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Objective: There are conflicting reports as to whether breastfed infants respond with higher antibody levels to conjugate Haemophilus influenzae type b (Hib) vaccine compared with formula-fed infants. These observations prompted us to investigate the effect of feeding method on the antibody concentration to Hib polyribosylribitol (PRP) both prior to and 3 months after the primary course of immunisation with Hib (PRP-OMP)., Methods: We measured plasma concentrations of IgG antibody to Hib PRP by enzyme-linked immunosorbent assay in blood samples from a total of 272 breastfed and formula-fed infants prior to immunisation (7 weeks of age, n = 82 and n = 148, respectively) and again 3 months after completion of the primary course of immunisation with Hib PRP-OMP (7 months of age, n = 88 and n = 132, respectively)., Results: Breastfeeding was associated with lower plasma antibody titres at both times (P < 0.01, T-test) with 49% of breastfed infants having anti-PRP concentrations below 1.0 microg/mL at age 7 months. There was no reported invasive Hib disease in this cohort of infants, and nationally the effectiveness of the Hib vaccination programme remains high., Conclusions: These data suggest that breastfeeding may be associated with immunomodulation of infant Hib immunisation responses with this immunisation regime. Further research is needed to determine whether differences in antibody concentration described here are primarily determined by factors directly attributed to breastfeeding or whether other environmental factors may play a significant role.

Objective: The aim of this study was to determine the site, extent, and resolution of tissue involvement when extensive limb swelling occurred in the injected limb for children who received diphtheria-tetanus-acellular pertussis or reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine at 4 to 6 years of age., Methods: Children who had experienced an injection site reaction at 18 months of age were assigned randomly to receive an intramuscular injection of either reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine or diphtheria-tetanus-acellular pertussis vaccine between 4 and 6 years of age. Children who developed extensive limb swelling were recruited for assessment by clinical examination; ultrasound studies of the affected and opposite (control) arms were performed 24 to 48 hours after immunization and 48 to 96 hours later., Results: Twelve children with extensive limb swelling were enrolled in the study. Ultrasound examinations demonstrated swelling of both the subcutaneous and muscle layers of the vaccinated arm. Ultrasound assessment showed that the swelling exceeded the clinical measurements of skin redness and swelling. Subcutaneous and muscle tissues expanded to 281% and 111% of the tissue thicknesses of the control arm, respectively. Repeat ultrasound examinations after 48 to 96 hours showed considerable resolution of muscle swelling, compared with subcutaneous tissue swelling. There was no significant difference in the extent of swelling detected between children who received diphtheria-tetanus-acellular pertussis vaccine and those who received reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine., Conclusion: Extensive limb swelling reactions after diphtheria-tetanus-acellular pertussis or reduced-antigen content booster immunizations involved swelling of subcutaneous and muscle tissues with swelling and duration more marked in subcutaneous tissue.

The aim of this 12-month prospective study was to compare reports describing the health-related quality of life (HRQL) of children with Juvenile idiopathic arthritis (JIA) obtained from parents and children, to investigate the extent to which the children's HRQL changed over a 12-month period, and to describe the relationship between children's HRQL, and their experience of pain and use of pain coping strategies. Fifty-four children aged 8-18 years with JIA and their parents completed standard questionnaires assessing children's HRQL, pain intensity, and pain coping strategies at baseline, 6 months, and 12 months. In general, children reported that their HRQL was better than was reported by parents. Both informants described children's HRQL as being very stable over the 12 months of the study. Consistent with the Biobehavioural Model of Pain, there was a significant negative relationship between children's HRQL and their experience of pain. However, there was little evidence that pain coping strategies mediated the relationship between children's experience of pain and their HRQL.

Haemophilus influenzae type b (Hib) is a pathogenic gram-negative bacterium associated with human disease, especially in young children. Protective immune response to Hib results from antibodies developed against the polyribosylribitol phosphate (PRP) capsular polysaccharide of the bacterium. Several investigators in the study of immune response to Hib have produced human monoclonal antibodies to PRP. Only two previous groups have reported the generation of murine anti-PRP monoclonal antibodies using either immunizing mice with inactivated Hib bacteria or a combination of in vivo and in vitro immunization of mice with PRP conjugate antigen (PRP-D). In this present study, we generated murine anti-PRP monoclonal antibody secreting hybridomas for the first time by simple in vivo immunization with PRP conjugate antigen (PRP-T). The anti-PRP antibodies from one hybridoma clone (B10) are further characterized and potential applications are discussed.

