Comparison of the rapid second generation directigen EIA with cell culture and immunofluorescence for the detection of respiratory syncytial virus in nasopharyngeal aspirates

BACKGROUND

A second generation-RSV enzyme immunoassay (EIA) was compared with cell culture and immunofluorescence to determine the improved efficacy of this reformulated system.

OBJECTIVES

This study was performed to identify whether the EIA might serve an ancillary function during non-operational virology hours, or whether the EIA may serve as a replacement of the commonly used direct fluorescent assay (DFA).

STUDY DESIGN

During the 1992-1993 (September-April) RSV season, 124 freshly collected nasopharyngeal (NP) aspirates were tested by the EIA and the DFA for the presence of antigen to the infectious agent. Infectivity was performed by tube culture cytopathic effect (TC-CPE) in parallel with the two antigen detection methodologies.

RESULTS

Thirteen of the 48 confirmed positive specimens (27%) failed to yield infectious virus by TC-CPE. The sensitivity, specificity, positive and negative predictive values of the EIA were 90, 95, 91 and 94% respectively. This observed sensitivity of 90% using freshly collected NP aspirates, represents a marked improvement over an earlier generation EIA kit.

CONCLUSIONS

Considering the simplicity and speed of this EIA (10 min), the test is recommended for use by medical personnel when facilities for DFA and traditional virus culture are not readily available.

Economic impact of an infection control education program in a specialized preschool setting

OBJECTIVE

To assess the economic impact, from a societal perspective, of a multidimensional infection control education program (ICEP) in a preschool for children with Down syndrome.

METHODS

Krilov et al implemented a comprehensive ICEP in a specialized preschool setting and reported a significant decrease in medical resource utilization and days absent from school. Clinical and economic data from Krilov et al and other sources were incorporated into a health-state transition (Markov) decision analysis model that estimated annual expected costs for the baseline and intervention years. Procedure and diagnosis codes were assigned to all physician office visits, emergency department visits, hospitalizations, and laboratory and diagnostic tests. Cost estimates then were derived using 1999 national reimbursement schedules and other sources. Productivity losses for parents were estimated using national wage rates. The costs of the ICEP were compared with the reduction in the costs of illness (direct medical costs plus costs associated with lost parental working time). The outcomes measured were mean annual costs of illness per child, total annual ICEP costs, and net annual costs or savings.

RESULTS

With a comprehensive ICEP, the mean costs of illness in the baseline year was $1235 per child, of which 68% and 14% were for productivity losses and physician visits, respectively. In the intervention year, the mean costs of illness per child was $615, of which 71% and 20% were for productivity losses and physician visits, respectively. The cost of the preexisting infection control (IC) practices in place at the onset of the study (baseline year) was $716. The comprehensive ICEP cost (intervention year) was $75 627, 92% of which was spent to hire a cleaning service to decontaminate toys 3 times per week. When a secondary analysis was performed to reflect a less intensive ICEP in a nonspecialized preschool setting, the mean costs of illness in the baseline and intervention years were $962 and $614 per child, respectively, representing a total annual cost-of-illness savings of $13 224 for the 38 children who participated in the study by Krilov et al. The annual incremental cost of the less intensive ICEP was $2371; therefore, the estimated net annual savings of the less intensive ICEP in a nonspecialized preschool was $10 853.

CONCLUSIONS

This study suggests that the reduction in the costs of illness could more than offset the cost of implementing a multidimensional ICEP in a preschool setting.

