© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Transplant Infectious Disease, ISSN 1398-2273
Immunogenicity of virosomal adjuvanted trivalent influenza vaccination in allogeneic stem cell transplant recipients A. Ambati, S. Einarsdottir, I. Magalhaes, T. Poiret, R. Bodenstein, K. LeBlanc, M. Brune, M. Maeurer, P. Ljungman. Immunogenicity of virosomal adjuvanted trivalent influenza vaccination in allogeneic stem cell transplant recipients. Transpl Infect Dis 2015: 17: 371–379. All rights reserved Abstract: Background. Influenza vaccination is generally recommended to hematopoietic stem cell transplant (HSCT) recipients. However, the seasonal subunit vaccination response is frequently suboptimal, and alternate more efficient vaccination systems must be examined. We compared the immunogenicity of an adjuvanted virosomal influenza and subunit vaccine in HSCT recipients. Methods. The immunogenicity after a single dose (0.5 mL) of adjuvanted trivalent virosomal vaccination was evaluated in a study cohort of 21 HSCT recipients and compared to a control cohort of 30 HSCT recipients who received a single dose (0.5 mL) of nonadjuvanted seasonal trivalent subunit vaccination over 4 seasons from 2010 to 2014. Whole blood interferon-gamma (IFN-c) release assays were tested, both before and 30 days after vaccination, in response to influenza pandemic (pdm) H1N1, H3N2, and B antigens. HLA-A*02 dextramers, to gauge for the absolute number of antigenspecific CD8+ T-cells, and pdm 2009 hemagglutinin inhibition (HI) assays, to test for neutralizing antibodies, were used as immunological readouts. Results. The pdm HI titers were poor in both cohorts with only 23% (5/21) after virosomal vaccination and 13.3% (4/30) in the seasonal vaccine cohort having protective titers (≥40). The delta change of IFN-c production in response to influenza pdm H1N1 (P = 0.005) and influenza B antigens (P = 0.01) were significantly elevated in blood from individuals who received the virosomal as compared to the seasonal vaccine. The IFN-c response to pdm H1N1 was stronger (P < 0.001), as compared to seasonal vaccination, in patients vaccinated >6 month post HSCT. We detected a significant increase in the frequency of matrix 1 (GILGFVTL) dextramerspecific CD8+ T-cells after the virosomal vaccine (P = 0.01). No differences were seen in the hemagglutinin-specific CD8+ T-cells between the 2 cohorts. Conclusion. Vaccination using a virosomal delivery system is beneficial in eliciting robust cellular immune responses to pdm H1N1 influenza in SCT recipients.
Hematopoietic stem cell transplant (HSCT) patients have a higher risk for viral infections. Respiratory viral infections, such as influenza, are important causes of
A. Ambati1,2, S. Einarsdottir3, I. Magalhaes1,4, T. Poiret1, R. Bodenstein1, K. LeBlanc1,5, M. Brune3, M. Maeurer1,4, P. Ljungman2,5 1
Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden, 2Department of Medicine, Karolinska Institutet, Huddinge, Sweden, 3Sahlgrens University Hospital, Goteborg, Sweden, 4Center for Allogeneic Stem Cell Transplantation, Karolinska University Hospital, Stockholm, Sweden, 5Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
Key words: transplantation; influenza vaccination; virosomal; adjuvant; seasonal; subunit; inactivated; interferon-gamma; dextramers Correspondence to: Prof. Per Ljungman, Department of Medicine, Karolinska Institutet, Huddinge, 14186 Sweden Tel: +460858582507 Fax: +46087748725 E-mail: [email protected]
Received 19 December 2014, revised 4 February 2015, accepted for publication 28 February 2015 DOI: 10.1111/tid.12382 Transpl Infect Dis 2015: 17: 371–379
morbidity in these patients (1–3). The emergence of new strains of influenza, such as during the H1N1 2009 pandemic (pdm), is of particular concern to HSCT
371
Ambati et al: Immunogenicity of virosomal flu vaccine in SCT recipients