The increasing array of strategies and models for improving clinical practice and patient outcomes can be confusing for clinicians. The Clinical Support Systems (CSS) model has proved to be effective in local environments because it demystifies the design and implementation of evidence-based practice improvement projects. The CSS model is simple and has a wide scope. It provides a broad framework with minimalist specifications, enabling clinicians to design their own systems of care that cut across fragmented organisational structures. Implementing simple rules can be an effective strategy for change in complex care systems. These rules do not impose solutions on clinicians, but rather, help them to find creative solutions that have meaning for them and are contextually relevant.

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.

Cell separation techniques are important in immunology. Major cell populations can be separated successfully with high purity. However, isolation of cells which are specific for particular antigens is more challenging because of the relatively small numbers of antigen-specific cells, and the lack of independent markers available to determine the purity of the isolated population. In this review, the literature describing three principal techniques used to separate antigen-specific cells has been reviewed. Particular emphasis has been placed on yield and purity; the two most important parameters of any purification method. The most promising isolation methods have used immunomagnetic sorting and multiparametric flow cytometric analysis.

IgG antibody can specifically suppress the antibody response to antigen. This has been explained by the hypothesis that signaling through the B cell antigen receptor is negatively modulated by the co-ligation of immunoglobulin with the receptor for IgG, FcgammaRIIb. We hypothesized that inhibitory signaling through FcgammaRIIb would be counter-productive in germinal center cells undergoing selection by affinity maturation, since these cells are thought to receive a survival/proliferative signal by interacting with antigen displayed on follicular dendritic cells. We have identified and characterized a population of B lymphocytes with low/negative FcgammaRIIb expression that are present in human tonsil. Phenotypically these cells correspond to germinal center B cells and comprise both centroblast and centrocyte populations. In examining expression at the molecular level we determined that these B cells do not express detectable mRNA for FcgammaRIIb. We examined several culture conditions to induce expression of FcgammaRIIb on germinal center cells but could not determine conditions that altered expression. We then examined the functional consequence of cross-linking membrane immunoglobulin and the receptor for IgG on human B lymphocytes. Our results cast some doubt on the value of anti-IgG as a model for antigen-antibody complexes in studying human B cell regulation.

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.

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.

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.

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.

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.

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.

The antibody response in the young infant is limited in several ways; in particular, responses generally are of low affinity and restricted to IgM. This raises the question whether the affinity maturation process, consisting of somatic mutation of immunoglobulin genes coupled with selection of high-affinity variants, is operative in the neonate. Re-arranged V(H)6 genes were amplified by polymerase chain reaction (PCR) from cord blood and from peripheral blood of infants. Heteroduplex analysis detected mutation in only 2/18 cord blood samples, while mutations were seen from about 10 days of age onwards. Cloning and sequencing of mutated neonatal V(H)6 genes showed that mutated sequences contained relatively few mutations (one to three mutations per sequence) compared with published values of about 10 in adult IgM sequences. Selection was not evident in the majority of neonatal samples. Thus mutation can occur in the human neonate, but is minimal and generally not accompanied by selection. The age at which affinity maturation develops effectively is yet to be defined.

The neonatal immune system responds to a restricted range of antigens, producing largely IgM antibody of low affinity. Comparison of the components of the B-cell antigen receptor complex shows significantly elevated membrane levels of IgM in neonatal B cells, compared with adult cells. CD79, which acts as the signal transducer for membrane immunoglobulin, is elevated in parallel with IgM, while IgD is elevated to a lesser degree. CD19, CD21, CD22 and CD81, which are all involved in transmitting activation signals when immunoglobulin is engaged, are not elevated. CD32, which is involved in negative regulation of activation, is present at reduced levels on cord B cells. The elevation of B-cell membrane IgM persists during infancy. Neonatal B cells respond in vitro to interleukin-4 (IL-4) by further elevation of membrane IgM levels. The elevated level of membrane IgM may make neonatal B cells easier to trigger by low concentrations of antigen, but in vitro activation and immunoglobulin modulation experiments did not show significant differences between cord and adult B-cell responses to anti-IgM.

