Influenza vaccination reveals sex dimorphic imprints of prior mild COVID-19

Acute viral infections can have durable functional impacts on the immune system long after recovery, but how they affect homeostatic immune states and responses to future perturbations remain poorly understood1-4. Here we use systems immunology approaches, including longitudinal multimodal single-cell analysis (surface proteins, transcriptome and V(D)J sequences) to comparatively assess baseline immune statuses and responses to influenza vaccination in 33 healthy individuals after recovery from mild, non-hospitalized COVID-19 (mean, 151 days after diagnosis) and 40 age- and sex-matched control individuals who had never had COVID-19. At the baseline and independent of time after COVID-19, recoverees had elevated T cell activation signatures and lower expression of innate immune genes including Toll-like receptors in monocytes. Male individuals who had recovered from COVID-19 had coordinately higher innate, influenza-specific plasmablast, and antibody responses after vaccination compared with healthy male individuals and female individuals who had recovered from COVID-19, in part because male recoverees had monocytes with higher IL-15 responses early after vaccination coupled with elevated prevaccination frequencies of 'virtual memory'-like CD8+ T cells poised to produce more IFNγ after IL-15 stimulation. Moreover, the expression of the repressed innate immune genes in monocytes increased by day 1 to day 28 after vaccination in recoverees, therefore moving towards the prevaccination baseline of the healthy control individuals. By contrast, these genes decreased on day 1 and returned to the baseline by day 28 in the control individuals. Our study reveals sex-dimorphic effects of previous mild COVID-19 and suggests that viral infections in humans can establish new immunological set-points that affect future immune responses in an antigen-agnostic manner.

Influenza vaccination and single cell multiomics reveal sex dimorphic immune imprints of prior mild COVID-19

Viral infections can have profound and durable functional impacts on the immune system. There is an urgent need to characterize the long-term immune effects of SARS-CoV-2 infection given the persistence of symptoms in some individuals and the continued threat of novel variants. Here we use systems immunology, including longitudinal multimodal single cell analysis (surface proteins, transcriptome, and V(D)J sequences) from 33 previously healthy individuals after recovery from mild, non-hospitalized COVID-19 and 40 age- and sex-matched healthy controls with no history of COVID-19 to comparatively assess the post-infection immune status (mean: 151 days after diagnosis) and subsequent innate and adaptive responses to seasonal influenza vaccination. Identification of both sex-specific and -independent temporally stable changes, including signatures of T-cell activation and repression of innate defense/immune receptor genes (e.g., Toll-like receptors) in monocytes, suggest that mild COVID-19 can establish new post-recovery immunological set-points. COVID-19-recovered males had higher innate, influenza-specific plasmablast, and antibody responses after vaccination compared to healthy males and COVID-19-recovered females, partly attributable to elevated pre-vaccination frequencies of a GPR56 expressing CD8+ T-cell subset in male recoverees that are "poised" to produce higher levels of IFNγ upon inflammatory stimulation. Intriguingly, by day 1 post-vaccination in COVID-19-recovered subjects, the expression of the repressed genes in monocytes increased and moved towards the pre-vaccination baseline of healthy controls, suggesting that the acute inflammation induced by vaccination could partly reset the immune states established by mild COVID-19. Our study reveals sex-dimorphic immune imprints and in vivo functional impacts of mild COVID-19 in humans, suggesting that prior COVID-19, and possibly respiratory viral infections in general, could change future responses to vaccination and in turn, vaccines could help reset the immune system after COVID-19, both in an antigen-agnostic manner.

Repeat vaccination reduces antibody affinity maturation across different influenza vaccine platforms in humans

Several vaccines are approved in the United States for seasonal influenza vaccination every year. Here we compare the impact of repeat influenza vaccination on hemagglutination inhibition (HI) titers, antibody binding and affinity maturation to individual hemagglutinin (HA) domains, HA1 and HA2, across vaccine platforms. Fold change in HI and antibody binding to HA1 trends higher for H1N1pdm09 and H3N2 but not against B strains in groups vaccinated with FluBlok compared with FluCelvax and Fluzone. Antibody-affinity maturation occurs against HA1 domain of H1N1pdm09, H3N2 and B following vaccination with all vaccine platforms, but not against H1N1pdm09-HA2. Importantly, prior year vaccination of subjects receiving repeat vaccinations demonstrated reduced antibody-affinity maturation to HA1 of all three influenza virus strains irrespective of the vaccine platform. This study identifies an important impact of repeat vaccination on antibody-affinity maturation following vaccination, which may contribute to lower vaccine effectiveness of seasonal influenza vaccines in humans

Here, Khurana et al. report the results of a phase 4 clinical trial with three FDA approved influenza vaccines and show that repeat influenza vaccination results in reduced antibody affinity maturation to hemagglutinin domain 1 irrespective of vaccine platform.

Patients with MS under daclizumab therapy mount normal immune responses to influenza vaccination

Objective:

The purpose of this study was to assess the potential immunosuppressive role of daclizumab, a humanized monoclonal antibody against the α chain of the interleukin 2 receptor, in vivo, by comparing immune responses to the 2013 seasonal influenza vaccination between patients with multiple sclerosis (MS) on long-term daclizumab therapy and controls.

Methods:

Previously defined subpopulations of adaptive immune cells known to correlate with the immune response to the influenza vaccination were evaluated by 12-color flow cytometry in 23 daclizumab-treated patients with MS and 14 MS or healthy controls before (D0) and 1 day (D1) and 7 days (D7) after administration of the 2013 Afluria vaccine. Neutralizing antibody titers and CD4⁺, CD8⁺ T cell, B cell, and natural killer cell proliferation to 3 strains of virus contained in the Afluria vaccine were assessed at D0, D7, and 180 days postvaccination.

Results:

Daclizumab-treated patients and controls demonstrated comparable, statistically significant expansions of previously defined subpopulations of activated CD8⁺ T cells and B cells that characterize the development of effective immune responses to the influenza vaccine, while proliferation of T cells to influenza and control antigens was diminished in the daclizumab cohort. All participants fulfilled FDA criteria for seroconversion or seroprotection in antibody assays.

Conclusion:

Despite the mild immunosuppressive effects of daclizumab in vivo demonstrated by an increased incidence of infectious complications in clinical trials, patients with MS under daclizumab therapy mount normal antibody responses to influenza vaccinations.

ISCOMATRIX™ adjuvant promotes epitope spreading and antibody affinity maturation of influenza A H7N9 virus like particle vaccine that correlate with virus neutralization in humans

In a previously reported phase I clinical trial, subjects vaccinated with two doses of an unadjuvanted H7N9 virus like particle (VLP) vaccine responded poorly (15.6% seroconversion rates with 45μg hemagglutinin (HA) dose). In contrast, 80.6% of subjects receiving H7N9 VLP vaccine (5μg HA) with ISCOMATRIX™ adjuvant developed hemagglutination-inhibition (HI) responses. To better understand the role of adjuvant, complete antibody epitope repertoires of post-vaccination sera were investigated using Whole Genome Fragment Phage Display Library (GFPDL). In addition, antibody affinity maturation following vaccination was measured against HA1 and HA2 antigenic domains using real time Surface Plasmon Resonance (SPR) based kinetic assays. Unadjuvanted H7N9-VLP vaccine generated primarily antibodies targeting the C-terminus of the HA1 domain, predicted to be mostly buried on the native HA spikes, while adjuvanted VLP vaccine generated antibodies against large epitopes in the HA1 spanning the receptor binding domain (RBD). SPR analysis using a functional H7-HA1 domain demonstrated that sera from adjuvanted H7N9-VLP vaccine induced higher total binding antibodies and significantly higher antibody affinity maturation to HA1 compared to sera from unadjuvanted vaccine. Total antibody binding and affinity to the HA1 (but not HA2) domain correlated with HI and neutralization titers. This study demonstrates that ISCOMATRIX™ adjuvanted vaccine promotes higher quality antibody immune response against avian influenza in naïve humans.

