[Respiratory syncytial virus infections and preventive options]. / Infectie met respiratoir syncytieel virus en mogelijkheden voor preventie.

Respiratory syncytial virus (RSV) is the most prominent pathogen found in respiratory tract infections in children and the most important cause of bronchiolitis in the first two years of life. In the Netherlands approximately 2000 children are admitted each winter season. A serious course is mostly seen in children younger than 3 months, (ex-)prematures, children with bronchopulmonary dysplasia or congenital cardiac anomalies, children with cystic fibrosis younger then 2 years and children with impaired T cell immunity; such cases not rarely require intensive care. Treatment (fluid, nutrition, bronchodilator agents, corticosteroids, oxygen and ventilation) is usually symptomatic. Antiviral therapy is only indicated in immunodeficient patients. For prevention by passive immunization palivizumab was recently registered in the Netherlands, a monoclonal antibody against RSV that has to be administered intramuscularly from the start of the RSV season (15 mg per kg bodyweight once a month during five months). In a number of large-scale American multicenter studies both the number of hospital admissions related to RSV infection and the mean duration of hospital stay showed a statistically significant reduction in high-risk children who had been treated with palivizumab. Palivizumab appears to be indicated in children from the categories with an increased risk for serious RSV disease.

Influenza virus serology--a comparative study.

Virus isolation or influenza virus antigen detection are the most rapid tests for diagnosis in the acute stage of influenza virus infection. As serology is easier to carry out, the synthesis of serum IgM, IgA and IgG was studied in two well-defined patient groups, infected with influenza B virus (cohort 1, n = 37) and influenza A virus (cohort 2, n = 40), diagnosed by antigen detection and/or virus isolation within 36 h after onset of symptoms. IgM was found in 13 influenza B patients (35%), IgA in 12 patients (32%), whereas a significant antibody rise was found in 33 patients (92%) by enzyme-linked immunosorbent assay (ELISA) and 74% by haemagglutination inhibition assay (HAI). For the influenza A cohort these numbers were respectively 18 (45%), 27 (68%) and 24 (62%) HAI (72%). In age-matched controls, who were bled on the first day of illness of the enrolled patient low prevalence was found for IgA and IgG, for influenza B respectively in 2 and 18%, and for influenza A in 4 and 39%. Studying the kinetics of the antibody response, we found that virus specific IgA and the bulk of IgG is synthesised within the first week of the infection. It is concluded that the finding of a specific serum IgA is highly indicative of an acute influenza infection.

The spectrum of antecedent infections in Guillain-Barré syndrome: a case-control study.

OBJECTIVE: To determine which antecedent infections are specifically associated with the Guillain-Barré syndrome (GBS). BACKGROUND: Infections with many agents have been reported preceding GBS. Some infections are related to specific clinical and immunologic subgroups in GBS. Most agents were reported in case reports and uncontrolled small series of GBS patients only, and their relation to GBS and its subgroups remains unclear. METHOD: A serologic study for 16 infectious agents in 154 GBS patients and 154 sex- and age-matched controls with other neurologic diseases. Acute phase, pretreatment samples were used from clinically well-defined GBS patients. The seasonal distribution of serum sampling in the GBS and control group was the same. RESULTS: Multivariate analysis showed that in GBS patients, infections with Campylobacter jejuni (32%), cytomegalovirus (13%), and Epstein-Barr virus (10%) were significantly more frequent than in controls. Mycoplasma pneumoniae infections occurred more often in GBS patients (5%) than in controls in univariate analysis. Infections with Haemophilus influenzae (1%), parainfluenza 1 virus (1%), influenza A virus (1%), influenza B virus (1%), adenovirus (1%), herpes simplex virus (1%), and varicella zoster virus (1%) were also demonstrated in GBS patients, but not more frequently than in controls. C. jejuni infections were associated with antibodies to the gangliosides GM1 and GD1b and with a severe pure motor form of GBS. Cytomegalovirus infections were associated with antibodies to the ganglioside GM2 and with severe motor sensory deficits. Other infections were not related to specific antiganglioside antibodies and neurologic patterns. CONCLUSIONS: Recent infections with C. jejuni, cytomegalovirus, Epstein-Barr virus, and M. pneumoniae are specifically related to GBS. The variety of infections may contribute to the clinical and immunologic heterogeneity of GBS.

