients was 78 and 71 % at 3 and 5 years, respectively. Event-free survival at 5 years (5-year EFS) was 57 % in the RT group, 73 % in the surgery group and 63 % in the surgery + RT group. In patients with complete resections, 5-year EFS did not improve with the addition of RT compared with surgery alone. There was no difference in the 5-year EFS in patients with partial (63 %) or total (64 %) resection of the affected ribs, and median follow-up was 4.71 years (range 0.40-13.48). CONCLUSIONS: Complete tumor resection is the best way to achieve local control of ES of the chest wall; additional RT is only useful in patients with incomplete resection. The main limitation of this study was its retrospective nature, and the benefit of total resection of the affected ribs could not be proved.

Pectus excavatum and cardiac surgery: simultaneous correction advocated.

BACKGROUND: Severe pectus excavatum may be present in combination with cardiac conditions requiring open-heart surgery. The best strategy for this situation has been debated controversially. PATIENTS AND METHODS: In a retrospective study, we analyzed all our patients undergoing concurrent pectus excavatum correction and open-heart surgery. RESULTS: Ten patients aged 9 to 70 years underwent a simultaneous combined surgical procedure between 2001 and 2013. Indications for cardiac surgery were various forms of congenital and acquired heart disease including coronary artery disease with internal thoracic artery grafts and ascending aortic aneurysms. A modified Ravitch procedure was performed for pectus excavatum correction (mean Haller-Index 5.0). Mean operating time was 364 (210-495) minutes and mean duration of cardiopulmonary bypass was 125 (54-222) minutes. All procedures were completed successfully. Postoperatively minor complications were observed in three patients. In-hospital and 30-day mortalities were nil. Good cosmetic and functional results were achieved in all patients. CONCLUSIONS: Our data demonstrate that simultaneous pectus excavatum correction and cardiac surgery is effective and reliable. A combined approach is advocated if candidates for cardiac surgery present with significant pectus excavatum deformity.

Surgical treatment in a patient with Klippel-Feil syndrome and anterior cervical meningomyelocele: a case report and review of literature.

INTRODUCTION: Klippel-Feil syndrome (KFS) is considered a rare developmental disorder characterized by mono- or multisegmental fusion of the cervical vertebrae which is frequently associated with diverse non-osseous, e.g. neural, visceral, cardiopulmonary and genitourinary development anomalies. Anterior cervical meningomyelocele (MMC) in KFS has only been described in two previous patients, both with non-surgical treatment. CLINICAL PRESENTATION: We present the case of a 26-year-old female suffering from KFS, presenting with progressive bilateral C6 paraesthesias, C7 and C8 motor weakness and myelopathy. Radiological imaging revealed incomplete osseous fusion of the vertebrae C2-Th1. The spinal cord was displaced ventro-caudally through a large anterior MMC, apparently fixed at the dorsal oesophagus, severely stretching the cervical nerve roots. Surgery was indicated due to progression of the symptoms and was performed through a combined partial sternotomy and ventral anterolateral cervical approach. Intraoperatively, both division of oesophago-dural adhesions and intradural untethering of adhesions of the myelon with caudal parts of the cele were performed. Evoked somatosensory potentials improved immediately and 6-day postoperative MRI revealed a nearly complete reposition of the spinal cord in its physiological position. Genetic sequence analyses ruled out mutation of the growth and differentiation factor 6 (GDF6). Apart from slight intermittent paraesthesia, symptoms resolved almost completely within weeks after operation. Both radiological and neurological improvement remained stable at 16 months of follow-up. CONCLUSION: KFS with anterior cervical MMC is rarely seen and may require surgery in case of clincial signs of nerve root compression or myelopathy. Osseous decompression, untethering and adhesiolysis under electrophysiological monitoring can provide sufficient radiological and clinical improvement.

Inhibition of p38 signaling curtails the SARS-CoV-2 induced inflammatory response but retains the IFN-dependent antiviral defense of the lung epithelial barrier.

SARS-CoV-2 is the causative agent of the immune response-driven disease COVID-19 for which new antiviral and anti-inflammatory treatments are urgently needed to reduce recovery time, risk of death and long COVID development. Here, we demonstrate that the immunoregulatory kinase p38 MAPK is activated during viral entry, mediated by the viral spike protein, and drives the harmful virus-induced inflammatory responses. Using primary human lung explants and lung epithelial organoids, we demonstrate that targeting p38 signal transduction with the selective and clinically pre-evaluated inhibitors PH-797804 and VX-702 markedly reduced the expression of the pro-inflammatory cytokines IL6, CXCL8, CXCL10 and TNF-α during infection, while viral replication and the interferon-mediated antiviral response of the lung epithelial barrier were largely maintained. Furthermore, our results reveal a high level of drug synergism of both p38 inhibitors in co-treatments with the nucleoside analogs Remdesivir and Molnupiravir to suppress viral replication of the SARS-CoV-2 variants of concern, revealing an exciting and novel mode of synergistic action of p38 inhibition. These results open new avenues for the improvement of the current treatment strategies for COVID-19.

