Cryopyrin-associated periodic syndrome in Australian children and adults: Epidemiological, clinical and treatment characteristics

AIM

Cryopyrin-associated periodic syndromes (CAPS) encapsulate three auto-inflammatory conditions, ranging in severity from mild (familial cold auto-inflammatory syndrome: FCAS), moderate (Muckle-Wells syndrome: MWS) and severe (neonatal onset multi-inflammatory disorder: NOMID). We aimed to describe the epidemiology, clinical features and outcomes of Australian children and adults with CAPS.

METHODS

Patients were identified and clinical data collected through a questionnaire sent during 2012-2013 to clinicians reporting to the Australian Paediatric Surveillance Unit and subscribing to the Australasian Societies for Allergy/Immunology, Rheumatology and Dermatology.

RESULTS

Eighteen cases of CAPS were identified (8 NOMID; 8 MWS, 2 FCAS); 12 in children <18 years of age. The estimated population prevalence of CAPS was 1 per million persons. Diagnostic delay was frequent, particularly in those with milder phenotypes (median diagnostic delay in MWS/FCAS 20.6 years compared with NOMID 2.1 years; P = 0.04). Common presenting features included urticaria (100%), periodic fever (78%), arthralgia (72%) and sensorineural hearing loss (61%). Almost all (90%) MWS patients had a family member similarly affected compared with none in the NOMID group (P = 0.004). A significant proportion of patients on anti-interleukin (IL)-1 therapy (n = 13) no longer had systemic inflammation. Only 50% with sensorineural hearing loss had hearing restored on anti-IL-1 therapy.

CONCLUSIONS

Although CAPS are rare, patients often endured prolonged periods of systemic inflammation. This is despite almost all MWS patients having family members with similar symptoms and children with NOMID presenting with chronic infantile urticaria associated with multi-system inflammation. Hearing loss in NOMID/MWS was frequent, and reversible in only 50% of cases.

Compound heterozygous mutations in the noncoding RNU4ATAC cause Roifman Syndrome by disrupting minor intron splicing

Roifman Syndrome is a rare congenital disorder characterized by growth retardation, cognitive delay, spondyloepiphyseal dysplasia and antibody deficiency. Here we utilize whole-genome sequencing of Roifman Syndrome patients to reveal compound heterozygous rare variants that disrupt highly conserved positions of the RNU4ATAC small nuclear RNA gene, a minor spliceosome component that is essential for minor intron splicing. Targeted sequencing confirms allele segregation in six cases from four unrelated families. RNU4ATAC rare variants have been recently reported to cause microcephalic osteodysplastic primordial dwarfism, type I (MOPD1), whose phenotype is distinct from Roifman Syndrome. Strikingly, all six of the Roifman Syndrome cases have one variant that overlaps MOPD1-implicated structural elements, while the other variant overlaps a highly conserved structural element not previously implicated in disease. RNA-seq analysis confirms extensive and specific defects of minor intron splicing. Available allele frequency data suggest that recessive genetic disorders caused by RNU4ATAC rare variants may be more prevalent than previously reported.

Roifman Syndrome is a rare disorder whose disease manifestations include growth retardation, spondyloepiphyseal dysplasia and immunodeficiency. Here, the authors use whole-genome sequencing to discover that rare compound heterozygous variants disrupting the small nuclear RNA gene RNU4ATAC cause Roifman Syndrome.