Oral priming with replicating adenovirus serotype 4 followed by subunit H5N1 vaccine boost promotes antibody affinity maturation and expands H5N1 cross-clade neutralization

A Phase I trial conducted in 2009-2010 demonstrated that oral vaccination with a replication competent Ad4-H5 (A/Vietnam) vector with dosages ranging from 107-1011 viral particles was well tolerated. HA-specific T-cell responses were efficiently induced, but very limited hemagglutination-inhibiting (HI) humoral responses were measured. However, a single boost of Ad4-H5-Vtn vaccinated individuals with a unadjuvanted licensed H5N1 (A/Vietnam) subunit vaccine resulted in superior HI titers compared with unprimed subjects. In the current study, the impact of Ad4-H5 priming on the quality of the polyclonal humoral immune response was evaluated using a real-time kinetics assay by surface plasmon resonance (SPR). Total binding of serum polyclonal antibodies from the Ad4-H5-Vtn primed groups against both homologous H5N1-A/Vietnam/1194/2004 (clade 1) and heterologous A/Indonesia-5/2005 (clade 2.1) HA1 head domain was significantly higher compared with sera from individuals that received subunit H5N1 vaccination alone. SPR measurements also demonstrated that the antigen-antibody complex dissociation rates (a surrogate for antibody affinity) of serum antibodies against the HA1 of H5N1-A/Vietnam were significantly higher in the Ad4-H5 primed groups compared with those from the unprimed group. Furthermore, strong correlations were observed between the antibody affinities for HA1 (but not HA2) and the virus neutralization titers against the homologous strain and a panel of heterologous clade 2 H5N1 strains. These findings support the concept of oral prime-boost vaccine approaches against pandemic influenza to elicit long-term memory B cells with high affinity capable of rapid response to variant pandemic viruses likely to emerge and adapt to human transmissions.

Vaccine-induced anti-HA2 antibodies promote virus fusion and enhance influenza virus respiratory disease

Vaccine-induced disease enhancement has been described in connection with several viral vaccines in animal models and in humans. We investigated a swine model to evaluate mismatched influenza vaccine-associated enhanced respiratory disease (VAERD) after pH1N1 infection. Vaccinating pigs with whole inactivated H1N2 (human-like) virus vaccine (WIV-H1N2) resulted in enhanced pneumonia and disease after pH1N1 infection. WIV-H1N2 immune sera contained high titers of cross-reactive anti-pH1N1 hemagglutinin (HA) antibodies that bound exclusively to the HA2 domain but not to the HA1 globular head. No hemagglutination inhibition titers against pH1N1 (challenge virus) were measured. Epitope mapping using phage display library identified the immunodominant epitope recognized by WIV-H1N2 immune sera as amino acids 32 to 77 of pH1N1-HA2 domain, close to the fusion peptide. These cross-reactive anti-HA2 antibodies enhanced pH1N1 infection of Madin-Darby canine kidney cells by promoting virus membrane fusion activity. The enhanced fusion activity correlated with lung pathology in pigs. This study suggests a role for fusion-enhancing anti-HA2 antibodies in VAERD, in the absence of receptor-blocking virus-neutralizing antibodies. These findings should be considered during the evaluation of universal influenza vaccines designed to elicit HA2 stem-targeting antibodies.

Novel antibody-independent receptor-binding SPR-based assay for rapid measurement of influenza vaccine potency

A WHO workshop organized following the 2009 H1N1 pandemic recommended development of alternative influenza vaccine potency assays as high priority that could expedite the release of vaccine lots in the face of future influenza pandemics. We have developed an antibody independent, simple, high throughput receptor-binding SPR-based potency assay, which does not require any reference antisera and could be used for rapid HA quantitation and vaccine release in pandemic scenarios. The assay utilizes synthetic glycans with sialic acid (SA) of either α-2,6 or α-2,3 linkage to galactose. Only functionally active forms of HA (trimers and oligomers) recognize the SA-glycans and are quantified in this receptor-binding SPR assay. The SA-glycan SPR assay demonstrated broad dynamic range for quantitation of HA content in influenza vaccines from different manufacturers for both seasonal (A/H1N1, A/H3N2, B lineages) and pandemic influenza (A/H5N1, A/H7N9) strains with high reproducibility and low variability across multiple assays. In addition, the SA-glycan SPR assay is indicative of active HA stability, and can accurately quantify HA content in alum and oil-in-water adjuvanted influenza vaccines. Importantly, there was a good agreement between HA content determined by the SPR-based potency assay and the traditional SRID assay.

A live attenuated influenza A(H5N1) vaccine induces long-term immunity in the absence of a primary antibody response

BACKGROUND

Highly pathogenic avian influenza A(H5N1) causes severe infections in humans. We generated 2 influenza A(H5N1) live attenuated influenza vaccines for pandemic use (pLAIVs), but they failed to elicit a primary immune response. Our objective was to determine whether the vaccines primed or established long-lasting immunity that could be detected by administration of inactivated subvirion influenza A(H5N1) vaccine (ISIV).

METHODS

The following groups were invited to participate in the study: persons who previously received influenza A(H5N1) pLAIV; persons who previously received an irrelevant influenza A(H7N3) pLAIV; and community members who were naive to influenza A(H5N1) and LAIV. LAIV-experienced subjects received a single 45-μg dose of influenza A(H5N1) ISIV. Influenza A(H5N1)- and LAIV-naive subjects received either 1 or 2 doses of ISIV.

RESULTS

In subjects who had previously received antigenically matched influenza A(H5N1) pLAIV followed by 1 dose of ISIV compared with those who were naive to influenza A(H5N1) and LAIV and received 2 doses of ISIV, we observed an increased frequency of antibody response (82% vs 50%, by the hemagglutination inhibition assay) and a significantly higher antibody titer (112 vs 76; P = .04). The affinity of antibody and breadth of cross-clade neutralization was also enhanced in influenza A(H5N1) pLAIV-primed subjects.

CONCLUSIONS

ISIV administration unmasked long-lasting immunity in influenza A(H5N1) pLAIV recipients, with a rapid, high-titer, high-quality antibody response that was broadly cross-reactive across several influenza A(H5N1) clades.

CLINICAL TRIALS REGISTRATION

NCT01109329.

DNA priming prior to inactivated influenza A(H5N1) vaccination expands the antibody epitope repertoire and increases affinity maturation in a boost-interval-dependent manner in adults

DNA priming improves the response to inactivated influenza A(H5N1) vaccination. We compared the immunogenicity of an H5 DNA prime (using strain A/Indonesia/5/2005) followed by an H5N1 monovalent inactivated vaccine boost at 4, 8, 12, 16, or 24 weeks to that of 2 doses of H5N1 monovalent inactivated vaccine in adults. Antibody epitope repertoires were elucidated by genome-fragment phage-display library analysis, and antibody avidities for HA1 and HA2 domains were measured by surface plasmon resonance. H5 DNA priming expanded the H5-specific antibody epitope repertoire and enhanced antibody avidity to the HA1 (but not the HA2) domain in an interval-dependent manner. Enhanced HA1 binding and avidity after an interval of ≥12 weeks between prime and boost correlated with improved neutralization of homologous and heterologous H5N1 strains. Clinical trials registration NCT01086657.