Epithelial cells infected with respiratory syncytial virus are resistant to the anti-inflammatory effects of hydrocortisone

In this work we continue our study of the biochemical responses of respiratory epithelial cells to infection with human paramyxovirus pathogens. In our earlier studies, we detected elevated concentrations of the proinflammatory chemokines MIP-1alpha and IL-8 in upper and lower respiratory tract secretions from patients infected with respiratory syncytial virus (RSV). Here we demonstrate the same trend for individuals infected with parainfluenza virus (PIV), with elevated concentrations of MIP-1alpha and IL-8 (means of 309 +/- 51 and 2280 +/- 440 pg/ml/mg protein, respectively) detected in nasal wash samples from 17 patients with culture-positive PIV. Similar to our findings with RSV, cells of the HEp-2 epithelial line and primary cultures of human bronchial epithelial cells respond to PIV infection with production and release of both MIP-1alpha and IL-8. Addition of the glucocorticoid anti-inflammatory agent hydrocortisone (200-1000 ng/ml) attenuated the production of MIP-1alpha and IL-8 in PIV-infected cells while having minimal to no effect on the production of these mediators from cells infected with RSV. Neither virus infection resulted in a change in the total cellular concentration of glucocorticoid receptors, nor did hydrocortisone exert any differential effect on viral replication. As repression of chemokine production by epithelial cells is likely to result in diminished recruitment of proinflammatory leukocytes, these results may explain in part why glucocorticoid therapy reduces the symptoms associated with acute PIV infection, but have little to no effect in the overall outcome in the case of RSV.

The differentiation of classic Kawasaki disease, atypical Kawasaki disease, and acute adenoviral infection: use of clinical features and a rapid direct fluorescent antigen test

OBJECTIVE

To compare the clinical and laboratory features of children with Kawasaki disease with those with acute adenoviral infection, which may mimic Kawasaki disease.

DESIGN

We retrospectively compared the medical records of children with Kawasaki disease and atypical Kawasaki disease with those of children with acute adenoviral infection. All children included were initially evaluated because their primary care physicians were concerned that they might have Kawasaki disease. The utility of a rapid direct fluorescent antigen test for adenovirus was evaluated. Thirty-six children with Kawasaki disease (23 with classic and 13 with atypical presentations) and 7 patients with acute adenoviral infection were studied.

SETTING

A tertiary care pediatric hospital.

RESULTS

Children with Kawasaki disease were more likely to have conjunctivitis (36 of 36 vs 4 of 7), strawberry) tongues (23 of 36 vs 1 of 7), perineal peeling (19 of 36 vs 0 of 7), and distal extremity changes (22 of 36 vs 0 of 7) than those with acute adenoviral infection. Children with acute adenoviral infection were more likely to have purulent conjunctivitis (3 of 7 vs 1 of 36) and exudative pharyngitis (3 of 7 vs 1 of 35). In addition to pyuria (13 of 26 vs 0 of 6), patients with Kawasaki disease had higher mean white blood cell counts (15.3 +/- 3.5 vs 11.5 +/- 6.0 x 10(9)/L), erythrocyte sedimentation rates (56 vs 42 mm/h), platelet counts (426 vs 259 x 10(9)/L), and levels of alanine aminotransferase (101 vs 18 U/L) than those with acute adenoviral infection. Children with Kawasaki disease had lower mean albumin levels (32 vs 36 g/L). A rapid antigen test for adenovirus had a specificity and sensitivity of 100% compared with viral culture.

CONCLUSIONS

Kawasaki disease and acute adenoviral infection can present with many of the same clinical characteristics. A rapid direct fluorescent antigen assay for adenovirus may be a helpful adjunctive test for distinguishing acute adenoviral infection from Kawasaki disease.

Influenza and respiratory syncytial virus. Update on infection, management, and prevention

This article is an overview of the epidemiology and spectrum of clinical disease attributed to influenza and respiratory syncytial virus in children. It separately discusses the pathogenesis of the two diseases and the host responses to the viruses to emphasize each infection's significance and need for a vaccine. Updates on current preventive measures and a preview of potential future vaccine developments are presented.

