A bivalent Neisseria meningitidis recombinant lipidated factor H binding protein vaccine in young adults: results of a randomised, controlled, dose-escalation phase 1 trial.

Neisseria meningitidis is a leading cause of meningitis and septicaemia, but a broadly-protective vaccine against endemic serogroup B disease is not licensed and available. The conserved, outer-membrane lipoprotein factor H binding protein (fHBP, also known as LP2086) is expressed as one of two subfamily variants in virtually all meningococci. This study investigated the safety, tolerability, and immunogenicity of a recombinant-expressed bivalent fHBP (r-fHBP) vaccine in healthy adults. Participants (N=103) aged 18-25 years were recruited into three ascending dose level cohorts of 20, 60, and 200µg of a bivalent r-fHBP vaccine formulation and randomised to receive vaccine or placebo at 0, 1, and 6 months. The vaccine was well tolerated. Geometric mean titres (GMTs) for r-fHBP subfamily-specific IgG antibodies increased 19-168-fold from pre-vaccination to post-dose 2 in a dose level-dependent manner. In addition, robust serum bactericidal assay using human complement (hSBA) responses for strains expressing both homologous and heterologous fHBP variants were observed. After three vaccinations, 16-52% of the placebo group and 47-90%, 75-100%, and 88-100%, of the 20, 60, and 200µg dose levels, respectively, had seroprotective (≥ 1:4) hSBA titres against six serogroup B strains. The bivalent r-fHBP vaccine was well tolerated and induced robust bactericidal activity against six diverse serogroup B strains in young adults at the 60 and 200µg dose levels.

Pulmonary haemosiderosis with juvenile idiopathic arthritis in a Malaysian child.

A rare case of childhood pulmonary haemosiderosis with juvenile idiopathic arthritis is discussed, with particular reference to treatment with hydroxychloroquine and sildenafil for pulmonary hypertension which occurs secondary to this disease.

A comparison of booster immunisation with a combination DTPa-IPV vaccine or DTPa plus IPV in separate injections when co-administered with MMR, at age 4-6 years.

This study evaluated GSK's combined DTPa-IPV vaccine (Infanrix-IPV) given as a fifth consecutive acellular pertussis booster dose in conjunction with the second dose of MMR vaccine (Priorix) in children aged 4-6 years. The immunogenicity and reactogenicity of this vaccine regimen was compared with separate injections of DTPa and IPV when given concomitantly with MMR. A cohort of 362 children previously primed with four doses of DTPa and OPV, and a single dose of MMR were randomized to receive either DTPa-IPV+MMR (N=181) or DTPa+IPV+MMR (N=181). Antibody concentrations were measured prior to and 1 month after the booster dose. After immunisation all subjects from both groups had seroprotective antibody levels against diphtheria, tetanus and the three poliovirus serotypes, > or = 96% showed vaccine response to PT, FHA and PRN, all were seropositive to mumps and rubella, and all but one subject were seropositive to measles. Immunogenicity results for each component antigen were similar for DTPa-IPV and separately co-administered DTPa and IPV. Local reactions were common with 24.0% and 31.1% of children experiencing swelling >50mm at the DTPa-IPV and DTPa injection sites, respectively. The DTPa-IPV combination did not increase the incidence or intensity of adverse events compared with separately administered DTPa+IPV. The response to the concomitantly administered MMR vaccine was similar in the two groups and similar to previously reported responses for a second dose of MMR. This combined DTPa-IPV vaccine has a similar reactogenicity profile to DTPa, is immunogenic when given as a booster dose at 4-6 years of age, and has no impact on the immunogenicity of a co-administered second dose of MMR vaccine.

Safety and immunogenicity of a combined DTPa-IPV vaccine administered as a booster from 4 years of age: a review.

A combined DTPa-IPV booster vaccine was administered as a 4th or 5th dose after DTPa or DTPw priming. Over 99% vaccines developed antibody levels considered to be protective to diphtheria, tetanus and poliovirus, and >95% mounted a response to acellular pertussis antigens. Rectal temperature >39.5 degrees C was observed in at most 3.2% of vaccinees. Swelling >50 mm occurred in 24% of DTPa-primed compared to 5.5% of DTPw-primed children. Large swelling involving the entire upper arm (extending to involve the elbow joint) was reported for up to 1.2% of DTPa-primed subjects, which is consistent with literature reports for other DTPa vaccines.

