Sensitivity and specificity of a qualitative RNA detection assay to diagnose HIV infection in young infants. Perinatal AIDS Collaborative Transmission Study.

OBJECTIVE: To evaluate the sensitivity and specificity of an RNA detection assay for diagnosing perinatal HIV infection. METHODS: Plasma and serum specimens taken during the first 3 months of life from HIV-infected and uninfected children enrolled in a cohort study were assayed for HIV RNA using the qualitative nucleic acid sequence-based amplification (NASBA) kit. Sensitivity, specificity, and predictive values were calculated. NASBA results from infected children were compared with DNA PCR results from the same blood samples. Autoantibody patterns of suspected false-positive specimens were compared with those of subsequent specimens from the same child to exclude specimen labelling errors. RESULTS: Amongst 131 specimens from 105 HIV-infected children, the sensitivity of the qualitative NASBA assay was 13 out of 34 [38%; 95% confidence interval (CI), 22-56] at < 7 days, 56 out of 58 (97%; 95% CI, 88-100) at 7-41 days, and 37 out of 39 (95%; 95% CI, 83-99) at 42-93 days of life. Of 252 specimens from 206 uninfected children, six tested positive and one tested indeterminate by NASBA. Four of these positive specimens had discordant autoantibody patterns suggesting mislabelling; excluding these, the test specificity was 245 out of 248 (99%; 95% CI, 97-100). Amongst 128 paired specimens from infected children, NASBA results were more often positive than those from DNA PCR (103 versus 92; P=0.01). Amongst infants with specimens drawn in the first week of life, the proportion born after > 4 h of membrane rupture was greater amongst those testing negative (81%) than those testing positive (46%; P=0.05). CONCLUSIONS: The qualitative NASBA RNA assay is highly specific and more sensitive than DNA PCR. Qualitative RNA assays may be useful for diagnosing and excluding perinatal HIV infection in children after the first week of life for such purposes as initiating antiretroviral therapy and other treatment, resolving parental uncertainty, determining timing of transmission, and providing endpoints for intervention trials.

Antiretroviral therapy of HIV infection in children.

Much progress has been made in the therapy of pediatric HIV infection, which has been transformed from a usually fatal disease into that of a chronic disease model. Early, aggressive therapy with the goal of complete suppression of viral replication (undetectable plasma virus) should be the therapeutic goal, but this new, more hopeful environment has been created at the cost of complexity and compromises in quality of life. The rapid pace of new developments and therapeutic complexities argue strongly for care in specialized centers or, at least, frequent consultation. Efforts are ongoing to develop simpler, more effective therapeutic regimens that suppress and ultimately eradicate infection and that stimulate immune reconstitution.

Serial analysis of the gut and respiratory microbiome in cystic fibrosis in infancy: interaction between intestinal and respiratory tracts and impact of nutritional exposures.

UNLABELLED: Pulmonary damage caused by chronic colonization of the cystic fibrosis (CF) lung by microbial communities is the proximal cause of respiratory failure. While there has been an effort to document the microbiome of the CF lung in pediatric and adult patients, little is known regarding the developing microflora in infants. We examined the respiratory and intestinal microbiota development in infants with CF from birth to 21 months. Distinct genera dominated in the gut compared to those in the respiratory tract, yet some bacteria overlapped, demonstrating a core microbiota dominated by Veillonella and Streptococcus. Bacterial diversity increased significantly over time, with evidence of more rapidly acquired diversity in the respiratory tract. There was a high degree of concordance between the bacteria that were increasing or decreasing over time in both compartments; in particular, a significant proportion (14/16 genera) increasing in the gut were also increasing in the respiratory tract. For 7 genera, gut colonization presages their appearance in the respiratory tract. Clustering analysis of respiratory samples indicated profiles of bacteria associated with breast-feeding, and for gut samples, introduction of solid foods even after adjustment for the time at which the sample was collected. Furthermore, changes in diet also result in altered respiratory microflora, suggesting a link between nutrition and development of microbial communities in the respiratory tract. Our findings suggest that nutritional factors and gut colonization patterns are determinants of the microbial development of respiratory tract microbiota in infants with CF and present opportunities for early intervention in CF with altered dietary or probiotic strategies. IMPORTANCE: While efforts have been focused on assessing the microbiome of pediatric and adult cystic fibrosis (CF) patients to understand how chronic colonization by these microbes contributes to pulmonary damage, little is known regarding the earliest development of respiratory and gut microflora in infants with CF. Our findings suggest that colonization of the respiratory tract by microbes is presaged by colonization of the gut and demonstrated a role of nutrition in development of the respiratory microflora. Thus, targeted dietary or probiotic strategies may be an effective means to change the course of the colonization of the CF lung and thereby improve patient outcomes.