Alterations in apoptosis of cord and adult peripheral blood mononuclear cells induced by in vitro infection with respiratory syncytial virus

Respiratory syncytial virus (RSV), a major cause of morbidity in children, results in severe lower respiratory tract infections. With an in vitro infection system of isolated cord or adult peripheral blood mononuclear cells, addition of virus to cell cultures resulted in significant reductions in cell deaths, as measured by 2 independent assays: quantitation of cells with subdiploid levels of DNA and cells with DNA strand breaks. Decreased cell death was observed in lymphocytes and monocytes of cord and adult samples, with more dramatic effects evident in cells from cord blood. This may be linked to the increased virulence observed in infants with RSV infection. These data suggest that RSV may be equipped with some mechanism to prevent apoptosis, which is a major component of the host defense system used to eliminate virally infected cells.

Neurobehavioral manifestations and sequelae of HIV and other infections

Central nervous system infections in children and adolescents involve a wide spectrum of illnesses, ranging from acute self-limited diseases, such as enteroviral meningitis, to severe diffuse or focal infections (i.e., arboviral encephalitis) resulting in devastating neurologic sequelae. All the clinical manifestations of CNS infections occur to some degree secondary to toxic mediators such as cytokines. These factors are neurotoxic and produce clinical manifestations such as encephalopathy, motor abnormalities, and seizures. Many of these diseases also produce radiculoneuropathies and vasculopathies (stroke). As a result, chronic neurologic conditions may result and are frequently associated with psychiatric disturbances and situational depression.

The differential impact of training stress and final examination stress on herpesvirus latency at the United States Military Academy at West Point

In this study, we searched for evidence for reactivation of three latent herpesviruses, Epstein-Barr virus (EBV), herpes simplex virus type-1 (HSV-1), and human herpesvirus 6 (HHV-6), in West Point cadets experiencing two different stressors. Blood samples were obtained from cadets before and after a 6-week training period known as "Cadet Basic Training" (CBT), at a baseline prior to final examinations, and then once again during the week of final examinations. Antibody titers to latent HSV-1, EBV, and HHV-6 were determined as a measure of the steady-state expression of latent virus. EBV virus capsid antigen (VCA) IgG antibody titers were unchanged in blood samples obtained prior to and immediately after CBT. However, EBV antibody titers were significantly higher in the blood sample obtained during examination week than in the baseline period before examination; they were also higher than antibody titers before/after CBT. None of the serum samples were positive for EBV VCA IgM antibodies, indicating that the changes in antibody titers to EBV were not associated with recent EBV infections in the class. No significant changes in antibody titers to HSV-1 or HSV-6 were found over the identical time periods, including examination week. Academic stress but not CBT modulated the steady-state expression of latent EBV, resulting in the reactivation of latent virus. The same stressors, however, did not affect the steady-state expression of latent HSV-1 or HSV-6, at least as measured by changes in antibody titers. The data provide additional evidence of the impact of different psychological stressors on the steady-state expression of latent herpesviruses.

Efficacy of Directigen RSV testing in patient management following admission from a paediatric emergency department

We investigated the use of the Directigen Respiratory Syncytial Virus test performed under 'Stat Laboratory' conditions, in the management of infants after admission from the Paediatric Emergency Department (ED). The study group consisted of 242 consecutive paediatric ED patients tested by Directigen in the Stat laboratory during the winter 1995-1996 respiratory virus season. Specimens were submitted to the Virology Laboratory for confirmatory consensus testing utilizing in part, an in-house multiplex immunofluorescence assay (IFA) and conventional virus isolation methodologies. The sensitivity, specificity, positive and negative predictive values for Directigen, IFA, and isolation, were 71, 91, 85, 80%; 98, 100, 100, 99%; and 51, 100, 100, 72% respectively. Re-testing of 17 discordant original NP aspirates using Directigen, suggested that errors were due to technologist interpretation as well as to overt assay failure. The low analytical sensitivity and specificity of Directigen precludes its use in the clinical setting described in this study. Evening or weekend specimen collection, followed by IFA testing in a centralized Virology Laboratory at the start of the next working day, produces reliable test results. Among the small number of pediatric patients who might be candidates for antiviral therapy IFA testing should be made available on an on-call basis by Virology Laboratory.

