A mobile app for the treatment of female mixed and urgency incontinence: a cost-effectiveness analysis in Sweden.

INTRODUCTION AND HYPOTHESIS: A previous randomized controlled trial (RCT) demonstrated that the app Tät II, for self-management of mixed urinary incontinence (MUI) and urgency urinary incontinence (UUI), yielded significant, clinically relevant improvements in symptom severity and quality of life (QoL) compared with a control group. We aimed to assess the cost-effectiveness of Tät II. METHODS: A cost-utility analysis with a 1-year societal perspective was carried out, comparing Tät II with an information app. Data were collected alongside an RCT: 122 community-dwelling women aged ≥18 years with MUI or UUI ≥2 times/week were randomized to 3 months of Tät II treatment focused on pelvic floor muscle training (PFMT) and bladder training (BT; n = 60), or to an information app (n = 62). Self-assessed data from validated questionnaires were collected at baseline and at 3-month and 1-year follow-ups. Costs for assessment, treatment delivery, incontinence aids, laundry, and time for PFMT and BT were included. We calculated quality-adjusted life-years (QALYs) using the International Consultation on Incontinence Modular Questionnaire Lower Urinary Tract Symptoms Quality of Life. The incremental cost-effectiveness ratio (ICER) between the groups was our primary outcome. Sensitivity analyses were performed. RESULTS: The mean age was 58.3 (SD = 9.6) years. Annual overall costs were €738.42 in the treatment group and €605.82 in the control group; annual QALY gains were 0.0152 and 0.0037 respectively. The base case ICER was €11,770.52; ICERs in the sensitivity analyses ranged from €-9,303.78 to €22,307.67. CONCLUSIONS: The app Tät II is a cost-effective treatment method for women with MUI and UUI.

Epidemiology and emm types of invasive group A streptococcal infections in Finland, 2008-2013.

Invasive Streptococcus pyogenes (group A streptococcus, GAS) infections are a major global cause of morbidity and mortality. We analysed the surveillance data on invasive GAS and the microbiological characteristics of corresponding isolates to assess the incidence and emm type distribution of invasive GAS infections in Finland. Cases defined as patients with isolations of blood and cerebrospinal fluid S. pyogenes are mandatorily notified to the National Infectious Disease Registry and sent to the national reference laboratory for emm typing. Antimicrobial data were collected through the network including all clinical microbiology laboratories. Pulsed-field gel electrophoresis (PFGE) analysis was performed to assess clonality. In total, 1165 cases of invasive GAS were reported in Finland during 2008-2013; the median age was 52 years (range, 0-100) and 54% were male. The overall day 7 case fatality rate was 5.1% (59 cases). The average annual incidence was 3.6 cases per 100,000 population. A total of 1122 invasive GAS isolates (96%) were analysed by emm typing; 72 different emm types were identified, of which emm28 (297 isolates, 26%), emm89 (193 isolates, 12%) and emm1 (132 isolates, 12%) were the most common types. During 2008-2013, an increase of erythromycin resistance (1.9% to 8.7%) and clindamycin (0.9% to 9.2%) was observed. This resistance increase was in parallel with the introduction of a novel clone emm33 into Finland. The overall incidence of invasive GAS infections remained stable over the study period in Finland. We identified clonal spread of macrolide-resistant invasive emm33 GAS type, highlighting the importance of molecular surveillance.

Clindamycin resistant emm33 Streptococcus pyogenes emerged among invasive infections in Helsinki metropolitan area, Finland, 2012 to 2013.

In 2012, blood, skin and soft tissue infections caused by clindamycin resistant Streptococcus pyogenes (group A streptococcus; GAS) appeared to be increasing in the Helsinki metropolitan area. We compared monthly percentages of clindamycin resistant isolates in the area between 2012 and 2013, with those in 2010 and 2011. Resistance frequency in terms of patient age was also studied. We reviewed the medical records of bacteraemic cases in 2012 and 2013 and linked the data to emm types. To inform on the emm distribution among GAS isolated from skin and soft tissue infections during the epidemic, GAS isolates of one month (March 2013) were emm typed. For GAS blood, skin, and soft tissue isolates taken together, the proportions of clindamycin resistant isolates were significantly higher in 2012 and 2013 (23% and 17%, respectively) compared with the two previous years (3%, p<0,001). The erythromycin resistance percentages were almost equal to clindamycin (22% and 17%) in 2012 and 2013, respectively. Clindamycin resistance was most frequent in GAS isolates of 40 to 60 year-old patients (148/417; 36%). Among clindamycin resistant isolates, 12 of 14 blood isolates from 2012 to 2013, and 11 of 13 skin and soft tissue isolates from March 2013, were emm33. Emm33 GAS bacteraemia was associated with clindamycin and erythromycin resistance (odds ratio (OR): 7.0; 95% confidence interval (CI): 1.9-25.3). Infection focus was mainly the skin; either cellulitis (7/12) or necrotising fasciitis (3/12). All emm33 GAS isolates harboured the ermTR resistance gene with constitutive macrolides, lincosamides and streptogramines B (MLS(B)) phenotype. Emm33 GAS was responsible for the higher proportion of clindamycin resistance in skin, soft tissue, and blood isolates locally in 2012 and 2013.