The expression of CD95 antigen was examined on adult and cord blood lymphocytes using a highly sensitive immunofluorescence/flow cytometric procedure. CD95 was expressed by the majority of circulating blood T cells in adults, and by a smaller proportion of CD4+ and CD8+ T cells in cord blood. The majority of circulating B cells did not react with seven CD95 antibodies, but three antibodies did stain B cells. In tonsil sections, CD95 was expressed throughout the tissue but germinal centres showed generally stronger staining than the surrounding follicular mantle and interfollicular areas. This was confirmed by flow cytometry, which showed expression preferentially on B cells with a germinal centre phenotype. Because different antibodies stained different proportions of B cells, CD95 epitopes were examined by inhibition, additive binding and protease susceptibility studies using a panel of ten CD95 antibodies. B cells apparently reacting selectively with CD95 antibodies were sorted and CD95 mRNA was reverse transcribed to cDNA and analyzed, in order to confirm the presence of CD95 in cells which reacted selectively and to explore the possible existence of CD95 isoforms. The major cDNA band was identical in the two populations. Inhibition of N-glycosylation suggested that the epitopes detected differentially could not be accounted for by differential N-glycosylation.

Objective: Although Pneumocystis carinii pneumonia (PCP) is known to occur in adults with systemic lupus erythematosus (SLE), this infection has rarely been described in childhood SLE. We describe 3 children with SLE who developed PCP and describe risk factors for this complication., Methods: A retrospective case review., Results: All 3 children had severe active SLE with organ involvement requiring immunosuppressive therapy, but the clinical presentations of PCP differed in each patient. They shared some of the known risk factors for opportunistic infection in adults with SLE, including lymphopenia, but severe lymphopenia (< 0.35 x 10(9)/1) was not seen., Conclusion: PCP is an uncommon but serious complication of childhood SLE, and should be considered in the presence of respiratory symptoms, however subtle. The role of oral chemoprophylaxis is discussed.

Objective: To describe the course of juvenile psoriatic arthritis (JPsA) defined by the "Vancouver Criteria.", Methods: A retrospective review of JPsA in 63 children, (44 girls, median age at onset 4.5 yrs; 19 boys, median age at onset 10.1 yrs) who fulfilled the Vancouver Criteria, as follows. Definite JPsA: arthritis with psoriasis, or arthritis with 3 of 4 minor criteria (nail pits, dactylitis, psoriasis-like rash, family history of psoriasis); probable JPsA: arthritis with 2 of the minor criteria., Results: At last followup, 50 children had definite JPsA and 13 had probable JPsA. Rheumatoid factor was absent in all; antinuclear antibody was present in 50%. Thirty-eight children were followed for > 5 yrs, 18 for > 10 yrs, and 7 for > 15 yrs. Forty-four children had active arthritis; 32% were in functional class I, 38% in class II, 22% in class III, and 8% in class IV. Of the 46 patients with oligoarticular onset, 21 remained oligoarticular, and 25 became polyarticular. Arthritis in the small joints of the hands and feet increased in frequency, with arthritis eventually occurring in proximal interphalangeal joints in 63%, metacarpophalangeal or metatarsophalangeal joints in 55%, and distal interphalangeal joints in 27%. Dactylitis occurred in 35%, most commonly in 2nd toes and index fingers. Nine patients (14%) developed chronic anterior uveitis. Eleven of 24 patients (46%) who initially had probable JPsA evolved to definite JPsA after a median of 2.1 yrs. Five developed psoriasis and the remainder developed additional minor criteria. The 13 patients with a current diagnosis of probable JPsA did not differ significantly from the 50 patients with definite JPsA with respect to number of joints involved at onset or during the disease course. Patients with psoriasis (n = 41) did not differ from those with definite JPsA without psoriasis (n = 9) with respect to the number of joints involved at onset or during the disease course, functional class, or need for 2nd line therapy., Conclusion: JPsA defined by the Vancouver Criteria is a relatively common chronic arthropathy of childhood that differs clinically, serologically, and genetically from both juvenile rheumatoid arthritis and juvenile ankylosing spondylitis.