Salmonella strains resistant to multiple antibiotics: therapeutic implications.

In summary we are confronted with the awareness that Salmonella organisms of various species have developed simultaneous resistance to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole. These strains are now widespread throughout much of Asia and the Middle East and have caused outbreaks of disease in man and animals in many different countries. Several reports document the appearance of these clinically resistant organisms in the United States, usually as a result of importation from abroad. Since most of the reported cases have been in infants, and given the duration of carriage and the impossibility of adequate hygienic precautions in this age group, secondary spread is to be expected. In this regard the Centers for Disease Control have already noted increased reports of S. mbandaka and S. alachua isolates from the states of Minnesota, Oregon and Washington and have attributed this increase to the infected infants adopted from India. Furthermore current patterns of international social mobility would seem to dictate the inevitability of continued importation of such multiply resistant organisms, especially from Third-World countries. In addition to immigration from abroad the selective pressure of antimicrobial usage in this country might contribute to the emergence of similar resistance patterns. Resistance to ampicillin and chloramphenicol has significantly increased in recent years, and one would expect to see more frequent resistance to TMP-SMX as this drug is used more commonly for the management of otitis media, urinary tract infections and other diseases of high prevalence.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation of varicella-zoster virus-infected cell proteins that elicit antibody production during primary varicella using the immune transfer method.

The varicella-zoster virus-infected cell proteins (VZV-ICPs) against which IgG, IgM and IgA antibodies were made in the course of primary varicella-zoster virus (VZV) infection were analysed by the immune transfer method. IgG antibodies were made against one or more of 18 VZV-ICPs by patients with varicella. IgM antibodies were produced which reacted with 21 VZV-ICPs. The spectrum of IgG antibody production during the first week after the onset of infection was limited to an average of three VZV-ICPs while IgM antibodies which reacted with an average of seven VZV-ICPs were detectable in the acute phase of varicella. Equivalent VZV IgG or IgM antibody titres by radioimmunoassay did not correlate with a similar pattern of antibody specificity for VZV-ICPs by immune transfer. A detectable immune response to all VZV-ICPs was not required for the recovery of individual patients from primary VZV infection.

Sequelae of maternally derived cytomegalovirus infections in premature infants.

Eighteen of 106 (17%) infants of seropositive mothers, with birth weights less than 1500 gm, acquired cytomegalovirus from a maternal source. Neutropenia, lymphocytosis, thrombocytopenia, and hepatosplenomegaly developed in some infants concomitant with the onset of CMV excretion. Infected infants who excreted CMV at less than 7 weeks of age had longer oxygen requirements than infants who did not excrete CMV until they were older. Passively derived maternal antibody to CMV fell more rapidly over the first few months of life in sick premature infants than would be expected in term infants. Among six infected premature infants, five had undetectable antibody titers when CMV excretion began. Loss of passively acquired antibody and early excretion of virus appear to be associated with symptomatic CMV infections in premature infants of seropositive mothers.

The CCR5Delta32 allele slows disease progression of human immunodeficiency virus-1-infected children receiving antiretroviral treatment.