Risk factors for respiratory syncytial virus associated apnoea.

UNLABELLED: Respiratory syncytial virus (RSV) infections are characterized by upper or lower respiratory tract symptoms including bronchiolitis and pneumonia. Apnoea may be the first sign of disease in children with RSV infection. The aims of this study were the identification of independent risk factors for RSV associated apnoea and the prediction of the risk for mechanical ventilation in children with RSV associated apnoea. Medical records of children younger than 12 months of age admitted with RSV infection between 1992 and 1995 to the Sophia Children's Hospital, were reviewed. Demographic parameters, clinical features and laboratory parameters (SaO2, pCO2 and pH) were obtained upon admission and during hospitalization. Children with and without apnoea were compared using univariate and multivariate logistic and linear regression analysis. One hundred and eighty-five patients with RSV infection were admitted of whom 38 (21%) presented with apnoea. Patients with apnoea were significantly younger, had a significantly lower temperature, higher pCO2 and lower pH and had on chest radiographs also more signs of atelectasis. The number of patients admitted to the ICU because of mechanical ventilation and oxygen administration was significantly higher in children with RSV associated apnoea. Apnoea at admission was a strong predictor for recurrent apnoea. The relative risk for mechanical ventilation increased with the number of episodes of apnoea: 2.4 (95% CI 0.8-6.6) in children with one episode of apnoea (at admission) versus 6.5 (95% CI 3.3-12.9) in children with recurrent episodes of apnoea. CONCLUSIONS: Age below 2 months is the strongest independent risk factor for RSV associated apnoea. Apnoea at admission increases the risk for recurrent apnoea. The risk for mechanical ventilation significantly increases in children who suffer from recurrent apnoea.

Transmission of hepatitis B virus among heart transplant recipients during endomyocardial biopsy procedures.

BACKGROUND: The unexpected conversion to HBsAg seropositivity of three cardiac allograft recipients prompted us to conduct a multidisciplinary study to identify the source, transmission mode, and extent of the hepatitis B virus (HBV) infection among the 256 cardiac allograft recipients of our hospital. METHODS: All recipients were retrospectively screened for serum markers of HBV infection. A selected genomic region defining subtypes of the viruses involved was amplified and sequenced. An epidemiologic case-control study for possible risk factors was conducted to identify the mode of transmission. RESULTS: Eighteen additional HBV-infected patients were identified, none of whom had shown symptoms of HBV infection. The involvement of one virus (subtype ayw 3) was shown in 20 of the 21 HBV-infected patients. This virus is found in less than 10% of HBV-infected individuals in The Netherlands. The demonstration of a common source of infection, combined with results of the epidemiologic study, identified posttransplantation endomyocardial biopsy procedures as the most likely mode of transmission. However, we also found evidence of secondary virus transmission by cardiac catheterization procedures to nonallograft recipients. CONCLUSIONS: The immunosuppressive therapy practiced in these patients to prevent allograft rejection may have not only facilitated virus transmission by causing high levels of viremia but also left the spreading of HBV undetected by causing a subclinical course of the infection. These findings stress the necessity of strict hygienic precautions during intravascular diagnostic procedures and indicate that vaccination against and routine monitoring for certain bloodborne infections in cardiac allograft recipients should be considered.

Respiratory syncytial virus specific serum antibodies in infants under six months of age: limited serological response upon infection.