Idiopathic systemic capillary leak syndrome in children

Adult subjects with systemic capillary leak syndrome (SCLS) present with acute and recurrent episodes of vascular leak manifesting as severe hypotension, hypoalbuminemia, hemoconcentration, and generalized edema. We studied clinical disease characteristics, serum cytokine profiles, and treatment modalities in a cohort of children with documented SCLS. Six children with SCLS were recruited from the United States, Australia, Canada, and Italy. Serum cytokines from SCLS subjects and a group of 10 healthy children were analyzed. Children with SCLS (aged 5-11 years old) presented with at least 1 acute, severe episode of hypotension, hypoalbuminemia, and hemoconcentration in the absence of underlying causes for these abnormalities. In contrast to what is observed in adult SCLS, identifiable infectious triggers precipitated most episodes in these children, and none of them had a monoclonal gammopathy. We found elevated levels of chemokine (C-C motif) ligand 2 (CCL2), interleukin-8, and tumor necrosis factor α in baseline SCLS sera compared with the control group. All patients are alive and well on prophylactic therapy, with 4 patients receiving intravenous or subcutaneous immunoglobulins at regular intervals. The clinical manifestations of pediatric and adult SCLS are similar, with the notable exceptions of frequent association with infections and the lack of monoclonal gammopathy. Prophylactic medication, including high dose immunoglobulins or theophylline plus verapamil, appears to be safe and efficacious therapy for SCLS in children.

Baked egg food challenges - clinical utility of skin test to baked egg and ovomucoid in children with egg allergy

BACKGROUND

Many children with IgE-mediated egg allergy can tolerate products containing extensively heated (baked) egg. Aside from food challenge, there are no tests which reliably predict tolerance to baked egg in egg-allergic individuals.

OBJECTIVES

To determine if skin prick test (SPT) to baked egg (muffin) and ovomucoid can predict the outcome of baked egg challenges in egg allergic patients.

METHODS

In this prospective study, children with a recent history of immediate allergic reactions to egg [and corroborative positive SPT or serum-specific IgE (ssIgE) to egg] or those with SPT/ssIgE > 95% PPV for egg allergy were invited to undergo an open standardized baked egg (muffin) challenge. SPT to egg white, ovomucoid, and fresh muffin were performed immediately prior to challenge.

RESULTS

One hundred and forty-three egg allergic children underwent baked egg challenge and of these, 90 (63%) tolerated 1 g of egg protein in a baked muffin. Of the 53 positive challenges, eight (15%) had respiratory and/or cardiovascular symptoms. The median SPT diameters in positive challenges compared with negative challenges were baked muffin - 6.0 mm/4.0 mm and ovomucoid 7.5 mm/5.0 mm respectively. Receiver operating characteristic (ROC) curves were generated for SPT to baked egg and ovomucoid. The area under the curve was 0.68 for baked egg, and 0.67 for ovomucoid. A muffin SPT of < 2 mm had a negative predictive value of 88% and an ovomucoid SPT ≥ 11 mm had a positive predictive value of 100%.

CONCLUSIONS AND CLINICAL RELEVANCE

A SPT of < 2 mm to muffin had a high negative predictive value to baked egg challenge. Ovomucoid SPT ≥ 11 mm was very likely to predict a reaction to baked egg. In these children, deferring the challenge would be appropriate.

Detection of chromosomal breakpoints in patients with developmental delay and speech disorders

Delineating candidate genes at the chromosomal breakpoint regions in the apparently balanced chromosome rearrangements (ABCR) has been shown to be more effective with the emergence of next-generation sequencing (NGS) technologies. We employed a large-insert (7-11 kb) paired-end tag sequencing technology (DNA-PET) to systematically analyze genome of four patients harbouring cytogenetically defined ABCR with neurodevelopmental symptoms, including developmental delay (DD) and speech disorders. We characterized structural variants (SVs) specific to each individual, including those matching the chromosomal breakpoints. Refinement of these regions by Sanger sequencing resulted in the identification of five disrupted genes in three individuals: guanine nucleotide binding protein, q polypeptide (GNAQ), RNA-binding protein, fox-1 homolog (RBFOX3), unc-5 homolog D (C.elegans) (UNC5D), transmembrane protein 47 (TMEM47), and X-linked inhibitor of apoptosis (XIAP). Among them, XIAP is the causative gene for the immunodeficiency phenotype seen in the patient. The remaining genes displayed specific expression in the fetal brain and have known biologically relevant functions in brain development, suggesting putative candidate genes for neurodevelopmental phenotypes. This study demonstrates the application of NGS technologies in mapping individual gene disruptions in ABCR as a resource for deciphering candidate genes in human neurodevelopmental disorders (NDDs).