Passive immunotherapies protect WRvFire and IHD-J-Luc vaccinia virus-infected mice from lethality by reducing viral loads in the upper respiratory tract and internal organs

Whole-body bioimaging was employed to study the effects of passive immunotherapies on lethality and viral dissemination in BALB/c mice challenged with recombinant vaccinia viruses expressing luciferase. WRvFire and IHD-J-Luc vaccinia viruses induced lethality with similar times to death following intranasal infection, but WRvFire replicated at higher levels than IHD-J-Luc in the upper and lower respiratory tracts. Three types of therapies were tested: licensed human anti-vaccinia virus immunoglobulin intravenous (VIGIV); recombinant anti-vaccinia virus immunoglobulin (rVIG; Symphogen, Denmark), an investigational product containing a mixture of 26 human monoclonal antibodies (HuMAbs) against mature virion (MV) and enveloped virion (EV); and HuMAb compositions targeting subsets of MV or EV proteins. Bioluminescence recorded daily showed that pretreatment with VIGIV (30 mg) or with rVIG (100 μg) on day -2 protected mice from death but did not prevent viral replication at the site of inoculation and dissemination to internal organs. Compositions containing HuMAbs against MV or EV proteins were protective in both infection models at 100 μg per animal, but at 30 μg, only anti-EV antibodies conferred protection. Importantly, the t statistic of the mean total fluxes revealed that viral loads in surviving mice were significantly reduced in at least 3 sites for 3 consecutive days (days 3 to 5) postchallenge, while significant reduction for 1 or 2 days in any individual site did not confer protection. Our data suggest that reduction of viral replication at multiple sites, including respiratory tract, spleen, and liver, as monitored by whole-body bioluminescence can be used to predict the effectiveness of passive immunotherapies in mouse models.

Recombinant HA1 produced in E. coli forms functional oligomers and generates strain-specific SRID potency antibodies for pandemic influenza vaccines

Vaccine production and initiation of mass vaccination is a key factor in rapid response to new influenza pandemic. During the 2009-2010 H1N1 pandemic, several bottlenecks were identified, including the delayed availability of vaccine potency reagents. Currently, antisera for the single-radial immunodiffusion (SRID) potency assay are generated in sheep immunized repeatedly with HA released and purified after bromelain-treatment of influenza virus grown in eggs. This approach was a major bottleneck for pandemic H1N1 (H1N1pdm09) potency reagent development in 2009. Alternative approaches are needed to make HA immunogens for generation of SRID reagents in the shortest possible time. In this study, we found that properly folded recombinant HA1 globular domain (rHA1) from several type A viruses including H1N1pdm09 and two H5N1 viruses could be produced efficiently using a bacterial expression system and subsequent purification. The rHA1 proteins were shown to form functional oligomers of trimers, similar to virus derived HA, and elicited high titer of neutralizing antibodies in rabbits and sheep. Importantly, the immune sera formed precipitation rings with reference antigens in the SRID assay in a dose-dependent manner. The HA contents in multiple H1N1 vaccine products from different manufacturers (and in several lots) as determined with the rHA1-generated sheep sera were similar to the values obtained with a traditionally generated sheep serum from NIBSC. We conclude that bacterially expressed recombinant HA1 proteins can be produced rapidly and used to generate SRID potency reagents shortly after new influenza strains with pandemic potential are identified.

Properly folded bacterially expressed H1N1 hemagglutinin globular head and ectodomain vaccines protect ferrets against H1N1 pandemic influenza virus

BACKGROUND

In the face of impending influenza pandemic, a rapid vaccine production and mass vaccination is the most effective approach to prevent the large scale mortality and morbidity that was associated with the 1918 "Spanish Flu". The traditional process of influenza vaccine production in eggs is time consuming and may not meet the demands of rapid global vaccination required to curtail influenza pandemic.

METHODOLOGY/PRINCIPAL FINDINGS

Recombinant technology can be used to express the hemagglutinin (HA) of the emerging new influenza strain in a variety of systems including mammalian, insect, and bacterial cells. In this study, two forms of HA proteins derived from the currently circulating novel H1N1 A/California/07/2009 virus, HA1 (1-330) and HA (1-480), were expressed and purified from E. coli under controlled redox refolding conditions that favoured proper protein folding. However, only the recombinant HA1 (1-330) protein formed oligomers, including functional trimers that bound receptor and caused agglutination of human red blood cells. These proteins were used to vaccinate ferrets prior to challenge with the A/California/07/2009 virus. Both proteins induced neutralizing antibodies, and reduced viral loads in nasal washes. However, the HA1 (1-330) protein that had higher content of multimeric forms provided better protection from fever and weight loss at a lower vaccine dose compared with HA (1-480). Protein yield for the HA1 (1-330) ranged around 40 mg/Liter, while the HA (1-480) yield was 0.4-0.8 mg/Liter.

CONCLUSIONS/SIGNIFICANCE

This is the first study that describes production in bacterial system of properly folded functional globular HA1 domain trimers, lacking the HA2 transmembrane protein, that elicit potent neutralizing antibody responses following vaccination and protect ferrets from in vivo challenge. The combination of bacterial expression system with established quality control methods could provide a mechanism for rapid large scale production of influenza vaccines in the face of influenza pandemic threat.

Vaccines with MF59 adjuvant expand the antibody repertoire to target protective sites of pandemic avian H5N1 influenza virus

Vaccines against influenza viruses with pandemic potential, including H5N1, are under development. Because of a lack of preexisting immunity to these viruses, adjuvants (immune potentiators or enhancers) are needed to improve immune responses, to conserve scarce vaccine, and for cross-protection against strains that have drifted evolutionarily from the original. Aluminum-based adjuvants do not improve vaccine immunogenicity for influenza subunit vaccines, whereas oil-in-water adjuvants are effective, especially with H5N1-inactivated vaccines. We used whole-genome-fragment phage display libraries followed by surface plasmon resonance (SPR) technologies to elucidate the effect of different adjuvants on the antibody repertoire against H5N1 vaccine in humans. The oil-in-water adjuvant MF59 induced epitope spreading from HA2 to HA1 in hemagglutinin (HA) and neuraminidase relative to unadjuvanted or aluminum-adjuvanted vaccines. Moreover, we observed an increase by a factor of 20 in the frequency of HA1-to-HA2-specific phage clones in sera after MF59-adjuvanted vaccine administration and a factor of 2 to 3 increase in the avidity of antibodies binding to properly folded HA1(28-319), as measured by SPR. The adjuvant-dependent increase in binding to conformational HA1 epitopes correlated with broadening of cross-clade neutralization and predicted improved in vivo protection. Thus, MF59 adjuvant improves the immune response to a H5N1 vaccine by inducing qualitative and quantitative expansion of the antibody repertoires with protective potential.

Antigenic fingerprinting of H5N1 avian influenza using convalescent sera and monoclonal antibodies reveals potential vaccine and diagnostic targets

BACKGROUND

Transmission of highly pathogenic avian H5N1 viruses from poultry to humans have raised fears of an impending influenza pandemic. Concerted efforts are underway to prepare effective vaccines and therapies including polyclonal or monoclonal antibodies against H5N1. Current efforts are hampered by the paucity of information on protective immune responses against avian influenza. Characterizing the B cell responses in convalescent individuals could help in the design of future vaccines and therapeutics.

METHODS AND FINDINGS

To address this need, we generated whole-genome-fragment phage display libraries (GFPDL) expressing fragments of 15-350 amino acids covering all the proteins of A/Vietnam/1203/2004 (H5N1). These GFPDL were used to analyze neutralizing human monoclonal antibodies and sera of five individuals who had recovered from H5N1 infection. This approach led to the mapping of two broadly neutralizing human monoclonal antibodies with conformation-dependent epitopes. In H5N1 convalescent sera, we have identified several potentially protective H5N1-specific human antibody epitopes in H5 HA[(-10)-223], neuraminidase catalytic site, and M2 ectodomain. In addition, for the first time to our knowledge in humans, we identified strong reactivity against PB1-F2, a putative virulence factor, following H5N1 infection. Importantly, novel epitopes were identified, which were recognized by H5N1-convalescent sera but did not react with sera from control individuals (H5N1 naïve, H1N1 or H3N2 seropositive).