Endogenous gas formation of carbon dioxide used for wound flooding--an experimental study with implications regarding gas microembolism during cardiopulmonary bypass.

BACKGROUND: Gas microembolisation is an identified risk in cardiac surgery. Flooding the wound with carbon dioxide is a method proposed to reduce this problem. The high solubility of carbon dioxide is beneficial, but may also cause problems. The gas solubility diminishes at warming and endogenous bubbles are formed when cold blood saturated with carbon dioxide is returned by cardiotomy suction. METHODS: The release of endogenous gas was measured at high resolution in an experimental digital model. A medium (water or blood) was incubated and equilibrated with gas (100% carbon dioxide or air) at a low temperature (10 °C or 23 °C). The temperature was increased to 37 °C and the gas release was measured, at rest and at fluid motion. RESULTS: The amount of carbon dioxide released at warming was substantial for both water and blood (both p=0.005). The effect was more pronounced when the temperature differential increased (p=0.005). However, blood and water differed in these terms: with water, the release of carbon-dioxide started instantly at warming; with blood, carbon dioxide remained dissolved and was released at fluid motion. When blood was warmed from 10 °C to 37 °C, the gas release corresponded to 44.4% (40.6/46.5) of the medium volume (median with quartile range). CONCLUSION: Gas dissolved in a medium becomes released at warming, as confirmed here. Blood exposed to carbon dioxide became heavily oversaturated at warming, with the gas instantly released at fluid motion. The amount of contained gas increased with a higher temperature differential. Our study has relevance to wound flushing, using carbon dioxide, in cardiac surgery. The clinical consequences of these findings remain to be answered.

A prediction of the renal and cardiovascular efficacy of aliskiren in ALTITUDE using short-term changes in multiple risk markers.

INTRODUCTION: We recently developed and validated in existing trials a novel algorithm (PRE score) to predict long-term drug efficacy based on short-term (month-6) drug-induced changes in multiple risk markers. To show the value of the PRE score for ongoing and planned clinical trials, we here report the predicted long-term cardio-renal efficacy of aliskiren in type 2 diabetes, which was investigated in the ALTITUDE trial, but unknown at the time this study was conducted. METHODS: We established the relation between multiple risk markers and cardio-renal endpoints (as defined in ALTITUDE) using a background database from past clinical trials. The short-term effect of aliskiren on multiple risk markers was taken from the AVOID trial. A PRE score was developed by multivariate Cox analysis in the background population and was then applied to the baseline and month-6 measurements of the aliskiren treatment arm of the AVOID trial to predict cardio-renal risk. The net risk difference at these time-points, after correction for placebo effects, was taken to indicate the estimated long-term cardio-renal risk change. RESULTS: Based on the PRE score, we predicted that aliskiren treatment in ALTITUDE would confer a relative risk change of -7.9% (95% CI -2.5 to -13.4) for the cardio-renal endpoint, a risk change of -5.1% (-1.2 to -9.0) for the CV endpoint and a non-significant risk change of -19.9% (-42.1 to +2.1) for the renal endpoint. CONCLUSIONS: PRE score estimations suggested that aliskiren has only a marginal additive protective effect on cardio-renal endpoints. These predictions were validated by the results of the ALTITUDE trial, confirming the potential of the PRE score to prospectively predict drug efficacy on cardio-renal outcomes.

In-treatment HDL cholesterol levels and development of new diabetes mellitus in hypertensive patients: the LIFE Study.