Safety of food challenges to extensively heated egg in egg-allergic children: a prospective cohort study

BACKGROUND

Many children with IgE-mediated allergy to egg can tolerate egg in baked foods. However, the clinical characteristics and severity of reactions of egg-allergic children who react to baked egg at open food challenge (OFC) are not well defined.

METHODS

Children presenting to our tertiary referral clinic with a diagnosis of egg allergy and following complete egg avoidance in their diet were offered OFC to baked egg. Challenges were performed with incremental dosages to a total of one baked muffin containing 1/6 egg (equivalent to 1 g egg protein) following a standardized protocol. Data were collected prospectively from 2009-2012.

RESULTS

Open food challenge to baked egg were carried out on 236 egg-allergic children who had been strictly avoiding egg in their diet. A total of 150 children (64%) passed and successfully incorporated baked egg into their diet. Eighty-six children (36%) reacted to their challenge. Of these, 12 (14%) experienced anaphylaxis (according to WAO criteria), including four to <100 mg extensively heated egg protein. Intramuscular adrenaline was administered to 5 of the 12 children, one of whom required a second dose due to persistent hypotension. Skin prick testing, asthma, or prior egg anaphylaxis were not predictive of challenge outcome.

CONCLUSION

The majority of children with IgE-mediated allergy to egg were able to tolerate 1 g of baked egg protein, but the outcome of OFC remained unpredictable, and 14% of children who failed OFC reacted with anaphylaxis. We recommend that OFC to baked egg should take place under medical supervision.

Intravenous immunoglobulin to treat severe atopic dermatitis in children: a case series

Severe cases of atopic dermatitis (AD) may require systemic immunosuppression to achieve disease control. Unfortunately, some cases continue to be refractory to management or develop unacceptable adverse effects. There are limited reports of the use of intravenous immunoglobulin (IVIg) in the treatment of severe AD, but results are inconsistent. In a retrospective study, we report 10 children with severe AD refractory to systemic immunosuppression and maximal topical therapy who were treated using IVIg. The children received monthly IVIg for an average of 24 months. This resulted in a significant improvement in symptoms, with fewer infection-related exacerbations and hospitalizations, allowing systemic immunosuppression to be tapered. The effect was associated with a significant decrease in serum immunoglobulin E and was sustained after cessation of IVIg in 50% of cases. No significant side effects attributable to the IVIg infusions were noted. In this cohort of children with severe AD and recurrent cutaneous infections, IVIg provided an effective treatment with minimal side effects and significant benefits in school attendance and quality of life.

Is Roifman syndrome an X-linked ciliopathy with humoral immunodeficiency? Evidence from 2 new cases

Roifman syndrome is a rare syndrome of bone dysplasia, growth retardation, retinal dystrophy and humeral immunodeficiency. Six cases have been reported to date, all of whom are male. We report a boy with clinical features of Roifman syndrome, whose older sister has skewed X-inactivation and a milder phenotype of the same disorder, supporting the hypothesis that this is an X-linked recessive condition. Both children had previously had a provisional diagnosis of Jeune dysplasia, and the boy had neonatal hip X-rays which demonstrated 'acetabular spurs' which are seen in a number of diseases thought to be caused by dysfunction of nonmotile cilia, including Jeune asphyxiating thoracic dystrophy. This finding in combination with other features such as retinal dystrophy, hepatic and renal disease suggests that the gene which is affected in Roifman syndrome may be involved with the function of nonmotile cilia and that Roifman syndrome may be the first example of a ciliopathy with associated immunodeficiency.