CONCLUSION

This is the first study, to our knowledge, describing the complete antibody repertoire following H5N1 infection. Collectively, these data will contribute to rational vaccine design and new H5N1-specific serodiagnostic surveillance tools.

Durable neutralizing antibodies after remote smallpox vaccination among adults with and without HIV infection

The only US licensed vaccine with established efficacy against smallpox, Dryvax, is contraindicated for HIV patients. Detectable smallpox-neutralizing antibodies are still present among US adults. This study compared vaccinia-neutralizing antibody titers between 20 HIV-infected and 20 uninfected veterans matched for age and military entry. Vaccinia-neutralizing antibodies were detected in 95% HIV-infected and 100% uninfected veterans; 40% HIV-infected and 70% uninfected adults had protective titers. Therefore, after robust vaccination, neutralizing antibodies are maintained for prolonged times despite CD4 cell depletion.

Subunit recombinant vaccine protects against monkeypox

The smallpox vaccine Dryvax, a live vaccinia virus (VACV), protects against smallpox and monkeypox, but is contraindicated in immunocompromised individuals. Because Abs to VACV mediate protection, a live virus vaccine could be substituted by a safe subunit protein-based vaccine able to induce a protective Ab response. We immunized rhesus macaques with plasmid DNA encoding the monkeypox orthologs of the VACV L1R, A27L, A33R, and B5R proteins by the intradermal and i.m. routes, either alone or in combination with the equivalent recombinant proteins produced in Escherichia coli. Animals that received only DNA failed to produce high titer Abs, developed innumerable skin lesions after challenge, and died in a manner similar to placebo controls. By contrast, the animals vaccinated with proteins developed moderate to severe disease (20-155 skin lesions) but survived. Importantly, those immunized with DNA and boosted with proteins had mild disease with 15 or fewer lesions that resolved within days. DNA/protein immunization elicited Th responses and binding Ab titers to all four proteins that correlated negatively with the total lesion number. The sera of the immunized macaques recognized a limited number of linear B cell epitopes that are highly conserved among orthopoxviruses. Their identification may guide future efforts to develop simpler, safer, and more effective vaccines for monkeypox and smallpox.

Clinical and immunological comparison of smallpox vaccine administered to the outer versus the inner upper arms of vaccinia-naive adults

BACKGROUND

Current recommendations direct health care providers to administer smallpox vaccine to the upper outer arm. However, concerns about cosmetically bothersome scarring, accidental contact transmission, interference by body tattoos, and even malignant transformation suggest evaluation of alternate vaccination sites is warranted.

METHODS

We randomized 20 vaccinia-naive adults to undergo smallpox vaccination on the outer (n = 10) or inner (n = 10) upper arm. Evaluations included major reaction ("take") rates and vaccination site cultures on postvaccination day 7, determination of serum vaccinia-specific neutralizing antibody titers on days 0 (prevaccination) and 21, and determination of adverse events.

RESULTS

On postvaccination day 7, a total of 18 participants (9 per group) had major reactions, 17 of whom had culture evidence of viable vaccinia. The inner and outer arm groups had similar major reaction mean sizes (P = .17), but the amount of erythema (in square centimeters) was smaller in the inner arm group (P = .05). At day 21, all participants had higher titers of vaccinia-specific neutralizing antibodies, compared with at day 0, and the geometric mean titer values of the 2 vaccine groups were similar (P = .45). Adverse event rates were similar.

CONCLUSION

The comparable clinical, immunological, and tolerability outcomes between smallpox vaccine applied to the conventional upper outer arm site versus the upper inner arm, coupled with modestly less vaccine-site erythema on the inner arm, indicate that the inner arm may be a suitable alternate vaccination site.

Enhanced immunogenicity and protective effect conferred by vaccination with combinations of modified vaccinia virus Ankara and licensed smallpox vaccine Dryvax in a mouse model

Significant adverse events are associated with vaccination with the currently licensed smallpox vaccine. Candidate new-generation smallpox vaccines such as the replication-defective modified vaccinia virus Ankara (MVA) produce very few adverse events in experimental animals and in limited human clinical trials conducted near the end of the smallpox eradication campaign. Efficacy evaluation of such new-generation vaccines will be extraordinarily complex, however, since the eradication of smallpox precludes a clinical efficacy trial and the correlates of protection against smallpox are unknown. A combination of relevant animal efficacy studies along with thorough comparative immunogenicity studies between traditional and new-generation smallpox vaccines will be necessary for vaccine licensure. In the present study, a variety of immune responses elicited by MVA and the licensed smallpox vaccine Dryvax in a murine model were compared, with a focus on mimicking conditions and strategies likely to be employed in human vaccine trials. Immunization of mice with MVA, using several relevant vaccination routes including needle-free delivery, elicited humoral and cellular immune responses qualitatively similar to those elicited by vaccination with Dryvax. Similar levels of vaccinia-specific IgG and neutralizing antibody were elicited by Dryvax and MVA when higher doses (approximately 1 log) of MVA were used for immunization. Antibody levels peaked at about 6 weeks post-immunization and remained stable for at least 15 weeks. A booster immunization of either MVA or Dryvax following an initial priming immunization with MVA resulted in an enhanced IgG titer and neutralizing antibody response. In addition, both Dryvax and various MVA vaccination protocols elicited antibody responses to the extracellular enveloped form of the virus and afforded protection against a lethal intranasal challenge with vaccinia virus WR.

CCR5 N-terminal Region Plays a Critical Role in HIV-1 Inhibition by Toxoplasma gondii-derived Cyclophilin-18

Molecular mimicry of chemokine ligands has been described for several pathogens. Toxoplasma gondii produces a protein, cyclophilin-18 (C-18), which binds to the human immunodeficiency virus (HIV) co-receptor CCR5 and inhibits fusion and infection of T cells and macrophages by R5 viruses but not by X4 viruses. We recently identified structural determinants of C-18 required for anti-HIV activity (Yarovinsky, F., Andersen, J. F., King, L. R., Caspar, P., Aliberti, J., Golding, H., and Sher, A. (2004) J. Biol. Chem. 279, 53635-53642). Here we have elucidated the fine specificity of CCR5 residues involved in binding and HIV inhibitory potential of C-18. To delineate the regions of CCR5 involved in C-18 binding, we analyzed C-18 inhibition of cells expressing CXCR4/CCR5 chimeric receptors and CCR5 with a truncated N terminus (Delta2-19). These experiments identified a critical role for the N terminus of CCR5 in C-18 binding and anti-HIV activity. Studies with a large panel of CCR5 N-terminal peptides, including Tyr-sulfated analogues, truncated peptides, and alanine-scanning mutants, suggested that each of the 12-17 amino acids in the N terminus of CCR5 are essential for C-18 binding and inhibitory activity. Tyr sulfation did not improve C-18 reactivity. This finding is of interest because the same CCR5 N-terminal region was shown previously to play a key role in binding of HIV-1 envelope glycoproteins. The elucidation of the functional C-18-binding mechanism may help in the rational design of novel antiviral agents against HIV.

Smallpox vaccine-induced antibodies are necessary and sufficient for protection against monkeypox virus

Vaccination with live vaccinia virus affords long-lasting protection against variola virus, the agent of smallpox. Its mode of protection in humans, however, has not been clearly defined. Here we report that vaccinia-specific B-cell responses are essential for protection of macaques from monkeypox virus, a variola virus ortholog. Antibody-mediated depletion of B cells, but not CD4+ or CD8+ T cells, abrogated vaccine-induced protection from a lethal intravenous challenge with monkeypox virus. In addition, passive transfer of human vaccinia-neutralizing antibodies protected nonimmunized macaques from severe disease. Thus, vaccines able to induce long-lasting protective antibody responses may constitute realistic alternatives to the currently available smallpox vaccine (Dryvax).