AIMS: Although hypertensive patients with low baseline HDL cholesterol levels have a higher incidence of diabetes mellitus, whether changing levels of HDL over time are more strongly related to the risk of new diabetes in hypertensive patients has not been examined. METHODS: Incident diabetes mellitus was examined in relation to baseline and in-treatment HDL levels in 7485 hypertensive patients with no history of diabetes randomly assigned to losartan- or atenolol-based treatment. RESULTS: During 4.7 ± 1.2 years follow-up, 520 patients (6.9%) developed new diabetes. In univariate Cox analyses, compared with the highest quartile of HDL levels (> 1.78 mmol/l), baseline and in-treatment HDL in the lowest quartile (< 1.21 mmol/l) identified patients with > 5-fold and > 9 fold higher risks of new diabetes, respectively; patients with baseline or in-treatment HDL in the 2nd and 3rd quartiles had intermediate risk of diabetes. In multivariable Cox analyses, adjusting for randomized treatment, age, sex, race, prior anti-hypertensive therapy, baseline uric acid, serum creatinine and glucose entered as standard covariates, and in-treatment non-HDL cholesterol, Cornell product left ventricular hypertrophy, diastolic and systolic pressure, BMI, hydrochlorothiazide and statin use as time-varying covariates, the lowest quartile of in-treatment HDL remained associated with a nearly 9-fold increased risk of new diabetes (hazard ratio 8.7, 95% CI 5.0-15.2), whereas the risk of new diabetes was significantly attenuated for baseline HDL < 1.21 mmol/l (hazard ratio 3.9, 95% CI 2.8-5.4). CONCLUSIONS: Lower in-treatment HDL is more strongly associated with increased risk of new diabetes than baseline HDL level.

A cathepsin-cleavage site between the adenovirus capsid protein IX and a tumor-targeting ligand improves targeted transduction.

Human adenoviruses have a great potential as anticancer agents. One strategy to improve their tumor-cell specificity and anti-tumor efficacy is to include tumor-specific targeting ligands in the viral capsid. This can be achieved by fusion of polypeptide-targeting ligands with the minor capsid protein IX. Previous research suggested that protein IX-mediated targeting is limited by inefficient release of protein IX-fused ligands from their cognate receptors in the endosome. This thwarts endosomal escape of the virus particles. Here we describe that the targeted transduction of tumor cells is augmented by a cathepsin-cleavage site between the protein IX anchor and the HER2/neu-binding ZH Affibody molecule as ligand. The cathepsin-cleavage site did not interfere with virus production and incorporation of the Affibody molecules in the virus capsid. Virus particles harboring the cleavable protein IX-ligand fusion in their capsid transduced the HER2/neu-positive SKOV-3 ovarian carcinoma cells with increased efficiency in monolayer cultures, three-dimensional spheroid cultures and in SKOV-3 tumors grown on the chorioallantoic membrane of embryonated chicken eggs. These data show that inclusion of a cathepsin-cleavage sequence between protein IX and a high-affinity targeting ligand enhances targeted transduction. This modification further augments the applicability of protein IX as an anchor for coupling tumor-targeting ligands.

A transductionally retargeted adenoviral vector for virotherapy of Her2/neu-expressing prostate cancer.

The efficacy of adenovirus (Ad)-based gene therapy of solid tumors, such as prostate cancer, is limited. One of the many problems is that the virus infects many different cell types in the body, resulting in high toxicity, whereas the target cancer cells are often less prone to wild-type Ad infection. Our aim was to develop genetically de- and retargeted Ad vectors to reduce off-target effects and increase target infection for prostate cancer. We have previously reported an Ad5 vector specific for the cancer-associated receptor Her2/neu, created by inserting Her2/neu-reactive Affibody(®) molecules (ZH) into the HI loop of a coxsackievirus and adenovirus receptor binding-ablated fiber (Ad[ZH/1]). In addition to virus retargeting to Her2/neu, this virus was further modified from wild-type Ad by changing the RGD motif in the penton base to EGD and by substitution of the KKTK motif in the third shaft repeat to RKSK, resulting in the vector Ad[ZH/3]. The ZH-containing vectors could be produced to high titers and were specific for their target, resulting in efficient infection and killing of Her2/neu-positive androgen-dependent PC346C prostate cancer cells in vitro. Here we show that the oncolytic Ad[ZH/3] vector significantly prolonged survival time and reduced serum prostate-specific antigen levels in an orthotopic prostate tumor model in nude mice to the same extent as wild-type Ad5. Our results show that Her2/neu targeting using Ad-based vectors for prostate cancer is feasible and may serve as a basis for the development of gene therapy of human prostate cancer as well as other Her2/neu-expressing cancers.