The role of the CCR5Delta32 allele in human immunodeficiency virus (HIV)-1-related disease progression was analyzed for 457 antiretroviral-naïve children who had participated in the Pediatric AIDS Clinical Trials Group 152 study, which demonstrated that didanosine (ddI) or zidovudine + ddI treatments were superior to zidovudine alone. The CCR5Delta32 allele was detected at an overall frequency of 6.1% (28/457). At study entry, heterozygote children (wild type [wt]/Delta32) had higher baseline median CD4(+) counts/mm(3) than wt/wt children had (1035 vs. 835 cells/mm(3); P=. 043), higher mean weight-for-age Z scores (-0.15 vs. -0.84; P=.01), and a trend toward less cortical atrophy (P=.059). During antiretroviral treatment and study follow-up, there was a trend toward less disease progression and death among heterozygote children than among wt/wt children (P=.056; relative hazard, 0.28; 95% confidence interval, 0.07-1.13) independent of the antiretroviral treatment to which they were randomized.

Evaluation of human T cell lymphotropic virus infection in a cohort of injecting drug users.

The diagnosis and confirmation of human T cell lymphotropic virus (HTLV) type II infection has proven difficult, since most assays depend on antigenic cross-reactivity between HTLV-I antigens and HTLV-II antibodies. Type-specific HTLV infection rates were evaluated in a cohort of 233 injecting drug users screened with an HTLV EIA. Of the 52 EIA-reactive specimens, 48 were indeterminate or negative by standard Western blot. Type-specific HTLV results determined by polymerase chain reaction (PCR) were 0, HTLV-I; 92%, HTLV-II; 6%, type indeterminate; and 2%, negative. Among 42 EIA-reactive, HTLV-II-PCR-positive individuals tested by a p21 envr Western blot, all were positive and 74% had antibodies to the tax protein. This study found a high rate (22.3%) of HTLV reactivity, with HTLV-II usually the sole responsible agent; shortcomings in standard HTLV-I-based diagnostics but usefulness of PCR and p21 envr Western blots for typing and confirmation of HTLV reactivity; and a high prevalence (74%) of anti-tax antibody among HTLV-II-seropositive subjects, suggesting increased potential for infectivity.

Predictive value of quantitative plasma HIV RNA and CD4+ lymphocyte count in HIV-infected infants and children.

CONTEXT: Pediatric human immunodeficiency virus (HIV) infection has unique viral pathogenetic features that preclude routine extrapolation from adult studies and require specific analysis. OBJECTIVES: To evaluate the prognostic value of 2 key laboratory markers-plasma RNA and CD4+ lymphocyte count-for HIV disease progression in infants and children and to establish targeted values for optimal outcome. DESIGN: Data from a cohort of 566 infants and children who participated in a randomized, placebo-controlled trial of nucleoside reverse transcriptase inhibitors (ACTG 152) were analyzed. The trial was conducted between 1991 and 1995 and enrolled a heterogeneous cohort of antiretroviral therapy-naive children (age, 3 months to 18 years); patients had a median follow-up of 32 months. MAIN OUTCOME MEASURES: The trial clinical end points consisted of time to first HIV disease progression (growth failure, decline in neurologic or neurodevelopmental function, opportunistic infections) or death. RESULTS: Baseline plasma RNA levels were high (age group medians, 5 x 10(4) to >10(6) copies/mL), and both baseline RNA and CD4+ lymphocyte count were independently predictive of subsequent clinical course. Risk reduction for disease progression between 49% and 64% was observed for each log10 reduction in baseline RNA and was linear without suggestion of a threshold or age effect. Disease progression predictive power was enhanced by the combined use of plasma RNA and CD4+ cell count. Marker values of less than 10000 copies/mL for plasma RNA and greater than 500 x 10(6)/L (<6.5 years of age) or greater than 200 x 10(6)/L (>6.5 years) for CD4+ cell count were associated with a 2-year disease progression rate of less than 5%. CONCLUSIONS: Two key laboratory markers--plasma RNA and CD4+ lymphocyte count-are independent predictors of clinical course among HIV-infected infants and children. The linear, age-independent relationship between log10 plasma RNA and relative risk of disease progression strongly supports therapeutic efforts to achieve plasma virus levels as low as possible.