recipients In a prospective study among 286 HSCT patients performed during the H1N1 2009 pd, 43.7% were hospitalized, 32.5% developed lower respiratory tract disease, 11.5% required mechanical ventilation, and 6.3% died from A/H1N1 infection (4). The treatment strategy encompasses early usage of neuraminidase inhibitors, such as oseltamivir, which are partly effective, yet the risk to develop resistance is pronounced (4). The use of antiviral prophylaxis with neuraminidase inhibitors is somewhat controversial. Tomblyn et al. (5) recommended quite broad use of prophylaxis during influenza outbreaks both to patients and non-vaccinated family members. However, in the more recent European Conference on Infections in Leukemia guidelines, Engelhard et al. (6) only recommend neuraminidase inhibitors as post-exposure prophylaxis. It should also be recognized that quite a substantial risk exists for development of resistance to these drugs (4). Preventive strategies include infection control and vaccination against influenza, while early diagnosis and subsequent treatment with antiviral drugs seem to be important to decrease both morbidity and mortality (7– 10). Patients are most vulnerable early after transplantation for complications to influenza, especially patients with lymphopenia (1, 7, 11). It is still controversial when influenza vaccination should be initiated after HSCT, although current international recommendations suggest starting 4–6 months after HSCT and possibly earlier in an outbreak situation (6, 12). The effect of vaccination is, however, frequently suboptimal and varies with the time from SCT between 10% and 50%, with the poorest results early after HSCT (9, 13, 14). Serological responses analyzed by hemagglutinin inhibition (HI) are generally poor before 6 months, and in some studies before 12 months, after HSCT (13–17). In previous studies, increases in interferon-gamma (IFN-c) production after vaccination could be measured, although decreased compared to healthy controls, along with an increase in influenza-specific CD8+ T-cells measured by soluble major histocompatibility complex (MHC) class I/peptide multimers after seasonal vaccination (18). In a study with non-adjuvanted vaccine against the 2009 H1N1 pdm virus, among 82 HSCT patients, 51% showed seroprotective titers to pdm H1N1 (16). With the use of AS03 adjuvanted vaccine, a 69% seroprotection rate was observed among 13 HSCT patients, owing to its superior immunogenicity, compared to the 18% seroprotection rate after trivalent seasonal non-adjuvanted influenza vaccine among 11 HSCT patients (19). Two doses of adjuvanted pdm vaccine resulted in better rates of seroprotection than a single dose (14, 17, 20– 22).
372
A different vaccine construct, which might lead to improved immune responses in HSCT recipients, is the adjuvanted trivalent virosomal vaccine that has been tested in adults, the elderly, and in immunocompromised patients (23). The virosomal vaccine is composed of phospholipids and phosphatidylcholine, complexed with influenza envelope glycoproteins hemagglutinin and neuraminidase (24). We tested the immunogenicity of the virosomal vaccine in HSCT recipients and compared the immune response patterns with a historical control group that had received the inactivated seasonal trivalent vaccine.
Materials and methods Study design The study was designed as an uncontrolled phase II study using an adjuvanted virosomal vaccine (Inflexal Vâ, Crucell Sweden AB, Solna, Sweden; EudraCT No: 2013-003403-19). The main endpoints were T-cell and serological immune responses. The inclusion criteria were adult allogeneic SCT recipients within 3– 24 months after transplantation, vaccinated according to Swedish and international guidelines (5, 6, 25). The immune responses were compared to a control cohort, collected from the Karolinska and Sahlgrenska transplant centers, who received the seasonal subunit vaccination during the 3 previous seasons. Patients who developed respiratory symptoms were sampled using a nasopharyngeal aspirate for a multiplex polymerase chain reaction (PCR) according to clinical routine. The Ethical Committees of the participating institutions approved the study (Diary no 2010/136931/4 and 2013/1499-31/1).