Course and outcome of chronic fatigue in children and adolescents

PURPOSE

To describe the epidemiology, symptoms, and psychosocial characteristics of children and adolescents evaluated in a chronic fatigue program and determine the course and outcome of the syndrome in these patients.

METHODS

During the summer of 1994, chart review was performed for the 58 patients evaluated between 1990 and 1994 and a telephone follow-up was conducted with 42 of the 58 families. Patients were predominantly female (71%) and white (94%), with 50% between the ages of 7 and 14 years and 50% between the ages of 15 and 21 years (mean age 14.6 years).

RESULTS

At time of presentation, 50% of patients had been fatigued for 1 to 6 months and 50% had been fatigued for 7 to 36 months. Sixty percent indicated the fatigue had begun with an acute illness and 60% had a history of allergies. Most commonly reported symptoms were fatigue (100%), headache (74%), sore throat (59%), abdominal pain (48%), fever (36%), and difficulties with concentration and/or memory (33%). Most patients had a worsening of school performance and a decrease in social activities. On follow-up, there was significant improvement in many patients during the summer after the first visit, with continued improvement in most patients during the second and third years. At time of the follow-up telephone call, 43% of families considered their child "cured" and 52% considered their child "improved," whereas only 5% considered their child to be "the same." Statistical analyses demonstrated no demographic or clinical factors that distinguished between those who did or did not participate in the follow-up study, or between those who did or did not do well on follow-up.

CONCLUSIONS

These data demonstrate that children and adolescents with chronic fatigue have a syndrome that is similar to that described in adults, but that the syndrome differs in several ways, most specifically, presentation earlier in the course of the illness and a more optimistic outcome.

Follow-up of children with respiratory syncytial virus bronchiolitis in 1986 and 1987: potential effect of ribavirin on long term pulmonary function. The Bronchiolitis Study Group

BACKGROUND

Hospitalization for respiratory syncytial virus (RSV) bronchiolitis is considered a risk factor for reactive airway disease and/or abnormal pulmonary function tests (PFTs) later in childhood. This study attempted to assess this observation with newer PFTs and to determine whether ribavirin therapy of initial RSV infection may affect the long term outcome.

METHODS

Medical records of all infants hospitalized with RSV infection in 1986 and 1987 at six institutions (North Shore University Hospital, Children's Hospital of Buffalo, University Florida-Gainesville, University of Connecticut, Children's Hospital National Medical Center, Denver Children's Hospital) were requested. Patients who could be contacted were recalled in 1993 and 1994 for PFTs and given a pulmonary status questionnaire.

RESULTS

One hundred patients were evaluated. Overall PFTs were within normal ranges. There was less "bronchitis" over the interval years in the ribavirin-treated patients (13 of 33) vs. those who did not receive ribavirin (44 of 67, P < 0.01). There was no difference for the diagnosis of reactive airway disease (15 of 33 ribavirin vs. 36 of 67 no ribavirin). Patients who received ribavirin were then matched by age (within 2 weeks) at initial RSV infection and underlying risk factor (bronchopulmonary dysplasia, heart disease). Of the 27 patients matched, the ribavirin patients had longer intensive care unit stays (median (25 to 75% interquartile range): 2 (0 to 7) vs. 0 (0 to 0), P < 0.05). On follow-up evaluation there were no significant differences in PFTs or reactive airway disease between the 2 groups. There was a trend toward lower forced expiratory volume at 1 s and midexpiratory flow rate (25 to 75%) in the ribavirin-treated group, and there were more reported pneumonias on follow-up in the ribavirin patients.

CONCLUSION

During our 5- to 6- year follow-up of children, status post bronchiolitis, we noted a good long term prognosis. No long term adverse effects on pulmonary function were detected. Despite being potentially sicker at presentation as assessed by intensive care unit stay, ribavirin recipients were doing equally well at the time of follow-up.