Most countries have active vaccination programmes for children aged two months and older. It is likely that many children presenting for medical procedures which require general anaesthesia have been vaccinated recently. Although there is no evidence suggesting increased risks associated with anaesthetizing recently vaccinated children there are many theoretical reasons why this situation needs critical assessment and review. After vaccination there is local swelling and pain at the site of the injection and the most common side effects seen are fever, malaise, headache, rash and myalgia which may last from one day to three weeks. Anaesthesia, stress and trauma are known to suppress the immune system. It is suggested that if possible, children should not be subjected to anaesthesia for elective procedures within two to three weeks after vaccination. Urgent procedures should be managed according to anaesthetic principles which will minimize the effect of anaesthesia on the physiological system affected by the immunization process at the time. Paediatric anaesthesia risk management programmes should include vaccination data to enable the risks of anaesthesia in recently vaccinated children to be analysed.

Mutation of the interleukin-2 (IL-2) receptor gamma chain, which also serves as a component of the receptor complexes for IL-4, 7, 9 and 15, results in severe immune deficiency. We hypothesized that the immunological immaturity of healthy neonates might be associated with low levels of expression of this receptor molecule. Using monoclonal antibody and a highly sensitive immunofluorescence method, we showed that IL-2 receptor gamma chain is expressed at significantly lower levels on cord blood cells compared with adult cells. IL-2-dependent T-cell activation in vitro was reduced in cord blood cells compared with adult cells, but B-cell responses to IL-4 were not obviously impaired. The lower level of expression of the gamma chain and some other cytokine receptor chains may contribute to the immunological immaturity of the newborn, by selectively depressing particular immunological mechanisms.

Objective: To determine the outcomes of bacterial meningitis in school-age survivors., Design: Prospective cohort study., Setting: Teaching pediatric hospital., Children: During 1983 through 1986, 158 meningitis survivors, ages 3 months to 14 years, treated at a single center were enrolled. Between 1991 and 1993, 130 children, 82% of the original cohort, were evaluated at a mean age of 8.4 years and a mean of 6.7 years after their meningitis., Outcome Measures: Blinded neurologic, neuropsychologic, audiologic, behavior, and socio-demographic assessments were compared with those from grade- and sex-matched control children. Multivariate analyses adjusted for age at testing and socio-demographic variables., Results: There was a systematic increase in risk of abnormality or poorer functioning for children with meningitis, compared with control children, across all categories tested, which was significant for fine motor function, Intelligence quotient (IQ) scores, and tests of school behavior, neuropsychologic function, and auditory figure-ground differentiation. Eleven children who had experienced meningitis (8.5%) had major deficits (IQ < 70, seizures, hydrocephalus, spasticity, blindness, or severe to profound hearing loss); a further 24 (18.5%) cases and 14 (10.8%) control children had minor deficits (IQ 70 to 80, inability to read, mild to moderate hearing loss, abnormalities in speech discrimination, or school behavior problems). Overall, children who had meningitis were at greater risk (26.9%) for disability. Children with acute neurologic complications had more adverse outcomes than those with uncomplicated meningitis and control children (39% vs 18% vs 11%, respectively)., Conclusions: One in four school-age meningitis survivors has either serious and disabling sequelae or a functionally important behavior disorder, neuropsychologic or auditory dysfunction adversely affecting academic performance. As a group, survivors function less well than their classroom peers, and risk is greatest for, but not confined to, those who had acute neurologic complications. All survivors require careful follow-up, at least until school age.

We describe 2 HLA-B27 positive children with seronegative enthesopathy and arthropathy (SEA) syndrome who developed spontaneous (nontraumatic) atlantoaxial subluxation early in their disease course. Neither child had evidence of spinal cord compression but both had progressive atlantoaxial subluxation in spite of conservative treatment. Both underwent elective posterior cervical (C1-C2) fusion.

Previous studies have suggested that, in vivo, activated T lymphocytes and neutrophils are important in immunity to nontypable Haemophilus influenzae. We now extend this work by showing that neutrophils pretreated with products of activated T lymphocytes or activated macrophages show significantly enhanced killing of nontypable H. influenzae. Lymphotoxin, a product of activated T lymphocytes, significantly enhanced the neutrophil-mediated killing of nontypable H. influenzae, and tumor necrosis factor, produced by activated T lymphocytes as well as macrophages stimulated by activated T lymphocytes, also significantly increased the bactericidal activity of neutrophils. These cytokine-induced effects were seen with short pretreatment times of neutrophils and were maximal by 30 min. The killing of H. influenzae by neutrophils required the presence of heat-labile opsonins. In the absence of these opsonins, both tumor necrosis factor and lymphotoxin were unable to promote the killing of the bacteria by neutrophils. Furthermore, the results showed that tumor necrosis factor-primed neutrophils displayed significantly increased expression of CR3 and CR4 that was associated with increased phagocytosis of complement-opsonized nontypable H. influenzae. These cytokines may play an important role in immunity toward nontypable H. influenzae by stimulating neutrophil bactericidal activity.