Beware the lymphopenia: a case of severe combined immunodeficiency

We present a case of a 2-month-old boy with partially treated meningitis and suspected Pneumocystis carinii pneumonia. A full blood count revealed profound lymphopenia. The child was diagnosed with adenosine deaminase deficiency, a rare cause of severe combined immunodeficiency (SCID). SCID is an immunological emergency and must be considered in any lymphopaenic infant with opportunistic infection. We discuss adenosine deaminase-deficient SCID, which can involve multiple systems and in which other treatment options apart from bone marrow transplant are available.

Chronic urticaria of neonatal onset: a potential sign of autoinflammation

We present a 6 year old boy with chronic urticaria of neonatal onset associated in childhood with features of neurological and joint inflammation. Genetic analysis confirmed the diagnosis of neonatal onset multi-inflammatory disorder (NOMID). Daily subcutaneous anti-IL-1 receptor antagonist therapy resulted in a dramatic and sustained amelioration of systemic inflammation. NOMID must be considered in any child with chronic urticaria of neonatal/infantile onset, particularly if associated with joint and/or neurological inflammation.

Treatment of a case of pediatric hypereosinophilic syndrome with anti-interleukin-5

We report the use of anti-interleukin-5 (mepolizumab) during an 18-month period in a pediatric hypereosinophilic syndrome. Infusions every 3 months allowed better control of hypereosinophilic syndrome flares and maintained blood eosinopenia with significantly less steroid use compared with all other therapies (prednisolone alone, interferon alpha, or imatinib mesylate).

Food protein-induced enterocolitis syndrome: 16-year experience

OBJECTIVE

The goal was to examine the demographic characteristics, causative foods, clinical features, treatments, and outcomes for children presenting with acute food protein-induced enterocolitis syndrome.

METHODS

This was a retrospective study of children with food protein-induced enterocolitis syndrome who presented to the Children's Hospital at Westmead (Sydney, Australia) over 16 years.

RESULTS

Thirty-five children experienced 66 episodes of food protein-induced enterocolitis syndrome. The mean age at initial presentation was 5.5 months. Children frequently experienced multiple episodes before a correct diagnosis was made. Twenty-nine children reacted to 1 food, and 6 reacted to 2 foods. Causative foods for the 35 children were rice (n = 14), soy (n = 12), cow's milk (n = 7), vegetables and fruits (n = 3), meats (n = 2), oats (n = 2), and fish (n = 1). In the 66 episodes, vomiting was the most common clinical feature (100%), followed by lethargy (85%), pallor (67%), and diarrhea (24%). A temperature of <36 degrees C at presentation was recorded for 24% of episodes. A platelet count of >500 x 10(9) cells per L was recorded for 63% of episodes with blood count results. Only 2 of the 19 children who presented to an emergency department with their initial reactions were discharged with correct diagnoses. Additional investigations of food protein-induced enterocolitis syndrome episodes presenting to the hospital were common, with 34% of patients undergoing abdominal imaging, 28% undergoing a septic evaluation, and 22% having a surgical consultation. Prognosis was good, with high rates of resolution for the 2 most common food triggers (ie, rice and soy) by 3 years of age.

CONCLUSIONS

Misdiagnosis and delays in diagnosis for children with food protein-induced enterocolitis syndrome were common, leading many children to undergo unnecessary, often painful investigations. Decreased body temperature and thrombocytosis emerge as additional features of the syndrome.

Immunocompromised children: conditions and infectious agents

Individuals with immunodeficiency, either primary or acquired, are increasingly common. These individuals have increased susceptibility to a range of infections which are uncommon in the normal host. An understanding of the individual's immune defect provides important information about the range of organisms that this individual may be susceptible to. As a corollary, identification of an 'opportunistic pathogen' may indicate the patient's type of underlying immune defect.