Impact of an infection control program in a specialized preschool

BACKGROUND

The purpose of this study was to design and implement a comprehensive infection control program and measure its effects on the number and types of infectious illnesses experienced by children attending a specialized preschool program.

METHODS

Participants in the study were children with Down syndrome enrolled in a school-based early intervention program. The ages of the children ranged from 6 weeks to 5 years. Through a series of parental questionnaires, the number and types of infections in the children were chronicled for a year before and a year after the implementation of an infection control intervention program. Interventions included infection control lectures, handouts, posters, and attention to environmental cleaning and disinfection, with an emphasis on toys. Compliance with these measures was monitored and recorded.

RESULTS

During the interventional year the median number of total illnesses/child/month decreased significantly from the baseline year (0.70 vs 0.53, p < 0.05), with a trend toward a decrease in the number of respiratory illnesses (0.67 vs 0.42, p < 0.07). Significant decreases were also seen for the median number of physician visits (0.50 vs 0.33, p < 0.05), courses of antibiotics administered (0.33 vs 0.28, p < 0.05), and days of school missed as a result of respiratory illness (0.75 vs 0.40, p < 0.05).

CONCLUSIONS

This study demonstrates a decrease in infection rates with the implementation of a comprehensive educational and environmental infection control program in a day care setting.

Psychosocial correlates of chronic fatigue syndrome in adolescent girls

Behavior problems and family functioning were investigated in a sample of 10 adolescent girls with chronic fatigue syndrome (CFS), 10 matched healthy adolescent girls, and 10 adolescents with childhood cancer in remission. Based on the adolescent girls' reports, the CFS group had significantly higher scores than the cancer and healthy comparison adolescent girls on somatic complaints and also significantly higher scores than the cancer controls on internalizing symptoms and depression. Parent reports resulted in significantly higher scores in the CFS group than the adolescent girls from the healthy comparison groups on internalizing scores and somatic complaints. There were no significant differences on any family variables.

Human herpesvirus-6 infection in children with first febrile seizures

We evaluated febrile convulsions prospectively in 42 children to investigate the association between acute human herpesvirus-6 (HHV-6) infection and first-time febrile convulsions, using both virologic and serologic methods. Eight children had primary HHV-6 infection documented by viral culture and an additional three by acute- and convalescent-phase serologic studies. These findings indicate that acute HHV-6 infection is a frequent cause of febrile convulsions in young children.

Evaluation of a rapid diagnostic test for respiratory syncytial virus (RSV): potential for bedside diagnosis

OBJECTIVE

Rapid detection of respiratory syncytial virus (RSV) infection can assist clinicians in decisions regarding antiviral therapy with ribavirin as well as instituting infection control measures. The Abbott TestPack RSV is a rapid RSV detection immunoassay that can be performed on respiratory secretions in 20 to 30 minutes without special laboratory equipment. The purpose of this study was to evaluate housestaff performance of the TestPack RSV at bedside as compared with laboratory testing of aliquots of the same specimen by tissue culture inoculation, direct fluorescent antibody (DFA) testing and TestPack RSV.

METHODS

During the 1991 through 1992 RSV season, 137 nasopharyngeal aspirates or washes obtained from pediatric patients < 4 years of age suffering from acute respiratory disease were assayed by the Food and Drug Administration-approved TestPack RSV as well as conventional tube culture and DFA testing.

RESULTS

66 of 137 (48%) specimens were positive for RSV as defined by: isolation and DFA-positive (n = 48) and DFA testing positive with negative culture (n = 18); blocking assay experiments using TestPack RSV confirmed culture-negative DFA-positive specimens as positive in 8/8 instances in which material for retesting was available. Using these definitions, the sensitivity and specificity for the assays were: housestaff TestPack RSV: 92%, 93%; laboratory TestPack RSV: 97%, 98%; virus isolation: 72%, 100%.

CONCLUSION

From these data, it appears that the TestPack RSV EIA in the field setting is reliable, although laboratory confirmation of results is important.