Effect of dietary nucleotide supplementation on growth and immune function in term infants: a randomized controlled trial.

OBJECTIVE: To examine the effect of nucleotide (NT)-supplemented cow's milk-based formula on growth and biochemical indices of immune function in healthy infants. DESIGN: Randomized controlled trial (RCT) of formula-fed term infants allocated to control formula with an innate level of NT at 10 mg/l (n = 102), or formula fortified with NT at 33.5 mg/l (n = 98). A parallel group of 125 breastfed infants followed the same protocol as a reference. OUTCOME MEASURES: Growth was assessed at enrolment, 7 weeks, 4 months and 7 months of age. Natural killer cell activity, cytokine production and lymphocyte subpopulations were assessed at 7 weeks of age. Antibody responses to diphtheria toxoid, tetanus toxoid and Haemophilus influenzae type b (Hib) immunizations were measured at 7 months of age. RESULTS: NT supplementation did not influence the growth of formula fed infants or any markers of immunity measured at 7 weeks of age. Antibody responses to tetanus toxoid were higher in the NT-supplemented group (n = 68) compared with the control group (n = 70) at 7 months of age (median (5th, 95% percentile): 1.57(0.42, 3.43) vs 1.01(0.41, 4.66) IU/ml, P < 0.03). A difference between treatments was seen in response to diphtheria toxoid but this effect disappeared when adjusted for hepatitis B immunization at birth. There was no effect of treatment on antibody responses to Hib immunization. CONCLUSIONS: Supplementation of formulas with NT at 33.5 mg/l resulted in a modest improvement in antibody response consistent with RCTs that used higher levels of NT supplementation. Whether this translates to clinical benefits in well-nourished infants requires further study. SPONSORSHIP: Supported by a grant from Wyeth Nutrition. Dr Makrides was supported by an RD Wright Fellowship from the National Health and Medical Research Council of Australia and Dr Gibson was partially supported by the MS McLeod Research Trust and a Senior Research Fellowship from the National Health and Medical Research Council of Australia.

Reactogenicity and immunogenicity profile of a two-dose combined hepatitis A and B vaccine in 1-11-year-old children.

This study was conducted to compare the reactogenicity, immunogenicity and safety of a combined two-dose (0, 6 months) hepatitis A and B vaccine (720ELU HAV, 20 mcg HBsAg) with the established three-dose (0, 1 and 6 months) hepatitis A and B vaccine (360ELU HAV, 10 mcg HBsAg). A total of 511 children aged 1-11 years who had not previously received a hepatitis A or B vaccine were enrolled in the study. Both vaccines were well tolerated, and were shown to be safe and immunogenic. The analysis, stratified according to two age groups (1-5 year and 6-11-year-old children) demonstrated that the reactogenicity profile of the two-dose schedule was at least as good as that of the established schedule. Both vaccines and schedules provided at least 98% seroprotection against hepatitis B and 100% seroconversion against hepatitis A, 1 month after the end of the vaccination course (Month 7).

Developmental immunology and vaccines: immune responses to vaccines in premature infants.

A comparatively small number of studies have assessed the safety, immunogenicity, efficacy and duration of immune responses in preterm infants compared with term infants for routinely recommended childhood immunizations.

The relationship between health-related quality of life, pain and coping strategies in juvenile idiopathic arthritis.

OBJECTIVES: To investigate the relationship between health-related quality of life (HRQL), experience of pain and pain coping strategies in children with juvenile idiopathic arthritis (JIA). To compare reports describing these variables obtained from children and their parents. METHODS: Participants were 59 children aged 8 to 18 yr with JIA and their parents. Parents and children completed the PedsQL generic core scales and arthritis module, the visual analogue scale of the Varni-Thompson Pediatric Pain Questionnaire, and the Waldron/Varni Pediatric Pain Coping Inventory. Parents rated children's functional disability using the Childhood Health Assessment Questionnaire. RESULTS: Parents reported significantly lower scores (indicating worse HRQL) than children on five of the eight PedsQL scales rating children's HRQL. Parents and children reported a significant negative relationship between pain levels and the PedsQL scores assessing children's physical, emotional and social functioning. They also reported a significant negative relationship between scores on several pain coping scales and scores on the PedsQL scales. However, the pattern of these relationships varied for reports from parents and children. CONCLUSIONS: Pain intensity and pain coping strategies have a significant and independent relationship with several domains that comprise the HRQL of children with JIA. However, parents and children have differing perceptions of the nature of these relationships. The differences emphasize the importance of clinicians obtaining information about children's HRQL, pain levels and pain coping strategies from both parents and children.