Allogeneic bone marrow transplantation with reduced intensity conditioning for chronic granulomatous disease complicated by invasive Aspergillus infection

Chronic granulomatous disease (CGD) is a rare disorder characterized by recurrent infections, often resulting in impaired quality of life and death. Allogeneic BMT provides a definitive cure for CGD, but carries a significant risk of mortality and morbidity. The risk is higher for those who have invasive fungal infection prior to transplant. Reduced intensity conditioning (RIC) is associated with less toxicity from the conditioning agents and may provide an alternative option for all non-malignant diseases. We report a case of successful allogeneic BMT after RIC for a case of X-linked CGD complicated by severe invasive aspergillosis (IA).

Treatment of an infant with X‐linked severe combined immunodeficiency (SCID‐X1) by gene therapy in Australia

OBJECTIVE

To report the outcome of gene therapy in an infant with X-linked severe combined immunodeficiency (SCID-X1), which typically causes a lack of T and natural killer (NK) cells.

DESIGN AND SETTING

Ex-vivo culture and gene transfer procedures were performed at The Children's Hospital at Westmead, Sydney, NSW, in March 2002. Follow-up to March 2005 (36 months) is available.

PATIENT

A 9-month-old male infant with confirmed SCID-X1 (including complete absence of T cells) with an NK+ phenotype (a less common variant of SCID-X1), and no HLA-identical sibling donor available for conventional bone marrow transplantation.

PROCEDURE

CD34+ haemopoietic progenitor cells were isolated from harvested bone marrow and cultured with cytokines to stimulate cellular replication. Cells were then genetically modified by exposure to a retrovirus vector encoding human gamma c (the common gamma chain of several interleukin receptors; mutations affecting the gamma c gene cause SCID-X1). Gene-modified cells (equivalent to 1.3 x 10(6) CD34+/gamma c+ cells/kg) were returned to the infant via a central line.

RESULTS

T cells were observed in peripheral blood 75 days after treatment, and levels increased rapidly to 0.46 x 10(9) CD3+ cells/L at 5 months. Within 2 weeks of the appearance of T cells, there was a distinct clinical improvement, with early weight gain and clearance of rotavirus from the gut. However, T-cell levels did not reach the reference range, and immune reconstitution remained incomplete. The infant failed to thrive and developed weakness, hypertonia and hyperreflexia in the legs, possibly the result of immune dysregulation. He went on to receive a bone marrow transplant from a matched unrelated donor 26 months after gene therapy.

CONCLUSIONS

This is the first occasion that gene therapy has been used to treat a genetic disease in Australia. Only partial immunological reconstitution was achieved, most likely because of the relatively low dose of gene-corrected CD34+ cells re-infused, although viral infection during the early phase of T-cell reconstitution and the infant's NK+ phenotype may also have exerted an effect.

Asthma prevention: breast is best?

Whilst breastfeeding has been considered to exert a preventative effect on the development of allergic disease, several recent publications have challenged this view, particularly with respect to the long-term outcomes for asthma. There are many other beneficial effects of breastfeeding apart from the possibility of allergy prevention. The suggestion that breastfeeding may increase the development of allergic disease raises concerns about the appropriate steps to take for primary prevention of allergy. It is concluded that breastfeeding can still be recommended for the beneficial effects in reducing atopic disease in childhood in addition to the other demonstrated benefits, and that there are unresolved questions concerning the few studies that suggest the possibility of increased allergic disease in later life.

Festschrift for Professor Margaret Burgess AO

In honour of the retirement of our director Margaret Burgess, National Centre for Immunisation Research and Surveillance (NCIRS) held a Festschrift on 5th to 6th February 2004. The themes of the event were Vaccines for the 21st Century and Congenital and Neonatal Infections. International guests attended the Festschrift, as well as over 180 colleagues and co-workers from across Australia. A summary of the presentations over these two fascinating days is provided herein.