Human breast milk has important immunoprotective and immunosuppressive functions for an infant. The purpose of this study was to extend the phenotype of milk cells and to measure soluble T cell receptor levels and cytokines in milk, and to compare these with neonatal and adult blood. Milk T cells had a more equivalent CD4:CD8 ratio than blood; milk CD4 T cells mainly expressed the CD45RO (antigen primed/memory) phenotype; milk CD8 cells had an equivalent CD11b:CD28 suppressor:cytotoxic phenotype; and milk T cells had 2-3-fold higher percentages of activated CD4 IL-2R and CD8 HML-1 or CD8 VLA-1 cells than blood. Soluble IL-2R, CD4 and CD8 concentrations were lower in milk than adult blood, although relatively increased when compared to the lower T cell concentration in milk. Breast milk contained high levels of IFN-gamma but low levels of other measured cytokines compared to blood. These distinct differences of T cells and their soluble products are likely to influence an infant's immune system.

Immune activity during infancy was investigated using blood samples from 30 neonates and 52 healthy infants between 2 and 15 months of age attending for immunization. The purpose of this study was to assess the total immune activity of T cells using soluble interleukin-2 receptor (IL-2R) and interferon-gamma concentrations. These were compared with the proportion of CD4 CD45RO-, IL-2R (CD25)-, and transferrin receptor (CD71)-positive peripheral blood lymphocytes. The median duration of breast-feeding and of introduction of solid feeds was 4.2 and 4.0 months, respectively. Compared to neonates, the mean +/- SE soluble IL-2R concentration peaked at 4 months of age (1670 +/- 94 vs 3060 +/- 252 U/ml; P < 0.0001), as did pooled interferon-gamma levels. The percentage of CD4 CD45RO T cells remained low and the proportion of activated peripheral blood lymphocytes decreased during infancy. We conclude that noncirculatory immune activity is increased during infancy and this is associated with weaning.

Infection with Mycobacterium avium, M. intracellulare and M. scrofulaceum (MAIS) organisms in normal children may result in cervical lymphadenopathy. There is a poor response to anti-tuberculous therapy and surgical excision of infected nodes is necessary. The diagnosis therefore requires consideration in children with cervical lymphadenopathy. A simple in vitro assay is described which may be useful for diagnosis prior to excision. Whole blood is cultured with M. avium purified protein derivative. After 24 h the plasma is removed and the concentration of gamma interferon (IFN-gamma) quantified by a radioimmunometric assay. In a prospective study of 38 children with neck lesions, 16 showed MAIS organisms isolated from cultures of excised tissue. The level of IFN-gamma produced by peripheral blood lymphocytes from children in the MAIS group was significantly greater when compared with children having operations for neck lesions that were not due to MAIS organisms (P < 0.001).

The humoral and mucosal immune responses to oral immunization with xenogeneic antibodies were studied using an animal model in which female rabbits were fed daily doses of the MOPC-315 murine IgA antibody, and were mated during the course of the feeding programme. Serum and colostrum samples were assayed for the presence of anti-idiotypic antibodies by ELISA assay, before and after depletion of anti-IgA antibodies, by affinity chromatography using another murine IgA idiotype. It was shown that all animals responded to exposure to the MOPC-315 idiotype with the production of serum anti-murine immunoglobulin antibodies and that four of six animals produced serum anti-idiotypic antibodies. That the immune response included antibodies directed against the antigen-binding site was confirmed by competition ELISA assay. Mucosal IgG and IgA anti-immunoglobulin antibodies were present in milk from all antibody-fed rabbits tested, and IgA anti-idiotypic antibodies were detectable in the colostrum of one rabbit. The results provide some support for the hypothesis that human exposure to xenogeneic antibodies, most commonly bovine milk immunoglobulins, may provoke the production of anti-idiotypic antibodies, and that such exposure may lead to disturbances of immune regulation.