Medical student interviewing skills and mother-reported satisfaction and recall.

BACKGROUND: Providing feedback to medical students about their interviewing skills is an important component of teaching programmes. There is very little information about mothers' views of medical student consultations in paediatrics, and in particular about what mothers consider to be the key elements of a successful consultation. Patient-centred interviewing is a model which emphasizes the active seeking of patient views. In association with appropriate clinical skills, it is reported to promote improved health outcomes. OBJECTIVES: To examine whether greater medical student clinical competence and more frequent use of patient-centred techniques is associated with higher maternal satisfaction, higher maternal rating of the medical student's interpersonal skills, and greater maternal recall of relevant diagnosis and treatment recommendations. METHOD: Two standardized 'medical student' videotaped interviews were created based on actual senior medical student consultations. Interview A demonstrated both higher student clinical competence and higher patient-centredness compared with interview B. Both videotaped interviews were viewed and then rated, using a questionnaire, by 11 mothers attending a teaching general practice. RESULTS: Significantly higher mean scores, indicating greater maternal satisfaction, were associated with interview A (P < 0.01 for all measures). Accurate recall for diagnosis and management was also significantly greater after interview A (mean diagnosis recall, interview A 35%, interview B 14%, P < 0.01; mean management recall, interview A 95%, interview B 57%, P < 0.01). CONCLUSIONS: Maternal satisfaction and recall were higher following a more clinically competent and patient-centred medical student interview. Maternal ratings of student interviews could be used as an additional method of assessment as well as providing feedback to medical students on their interview skills development.

The Fc receptor for IgG (Fc gamma RII; CD32) on human neonatal B lymphocytes.

B cells express an Fc receptor for IgG (FcgammaRII; CD32) which is involved in feedback inhibition of antibody production. Engagement of FcgammaRII during ligation of the antigen receptor provides an inhibitory signal. FcgammaRII exists as several isoforms, with FcgammaRIIb (which carries an immunoreceptor tyrosine-based inhibition motif; ITIM) being predominant form on adult B cells. The inhibitory role of FcgammaRIIb may be unhelpful to the infant, since primary exposure to infectious agents is likely to be in the presence of maternal IgG. We hypothesized that neonatal B cells would be less susceptible to feedback inhibition by antibody, either through the expression of activation-competent FcgammaRII isoforms (FcgammaRIIa and FcgammaRIIc) or through reduced expression of the inhibitory FcgammaRIIb isoforms. Cord and adult B cells were examined for expression of FcgammaRII isoforms using monoclonal antibodies and RT-PCR. In vitro assays were performed to assess susceptibility of cord and adult cells to FcgammaRII-mediated suppression. Although there is no phenotypic difference in FcgammaRII expression (FcgammaRIIb predominating on both adult and cord B cells), FcgammaRIIb is expressed at lower levels on cord cells. This quantitative difference in FcgammaRIIb expression may explain the reduced susceptibility of cord B cells to antibody-mediated inhibition observed in these experiments.

Storage at -3 degrees C for 24 h alters the immunogenicity of pertussis vaccines.

The immunogenicity of pertussis antigens in an acellular and a whole-cell triple antigen vaccine used for childhood immunisation was assessed in murine models after storage of vaccines below 0 degree C. Swiss outbred and Balb/c mice received DTPa or DTPw vaccine or placebo. Vaccines were stored at 2-8 degrees C (ideal), or at -3 degrees C for 24 h. Pre and post immunisation IgG responses to pertussis toxin (PT), filamentous haemagglutinin (FHA) and pertactin (PRN) were measured using enzyme immunoassays (EIA). In Balb/c mice, responses to pertactin after receiving adversely stored DTPa were significantly reduced (P = 0.005, difference in GMCs 145.9% [24.6-385.4%]). A reduction in GMC to pertactin was also seen in response to adversely stored DTPw (P = 0.190,224.1% [83.8-599.2%]). Outbred mice receiving adversely stored DTPa had lower IgG antibody responses to FHA than those receiving correctly stored vaccine (P = 0.002,522.2% [26.1-2155.6%]). Outbred mice also had a significantly lower response to FHA after administration of DTPw (P = 0.009,14.0% [3.8-51.9%]). Responses to DTPa in both strains generally were greater than those to DTPw. Storage of pertussis vaccines below 0 degree C appears to alter the immunogenicity of PRN and FHA. Further study is required to determine the effects of such storage on vaccine protective efficacy.