Induction of smooth muscle cell migration during arteriogenesis is mediated by Rap2.

OBJECTIVE: Collateral artery growth or arteriogenesis is the primary means of the circulatory system to maintain blood flow in the face of major arterial occlusions. Arteriogenesis depends on activation of fibroblast growth factor (FGF) receptors, but relatively little is known about downstream mediators of FGF signaling. METHODS AND RESULTS: We screened for signaling components that are activated in response to administration of FGF-2 to cultured vascular smooth muscle cells (VSMCs) and detected a significant increase of Rap2 but not of other Ras family members, which corresponded to a strong upregulation of Rap2 and C-Raf in growing collaterals from rabbits with femoral artery occlusion. Small interfering RNAs directed against Rap2 did not affect FGF-2 induced proliferation of VSMC but strongly inhibited their migration. Inhibition of FGF receptor-1 (FGFR1) signaling by infusion of a sulfonic acid polymer or infection with a dominant-negative FGFR1 adenovirus inhibited Rap2 upregulation and collateral vessel growth. Similarly, expression of dominant-negative Rap2 blocked arteriogenesis, whereas constitutive active Rap2 enhanced collateral vessel growth. CONCLUSIONS: Rap2 is part of the arteriogenic program and acts downstream of the FGFR1 to stimulate VSMC migration. Specific modulation of Rap2 might be an attractive target to manipulate VSMC migration, which plays a role in numerous pathological processes.

3D Ex vivo tissue platforms to investigate the early phases of influenza a virus- and SARS-CoV-2-induced respiratory diseases.

Pandemic outbreaks of viruses such as influenza virus or SARS-CoV-2 are associated with high morbidity and mortality and thus pose a massive threat to global health and economics. Physiologically relevant models are needed to study the viral life cycle, describe the pathophysiological consequences of viral infection, and explore possible drug targets and treatment options. While simple cell culture-based models do not reflect the tissue environment and systemic responses, animal models are linked with huge direct and indirect costs and ethical questions. Ex vivo platforms based on tissue explants have been introduced as suitable platforms to bridge the gap between cell culture and animal models. We established a murine lung tissue explant platform for two respiratory viruses, influenza A virus (IAV) and SARS-CoV-2. We observed efficient viral replication, associated with the release of inflammatory cytokines and the induction of an antiviral interferon response, comparable to ex vivo infection in human lung explants. Endolysosomal entry could be confirmed as a potential host target for pharmacological intervention, and the potential repurposing potentials of fluoxetine and interferons for host-directed therapy previously seen in vitro could be recapitulated in the ex vivo model.

Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure -A clinical practice Guideline Level 3.

Aims Worldwide applications of extracorporeal circulation for mechanical support in cardiac and circulatory failure, which are referred to as extracorporeal life support (ECLS) or veno-arterial extracorporeal membrane oxygenation (va-ECMO), have dramatically increased over the past decade. In spite of the expanding use and the immense medical as well as socio-economic impact of this therapeutic approach, there has been a lack of interdisciplinary recommendations considering the best available evidence for ECLS treatment. Methods and Results In a multiprofessional, interdisciplinary scientific effort of all scientific societies involved in the treatment of patients with acute cardiac and circulatory failure, the first evidence- and expert consensus-based guideline (level S3) on ECLS/ECMO therapy was developed in a structured approach under regulations of the AWMF (Association of the Scientific Medical Societies in Germany) and under use of GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. This article presents all recommendations created by the expert panel, addressing a multitude of aspects for ECLS initiation, continuation, weaning and aftercare as well as structural and personnel requirements. Conclusions This first evidence- and expert consensus-based guideline (level S3) on ECLS/ECMO therapy should be used to apply the best available care nationwide. Beyond clinical practice advice, remaining important research aspects for future scientific efforts are formulated.

Blunt Chest Trauma in Polytraumatized Patients: Predictive Factors for Urgent Thoracotomy.

PURPOSE: Current guidelines on urgent thoracotomy of polytraumatized patients are based on data from perforating chest injuries. We aimed to identify predictive factors for urgent thoracotomy after chest-tube placement for blunt chest trauma in a civilian setting. METHODS: Polytraumatized patients (Injury Severity Score ≥16) with blunt chest trauma, submitted to a level I trauma centre during a period of 12 years that received at least one chest tube were included. Trauma mechanism, chest-tube output, haemoglobin values, need for cellular blood products, coagulopathies, rib fracture pattern, thoracotomy, and mortality were retrospectively analysed. RESULTS: 235 polytraumatized patients were included. Patients that received urgent thoracotomy (UT, n = 10) showed a higher mean chest-tube output within 24 h with a median (Mdn) of 3865 (IQR 2423-5156) mL compared to the group with no additional thoracic surgery (NT, n = 225) with Mdn 185 (IQR 50-463) mL (p < 0.001). The cut-off 24-h chest-tube output value for recommended thoracotomy was 1270 mL (ROC-Curve). UT showed an initial haemoglobin of Mdn 11.7 (IQR 9.2-14.3) g/dL and an INR value of Mdn 1.27 (IQR 1.11-1.69) as opposed to Mdn 12.3 (IQR 10-13.9) g/dL and Mdn 1.13 (IQR 1.05-1.34) in NT (haemoglobin: p = 0.786; INR: p = 0.215). There was an average number of 7.1(±3.4) rib fractures in UT and 6.7(±4.8) in NT (p = 0.649). CONCLUSIONS: Chest-tube output remains the single most important predictive factor for urgent thoracotomy also after blunt chest trauma. Patients with a chest-tube output of more than 1300 mL within 24 h after trauma should be considered for transfer to a level I trauma centre with standby thoracic surgery.

[Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure : Short version of the S3 guideline]. / Einsatz der extrakorporalen Zirkulation (ECLS/ECMO) bei Herz- und Kreislaufversagen : Kurzversion der AWMF-S3-Leitlinie.

In Germany, a remarkable increase regarding the usage of extracorporeal membrane oxygenation (ECMO) and extracorporeal life support (ECLS) systems has been observed in recent years with approximately 3000 ECLS/ECMO implantations annually since 2015. Despite the widespread use of ECLS/ECMO, evidence-based recommendations or guidelines are still lacking regarding indications, contraindications, limitations and management of ECMO/ECLS patients. Therefore in 2015, the German Society of Thoracic and Cardiovascular Surgery (GSTCVS) registered the multidisciplinary S3 guideline "Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure" to develop evidence-based recommendations for ECMO/ECLS systems according to the requirements of the Association of the Scientific Medical Societies in Germany (AWMF). Although the clinical application of ECMO/ECLS represents the main focus, the presented guideline also addresses structural and economic issues. Experts from 17 German, Austrian and Swiss scientific societies and a patients' organization, guided by the GSTCVS, completed the project in February 2021. In this report, we present a summary of the methodological concept and tables displaying the recommendations for each chapter of the guideline.

Noncaseating granulomatous diseases in germ cell cancer patients-A single-center experience.

OBJECTIVES: In patients with testicular Germ Cell Tumors (GCT) noncaseating granulomatous diseases such as Sarcoid Like Lesions (SLL) or Sarcoidosis can mimic metastasis due to hilar or mediastinal lymphadenopathy. Due to the clinical and prognostic impact, exclusion of malignant diseases is mandatory. MATERIAL AND METHODS: Retrospectively, data from 636 GCT patients, who were seen in the course of tumor surveillance/follow-up were collected. Focus was put on the detection of tumor relapse vs. noncaseating granulomatous reactions. For the differential diagnosis of thoracic lymphadenopathy or pulmonary infiltrates either bronchoscopy (e.g., endobronchial ultrasound-guided transbronchial needle aspiration, endobronchial ultrasound-guided transbronchial needle aspiration) or thoracic surgery was performed. Both GCT patients with either tumor relapse or coexisting SLL were compared to GCT patients without SLL and tumor relapse. RESULTS: Twenty-nine patients suffered from suspected tumor relapse. Whereas thoracic relapses were suspected in 15 patients on chest computed tomography, thoracic relapse was confirmed in 5 cases by open surgery. In 2 cases open surgery yielded reactive lymphadenitis, and in 8 cases SLL was diagnosed either via EBUS-TBNA (n = 7) or thoracoscopic wedge resection plus lymphadenectomy (n = 1). With focus on overall survival, no relevant difference was found between all tested subgroups (P = 0.265; logrank test). CONCLUSIONS: In GCT patients, the coexistence of noncaseating granulomatous disease is common. Minimal invasive bronchoscopic techniques can serve for the cytopathologic exclusion of malignant thoracic manifestations. In our monocenter patient group the coexistence of SLL did not have any prognostic impact on overall survival.

Antiviral potential of human IFN-α subtypes against influenza A H3N2 infection in human lung explants reveals subtype-specific activities.

Influenza is an acute respiratory infection causing high morbidity and mortality in annual outbreaks worldwide. Antiviral drugs are limited and pose the risk of resistance development, calling for new treatment options. IFN-α subtypes are immune-stimulatory cytokines with strong antiviral activities against IAV in vitro and in vivo. However, the clinical use of IFN-α2, the only licensed subtype of this multi-gene family, could not prevent or limit IAV infections in humans. However, the other subtypes were not investigated.Therefore, this study evaluated the induction and antiviral potential of all human IFN-α subtypes during H3N2 IAV infection in human lung explants. We found that subtypes with weak antiviral activities were preferentially induced during IAV infection in human lungs. Intriguingly, non-induced subtypes α16, α5 and α4 suppressed viral replication up to 230-fold more efficiently than α2. Furthermore, our results demonstrate that subtypes with stronger antiviral activities induce higher expression of IAV-specific restriction factors and that MxA expression is a determinant of the subtype-specific antiviral activity towards H3N2 IAV. These results corroborate that IFN-α subtypes exhibit differential antiviral activities and emphasize that subtypes α16, α5 and α4 should be further investigated for the prevention and treatment of severe infections with seasonal H3N2 IAV.