Inactivation of respiratory syncytial virus by detergents and disinfectants

The activity of a number of detergents and disinfectants against respiratory syncytial virus (RSV) was evaluated in an in vitro assay system. Equal volumes of RSV and serial 10-fold dilutions of the test agents were mixed at 4 degrees C for 5 minutes. The RSV titer in each mixture was compared with that of untreated RSV alone. In 14 experiments with input RSV titers ranging from 2.6 x 10(3) to 2 x 10(7) plaque-forming units/ml, a 10-fold dilution of 5.25% sodium hypochlorite (generic bleach) inactivated (> or = 3-log reduction in titer) the virus. With lower RSV titers inactivation was also observed at a 100-fold dilution of bleach. Fetal calf serum concentrations up to 50% as an organic load did not diminish the bleach effect. The degree of RSV inactivation was also defined for Lysol, povidone-iodine, Amphyl, Hibiclens, Osyl, ethanol and Listermint. The short contact time, the reproducible nature of the findings and the continued effectiveness with increasing organic loads all suggest that detergents and disinfectants can potentially play an important role in decreasing the spread of RSV infection.

Reduced environmental exposure to aerosolized ribavirin using a simple containment system

To minimize the exposure of health care workers to aerosolized ribavirin, we designed a double tent containment system with circulating mist and suction applied between the tents and we evaluated the ability of this system to contain and evacuate aerosolized ribavirin. While the drug was administered with this system at three institutions, three air sampling pumps at different locations in the room and one worn by the investigator (personal breathing zone) collected air samples onto filters for assay of ambient ribavirin. Ribavirin determinations were made by high performance liquid chromatography. A 5- to greater than 20-fold decrease in ambient ribavirin concentrations was observed with the containment system compared with those detected with a single oxyhood in use. The personal breathing zone concentration was 566.0 micrograms/m3 with the oxyhood alone and fell to a mean concentration of 43.81 +/- 33.40 micrograms/m3 with the containment system. Though the risk to exposed health care workers is unknown, this system offers a simple way to decrease significantly occupational exposure to ribavirin.

Cefuroxime treatment failure of nontypable Haemophilus influenzae meningitis associated with alteration of penicillin-binding proteins

A 10-year-old boy presented with nuchal rigidity and cerebrospinal fluid (CSF) leukocytosis initially and again on day 6 of intravenous cefuroxime therapy (200 mg/kg/day). Both CSF specimens yielded nontypable beta-lactamase-negative Haemophilus influenzae that were susceptible by disk tests but relatively resistant to cefuroxime (MIC, 8- to 16-fold greater than that of control isolates). To define the mechanism of resistance, the cefuroxime resistance marker was transformed to a susceptible H. influenzae recipient; inactivation and permeability of beta-lactam substrate were tested and the penicillin-binding protein (PBP) profiles were examined. Inactivation of beta-lactam substrate was not detected and reduced permeability was not found. However, reduced beta-lactam binding to PBPs 4 and 5 was observed; 18- to 27-fold more penicillin and 2.5-to 4-fold more cefuroxime was required to saturate or block 50% of the binding sites of these PBPs, respectively. Thus, reduced affinity of PBPs 4 and 5 for beta-lactam substrate appears to be the mechanism of cefuroxime resistance in this strain. The reduced affinity of these targets appears to have contributed to the bacteriologic and clinical failure in this patient.

Disseminated adenovirus infection with hepatic necrosis in patients with human immunodeficiency virus infection and other immunodeficiency states

Disseminated adenovirus infection with fatal hepatic necrosis has been reported in 16 patients, 15 of whom had immunocompromising conditions. Herein we report three patients with AIDS and fatally disseminated adenovirus infection with hepatic necrosis. The median age of these 16 patients was 4.7 years, and their illness was characterized by fever (13 of 16 patients), coagulopathy (10 of 16), lower respiratory tract disease (10 of 16), and gastrointestinal hemorrhage (five of 16) in addition to clinical evidence of hepatitis. The adenoviruses isolated were the commonly found serotypes 1, 2, 3, 5, and 7 for 13 of the 15 cases for which this determination was available. With the high frequency of adenovirus infection in humans and the increasing prevalence of human immunodeficiency virus infection in children, it seems likely that this syndrome will continue to be seen.