Regulation of human neutrophil-mediated cartilage proteoglycan degradation by phosphatidylinositol-3-kinase.

The ability of neutrophils to degrade cartilage proteoglycan suggests that the neutrophils that accumulate in the joints of rheumatoid arthritis patients are mediators of tissue damage. The regulatory mechanisms which are relevant to the proteoglycan-degrading activity of neutrophils are poorly understood. Since phosphatidylinositol 3-kinase (PI3-K), protein kinase C (PKC), the extracellular signal-regulated protein kinase (ERK)1/ERK2 and cyclic adenosine monophosphate (cAMP) have been reported to regulate neutrophil respiratory burst and/or degranulation, a role for these signalling molecules in regulating proteoglycan degradation was investigated. Preincubation of human neutrophils with GF109203X (an inhibitor of PKC), PD98059 (an inhibitor of MEK, the upstream regulator of ERK1/ERK2) or with forskolin or dibutyryl cAMP, failed to suppress proteoglycan degradation of opsonized bovine cartilage. In contrast, preincubation of neutrophils with wortmannin or LY294002, specific inhibitors of PI3-K, inhibited proteoglycan degradation. Incubation of neutrophils with cartilage resulted in the activation of PI3-K in neutrophils, consistent with a role for PI3-K in proteoglycan degradation. Activation of PI3-K and proteoglycan degradation was enhanced by tumour necrosis factor-alpha. Degradation caused by neutrophils from the synovial fluid of rheumatoid arthritis patients was also inhibited by wortmannin. These data demonstrate that the proteoglycan degradative activity of neutrophils required PI3-K but not PKC or the ERK1/ERK2/ERK5 cascades and was insensitive to increases in intracellular cAMP concentrations.

Restricted polymorphism of the mannose-binding lectin gene of indigenous Australians.

Mannose-binding lectin (MBL) is an important complement-activating protein of the human innate immune system. Deficiency of MBL is associated with an increased risk of various infections and arises from three structural gene mutations in exon 1 (variants B, C and D) and/or the presence of a low efficiency promoter. The C allele is found in sub-Saharan Africa whereas the B allele is found elsewhere, suggesting that these mutations occurred after the suggested hominid migration out of Africa [100-150 000 years before present (BP)]. Paradoxically, these alleles may have a selective advantage in protection against intracellular pathogens and occur at particularly high frequencies in sub-Saharan Africa (C variant) and South America (B variant). Since hominids reached Australia at least 50 000 years ago, a study of MBL polymorphisms in the indigenous population was of interest. Using heteroduplex technology we found a paucity of MBL structural gene mutations in two population groups from geographically distinct regions. Of 293 individuals tested, 289 were wild-type and four were heterozygous for either the B or D allele. In each individual with an MBL mutation the HLA haplotype profile suggested some Caucasian admixture. We also found a restricted range of MBL promoter haplotypes and the serum MBL levels were higher than those of any other ethnic group studied to date (median 3.07 microg/ml). Our data suggest that the B mutation probably arose between 50 000 and 20 000 BP. Its absence from the founder gene pool of indigenous Australians may also partly explain their vulnerability to intracellular infections such as tuberculosis.

Expression of the costimulator molecules, CD40 and CD154, on lymphocytes from neonates and young children.

Differential expression of the costimulator molecules CD40 and CD154 on neonatal lymphocytes may be one explanation for limited T-dependent antibody responses in human neonates. CD40 was expressed at similar levels on resting B cells from adults, young children (2-20 months of age) or cord blood. CD40 expression was higher on cord blood B cells compared to adult B cells after stimulation with PMA and ionomycin, but similar on adult and cord blood B cells activated by CD3-stimulated T cells. In contrast to previous reports, cord blood T cells stimulated with PMA and ionomycin expressed adult levels of CD154 initially, but this expression was more transient on cord blood T cells. When adult and cord blood mononuclear cells were stimulated with CD3 mAb, T cells from some cord blood specimens showed different kinetics of CD154 expression compared with adult T cells. However, some cord blood specimens showed adult patterns of T cell CD154 expression. When mononuclear cells were depleted of B cells and monocytes prior to stimulation with CD3 mAb, the MFI and percentage of T cells expressing CD154 increased, with adult and cord T cells showing similar patterns of expression. These results show some differences in expression of CD40 and CD154 between neonatal and adult lymphocytes, but do not directly account for the relative deficiencies of humoral immunity in neonates.