Patients Twenty-one allogeneic SCT recipients were included in the study and given the virosomal influenza vaccine (Table 1). Serum and blood samples were collected before and at 4 weeks after vaccination. The study nurse called the patients regularly to inquire about symptoms of influenza-like illness and all symptomatic patients were requested to visit the clinic for sampling and the samples analyzed by multiplex PCR. In addition, questioning and sampling, as needed, were also performed when the patients visited the clinic. The control cohort consisted of 30 patients. At the time of vaccination in the study cohort, 11 patients were >6 months and 10 patients 6 months
11
18
6 months and 12 patients 6 months (Fig. 1). In contrast, the seasonal trivalent vaccine was poor (median
Immunogenicity of virosomal adjuvanted trivalent influenza vaccination in allogeneic stem cell transplant recipients A. Ambati, S. Einarsdottir, I. Magalhaes, T. Poiret, R. Bodenstein, K. LeBlanc, M. Brune, M. Maeurer, P. Ljungman. Immunogenicity of virosomal adjuvanted trivalent influenza vaccination in allogeneic stem cell transplant recipients. Transpl Infect Dis 2015: 17: 371–379. All rights reserved Abstract: Background. Influenza vaccination is generally recommended to hematopoietic stem cell transplant (HSCT) recipients. However, the seasonal subunit vaccination response is frequently suboptimal, and alternate more efficient vaccination systems must be examined. We compared the immunogenicity of an adjuvanted virosomal influenza and subunit vaccine in HSCT recipients. Methods. The immunogenicity after a single dose (0.5 mL) of adjuvanted trivalent virosomal vaccination was evaluated in a study cohort of 21 HSCT recipients and compared to a control cohort of 30 HSCT recipients who received a single dose (0.5 mL) of nonadjuvanted seasonal trivalent subunit vaccination over 4 seasons from 2010 to 2014. Whole blood interferon-gamma (IFN-c) release assays were tested, both before and 30 days after vaccination, in response to influenza pandemic (pdm) H1N1, H3N2, and B antigens. HLA-A*02 dextramers, to gauge for the absolute number of antigenspecific CD8+ T-cells, and pdm 2009 hemagglutinin inhibition (HI) assays, to test for neutralizing antibodies, were used as immunological readouts. Results. The pdm HI titers were poor in both cohorts with only 23% (5/21) after virosomal vaccination and 13.3% (4/30) in the seasonal vaccine cohort having protective titers (≥40). The delta change of IFN-c production in response to influenza pdm H1N1 (P = 0.005) and influenza B antigens (P = 0.01) were significantly elevated in blood from individuals who received the virosomal as compared to the seasonal vaccine. The IFN-c response to pdm H1N1 was stronger (P < 0.001), as compared to seasonal vaccination, in patients vaccinated >6 month post HSCT. We detected a significant increase in the frequency of matrix 1 (GILGFVTL) dextramerspecific CD8+ T-cells after the virosomal vaccine (P = 0.01). No differences were seen in the hemagglutinin-specific CD8+ T-cells between the 2 cohorts. Conclusion. Vaccination using a virosomal delivery system is beneficial in eliciting robust cellular immune responses to pdm H1N1 influenza in SCT recipients.
Hematopoietic stem cell transplant (HSCT) patients have a higher risk for viral infections. Respiratory viral infections, such as influenza, are important causes of
A. Ambati1,2, S. Einarsdottir3, I. Magalhaes1,4, T. Poiret1, R. Bodenstein1, K. LeBlanc1,5, M. Brune3, M. Maeurer1,4, P. Ljungman2,5 1
Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden, 2Department of Medicine, Karolinska Institutet, Huddinge, Sweden, 3Sahlgrens University Hospital, Goteborg, Sweden, 4Center for Allogeneic Stem Cell Transplantation, Karolinska University Hospital, Stockholm, Sweden, 5Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
Key words: transplantation; influenza vaccination; virosomal; adjuvant; seasonal; subunit; inactivated; interferon-gamma; dextramers Correspondence to: Prof. Per Ljungman, Department of Medicine, Karolinska Institutet, Huddinge, 14186 Sweden Tel: +460858582507 Fax: +46087748725 E-mail: [email protected]
Received 19 December 2014, revised 4 February 2015, accepted for publication 28 February 2015 DOI: 10.1111/tid.12382 Transpl Infect Dis 2015: 17: 371–379
morbidity in these patients (1–3). The emergence of new strains of influenza, such as during the H1N1 2009 pandemic (pdm), is of particular concern to HSCT
371
Ambati et al: Immunogenicity of virosomal flu vaccine in SCT recipients