Antibody-mediated enhancement of respiratory syncytial virus infection in two monocyte/macrophage cell lines

Monoclonal antibodies (MAbs) specific for two surface glycoproteins of respiratory syncytial virus (RSV) were found to enhance RSV infection in two macrophagelike cell lines (P388D1 and THP-1). MAbs to an irrelevant antigen (pneumococcal polysaccharide) and to the nucleocapsid of RSV did not enhance infection. Blocking either the Fc segment of the monoclonal antibody of the Fc receptor on the cells diminished the enhancement, suggesting that this phenomenon involves attachment of the monoclonal antibody to the virus followed by attachment of the Fc of this complex to the Fc receptor on the cells. These data indicate that antibody-mediated enhancement of RSV infection can occur in vitro in macrophages. This enhancement may contribute to the pathogenesis of RSV bronchiolitis and the more severe RSV disease seen in recipients of formalin-inactivated RSV vaccine.

Characterization of the serologic profile of children with human immunodeficiency virus infection: correlation with clinical status

Serum samples from 28 children with symptomatic human immunodeficiency virus (HIV) infection were studied for the presence of HIV antigen. Their humoral immune response profile, including anti-HIV specific isotypic responses and neutralizing titers, was characterized. Additionally, serum specimens from 12 of these children were tested for their ability to mediate antibody-dependent cellular cytotoxicity (ADCC) against HIV envelope antigens. Analysis of our results showed that children with acquired immunodeficiency syndrome (AIDS) were much more likely to have serum antigenemia and an absence of anti-p24 antibodies than those with AIDS-related complex (ARC). A significant association was also noted between a more stable clinical status and a strong anti-p24 antibody response with detectable antibodies to other HIV antigens in multiple antibody subclasses. This suggests that the longitudinal evaluation of antigen/antibody profiles may aid in the assessment of prognosis for children with HIV infection. Sera from 6/6 patients with ARC and 4/6 patients with AIDS were able to mediate ADCC. No correlation was found between clinical status and the titers of neutralizing antibodies.

Pediatric acquired immunodeficiency syndrome-related complex: clinical and immunologic features

The long term clinical outcome for infants and children with the pediatric acquired immunodeficiency syndrome-related complex is unknown. This report describes our experience with 14 patients with acquired immunodeficiency syndrome-related complex who have been followed for 11 to 71 months since the onset of their symptoms. The most frequent clinical features at presentation were persistent generalized lymphadenopathy (14 of 14), hepatosplenomegaly (11 of 14) and a history of recurrent otitis media (7 of 14). Except for hypergammaglobulinemia (14 of 14) and reversed T4/T8 ratios (9 of 14), immunologic analyses, including in vitro responses to mitogens and antibody responses following immunization, revealed no consistent abnormalities. Over the course of follow-up, none of the patients have developed serious or opportunistic infections and 12 of 14 have shown catch up or age-appropriate growth. The T4/T8 ratios have remained stable in 8 of 11 and improved in 2 of 11 patients. Gradual regression of hepatosplenomegaly and lymphadenopathy has been noted patients. Although follow-up studies over a longer period are needed to confirm our observations to date, acquired immunodeficiency syndrome-related complex may represent a prolonged plateau in the course of human immunodeficiency virus infection in many infected children. Detailed immunologic evaluation of these patients may help to identify a subset of children that could benefit from periodic gamma-globulin or chronic antibiotic therapy.