The decline of maternal respiratory syncytial virus (RSV) specific serum antibodies was studied in 45 children during the first 6 months of life, using a virus neutralization assay and competition ELISAs measuring fusion protein and glycoprotein specific antibodies. In all children RSV neutralizing antibodies were demonstrated at birth, with titers ranging from 33 to 1382. The calculated mean half life of these antibodies was 26 days. Furthermore, in a group of 38 children with suspected RSV infection, all younger than 6 months of age on admission, the diagnostic value of serological assays was evaluated. In 32 children RSV infection was confirmed by virus isolation, direct immune fluorescence and RT-PCR. In 7 patients of this group a significant titer rise in virus neutralization assay was demonstrated. Six additional RSV infected children could be identified by showing the presence of RSV-specific IgM or IgA serum antibodies or by showing an increase in fusion protein or glycoprotein specific antibodies. All serological tests together identified 13 (41%) of the 32 RSV infected patients. It is concluded that in children of this age group, which represent the majority of patients hospitalized with RSV infections, serological assays not only have a limited diagnostic value but are of limited value for sero-epidemiological studies.

Local variability in respiratory syncytial virus disease severity.

Respiratory syncytial virus (RSV) lower respiratory tract infections are considered to be a serious disease in centres such as the Sophia Children's Hospital (Rotterdam, the Netherlands), but as more benign infections in others such as the Geneva Children's Hospital (Switzerland). To assess the clinical severity of RSV infections at the two sites, 151 infants primarily admitted with a virologically confirmed RSV infection were studied prospectively (1994-5) and retrospectively (1993-4) (55 infants in Geneva and 96 in Rotterdam). Parameters of RSV morbidity which were more severe in Rotterdam during the two winter seasons were apnoea (1.8 v 23.9%), the rate of admission to the intensive care unit (3.6 v 28.1%), mechanical ventilation (0 v 7.3%), and length of stay in hospital (6.8 v 9.1 days). In Geneva higher respiratory rates (59.2 v 51.2), more wheezing (65.5 v 28.8%), and more retractions (81.8 v 63.3%) were recorded. Fewer infants younger than 4 months (54.9 v 68.7%), but more breast fed infants (94.1 v 38.5%), were admitted in Geneva, although the morbidity parameters remained different after correction for these two variables in multivariate analyses. Thus unidentified local factors influence the pattern and severity of RSV infection and may affect the results of multicentre prophylactic and therapeutic studies.

[Indications for influenza vaccination in children with lung disorders. Dutch Association for Pediatric Medicine]. / Indicaties voor influenzavaccinatie bij kinderen met longaandoeningen. Nederlandse Vereniging voor Kindergeneeskunde.

The Dutch Association for Paediatric Medicine has formulated guidelines regarding influenza vaccination of children with pulmonary disease. Influenza virus is the most frequent cause of airway infections in humans over two years of age. It may lead to serious morbidity in children with pulmonary disease: exacerbations, (transient) disturbances in pulmonary function, and symptoms lasting weeks, but mortality is probably very low. The effects of influenza vaccination of children with pulmonary disease are similar to those in normal healthy children. A positive long-term effect on the asthma has never been demonstrated. It is advised that children with moderate to severe asthma who require treatment to be vaccinated against influenza every year. If the first vaccination ever occurs before the age of six years, it should be followed by a booster vaccination after four weeks. In both instances, a full vaccination dose should be administered.

Prevalence and risk factors for hepatitis B virus infections among visitors to an STD clinic.