Interferon-gamma levels in nasopharyngeal secretions of infants with respiratory syncytial virus and other respiratory viral infections

Respiratory syncytial virus (RSV) infection, one of the most common causes of hospitalization of children in developed countries, has been implicated as a cause of asthma. We aimed to characterize the cytokine profile in nasopharyngeal aspirates (NPAs) taken from infants during upper respiratory tract infection to investigate whether RSV induced a unique immune response as compared with other viruses. Additionally, we sought to determine whether this profile was influenced by the infants' atopic status. A prospective birth cohort of babies at high risk of atopy was recruited. Ratios of a T-helper 1 (Th1) cytokine, interferon gamma (IFN-gamma) and a T-helper 2 (Th2)-like cytokine, interleukin-10 (IL-10), in NPAs were determined during episodes of respiratory tract infections in the first year. The viral aetiology of the respiratory tract infections was determined using polymerase chain reaction (PCR), culture and immunofluorescence. Atopic status was ascertained at 1 year of age using skin prick tests. Participants were recruited antenatally and subsequently followed in the community. Sixty babies with one or both parents atopic were enrolled into the study. IFN-gamma : IL-10 ratios in NPAs during upper respiratory tract infections and their correlation with viral aetiology and atopic status were the main outcome measures. The mean IFN-gamma : IL-10 ratio was significantly lower (due to lower IFN-gamma) during RSV infections than during infections with other viruses (P = 0.035). The cytokine ratio, however, did not differ between infants with or without wheeze during URTIs (P = 0.44), or between infants who were atopic or non-atopic (P = 0.49). This study suggests that RSV is associated with lower IFN-gamma production in young babies, regardless of their atopic status, compared to upper respiratory tract infections where either another virus is detected or where no viral identification is made.

The emergence of resistant pneumococcal meningitis--implications for empiric therapy

BACKGROUND

Following the emergence of penicillin and cephalosporin resistant pneumococcal meningitis in the United States, inclusion of vancomycin in empiric therapy for all suspected bacterial meningitis was recommended by the American Academy of Pediatrics. Few data are available to evaluate this policy.

AIMS

To examine the management and clinical course in relation to antibiotic therapy of a large unselected cohort of children with pneumococcal meningitis in a geographic area where antibiotic resistance has recently increased.

METHODS

Retrospective review of all cases of pneumococcal meningitis in a defined population (Sydney, Australia), 1994-99.

RESULTS

A total of 104 cases without predisposing illnesses were identified; timing of lumbar puncture (LP) was known in 103. Resistance to penicillin increased from 0 to 20% over the study period. Only 57 (55%) had an early LP (prior to parenteral antibiotics); 55 (96%) had organisms on Gram stain. Severe disease (intensive care admission or death) increased significantly from 57 cases with early LP (28%) to 33 with delayed LP (42%) to 13 with no LP (62%). Evidence of pneumococcal infection was available within 24 hours in 85% of those with delayed or no LP. Outcome was not related to empiric vancomycin use, which increased from 5% prior to 1998 to 48% in 1999.

CONCLUSION

LP is frequently delayed in pneumococcal meningitis. Based on disease severity, empiric vancomycin is most justified when LP is deferred. If an early LP is done, vancomycin can be withheld if Gram positive diplococci are not seen.

Congenital annular erythema persisting in a 15-year-old girl

We present a 15-year-old girl who has had a persisting extensive annular erythematous eruption since birth. Otherwise, she is healthy and developmentally normal. Multiple investigations throughout the years have been normal or negative. Numerous treatments have been tried, but with little success. Both clinical and histological examination fit no known classification. It is most consistent with annular erythema of infancy but could be the first reported case of a new entity. A review of other causes of annular erythema in infancy is presented.