Comparison of three enzyme-linked immunosorbent assays and a direct fluorescent-antibody test for detection of respiratory syncytial virus antigen

We prospectively evaluated three enzyme immunoassays (EIAs) and a direct fluorescent-antibody (DFA) test for respiratory syncytial virus detection. Of 90 specimens, 79% gave the same results in all four tests (30 positive and 41 negative) and 97% were in agreement in three of the four assays. The agreement between the direct fluorescent-antibody test and each enzyme immunoassay was greater than or equal to 86%.

Respiratory virus infection of peripheral blood monocytes: correlation with ageing of cells and interferon production in vitro

The ability of respiratory syncytial virus (RSV) and parainfluenza virus type 3 (PIV3) to replicate in peripheral blood monocytes cultured in vitro for 1, 2, 4 or 7 days prior to infection was investigated. Inoculation of 1-day old monocytes produced at least tenfold less new virus than infection of the older, more macrophage-like cells for both viruses. PIV3 induced extensive syncytium formation, whereas RSV caused a cytopathic effect manifest by increased rounding of the cells with minimal syncytium formation. Supernatants of infected monocytes were assayed for human interferon-alpha (HuIFN-alpha) in an attempt to explain the restricted viral replication in the youngest monocytes. In PIV3-infected cells, HuIFN-alpha production was inversely correlated with new virus formation. Monocytes infected after 1 day in culture produced 800 IU/ml of HuIFN-alpha; the older cells produced 100 to 200 IU/ml. In contrast, monocytes infected on day 1 with RSV produced minimal amounts (1.5 IU/ml) of HuIFN-alpha. Increasing amounts of HuIFN-alpha were detected in cells infected with RSV after 2, 4 or 7 days in culture, reaching a maximum of 400 IU/ml on day 7. Further investigation of the apparent restriction of replication in young monocyte cultures may be helpful in understanding the pathogenesis of these respiratory infections.

Varicella zoster immunoglobulin after postnatal exposure to varicella: survey of experts

A questionnaire based on a hypothetical 6-day-old infant exposed to a sibling with varicella was mailed to 316 Pediatric Infectious Diseases Society members to determine their recommendations for administration of varicella zoster immunoglobulin (VZIG). Of the 137 faculty members who responded 20% would recommend VZIG for the infant described (13% were undecided). When further information including a negative maternal history for varicella, prematurity or maternal varicella infection occurring 1 week after delivery was considered, the numbers who recommended VZIG (43, 46 and 52%, respectively) rose significantly (P less than 0.01). Twenty-two physicians had knowledge of a severe case of varicella following postnatal exposure. Only 33% of faculty members surveyed feel there are no indications for VZIG in infants exposed after 48 hours of age.

Imipenem/cilastatin in acute pulmonary exacerbations of cystic fibrosis

Nineteen patients with pulmonary exacerbations of cystic fibrosis due to Pseudomonas aeruginosa were given imipenem/cilastatin for six to 10 days at dosages of 30-90 mg/kg per day. Mean Shwachman scores rose from 46.6 to 50.3 (P less than .001), clinical efficacy scores from 34.3 to 43.3 (P less than .001), vital capacity from 53.7% to 58.5% of the predicted value (P less than .01), forced expiratory volume in 1 sec from 39.5% to 42.6%, and partial pressure of oxygen in arterial blood from 68.2 mm Hg to 72.6 mm Hg. Treatment failed in only two instances. The concentration of P. aeruginosa in the sputum decreased to a modest extent (8.5 log10 cfu/ml on day 1, 8.1 log10 cfu/ml on day 10; P greater than .1). Four patients had imipenem-resistant strains of P. aeruginosa at the start of therapy, and 11 additional patients developed resistant strains during treatment; in eight patients greater than 90% of all Pseudomonas organisms in the sputum were resistant at the end of therapy. Six patients acquired Candida in their sputum. There was no correlation between bacteriologic improvement or the development of resistance to imipenem and either clinical outcome or improvement in pulmonary function. In summary, imipenem/cilastatin therapy is associated with a good clinical outcome in patients with cystic fibrosis, but resistance emerges rapidly.