OBJECTIVE: To determine the prevalence and risk factors for hepatitis B virus (HBV) infections among individuals attending an STD clinic in a low endemic region. STUDY DESIGN: A total of 1228 women and 1648 men attending the STD clinic at the University Hospital Rotterdam, Netherlands, were examined for HBV infection by determination of hepatitis B surface antigen (HBsAg) and antibodies to hepatitis B core antigen (anti-HBc). Demographic characteristics, information on sexual behaviour, and intravenous drug use were recorded. RESULTS: The seroprevalence of HBsAg was 1.4% in women and 2.1% in men (0% in homosexual men). The seroprevalence of anti-HBc was 13% in women and 20% in men (36% in homosexual men). Native country, intravenous drug use, a history of STD, and the number of partners in the past half year (inversely) were independent risk factors for HBsAg positivity in women and heterosexual men. For anti-HBc independent associations were observed for native country, age, intravenous drug use, commercial sex, number of lifetime partners, homosexual contacts, orogenital contact (inverse), and a history of STD. CONCLUSION: The HBV prevalence in the STD clinic attendants was high, exceeding the national estimate, and indicates that the STD clinic population may be considered a high risk group. Our data confirmed an increased risk for HBV infections among established risk groups. Therefore, these risk groups should be routinely screened to identify HBV cases for counselling and contact tracing.

Adjuvancy and reactogenicity of N-acetylglucosaminyl-N-acetylmuramyl-dipeptide (GMDP) orally administered just prior to trivalent influenza subunit vaccine. A double-blind placebo-controlled study in nursing home residents.

One hundred and fifty-three nursing home residents received 0, 5, 25 or 50 mg N-acetylglucosaminyl-N-acetylmuramyl-dipeptide (GMDP) orally, and trivalent influenza subunit vaccine intramuscularly. One day after intervention, there was a strong increase of total leucocytes, monocytes and neutrophils in the groups receiving 25 or 50 mg GMDP. A GMDP dose dependent increase in systemic, but not in local, vaccine side-effects was observed. No significant differences in post-vaccination haemagglutination inhibiting serum antibody titres were observed between the four groups, indicating that oral administration of GMDP together with influenza vaccination, does not lead to a higher vaccine efficacy.

Relationship between clinical severity of respiratory syncytial virus infection and subtype.

The relationship between clinical severity of respiratory syncytial virus (RSV) infection and distribution of subtype A or B was investigated. The data of 232 children, who were admitted with RSV infection or diagnosed in the outpatient department of the Sophia Children's Hospital, Rotterdam between 1992 and 1995, were studied. The diagnosis of RSV was confirmed by a direct immunofluorescence assay. Subtyping was performed by an indirect immunofluorescence assay using specific monoclonal antibodies. Gender, age at diagnosis, gestational age and birth weight, the presence of underlying diseases, feeding difficulties, the presence of wheezing and retractions, respiratory rate, temperature, clinical diagnosis at presentation, oxygen saturation (SaO2), carbon dioxide tension (PCO2), and pH, characteristics of hospitalisation, and the need for mechanical ventilation were observed. Analysis was performed on data from all patients diagnosed with RSV infection in the period between 1992 and 1995 spanning three RSV seasons, and separately on the RSV season 1993-4. The outcome of the three year analysis (150 (64.7%) subtype A v 82 (35.3%) subtype B) was compared with the outcome of the season 1993-4, a mixed epidemic with 37 (60.7%) subtype A and 24 (39.3%) subtype B isolates. None of the variables observed in the season 1993-4 differed significantly between RSV subtype A and B. Similar results were obtained from the analysis in the period 1992 until 1995, with the exception of PCO2 (a higher PCO2 was found in subtype A, p < 0.001) and retractions (more retractions were noted in patients with subtype A, p = 0.03). After correcting for possible confounders using regression analysis, these differences were not significant anymore. The data indicate that there is no relationship between clinical severity of RSV infection and subtype.

Diagnostic assays in cytomegalovirus retinitis: detection of herpesvirus by simultaneous application of the polymerase chain reaction and local antibody analysis on ocular fluid.