Expression of the costimulator molecules, CD80, CD86, CD28, and CD152 on lymphocytes from neonates and young children.

The expression of CD80, CD86, CD28, and CD152 were examined on peripheral blood lymphocytes from adults, neonates (cord blood lymphocytes) and young children (2-20 months of age). There was no difference in the expression of CD80 or CD86 between adult and neonatal B cells, either resting or activated. A higher percentage of resting T cells expressed CD28 in neonates and young children compared to adults. CD28 expression was similar on adult and neonatal T cells activated with PMA and ionomycin. However, CD28 was expressed at greater intensity on a higher percentage of neonatal T cells than adult T cells stimulated with CD3. CD152 expression was lower on neonatal T cells than adult T cells stimulated with PMA and ionomycin and undetectable on neonatal T cells stimulated with CD3. In contrast, intracellular CD152 was equivalent in adult and neonatal T cells stimulated with PMA and ionomycin, suggesting trafficking of CD152 to the cell surface may be differentially regulated in neonatal T cells. Since the T cell response is determined by the balance of signals received from CD28 and CD152, high levels of CD28 expression and lower surface expression of CD152 on neonatal T cells may represent specialisation to promote activation of neonatal T cells.

Interleukin 2 receptor regulation and IL-2 function in the human infant.

IL-2 receptor is expressed at low levels on adult blood lymphocytes, and at lower levels on cord blood cells. IL-2 receptor alpha and beta chain expression increases gradually from 0-18 months of age. The level of soluble CD25 (IL-2 receptor alpha chain) has been reported to be elevated in cord blood. Quantitative RT-PCR showed that adult cells express 10 times as much CD25 mRNA as cord cells. Cord plasma showed only a marginal ability to strip CD25 from the membrane. To assess the functional consequences of low IL-2 receptor expression, cord and adult cells were activated in vitro. The response was stimulus-dependent, but cord cells upregulated CD25 readily. Cord and adult cells proliferated in an IL-2-dependent assay to a similar extent. Infants suffering acute infection showed marginally higher levels of membrane CD25 expression than infants without overt infection. Thus neonatal and infant lymphocytes express lower levels of IL-2 receptors than adult cells, reflecting lower mRNA concentrations at least for CD25; they are able to up-regulate receptors in response to in vitro stimulation and are able to respond in vitro to IL-2-dependent stimulation; however in vivo there may be a dampening down of the IL-2 system in infancy.

Somatic mutation of immunoglobulin V(H)6 genes in human infants.

Infants respond to antigen by making antibody that is generally of low affinity for antigen. Somatic hypermutation of immunoglobulin genes, and selection of cells expressing mutations with improved affinity for antigen, are the molecular and cellular processes underlying the maturation of antibody affinity. We have reported previously that neonates and infants up to 2 months of age, including individuals undergoing strong immunological challenge, show very few mutated V(H)6 sequences, with low mutation frequencies in mutated sequences, and little evidence of selection. We have now examined immunoglobulin genes from healthy infants between 2 and 10 months old for mutation and evidence of selection. In this age group, the proportion of V(H)6 sequences which are mutated and the mutation frequency in mutated sequences increase with age. There is evidence of selection from 6 months old. These results indicate that the process of affinity maturation, which depends on cognate T-B cell interaction and functional germinal centres, is approaching maturity from 6 months old.

Medical student education in paediatrics and child health: where are we going?

In most undergraduate medical curricula, learning is becoming less content based and the emphasis is changing to problem based learning, continuing self directed learning, and the use of a wide range of learning resources. Particular needs in paediatrics and child health are an increasing emphasis on learning in ambulatory care and community based health facilities, and on assessment processes which are formative and reflect the learning objectives appropriately. A wide range of resources is needed for learning at a time when teaching hospital and health system facilities face significant financial restraints.