Viral measurement by polymerase chain reaction-based assays in human immunodeficiency virus-infected infants.

Serial samples from human immunodeficiency virus-infected infants in the first year of life were analyzed by quantitative human immunodeficiency virus polymerase chain reaction assays. Very high, persistent levels of plasma RNA and proviral DNA were detected throughout the study period, suggesting the absence of an effective immune response. Most patients had normal CD4 lymphocyte counts and were symptom free for the first 3 to 6 months despite high levels of viral replication. These findings support the evaluation of early intervention (before symptoms develop) and efforts to establish the predictive value of these assays.

Virologic and immunologic response to nucleoside reverse-transcriptase inhibitor therapy among human immunodeficiency virus-infected infants and children.

Plasma human immunodeficiency virus RNA and CD4 lymphocyte response to nucleoside reverse-transcriptase therapy were evaluated in a large, comparative pediatric trial. Both baseline values and changes in the two laboratory markers over time correlated well with clinical outcome and possessed independent predictive value. In comparison of RNA reduction from baseline between the dideoxyinosine (ddI) and zidovudine+ddI therapeutic arms, marginal superiority of the combination arm was not correlated with an observed clinical benefit. Despite the size of this trial and the significantly higher rate of clinical end points in the zidovudine monotherapy group, attempts to establish surrogacy for plasma RNA were difficult. Nevertheless, plasma RNA and CD4 lymphocyte count together possess strong clinical predictive power and are valuable tools for both the clinician and the evaluation of new therapies.

Failure of antepartum maternal cultures to predict the infant's risk of exposure to herpes simplex virus at delivery.

In 414 pregnant women with a history of recurrent genital herpes simplex infection, we studied the correlation between asymptomatic viral shedding in late pregnancy and at the time of delivery. Antepartum cultures for asymptomatic reactivation of herpes simplex virus were positive in 17 of the 414 women (4.1 percent). None of these women had positive cultures at the time of delivery. Cultures of specimens obtained at delivery from 5 of 354 asymptomatic mother-infant pairs (1.4 percent) were positive for asymptomatic excretion of herpes simplex virus. None of these women had had antepartum cultures that documented asymptomatic excretion of herpes simplex virus, despite the fact that culturing was repeatedly performed during the four weeks before delivery. Asymptomatic shedding of herpes simplex virus occurred with the same frequency at delivery, whether or not any episodes of symptomatic recurrence were noted during the pregnancy (1.4 vs. 1.3 percent). We conclude that antepartum maternal cultures do not predict the infant's risk of exposure to herpes simplex virus at delivery.

Use of human immunodeficiency virus (HIV) human hyperimmune immunoglobulin in HIV type 1-infected children (Pediatric AIDS clinical trials group protocol 273).

The clinical, immunologic, and virologic effects and the pharmacokinetics of human immunodeficiency virus (HIV) human hyperimmune immunoglobulin (HIVIG) were assessed in 30 HIV-infected children aged 2-11 years. All had moderately advanced disease with an immune complex-dissociated (ICD) p24 antigen >70 pg/mL and were on stable antiviral therapy. Three groups of 10 children received 6 monthly infusions of 200, 400, or 800 mg/kg of HIVIG, and serial immunologic and virologic assays were performed. HIVIG doses as high as 800 mg/kg were safe and well tolerated. The half-life of HIVIG, determined by serial p24 antibody titers, was 13-16 days, the volume of distribution was 102-113 mL/kg, and clearance was 5.6-6.0 mL/kg/day. Plasma ICD p24 decreased during the infusions, but CD4 cell levels, plasma RNA copy number, cellular virus, immunoglobulin levels, and neutralizing antibody titers were minimally affected by the infusions. Clinical status did not change during the 6-month infusion and 3-month follow-up periods.