Detection of Streptococcus pneumoniae carriage by the Binax NOW test with nasal and nasopharyngeal swabs in young children.

The rapid detection of carriage of Streptococcus pneumoniae could assist in the management of pneumococcal infection, such as acute otitis media. We evaluated the reliability of the Binax NOW test in the exclusion and detection of pneumococcal carriage by nasal samples from 139 children and using nasopharyngeal samples from 250 children (aged 6-35 months) with respiratory infection with or without acute otitis media. The Binax NOW test results were compared with culture-based detection of carriage of S. pneumoniae. The Binax NOW test from the nasal samples had a sensitivity of 95%, a specificity of 78%, and the positive and negative predictive values were 83 and 93%, respectively; and for the nasopharyngeal samples the corresponding numbers were 88%, 95%, 96%, and 87%. When rapid knowledge of the carriage status of S. pneumoniae is needed, the Binax NOW test is a reliable method for the exclusion of carriage using nasal sampling, and in the detection of carriage using nasopharyngeal sampling.

Distribution of Chlamydia trachomatis ompA genovars and the new variant of C. trachomatis in the Göteborg area, Sweden.

The aims of this study were to assess the proportion of the new variant of Chlamydia trachomatis (nvCT) and the distribution of ompA genovars among C. trachomatis-positive patients in the Göteborg area, Sweden. Consecutive urine samples positive for C. trachomatis using BD ProbeTec ET (177 patients, 88 men and 89 women) were collected. An nvCT-specific real-time polymerase chain reaction (PCR) assay was used to investigate the nvCT prevalence. To identify the genovars, a 990-bp ompA DNA segment from 105 specimens was sequenced. Seventeen percent (30/177) of all specimens contained nvCT. Nine different genovars were identified. About 50% were of genovar E, followed by F 16%, G 11%, K 8%, and D 5%, representing about 90% of the specimens in Göteborg. The occurrence of nvCT and the dominance of genovar E in Göteborg is similar to those in other areas of Sweden. To cover about 90% of the C. trachomatis infections in Sweden, the serovars D, E, F, G, and K should be included in future vaccines based on the major outer membrane protein.

Economic evaluation of nursing practices: a review of literature.

BACKGROUND: The importance of cost-effectiveness of nursing practices and its influence on prioritizations has been discussed in literature. It is, however, unclear to what extent health economic analysis has been used in the area of nursing. AIM: The aim of this paper was to investigate how studies of nursing practices apply economic evaluations. METHODS: A literature review was conducted that included studies through August 2007. The search was performed using Medline, CINAHL, PsycINFO, Econlit, DARE, HTA, NHS EED, Cochrane reviews and clinical trials with a search term connected to nursing and health economics. Protocols were used in the screening procedure and the result is reported in a descriptive form. RESULTS: The search identified 115 studies published between 1984 and August 2007. Studies were found in the following nursing practices: provision of support and treatment (n = 17); assessing suffering/well-being (n = 1); preventing or treating ill health (n = 53); and organization of individual care (n = 44). In 22% of all studies, the authors explicitly presented the health economic method used. In 25% of all studies, the perspective of the economic analysis was explicitly stated and a large variability in cost was considered in the analysis. In 82 studies, the authors reported cost-effective intervention. CONCLUSIONS: Although economic evaluation of nursing practice has increased, it is still a rather small area. According to the items elucidated in this study, further methodological improvement is needed to evaluate the economics of nursing.

Re-targeted adenovirus vectors with dual specificity; binding specificities conferred by two different Affibody molecules in the fiber.

Vectors based on Adenovirus type 5 (Ad5) are among the most common vectors in cancer gene therapy trials to date. However, for increased efficiency and safety, Ad5 should be de-targeted from its native receptors and re-targeted to a tumor antigen. We have described earlier an Ad5 vector genetically re-targeted to the tumor antigen HER2/neu by a dimeric version of the Affibody molecule ZH inserted in the HI-loop of the fiber knob of a coxsackie and adenovirus receptor-binding ablated fiber. This virus showed almost wild-type growth characteristics and infected cells through HER2/neu. Here we generate vectors with double specificity by incorporating two different Affibody molecules, ZH (HER2/neu-binding) and ZT (Taq polymerase-binding), at different positions relative to one another in the HI-loop. Receptor-binding studies together with viral production and gene transfer assays showed that the recombinant fiber with ZT in the first position and ZH in the second position (ZTZH) bound to both its targets, whereas surprisingly, the fiber with ZHZT was devoid of binding to HER2/neu. Hence, it is possible to construct a recombinant adenovirus with dual specificity after evaluating the best position for each ligand in the fiber knob.