AIM: To determine the value of the polymerase chain reaction (PCR) technique and the analysis of intraocularly produced antibodies by calculating a Goldmann-Witmer quotient (GWq) as diagnostic assays in the confirmation of a clinically diagnosed cytomegalovirus (CMV) retinitis in a group of unselected AIDS patients. METHODS: Eleven samples of undiluted ocular fluid, obtained from nine AIDS patients with a clinically diagnosed CMV retinitis were analysed for the presence of genomic DNA from CMV, HSV-1, VZV, and EBV by PCR. Nine of these samples were analysed for the presence of locally produced IgG antibodies against these herpesviruses by calculating a GWq. Ten samples obtained from patients with various entities of clinical non-herpetic uveitis and 17 samples of aqueous humour obtained at cataract surgery were used as controls. RESULTS: In 10 out of 11 samples from AIDS patients (91%) the presence of CMV DNA was demonstrated. In four out of nine (44%) patients this was accompanied by CMV DNA in the blood indicating a CMV viraemia. In one sample, VZV DNA was detected and in another sample both CMV and VZV DNA were detected. No HSV-1 or EBV DNA could be demonstrated in these 11 samples. In contrast, simultaneous analysis of locally produced IgG antibodies against herpesviruses could not confirm the initial diagnosis of CMV retinitis. Ocular fluid samples obtained from 10 control uveitis patients were negative for DNA from CMV, VZV, and EBV by PCR. In one of 10 uveitis control samples HSV-1 DNA was detected; antibody analysis did not confirm this. In the uveitis control group, a significant GWq was calculated in one sample for HSV-1 and in another sample for VZV. The cataract control samples were all herpesvirus DNA negative by PCR. CONCLUSIONS: To establish the diagnosis of CMV retinitis in AIDS patients, ophthalmoscopic examination is a sensitive method. In confirming a diagnosis in indistinctive cases, application of a PCR assay detecting CMV DNA is a more sensitive method than analysis of locally produced antibodies by calculating a GWq. In clinical non-herpetic uveitis, secondary release of HSV-1 and VZV should be considered requiring additional therapeutic anticipation.

Successful treatment with ganciclovir of presumed Epstein-Barr meningo-encephalitis following bone marrow transplant.

Epstein-Barr virus-specific polymerase chain reaction was used to diagnose EBV-meningo-encephalitis in a bone marrow transplant recipient. The patient made complete recovery with ganciclovir treatment. Pitfalls in diagnosis with EBV-PCR and the potential therapeutic efficacy of ganciclovir in EBV infections are discussed.

Sense and nonsense of influenza vaccination in asthma and chronic obstructive pulmonary disease.

Although influenza is generally seen as an important cause of excess mortality in patients with asthma or chronic obstructive pulmonary disease (COPD), this mortality is nearly exclusively present in patients over the age of 60. Morbidity in patients with asthma or COPD is related to respiratory infections, including influenza. Vaccination against influenza has proven to be effective in nursing home populations, decreasing both mortality and morbidity during epidemics of influenza A. In younger patients with asthma or COPD, however, the effect of vaccination is more ambiguous. Exacerbation of respiratory disease is not due to influenza vaccination (except in allergy to chicken protein), from which we can conclude that influenza vaccination is a safe method to prevent a potentially serious respiratory infection in patients with asthma or COPD.

Detection of respiratory syncytial virus by RNA-polymerase chain reaction and differentiation of subgroups with oligonucleotide probes.

The polymerase chain reaction (RNA-PCR) was used for specific detection of respiratory syncytial virus (RSV) genomes in clinical specimens. A set of primers was selected from conserved regions of the 1B and N genes for detection of both subgroups. The primers were found to be RSV specific, all RSV strains generated a 218 bp product, and no RSV specific amplified product was obtained when nucleic acids from a variety of micro-organisms from the respiratory tract were subjected to the RNA-PCR. We took advantage of the sequence heterogeneity of the amplified products to discriminate between the A and B strains by hybridisation with subgroup specific oligonucleotide probes. This additional hybridisation assay increased the sensitivity of the RNA-PCR tenfold. The RNA-PCR was tested on clinical specimens from children with symptoms of an infection of the respiratory tract. The results were compared with isolation of RSV in cell culture and direct immunofluorescence. From 93 specimens tested, 31 were found positive by all three techniques. Six additional positive results were detected using RNA-PCR. From these 37 RSV positive specimens 33 (92%), including all 6 additional positives, were subgroup A and only 4 were subgroup B strains. Thus, the RNA-PCR is a specific and sensitive technique for the detection and subgroup classification of RSV genomes.