Pertussis antibody levels in infants immunized with an acellular pertussis component vaccine, measured using whole-cell pertussis ELISA

A commercially available whole-cell pertussis IgG ELISA was used to test the response of 137 2-month-old infants to immunization with a trivalent acellular pertussis vaccine. The pre-immunization geometric mean (GM) IgG index was 6.96 (95% confidence interval (CI) 5.88-8.04) and the postimmunization GM index was 13.16 (95% CI 12. 20-14.11), P < 0.001. Eighty percent of subjects (110/137) had a significant 1.5-fold increase of pertussis IgG index (97/137, 71%) or a postimmunization IgG index > 10 (93/137, 68%). In single antigen ELISA, 83% showed at least a fourfold increase in pertussis toxin-specific IgG (PT-IgG) and 91% showed an increase in IgG specific for filamentous haemagglutinin (FHA-IgG). Four percent had high pre- immunization antibody levels (index > 20), likely to reflect recent maternal exposure to pertussis. This correlated with a smaller increase in pertussis IgG index. A decline in pertussis IgG index postimmunization occurred in 17/24 infants (71%) whose pre-immunization IgG index was > 10. This postimmunization pertussis IgG index was not significantly different to that of infants with a low pre-immunization index. A similar trend was noted with PT-IgG and FHA-IgG results. The whole-cell ELISA can detect a response to acellular pertussis vaccination in most infants if both antibody index and degree of seroconversion are calculated and at least one criterion is satisfied.

A comparison of IL-2 levels in nasopharyngeal and endotracheal aspirates of babies with respiratory syncytial viral bronchiolitis

BACKGROUND

Cytokines such as IL-2 are thought to be important in the pathogenesis of respiratory tract inflammation. Cytokine levels in nasopharyngeal aspirates (NPAs) have been used as a measure of respiratory inflammation in children with viral infections, but it is unclear whether they reflect levels in the lower respiratory tract.

OBJECTIVE

We sought to assess the correlation between IL-2 levels in the nasopharyngeal and endotracheal secretions of children intubated with respiratory syncytial virus (RSV)-positive bronchiolitis.

METHODS

NPA and endotracheal aspirates were collected concurrently from intubated infants with RSV-positive bronchiolitis. IL-2 levels were assayed by ELISA, and the results were compared according to collection site.

RESULTS

Nine paired specimens were collected. IL-2 levels ranged from 31 pg/mL to 8040 pg/mL. No significant difference was found in the geometric mean IL-2 values from the 2 collection sites. The intraclass correlation coefficient between NPA IL-2 levels and endotracheal aspirate IL-2 levels was 0.83.

CONCLUSION

IL-2 levels in NPAs are comparable with those in the lower respiratory tracts of infants with RSV-positive bronchiolitis. NPA cytokine levels provide a simple and useful means of assessing respiratory tract inflammation.

Repeated prevalence surveys of paediatric hospital-acquired infection

Hospital-acquired infection (HAI) results in an enormous burden of excess morbidity, mortality and cost in both adults and children. Monitoring HAI is difficult, especially with limited resources, but it is vital if infection control measures are to be appropriately implemented and assessed. Cross-sectional prevalence surveys, repeated every six months, have been used effectively to monitor HAI in adults, but this technique has not been previously employed in the paediatric population. We performed prevalence surveys of HAI on a single day once every six months for five years, using a standardized questionnaire. Of the 1623 inpatients surveyed, 125 (7.7%) had HAI and 352 (21%) had community-acquired infection. In those with HAI, central-line infections, pneumonia, and wound infections predominated. A hospital stay of greater than seven days was associated with a sixfold increase in the risk of HAI. In addition, admission to a paediatric or neonatal intensive care unit, the presence of a urinary or vascular catheter, the presence of an endotracheal tube, immunosuppression and recent surgery were all associated with a significantly increased risk of HAI. In contrast to other studies, younger children were not at increased risk of HAI; admission to the neonatal unit, rather than age per se, was associated with increased risk. We conclude that repeated prevalence surveys enable simple and cost-effective assessment of HAI, facilitating appropriate infection control interventions. They should be used more widely in the paediatric setting.