Reduction in albuminuria translates to reduction in cardiovascular events in hypertensive patients with left ventricular hypertrophy and diabetes.

In type 2 diabetes the degree of albuminuria is strongly related to progression of diabetic renal disease, as well as to the risk for cardiovascular complications. If normoalbuminuria is maintained, the risk of diabetic nephropathy is very low. In individuals with microalbuminuria, the rate of decline in glomerular filtration rate is closely related to the degree of albuminuria, and regression to normoalbuminuria slows down the rate of decline in renal function. Data from the LIFE-diabetes subgroup showed that levels of albuminuria well below what is usually defined as microalbuminuria, strongly predicted risk for cardiovascular complications. This indicates that when albuminuria is used as a risk predictor for cardiovascular events, so called normal values should be redefined. Traditional values for normo-micro-macroalbuminuria are primarily defined as predictors for the risk of development of diabetic nephropathy. In the LIFE-diabetes subgroup we found that reduction in albuminuria was more pronounced in losartan-based as compared with atenolol-based treatment. The benefit in favor of losartan was partly related to its major influence on albuminuria. Individuals with the highest baseline values of albuminuria had the greatest benefit in terms of reduction in cardiovascular morbidity and mortality on losartan as compared with atenolol. The level of albuminuria during treatment was closely related to the risk for cardiovascular events. We conclude that tiny amounts of albuminuria, well below traditional levels for microalbuminuria, predict cardiovascular morbidity and mortality. Reduction in albuminuria during treatment translates to reduction in cardiovascular events. Monitoring of albuminuria should be an integrated part of management of hypertension in diabetic as well as nondiabetic patients.

The value of caries preventive care among 19-year olds using the contingent valuation method within a cost-benefit approach.

OBJECTIVES: The aim of this study was to explore adolescents with high and no caries experience and their preferences for caries preventive dental care. Their willingness-to-pay (WTP) for preventive dental care was elicited using the contingent valuation method (CVM) within a cost-benefit approach. METHODS: Eighty-two individuals (19-year olds) agreed to participate in an exploratory case-control study. Thirty individuals with high caries experience formed the test group. The control group consisted of 52 individuals with no caries experience, selected randomly from a caries-free population. Using personal questionnaires in combination with the CVM, we elicited respondents' WTP for preventive dental care. The data were used to: (a) compare WTP between study groups, and (b) calculate net social benefit (NSB) in cost-benefit analysis (CBA). RESULTS: The result shows a mean yearly WTP for the high- and low-risk group of 1405 SEK and 1087 SEK (7.70 SEK = US$1; July 2005), respectively. Two variables were associated with the differences between the groups: caries risk (i.e. group designation) and housing. Using these WTP values, the CBA showed positive NSB values for both study groups. CONCLUSIONS: Through use of the CVM, 19-year olds' WTP for caries preventive measures was elicited. An NSB >0 was found, which means that benefits exceeded the costs for prevention. Despite the small sample size and restriction to one Swedish county, the results indicate that the methods used in this study are suitable for further testing and analyses.

A pilot study of the use of oral health-related quality of life measures as an outcome for analysing the impact of caries disease among Swedish 19-year-olds.

OBJECTIVES: To be useful as a supplement for health economic evaluations in caries preventive care, the oral health-related quality of life (OHRQOL) measures must be able to discriminate for caries disease. The aim of this study was therefore to explore whether any differences existed in perceived OHRQOL among adolescents with either high or no caries experience. METHODS: Eighty-two individuals (all 19-year-olds) agreed to participate in a pilot exploratory case-control study. Thirty individuals with high caries experience formed the test group. The control group consisted of 52 individuals with no caries experience, selected randomly from a caries-free population. OHRQOL scores were collected for analysis through personal interviews using two OHRQOL measures, the Child Perceptions Questionnaire (CPQ(11-14)) and Oral Health Impact Profile-14 (OHIP-14). RESULTS: The OHRQOL measures used were not able to discriminate between young adults with high and no caries risk experience with respect to perceived OHRQOL. Despite a consistently higher impact score for the test group throughout the overall and subscale scores, the differences were not statistically significant except for one of the subscale scores, oral symptoms. CONCLUSIONS: This study indicates that the prevalence and incidence of caries must be seen as too low in Sweden to have major influence on young adults' perceived OHRQOL and well-being. Therefore, the usefulness of OHRQOL measures in supplementing outcome measurement in health economic evaluations, particularly those that focus on caries preventive strategies, must be questioned.