Detection of cytomegalovirus mRNA and DNA encoding the immediate early gene in peripheral blood leukocytes from immunocompromised patients.

Detection of cytomegalovirus (CMV) DNA in peripheral blood leukocytes has been shown to be a sensitive marker of CMV infection. However, the specificity with regard to its clinical significance is less clear, since infections considered to be latent may be detected. In this report, the presence of CMV immediate early antigen (IEA) DNA and mRNA in peripheral blood leukocytes detected by PCR was investigated and related to the appearance of CMV pp65 antigen, CMV serology, and clinical status. Thirty-seven consecutive samples were submitted to the laboratory from 36 immunocompromised patients, on a routine basis for analysis because of a potential risk of CMV infection. To facilitate differentiation between DNA and mRNA, primers were chosen in exons 2 and 3 of the immediate early gene of CMV. Keratin type I mRNA and the ssu rRNA gene served as internal controls. Thirty specimens were CMV antibody positive, of which 11 were also CMV IEA DNA positive. Two of seven seronegative samples were CMV IEA DNA positive. No relation was found between serology and the presence of CMV IEA DNA as determined in 37 samples. Five of 32 samples that could be analyzed were positive for CMV IEA mRNA, of which four were also positive in the pp65 antigen detection technique. A clear relation was found between the presence of CMV IEA mRNA and CMV pp65 antigen in leukocytes and with the clinical findings as well (P < 0.01). It is concluded that detection of CMV mRNA may have a role in diagnosis of an active clinically relevant CMV infection.

[Hepatitis B in children in 4 university centers in The Netherlands]. / Hepatitis B bij kinderen in vier universitaire centra in Nederland.

OBJECTIVE: To evaluate the prevalence and the natural course of hepatitis B infection in children. DESIGN: Retrospective longitudinal. SETTING: Four university pediatric centres. METHOD: To explore the possibility of starting a trial with interferon alpha, data of viral and biochemical tests and biopsies of children younger than 16 years were studied. RESULTS: In a period of 10 years (1980-1990) 145 patients, of whom 74% were not of original Dutch descent, were found positive for HBsAg. The data of 142 patients could be analysed. Seroconversion was seen in 27 patients and 42 were already anti-HBe positive at the time of presentation. Chronic hepatitis, representing the category which could benefit from interferon alpha treatment, was found in 24 patients. Severe complications of the hepatitis were found in 4% of the children, including hepatocellular carcinoma and cirrhosis. Follow-up was insufficient so the seroconversion rate could only be estimated at 12% for the first year following the diagnosis. CONCLUSION: As a result of this study the authors present a proposal for a therapeutic trial with interferon alpha. This is a national protocol under the auspices of the section for pediatric gastroenterology of the Nederlandse Vereniging voor Kindergeneeskunde (Netherlands Pediatric Association).

Prospective application of reverse transcriptase polymerase chain reaction for diagnosing influenza infections in respiratory samples from a children's hospital.

A prospective clinical evaluation of the reverse transcriptase polymerase chain reaction (RNA PCR) for detection of influenza viruses was carried out with specimens from 342 patients of a children's hospital in The Netherlands. The RNA PCR, carried out directly on the specimens without an organic extraction, showed a sensitivity and specificity which are superior to those of direct immunofluorescence and comparable to those of cell culture combined with immunofluorescence (culture/IF). Negative results can be obtained within 2 days by the RNA PCR but may take up to 14 days by culture/IF. Because culturing is the standard technique for the detection of respiratory viruses, at this moment there are no strong arguments to replace culture/IF with RNA PCR for the detection of influenza A virus.