Identification of a linear peptide recognized by monoclonal antibody 2D7 capable of generating CCR5-specific antibodies with human immunodeficiency virus-neutralizing activity

CCR5 is the major coreceptor for human immunodeficiency virus (HIV) infection. The murine monoclonal antibody (MAb) 2D7, which recognizes a conformation-dependent epitope in the second extracellular loop of CCR5, is one of the most potent inhibitors of R5 virus cell entry. However, attempts to humanize 2D7 for in vivo human use have been unsuccessful so far. A filamentous phage library expressing random peptides was used to identify a peptide mimitope that is recognized by MAb 2D7. A synthetic peptide containing this sequence (2D7-2SK) bound to MAb 2D7 with high affinity and reversed its HIV type 1 (HIV-1) fusion inhibitory activity. The peptide contains sequence homologies to two distal regions of the second extracellular loop of human CCR5, both of which are required for MAb 2D7 binding. Rabbit anti-2D7-mimitope antibodies competed with MAb 2D7 for binding to the 2D7-2SK peptide in Biacore biosensor testing. Importantly, the rabbit anti-2D7-2SK antibodies bound to CCR5 on cells and specifically inhibited R5 (but not X4) envelope-mediated syncytium formation. These antibodies also neutralized infection of human peripheral blood mononuclear cells with R5 HIV isolates comparably to MAb 2D7. In summary, we have identified a novel peptide that closely mimics the MAb 2D7 epitope on CCR5. This peptide could be included as a potential vaccine candidate or to isolate 2D7-like human antibodies as entry inhibitors for R5 viruses.

Smallpox vaccine does not protect macaques with AIDS from a lethal monkeypox virus challenge

It is unknown whether smallpox vaccination would protect human immunodeficiency virus type 1 (HIV-1)-infected individuals, because helper CD4(+) cells, the targets of HIV-1 infection, are necessary for the induction of both adaptive CD8(+) cell and B cell responses. We have addressed this question in macaques and have demonstrated that, although smallpox vaccination is safe in immunodeficient macaques when it is preceded by immunization with highly attenuated vaccinia strains, the macaques were not protected against lethal monkeypox virus challenge if their CD4(+) cell count was <300 cells/mm(3). The lack of protection appeared to be associated with a defect in vaccinia-specific immunoglobulin (Ig) switching from IgM to IgG. Thus, vaccination strategies that bypass CD4(+) cell help are needed to elicit IgG antibodies with high affinity and adequate tissue distribution and to restore protection against smallpox in severely immunocompromised individuals.

Structural Determinants of the Anti-HIV Activity of a CCR5 Antagonist Derived from Toxoplasma gondii

The protozoan parasite Toxoplasma gondii possesses a protein, cyclophilin-18 (C-18), which binds to the chemokine receptor CCR5, induces interleukin-12 production from murine dendritic cells, and inhibits fusion and infectivity of human immunodeficiency virus 1 (HIV-1) R5 viruses by co-receptor antagonism. Site-directed mutagenesis was employed to identify the domains in C-18 responsible for its CCR5 binding and antiviral functions. To do so we focused on amino acid differences with Plasmodium falciparum cyclophilin, which, although 53% identical with C-18, has minimal binding activity for CCR5, and we generated 22 mutants with substitutions in the regions of non-homology located on the putative surface of the molecule. Two mutations situated on the face of C-18, predicted to be involved in its interaction with the ligand cyclosporin A, were shown to be critical for CCR5-binding and the inhibition of HIV-1 fusion and infectivity. In contrast, four mutations in C-18 specifically designed to abolish the peptidyl-prolyl cis-trans-isomerase activity of the protein failed to inactivate its CCR5 binding and HIV inhibitory activities. Interleukin-12 induction by C-18, on the other hand, was abrogated by mutations effecting either the CCR5 binding or enzymatic function of the molecule. These findings shed light on the structural basis of the molecular mimicry of the chemokine function by a pathogen-derived protein and provide a basis for further modification of C-18 into an antiviral agent.

Inhibition of HIV-1 infection by a CCR5-binding cyclophilin from Toxoplasma gondii

The activation of murine dendritic cells by Toxoplasma gondii has recently been shown to depend on a parasite protein that signals through the chemokine receptor CCR5. Here we demonstrate that this molecule, cyclophilin-18 (C-18), is an inhibitor of HIV-1 cell fusion and infection with cell-free virus. T gondii C-18 efficiently blocked syncytium formation between human T cells and effector cells expressing R5 but not X4 envelopes. Neither human nor Plasmodium falciparum cyclophilins possess such inhibitory activity. Importantly, C-18 protected peripheral blood leukocytes from infection with multiple HIV-1 R5 primary isolates from several clades. C-18 bound directly to human CCR5, and this interaction was partially competed by the beta-chemokine macrophage inflammatory protein 1 beta (MIP-1 beta) and by HIV-1 R5 gp120. In contrast to several other antagonists of HIV coreceptor function, C-18 mediated inhibition did not induce beta-chemokines or cause CCR5 downmodulation, suggesting direct blocking of envelope binding to the receptor. These data support the further development of C-18 derivatives as HIV-1 inhibitors for preventing HIV-1 transmission and for postexposure prophylaxis.

Modeling a Safer Smallpox Vaccination Regimen, for Human Immunodeficiency Virus Type 1–Infected Patients, in Immunocompromised Macaques

We have modeled smallpox vaccination with Dryvax (Wyeth) in rhesus macaques that had depletion of CD4(+) T cells induced by infection with simian immunodeficiency virus or simian/human immunodeficiency virus. Smallpox vaccination induced significantly larger skin lesions in immunocompromised macaques than in healthy macaques. Unexpectedly, "progressive vaccinia" was infrequent. Vaccination of immunocompromised macaques with the genetically-engineered, replication-deficient poxvirus NYVAC, before or after retrovirus infection, was safe and lessened the severity of Dryvax-induced skin lesions. Neutralizing antibodies to vaccinia were induced by NYVAC, even in macaques with severe CD4(+) T cell depletion, and their titers inversely correlated with the time to complete resolution of the skin lesions. Together, these results provide the proof of concept, in macaque models that mirror human immunodeficiency virus type 1 infection, that a prime-boost approach with a highly attenuated poxvirus followed by Dryvax increases the safety of smallpox vaccination, and they highlight the importance of neutralizing antibodies in protection against virulent poxvirus.

Development of a novel vaccinia-neutralization assay based on reporter-gene expression

In anticipation of large-scale smallpox vaccination, clinical trials of new vaccine candidates with improved safety profiles, and new vaccinia immune globulin (VIG) products, there is an immediate need to develop new assays to measure vaccinia-specific immune responses. The classical assay to measure vaccinia neutralization, the plaque-reduction neutralization test (PRNT), is slow, labor intensive, and difficult to validate and transfer. Here we describe the development of a novel vaccinia-neutralization assay based on the expression of a reporter gene, beta-galactosidase (beta-Gal). Using a previously constructed vaccinia-beta-Gal recombinant virus, vSC56, we developed a neutralization assay that is rapid, sensitive, and reproducible. The readout is automated. We show that the neutralizing titers, ID(50), for several VIG products measured by our assay were similar to those obtained by PRNTs. A new Food and Drug Administration VIG standard was established for distribution to other laboratories. The new assay will serve as an important tool both for preclinical and clinical trials of new smallpox vaccines and for evaluation of therapeutic agents to treat vaccine-associated adverse reactions.