recipients In a prospective study among 286 HSCT patients performed during the H1N1 2009 pd, 43.7% were hospitalized, 32.5% developed lower respiratory tract disease, 11.5% required mechanical ventilation, and 6.3% died from A/H1N1 infection (4). The treatment strategy encompasses early usage of neuraminidase inhibitors, such as oseltamivir, which are partly effective, yet the risk to develop resistance is pronounced (4). The use of antiviral prophylaxis with neuraminidase inhibitors is somewhat controversial. Tomblyn et al. (5) recommended quite broad use of prophylaxis during influenza outbreaks both to patients and non-vaccinated family members. However, in the more recent European Conference on Infections in Leukemia guidelines, Engelhard et al. (6) only recommend neuraminidase inhibitors as post-exposure prophylaxis. It should also be recognized that quite a substantial risk exists for development of resistance to these drugs (4). Preventive strategies include infection control and vaccination against influenza, while early diagnosis and subsequent treatment with antiviral drugs seem to be important to decrease both morbidity and mortality (7– 10). Patients are most vulnerable early after transplantation for complications to influenza, especially patients with lymphopenia (1, 7, 11). It is still controversial when influenza vaccination should be initiated after HSCT, although current international recommendations suggest starting 4–6 months after HSCT and possibly earlier in an outbreak situation (6, 12). The effect of vaccination is, however, frequently suboptimal and varies with the time from SCT between 10% and 50%, with the poorest results early after HSCT (9, 13, 14). Serological responses analyzed by hemagglutinin inhibition (HI) are generally poor before 6 months, and in some studies before 12 months, after HSCT (13–17). In previous studies, increases in interferon-gamma (IFN-c) production after vaccination could be measured, although decreased compared to healthy controls, along with an increase in influenza-specific CD8+ T-cells measured by soluble major histocompatibility complex (MHC) class I/peptide multimers after seasonal vaccination (18). In a study with non-adjuvanted vaccine against the 2009 H1N1 pdm virus, among 82 HSCT patients, 51% showed seroprotective titers to pdm H1N1 (16). With the use of AS03 adjuvanted vaccine, a 69% seroprotection rate was observed among 13 HSCT patients, owing to its superior immunogenicity, compared to the 18% seroprotection rate after trivalent seasonal non-adjuvanted influenza vaccine among 11 HSCT patients (19). Two doses of adjuvanted pdm vaccine resulted in better rates of seroprotection than a single dose (14, 17, 20– 22).
372
A different vaccine construct, which might lead to improved immune responses in HSCT recipients, is the adjuvanted trivalent virosomal vaccine that has been tested in adults, the elderly, and in immunocompromised patients (23). The virosomal vaccine is composed of phospholipids and phosphatidylcholine, complexed with influenza envelope glycoproteins hemagglutinin and neuraminidase (24). We tested the immunogenicity of the virosomal vaccine in HSCT recipients and compared the immune response patterns with a historical control group that had received the inactivated seasonal trivalent vaccine.
Materials and methods Study design The study was designed as an uncontrolled phase II study using an adjuvanted virosomal vaccine (Inflexal Vâ, Crucell Sweden AB, Solna, Sweden; EudraCT No: 2013-003403-19). The main endpoints were T-cell and serological immune responses. The inclusion criteria were adult allogeneic SCT recipients within 3– 24 months after transplantation, vaccinated according to Swedish and international guidelines (5, 6, 25). The immune responses were compared to a control cohort, collected from the Karolinska and Sahlgrenska transplant centers, who received the seasonal subunit vaccination during the 3 previous seasons. Patients who developed respiratory symptoms were sampled using a nasopharyngeal aspirate for a multiplex polymerase chain reaction (PCR) according to clinical routine. The Ethical Committees of the participating institutions approved the study (Diary no 2010/136931/4 and 2013/1499-31/1).
Patients Twenty-one allogeneic SCT recipients were included in the study and given the virosomal influenza vaccine (Table 1). Serum and blood samples were collected before and at 4 weeks after vaccination. The study nurse called the patients regularly to inquire about symptoms of influenza-like illness and all symptomatic patients were requested to visit the clinic for sampling and the samples analyzed by multiplex PCR. In addition, questioning and sampling, as needed, were also performed when the patients visited the clinic. The control cohort consisted of 30 patients. At the time of vaccination in the study cohort, 11 patients were >6 months and 10 patients 6 months
11
18
6 months and 12 patients 6 months (Fig. 1). In contrast, the seasonal trivalent vaccine was poor (median