Pasteurised and raw bovine milk and bovine colostrum samples were assayed by enzyme-linked immunoassay for the presence of antibodies directed against a selection of allergens of importance in human atopic disease. Samples were tested for the presence of antibodies directed against or cross-reacting with ryegrass pollen, house dust mites, Aspergillus mould and wheat proteins. Antibodies of each specificity were detected in every sample tested, including all samples of commercial pasteurised milk. The results are discussed with reference to a hypothesis that dietary xenogeneic antibodies may play a role in the emergence of some human atopic disease, and the recent demonstration that oral immunisation with xenogeneic antibodies may lead to the production of anti-immunoglobulin antibodies including anti-idiotypic antibodies.

Sixty-seven children with symptomatic IgA deficiency were studied on two separate occasions. Eighteen had aIgAd at presentation, and 49 had pIgAd. IgA concentrations had risen to the normal range for age in 22.2% of children presenting with aIgAd and 77.6% presenting with pIgAd when restudied at a median interval of 3.2 and 3.0 years, respectively. IgG subclass concentrations were measured by enzyme immunoassay in serum samples collected at enrollment from 12 children with aIgAd and 22 children with pIgAd. IgG2 and IgG4 concentrations for these 34 children were below the 5th centile for age and sex more frequently than expected (IgG2: chi square 5.8, P less than 0.025; IgG 4: chi square 18.4, P less than 0.0005). The prevalence of IgG2 deficiency or IgG4 deficiency did not differ significantly between those with aIgAd and those with pIgAd. IgG2 concentrations remained below the 5th centile more frequently than expected when retested in 31 children whose pIgAd had resolved (chi square 4.6, P less than 0.05). Children with aIgAd at presentation had IgG1 and IgG2 concentrations above the 95th centile more frequently than expected (IgG1: chi square 19.7, P less than 0.0005; IgG2: chi square 13.5, P less than 0.001) but this was not seen for IgG3 and IgG4 concentrations. Children with pIgAd did not have elevated IgG1 or IgG2 concentrations at presentation. High IgG1 and IgG2 concentrations in aIgAd may be a compensatory mechanism to afford protection from infection or could be part of a selective secondary response to repeated episodes of infection.

Polymeric IgA (PIgA) and immune complex concentrations in IgA-related renal disease were measured in cross sectional and longitudinal studies to establish the relationship between these parameters and both mucosal infection and renal dysfunction. These studies were performed in 50 patients with IgA nephropathy (IgAN), 17 patients with Henoch Schönlein purpura nephritis (HSPN), 11 control patients with IgA negative, diffuse mesangial proliferative glomerulonephritis (DMPGN) and 50 healthy controls. Total PIgA (PIgAT) and PIgA subclass concentrations were measured using a secretory component binding enzyme immunoassay and isotype specific immune complex concentrations were measured using conglutinin (K) binding immunoassays. In cross sectional studies patients with IgAN were found to have increased concentrations of PIgAT, PIgA1, K-IgA1 and K-IgA2 compared to controls. In the longitudinal studies controls and patients had significant increases in PIgAT and PIgA1 concentrations during infection. However, in patients with IgAN, the increases were greater, persisted for longer, and PIgA2 concentrations were also increased. K-IgA1 and K-IgA2 concentrations increased significantly during episodes of infection in IgAN patients in contrast to controls. Patients with HSPN had results similar to those of IgAN patients. No significant correlation was found between PIgA or K-IgA concentrations, and either serum creatinine concentrations or the degree of hematuria. The results indicate that patients with IgA-related renal disease have abnormal regulation of PIgA and immune complexed IgA, and that these abnormalities are exaggerated during mucosal infection.

Six hundred and eighty two assessments were performed on 641 babies under 6 months of age who presented to the emergency department of the Royal Children's Hospital, Melbourne, to try and determine the best markers of serious illness in young infants. Detailed, specific questions that quantified a baby's functional response to illness gave the most useful information. As a group, the six most common predictive symptoms of serious illness were: taking less than half the normal amount of feed over the preceding 24 hours, breathing difficulty, having less than four wet nappies in the preceding 24 hours, decreased activity, drowsiness, and a history of being both pale and hot. The presence of the corresponding sign on examination increased the predictive value of the symptom by 10-20%. Specific, highly predictive (though less common) signs included moderate to severe chest wall recession, respiratory grunt, cold calves, and a tender abdomen. A list of low, medium, and high risk symptoms has been constructed and the five measurements that were most useful in predicting serious illness in young infants have been detailed.