CXCR4 heterogeneity in primary cells: possible role of ubiquitination

The chemokine receptor CXCR4 is a primary coreceptor for the HIV-1 virus. The predicted molecular weight (MW) of glycosylated CXCR4 is 45-47 kDa. However, immunoblots of whole cell lysates from human lymphocytes, monocytes, macrophages, and the Jurkat T-lymphocyte line revealed multiple MW isoforms of CXCR4. Three of the bands could be precipitated by anti-CXCR4 monoclonal antibodies (101 and 47 kDa) or coprecipitated with CD4 (62 kDa). Expression of these isoforms was enhanced by infection with a recombinant vaccinia virus encoding CXCR4. In immunoblots of two-dimensional gels, antiubiquitin antibodies reacted with the 62-kDa CXCR4 species from monocytes subsequent to coprecipitation with anti-CD4 antibodies. Culturing of monocytes and lymphocytes with lactacystin enhanced the amount of the 101-kDa CXCR4 isoform in immunoblots by three- to sevenfold. In lymphocytes, lactacystin also increased cell-surface expression of CXCR4, which correlated with enhanced fusion with HIV-1 envelope-expressing cells. Similar increases in the intensity of the 101-kDa isoform were seen after treatment with the lysosomal inhibitors monensin and ammonium chloride. Antiubiquitin antibodies reacted with multiple proteins above 62 kDa, which were precipitated with anti-CXCR4 antibodies. Our data indicate that ubiquitination may contribute to CXCR4 heterogeneity and suggest roles for proteasomes and lysosomes in the constitutive turnover of CXCR4 in primary human cells.

Dissection of human immunodeficiency virus type 1 entry with neutralizing antibodies to gp41 fusion intermediates

Human immunodeficiency virus type 1 (HIV-1) entry requires conformational changes in the transmembrane subunit (gp41) of the envelope glycoprotein (Env) involving transient fusion intermediates that contain exposed coiled-coil (prehairpin) and six-helix bundle structures. We investigated the HIV-1 entry mechanism and the potential of antibodies targeting fusion intermediates to block Env-mediated membrane fusion. Suboptimal temperature (31.5 degrees C) was used to prolong fusion intermediates as monitored by confocal microscopy. After transfer to 37 degrees C, these fusion intermediates progressed to syncytium formation with enhanced kinetics compared with effector-target (E/T) cell mixtures that were incubated only at 37 degrees C. gp41 peptides DP-178, DP-107, and IQN17 blocked fusion more efficiently (5- to 10-fold-lower 50% inhibitory dose values) when added to E/T cells at the suboptimal temperature prior to transfer to 37 degrees C. Rabbit antibodies against peptides modeling the N-heptad repeat or the six-helix bundle of gp41 blocked fusion and viral infection at 37 degrees C only if preincubated with E/T cells at the suboptimal temperature. Similar fusion inhibition was observed with human six-helix bundle-specific monoclonal antibodies. Our data demonstrate that antibodies targeting gp41 fusion intermediates are able to bind to gp41 and arrest fusion. They also indicate that six-helix bundles can form prior to fusion and that the lag time before fusion occurs may include the time needed to accumulate preformed six-helix bundles at the fusion site.

Immunoglobulin G3 from polyclonal human immunodeficiency virus (HIV) immune globulin is more potent than other subclasses in neutralizing HIV type 1

Passive antibody prophylaxis against human immunodeficiency virus type 1 (HIV-1) has been accomplished in primates, suggesting that this strategy may prove useful in humans. While antibody specificity is crucial for neutralization, other antibody characteristics, such as subclass, have not been explored. Our objective was to compare the efficiencies of immunoglobulin G (IgG) subclasses from polyclonal human HIV immune globulin (HIVIG) in the neutralization of HIV-1 strains differing in coreceptor tropism. IgG1, IgG2, and IgG3 were enriched from HIVIG by using protein A-Sepharose. All three subclasses bound major HIV-1 proteins, as shown by Western blot assay and enzyme-linked immunosorbent assay. In HIV-1 fusion assays using X4, R5, or X4R5 envelope-expressing effector cells, IgG3 more efficiently blocked fusion. In neutralization assays with cell-free viruses using X4 (LAI, IIIB), R5 (BaL), and X4R5 (DH123), a similar hierarchy of neutralization was found: IgG3 > IgG1 > IgG2. IgG3 has a longer, more flexible hinge region than the other subclasses. To test whether this is important, IgG1 and IgG3 were digested with pepsin to generate F(ab')(2) fragments or with papain to generate Fab fragments. IgG3 F(ab')(2) fragments were still more efficient in neutralization than F(ab')(2) of IgG1. However, Fab fragments of IgG3 and IgG1 demonstrated equivalent neutralization capacities and the IgG3 advantage was lost. These results suggest that the IgG3 hinge region confers enhanced HIV-neutralizing ability. Enrichment and stabilization of IgG3 may therefore lead to improved HIVIG preparations. The results of this study have implications for the improvement of passive immunization with polyclonal or monoclonal antibodies and suggest that HIV-1 vaccines which induce high-titer IgG3 responses could be advantageous.

Human peripheral blood T cells, monocytes, and macrophages secrete macrophage inflammatory proteins 1alpha and 1beta following stimulation with heat-inactivated Brucella abortus

Heat-killed Brucella abortus (HBa) has been proposed as a carrier for therapeutic vaccines for individuals with immunodeficiency, due to its abilities to induce interleukin-2 (IL-2) and gamma interferon (IFN-gamma) in both CD4(+) and CD8(+) T cells and to upregulate antigen-presenting cell functions (including IL-12 production). In the current study, we investigated the ability of HBa or lipopolysaccharide isolated from HBa (LPS-Ba) to elicit beta-chemokines, known to bind to the human immunodeficiency virus type 1 (HIV-1) coreceptor CCR5 and to block viral cell entry. It was found that human peripheral blood mononuclear cells secreted beta-chemokines following stimulation with HBa, and this effect could not be blocked by anti-IFN-gamma neutralizing antibodies. Among purified T cells, macrophage inflammatory protein 1alpha and 1beta (MIP-1alpha and MIP-1beta, respectively) secretion was observed primarily in human CD8(+) T cells. The kinetics of beta-chemokine induction in T cells were slow (3 to 4 days). The majority of beta-chemokine-producing CD8(+) T cells also produced IFN-gamma following HBa stimulation, as determined by triple-color intracellular staining. A significant number of CD8(+) T cells contained stored MIP-1beta that was released after HBa stimulation. Both HBa and LPS-Ba stimulated high levels of MIP-1alpha and MIP-1beta production in elutriated monocytes and even higher levels in macrophages. In these cells, beta-chemokine mRNA was upregulated within 30 min and proteins were secreted within 4 h of stimulation. The monocyte- and macrophage-derived beta-chemokines were sufficient to block CCR5-dependent HIV-1 envelope-mediated cell fusion. These data suggest that, in addition to the ability of HBa to elicit antigen-specific humoral and cellular immune responses, HBa-conjugated HIV-1 proteins or peptides would also generate innate chemokines with antiviral activity that could limit local viral spread during vaccination in vivo.

Management of neonatal ureteropelvic junction obstruction

No topic in urology is more contentious than the management of neonatal ureteropelvic junction obstruction. Those favoring early diagnosis and correction of obstruction in early infancy cite excellent return of function and superior surgical results compared with delayed repair. Others believe that hydronephrosis improves or resolves with growth in many instances. In the most widely quoted series, almost all such patients improved. This article attempts to separate opinion from fact. The arguments for early surgery and for observation, even when obstruction has been diagnosed, are reviewed. Several experiences with long-term surveillance are summarized.

Long-term efficacy of simple behavioral therapy for daytime wetting in children

PURPOSE

Behavioral therapy has proved benefit for children with daytime wetting but most studies have used biofeedback techniques and provide no long-term assessment of results. We previously reported similar results using simple behavioral therapy without biofeedback. We report the long-term efficacy of behavioral therapy for daytime wetting.

MATERIALS AND METHODS

Our program of behavioral therapy included timed voiding, modification of fluid intake, positive reinforcement techniques and pelvic floor (Kegel) exercises to promote pelvic floor strengthening and relaxation. Questionnaires to assess therapeutic efficacy were mailed to patients who had completed therapy more than 1 year previously.