Acyclovir for the prevention and treatment of varicella zoster in children, adolescents and pregnancy

Varicella causes a mild, self-limiting childhood disease that may reactivate years later as shingles. In immunocompromised patients with altered cell mediated immunity, and rarely in healthy individuals, varicella results in a life-threatening infection. The antiviral drug, acyclovir, substantially reduces the mortality and risk of severe disease in these groups of patients. Early commencement of acyclovir is recommended for children with both varicella and altered cell mediated immunity, newborns during the first 2 weeks of life, preterm infants in the neonatal nursery, and severe varicella or shingles (including ocular zoster) in any patient, as well as during pregnancy. Acyclovir may be considered in children with serious cardiopulmonary disease or chronic skin disorders where varicella may exacerbate the underlying disease or increase the risk of secondary bacterial sepsis. Acyclovir, however, is not recommended for healthy individuals without severe disease, as a prophylactic agent against varicella, for asthmatics receiving aerosolized or low-dose oral steroids and/or as treatment of the post-varicella syndromes. When acyclovir is prescribed it should be given intravenously to those with severe disease, those at risk of dissemination and in children younger than 2 years of age.

"On the spot' vaccination: does it work?

OBJECTIVE

To trial and evaluate a system of "on the spot' vaccination for children up to the age of 15 years in the Early Childhood Centres of the Central Sydney Area Health Service, at the Royal Alexandra Hospital for Children and in a number of general practices in the area.

METHODOLOGY

A brief questionnaire was used to collect data from parents and health care professionals about the child's vaccination status and vaccines given "on the spot'.

RESULTS

Over an 8 week period in August-September 1993, 5162 questionnaires were completed; 71% of children were up to date with their vaccination. If Haemophilus influenzae type b vaccine, which had been introduced only 2 months before commencement of the study, was excluded, 84% of the children were up to date. A total of 441 children were given 663 vaccinations "on the spot'. Very few children were too ill to be vaccinated (6%). However, only 30% of those who needed vaccination "on the spot' actually received it (441 of 1480), and only 41% (24 of 58) of a subset of those who were not vaccinated were known to have complied 1 month later. Children attending Early Childhood Centres were younger than children attending general practices or the hospital.

CONCLUSIONS

A high proportion of children who attended for routine or acute health care had vaccinations overdue (30%). If this scheme could be continued and expanded it would have an important impact on vaccination coverage, and hence on the incidence of vaccine-preventable diseases.

Radioimmunoassay for the detection of active-site specific thrombin inhibitors in biological fluids. I. Assay characteristics and quantitation of recombinant hirudin

A sensitive radioimmunoassay (RIA) for the quantitation of recombinant (r) hirudin in biological fluids is described. Taking advantage of the highly specific hirudin-thrombin interaction, a monoclonal antibody to human alpha-thrombin was used to capture hirudin-thrombin complexes in a competitive binding assay. Quantitation of r.hirudin in buffer, plasma or urine at concentrations ranging from 0.17 to 20 ng/ml (1.7 x 10(-3) to 2 x 10(-2) antithrombin units/ml) was achieved. In the absence of competing unlabelled r.hirudin the assay also measured alpha-thrombin (from 2 x 10(-4) to 1 x 10(-2) NIH units/ml) in citrated or defibrinated human plasma. A series of peptides corresponding to the carboxyl-terminal region of hirudin and with varying anticoagulant activities did not displace 125I-r.hirudin in the RIA described, confirming published data that these hirudin fragments bind to a site distant to the catalytic site of thrombin. The assay was used to test hirudin clearance after bolus i.v. injections of 0.1 mg r.hirudin [Val1-Val2] into human volunteers. The plasma concentrations and elimination kinetics of r.hirudin were in good agreement with published data and a close correlation between hirudin plasma concentration and prolonged clotting time was observed.