Total IgG concentrations, IgG antibody concentrations to pooled Escherichia coli antigens, and IgG anti-E. coli antibody avidity were measured in cord and maternal serum samples collected from 52 mother-infant pairs after premature delivery (mean gestational age 28 wk, range 23-33 wk). The mean IgG anti-E. coli antibody concentration in cord serum (1.86 relative units/mL) was markedly lower than in maternal serum (5.42 relative units/mL) at this gestation (p less than 0.0001). Cord serum IgG anti-E. coli antibody concentrations correlated closely with maternal IgG anti-E. coli concentrations when controlled for the effect of gestational age (partial correlation coefficient 0.89; p less than 0.001) but only weakly with gestational age when controlled for maternal IgG antibody concentrations (partial correlation coefficient 0.23; p = 0.06). The mean ratio of cord to maternal IgG anti-E. coli antibody concentrations was considerably lower than the mean ratio for total IgG concentrations (0.34 versus 0.72; p less than 0.001). The mean avidity of IgG antibody for the pooled E. coli antigens was significantly greater in cord serum than in maternal serum (2.45 versus 1.99M; p less than 0.0001). There was a close correlation between cord and maternal antibody avidity (r = 0.70; p less than 0.001), but cord IgG antibody avidity did not correlate with gestational age (r = -0.07; p = 0.61), nor with cord IgG anti-E. coli antibody concentrations (r = 0.10; p = 0.50).(ABSTRACT TRUNCATED AT 250 WORDS)

Concentrations of immunoglobulins and anti-Escherichia coli antibody were studied longitudinally in tracheobronchial aspirates from 33 premature intubated neonates, median gestational age 27 weeks. Aspirates collected at birth contained IgG, IgA, and IgM in 100%, 93%, and 79% of samples, respectively. The median IgA concentration at birth was 0.7 micrograms/mg total protein and increased to 5.8 micrograms/mg protein by the sixth week. IgG and IgM antibodies to E coli were present in 90% and 30%, respectively, of tracheobronchial aspirates collected at birth. Samples from three of 28 neonates (11%) contained IgA anti-E coli antibody at birth, and the proportion with IgA antibody rose to 50% during the sixth week. Secretory component associated IgA and IgM were detectable in samples tested at birth and at 4 weeks of age, and secretory component associated anti-E coli antibody was present in aspirates from three of nine neonates studied at 4 weeks of age, but had not been detectable at birth.

A microassay for human committed progenitor cells (CFU-c) has been developed using 24-well, 16 mm diameter culture dishes. Comparisons were made of simultaneous cultures of 21 samples in both 35 mm and 16 mm culture dishes employing two sources of colony-stimulating factor (CSF). The microassay does not differ significantly from the standard 1 ml 35 mm assay, apart from some enhancement of colony numbers in the 16 mm dish. Other advantages of the microassay are that it is economical with respect to cells, media, and space; and it is possible to increase the number of experiments fivefold which can be performed with the same number of cells.

Human secretory component bound covalently to Sepharose 4B has been used as an affinity adsorbent to isolate and purify polymeric immunoglobulin from cell culture supernatants. The method was used to isolate murine IgM isotype anti-trinitrophenol antibody and rat IgM isotype anti-lymphocyte antibody from hybridoma cell culture supernatants. Gel filtration of the eluted antibodies followed by enzyme immunoassay showed that all recovered IgM was of pentameric molecular size. Murine IgA isotype anti-dinitrophenol antibody and murine IgA anti-human rotavirus antibody were isolated from cell culture supernatants of a plasmacytoma and a hybridoma respectively. Most of the IgA recovered following affinity adsorption with secretory component was of greater molecular size than dimer. Murine IgG was not adsorbed by secretory component bound to Sepharose. Eluted antibody retained antigen binding activity. Affinity chromatography using human secretory component bound covalently to a solid phase provides an antigen-independent technique for purification of murine and rat IgA and IgM polymeric immunoglobulin from cell cultures.

We describe a child with primary defect of polymorph bacterial killing associated with systemic lungs erythematosus. We suggest that her autoimmune disease results from chronic bacterial antigen stimulation and propose a hypothetical model linking immunodeficiency with autoimmunity.