RESULTS

A total of 48 patients responded. Mean ages at the time of the initial clinic visit and questionnaire were 8.2 and 12.9 years, respectively. Improvement in symptoms was noted in approximately 74% of the cases during the first year following therapy. At a mean of 4. 7 years after treatment 59.4% of the patients had improved daytime urinary control, 51.1% improved daytime urinary frequency and 45.6% improved daytime urinary urgency. The frequency of urinary tract infections decreased in 56.4% of the cases. Measures of psychological well-being were also noted to be improved in a majority of patients. A total of 77.3% of the patients stated that they would recommend the program to others.

CONCLUSIONS

Simple behavioral therapy without biofeedback techniques is an effective and durable first line therapy for children with daytime wetting.

Experience with transurethral incision of ureteroceles

OBJECTIVES

The value of primary transurethral ureterocele incision was investigated in the treatment of ureteroceles in infants and children.

METHODS

The charts and radiographic studies of 13 patients between the ages of 2 weeks and 8 years who underwent transurethral incision of 14 ureteroceles as primary surgical therapy at our institution were reviewed.

RESULTS

57% of the ureteroceles were intravesical and 43% extravesical. 64.3% were associated with the upper pole of a duplicated system. All 14 ureteroceles were associated with a functional renal moiety. Endoscopic incision achieved ureterocele decompression in 13 of 14 ureteroceles (93%). Preexisting hydronephrosis improved or resolved in 10 of 14 cases (71.4%). Renal function after decompression was not shown to be significantly altered or improved. 5 of 13 patients (38%) required definite surgical reconstruction for recurrent urinary tract infections, upper pole vesicoureteral reflux, hydronephrosis and lower pole vesicoureteral reflux within a mean follow-up period of 14 months.

CONCLUSION

Transurethral incision has a limited role in the treatment of ureteroceles in children. In many or even most cases it cannot be expected to constitute long-term definite treatment for ureteroceles. It is mainly indicated in patients with urosepsis, prolapsing ureteroceles with functional bladder neck obstruction or massive reflux into other renal segments. In these settings it reliably achieves decompression and allows effective treatment of infection. The function of the previously obstructed renal segment can be reevaluated at later point in time to assess whether it should be saved. The delay permits interim growth that is likely to make bladder reconstruction easier.

The incidence of nephrolithiasis in patients with spinal neural tube defects

PURPOSE

Bladder stones are common in patients with spinal neural tube defects but there are little data on the incidence of renal calculi in this population. We examined the incidence, nature and risk factors of nephrolithiasis in our clinic population of patients with neural tube defects.

MATERIALS AND METHODS

We retrospectively reviewed the charts and radiological studies of 327 patients followed at our neural tube defects clinic with routine radiological imaging of the urinary tract. Additional confirmatory studies were performed when stones were noted.

RESULTS

Renal calculi were identified in 20 patients with neural tube defects (6.1%). The incidence of nephrolithiasis increased with age. Renal stones were noted in 19 patients (10.7%) 12 years old or older. Management of the stones in these patients resulted in overall 53% stone-free and 87% recurrence rates after intervention. Major risk factors for new and/or recurrent renal stone formation were bacteriuria in 95% of the cases, lower urinary tract reconstruction in 80%, pelvicalicectasis in 70%, vesicoureteral reflux in 65%, a thoracic level spinal defect in 60% and renal scarring in 55%.

CONCLUSIONS

These data suggest that there is a higher incidence of nephrolithiasis in patients with neural tube defects than in the general population and the risk of stone recurrence is also elevated. Most patients with stones had undergone lower urinary tract reconstruction. Other risk factors were bacteriuria, pelvicalicectasis, vesicoureteral reflux and a thoracic level neural tube defect.

The incidence of nephrolithiasis in patients with spinal neural tube defects

PURPOSE

Bladder stones are common in patients with spinal neural tube defects but there are little data on the incidence of renal calculi in this population. We examined the incidence, nature and risk factors of nephrolithiasis in our clinic population of patients with neural tube defects.

MATERIALS AND METHODS

We retrospectively reviewed the charts and radiological studies of 327 patients followed at our neural tube defects clinic with routine radiological imaging of the urinary tract. Additional confirmatory studies were performed when stones were noted.

RESULTS

Renal calculi were identified in 20 patients with neural tube defects (6.1%). The incidence of nephrolithiasis increased with age. Renal stones were noted in 19 patients (10.7%) 12 years old or older. Management of the stones in these patients resulted in overall 53% stone-free and 87% recurrence rates after intervention. Major risk factors for new and/or recurrent renal stone formation were bacteriuria in 95% of the cases, lower urinary tract reconstruction in 80%, pelvicalicectasis in 70%, vesicoureteral reflux in 65%, a thoracic level spinal defect in 60% and renal scarring in 55%.

CONCLUSIONS

These data suggest that there is a higher incidence of nephrolithiasis in patients with neural tube defects than in the general population and the risk of stone recurrence is also elevated. Most patients with stones had undergone lower urinary tract reconstruction. Other risk factors were bacteriuria, pelvicalicectasis, vesicoureteral reflux and a thoracic level neural tube defect.

Orchiopexy for impalpable testis: high spermatic vessel division is a safe maneuver

PURPOSE

This review was performed to assess the effect of protecting the collateral circulation between spermatic and vasal vessels by leaving a strip of peritoneum attached to the lower spermatic cord in patients in whom the spermatic vessels needed to be divided to bring the testis into good scrotal position.

MATERIALS AND METHODS

Between 1983 and 1994, 22 boys were encountered in whom 1 testis was always normal in size and position, and the other was intra-abdominal and would not be in normal scrotal position after complete cord straightening. A strip of peritoneum had been left attached to the spermatic cord before full mobilization. After high division of the spermatic vessels the testes were brought in the mid scrotum during the same operation.

RESULTS

All testes remained in scrotal position except 1 which retracted and was subsequently removed. None became atrophic.

CONCLUSIONS

Division of the spermatic vessels, the Fowler-Stephens maneuver, can safely be performed during an initial operation as long as its possible need is anticipated, and the collateral circulation between the vasal vessels and spermatics is not disrupted. Secondary orchiopexy for inadequate cord length is now rarely required. This type of open orchiopexy for high impalpable testis is safe, is easy to learn, has no increased morbidity and is generally less expensive than a laparoscopic approach.

Sonographic appearance of the bladder after endoscopic incision of ureteroceles

OBJECTIVE

Our intent was to describe the range of postoperative sonographic appearances of the bladder after endoscopic incision of ureteroceles.

CONCLUSION

Preoperative and postoperative sonographic examinations of the bladder were reviewed in 14 patients (15 ureteroceles) who underwent endoscopic ureterocele incision. Five different appearances of the ureterovesical junction after endoscopic incision were found: a pseudomass (5/15), focal mucosal thickening (3/15), residual ureterocele with decrease in size (3/15), persistent unchanged ureterocele (1/15), and no residual abnormality (3/15). The most common postoperative sonographic appearance associated with development of vesicoureteral reflux was a mucosal pseudomass (4/6). The other bladder sonographic appearances had no correlation with development of reflux, degree of hydronephrosis, or success of the surgery.

Renal ultrasound changes after pyeloplasty in children with ureteropelvic junction obstruction: long-term outcome in 47 renal units

PURPOSE

We evaluated the use of renal ultrasound for monitoring pyelocaliectasis after pyeloplasty in children.

MATERIALS AND METHODS

Changes in pyelocaliceal dilatation following pyeloplasty were assessed by serial ultrasound. Of 104 children 0 to 12 years old who underwent pyeloplasty between 1982 and 1992, 44 (47 renal units) were monitored with serial ultrasound for at least 2 years (range 2 to 9, mean 3.8). Patient ages at pyeloplasty were 0 to 3 months (17), 4 to 12 months (8), 1 to 6 years (13) and 7 to 12 years (6). Preoperative and postoperative ultrasound was reviewed by a single pediatric radiologist blinded to the date of surgery. The degree of pyelocaliectasis was graded as 0 to 4 according to the classification of the Society for Fetal Urology.