Adenovirus 5 vector genetically re-targeted by an Affibody molecule with specificity for tumor antigen HER2/neu.

In order to use adenovirus (Ad) type 5 (Ad5) for cancer gene therapy, Ad needs to be de-targeted from its native receptors and re-targeted to a tumor antigen. A limiting factor for this has been to find a ligand that (i) binds a relevant target, (ii) is able to fold correctly in the reducing environment of the cytoplasm and (iii) when incorporated at an optimal position on the virion results in a virus with a low physical particle to plaque-forming units ratio to diminish the viral load to be administered to a future patient. Here, we present a solution to these problems by producing a genetically re-targeted Ad with a tandem repeat of the HER2/neu reactive Affibody molecule (ZH) in the HI-loop of a Coxsackie B virus and Ad receptor (CAR) binding ablated fiber genetically modified to contain sequences for flexible linkers between the ZH and the knob sequences. ZH is an Affibody molecule specific for the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) that is overexpressed in inter alia breast and ovarian carcinomas. The virus presented here exhibits near wild-type growth characteristics, infects cells via HER2/neu instead of CAR and represents an important step toward the development of genetically re-targeted adenoviruses with clinical relevance.

Efficient incorporation of a functional hyper-stable single-chain antibody fragment protein-IX fusion in the adenovirus capsid.

Recombinant adenoviruses are frequently used as gene transfer vehicles for therapeutic gene delivery. Strategies to amend their tropism include the incorporation of polypeptides with high affinity for cellular receptors. Single-chain antibodies have a great potential to achieve such cell type specificity. In this study, we evaluated the efficiency of incorporation of a single-chain antibody fused with the adenovirus minor capsid protein IX in the capsid of adenovirus type 5 vectors. To this end, the codons for the single-chain antibody fragments (scFv) 13R4 were fused with those encoding of pIX via a 75-Angstrom spacer sequence. The 13R4 is a hyper-stable single-chain antibody directed against beta-galactosidase, which was selected for its capacity to fold correctly in a reducing environment such as the cytoplasm. A lentiviral vector was used to stably express the pIX.flag.75.13R4.MYC.HIS fusion gene in 911 helper cells. Upon propagation of pIX-gene deleted human adenovirus-5 vectors on these cells, the pIX-fusion protein was efficiently incorporated in the capsid. Here, the 13R4 scFv was functional as was evident from its capacity to bind its ligand beta-galactosidase. These data demonstrate that the minor capsid protein IX can be used as an anchor for incorporation of single-chain antibodies in the capsids of adenovirus vectors.

Decreased immune reactivity towards a knobless, affibody-targeted adenovirus type 5 vector.

In this study, a prototype Adenovirus type 5 (Ad5) vector deleted of the fiber knob domain and carrying an Affibody molecule as the targeting ligand showed decreased susceptibility to human pre-existing antibodies. This vector, Ad5/R7-Z(taq)Z(taq), has short fibers carrying seven shaft repeats, a non-native trimerization signal and an affibody molecule (Z(taq)) reactive to Taq polymerase. Ad5/R7-Z(taq)Z(taq) could be specifically targeted to 293 cells stably expressing membrane-bound anti-Z(taq) idiotypic affibody called Z(ztaq) (293Z(ztaq)). Sera from 50 blood donors were analyzed for neutralization activity (NA) against the parental Ad5/Fiwt vector and knobless Ad5/R7-Z(taq)Z(taq) on 293Z(ztaq) cells. Twenty-three sera had NA titers (> or =1:64) against Ad5/Fiwt (46%) and only two against Ad5/R7-Z(taq)Z(taq) (4%). Characterization of sera with NA titers showed that the knob domain is one of the targets of the antibodies. Neutralization assays using sera pre-adsorbed on knob and hexon proteins showed that the NA of the sera was carried mainly by anti-knob and anti-hexon antibodies, but in certain sera the anti-hexon antibodies represent the major population of the neutralizing antibodies (NAbs). Our results suggested that a combination of knob deletion and hexon switching could be an effective strategy for Ad vectors to better evade the anti-Ad NAbs.