RESULTS

Preoperative ultrasound revealed grade 4 pyelocaliectasis in 26 kidneys (55%) and grade 3 disease in 21 (45%). Grade was the same or worse 1 month after pyeloplasty in the majority of kidneys (92%) studied at this interval. Of the 47 renal units assessed 43 (91%) showed improvement in pyelocaliectasis during postoperative followup. Only 38% of the kidneys improved during the first 6 months of followup, while 81% were improved 2 years postoperatively. Improvement to grade 0 or 1 dilatation occurred in only 9 kidneys (19%). The rate of resolution of pyelocaliectasis was not related to preoperative grade or patient age at pyeloplasty.

CONCLUSIONS

Improvement on renal ultrasound after pyeloplasty appears to be gradual. Less than half of the patients had improvement in the initial 6 months after pyeloplasty and pyelocaliectasis rarely resolved completely. While renal ultrasound can provide an accurate and cost-effective means of monitoring children on a long-term basis after pyeloplasty, sonographic evaluation in the early postoperative period commonly shows increased or unchanged pyelocaliectasis.

A new approach to the closure of cloacal exstrophy

Cloacal exstrophy patients are often difficult to reconstruct. Urinary continence is usually achievable only with a catheterizable stoma of some type. Since cloacal exstrophy is usually associated with omphalocele or gastroschisis, one-stage closure of the abdominal wall defect is frequently impossible. We prefer to incorporate the exstrophic large bowel, which separates the hemibladders, into the closed bladder as a sort of "natural" augmentation to maximize its volume for use as a continent reservoir. If a silastic "silo" or synthetic mesh is required to close the abdominal wall, excessive scarring occurs and later creation of a continent stoma is usually difficult and time-consuming. In all but those with the smallest abdominal wall defects we recommend that the omphalocele and upper abdominal wall be repaired first, replacing the evicted gut into the peritoneal cavity. During nutritional stabilization a tissue expander is placed under the superficial musculature of the chest wall. The flap is enlarged by gradual inflation of the tissue expander until it fills the abdominal wall defect left by subsequent closure of the cloacal exstrophy. The flap is then rotated inferiorly with blood supply intact at the time of bladder closure to make good the remaining abdominal wall defect. This flap improves the appearance of the abdominal wall and reduces scarring. Thus, this approach has the possibility of making subsequent operations to provide continence shorter, simpler, and more successful in most infants with cloacal exstrophy.

Pediatric urology manpower report 1995. Ellen Shapiro on behalf of the American Association of Pediatric Urologists

PURPOSE

The quality and efficiency of any health care system depend on an appropriate level of manpower. The manpower issues of tomorrow will be influenced by the number of physicians and specialists trained today. The objectives of this manpower survey of pediatric urologists in the United States were to determine anticipated manpower requirements and provide caveats related to the practice of pediatric urology.

MATERIALS AND METHODS

A manpower questionnaire was distributed to pediatric urologists at the American Urological Association meeting in Las Vegas, Nevada in April 1995. Of the 234 distributed questionnaires 204 (87%) were completed and entered into a computer program.

RESULTS

Of responding pediatric urologists 70% were younger than 50 years, 81% practiced full-time pediatric urology and 45% were university based. The rates of respondents indicating that their present workload was too busy, appropriate or not busy enough were 10, 70 and 20%, respectively. A total of 71% of respondents indicated that they would discourage a newly trained individual from setting up a practice in their area. Of practicing pediatric urologists 26% intended to retire within the next 10 years. In April 1995, 80 respondents (39%) representing 67 practices were considering adding an associate within the next 10 years. By the end of 1995 only 56 practices will remain that will add an associate within the next 10 years. A total of 82% of respondents believed that there was an excess number of pediatric urology training programs.

CONCLUSIONS

The pediatric urology community presently trains 10 to 15 pediatric fellows per year. Based on the 1995 manpower survey, if this trend continues an excess of 40 to 90 pediatric urologists will be trained in the next 10 years. The conclusion that there is an overabundance of pediatric urologists in training is supported by the general consensus of practicing pediatric urologists. Policies related to the training of pediatric urology fellows and urology residents should depend, not on the manpower needs at individual medical centers, but on the collective needs of our specialty and the patients whom we serve.

Use of the expanded thoracoepigastric myocutaneous flap in the closure of cloacal exstrophy

We describe the first reported use of an expanded thoracoepigastric myocutaneous flap in the closure of cloacal exstrophy. This approach offers several distinct advantages. The expander increases the available cutaneous surface area of the thoracoepigastric region, improves vascularity, induces a fibrous capsule that augments the abdominal wall, permits primary closure, and avoids prosthetic adjuncts that increase scarring and hinder delayed urinary tract reconstruction. Osteotomy and spica casting may be obviated by using this flap, but mesh may be required eventually. We anticipate its use in all future cases in which the abdomen cannot be closed safely at the primary procedure at this institution. This technique also should be considered for classic bladder exstrophy or any other large congenital or acquired defect of the lower abdomen.

Are modern imaging techniques over diagnosing ureteropelvic junction obstruction?

Since the widespread use of real-time ultrasonography in the early 1980s, ureteropelvic junction obstruction has been diagnosed at earlier ages and prenatally on a presumptive basis. However, substantial controversy exists over the diagnosis and treatment of ureteropelvic junction obstruction. We conducted an epidemiological study to determine if modern imaging techniques are leading to the over diagnosis of ureteropelvic junction obstruction. Records were collected retrospectively from 3 hospitals serving 2 adjacent counties to determine the number of pyeloplasties performed in 1970 to 1992. The 2 university hospitals and 1 large private hospital provide a wide variety of services and choice of urologists, and so it was assumed that most patients requiring pyeloplasty in the area would be captured. Of the 555 pyeloplasties 240 (43%) were performed on children 12 years old or younger. Logistic regression analysis revealed an overall increase of pyeloplasties per year of 56.8% in 23 years, which was not markedly different from the population growth in the area in the same period (49.3%). A statistically significant increase in the number of pyeloplasties performed in the first year of life was noted. This trend appeared to begin in 1981: 8 pyeloplasties were performed in the first year of life between 1970 and 1980 compared to 91 between 1981 and 1992. Pyeloplasties in children 1 to 6 years old increased with time at a much lower rate that was not statistically significant and the number of pyeloplasties decreased in those 7 to 12 years old. Therefore, it appears that modern imaging techniques are not leading to an over diagnosis of ureteropelvic junction obstruction but to detection of the disease at an earlier age.

Acute pancreatitis in children: CT findings of intra- and extrapancreatic fluid collections

PURPOSE

To determine the location and importance of fluid collections in children with acute pancreatitis.

MATERIALS AND METHODS

The authors retrospectively reviewed the abdominal computed tomographic (CT) scans of 28 children with acute pancreatitis. CT scans were evaluated for pancreatic size and distribution of intra- and extrapancreatic fluid collections. Extrapancreatic fluid was classified as (a) peritoneal, (b) retroperitoneal, (c) mesenteric, or (d) ligamentous.

RESULTS

Fourteen children (50%) had complicated pancreatitis associated with fluid collections. Intrapancreatic fluid was identified in only two patients (7%), whereas extrapancreatic fluid was seen in 14 (50%). Extrapancreatic fluid was most often seen in the anterior pararenal space, followed by the lesser sac, lesser omentum, and transverse mesocolon. The fluid collections diminished spontaneously in 11 patients (78%). Three patients with persistent fluid collections required surgical intervention for associated abnormalities.

CONCLUSION

Intrapancreatic fluid collections are rare in children with pancreatitis. Extrapancreatic fluid collections tend to be extensive, but most diminish spontaneously.