Mona Rigaud

Evaluation of Tuberculosis Diagnostics in Children: 1. Proposed Clinical Case Definitions for Classification of Intrathoracic Tuberculosis Disease. Consensus From an Expert Panel

There is a critical need for improved diagnosis of tuberculosis in children, particularly in young children with intrathoracic disease as this represents the most common type of tuberculosis in children and the greatest diagnostic challenge. There is also a need for standardized clinical case definitions for the evaluation of diagnostics in prospective clinical research studies that include children in whom tuberculosis is suspected but not confirmed by culture of Mycobacterium tuberculosis. A panel representing a wide range of expertise and child tuberculosis research experience aimed to develop standardized clinical research case definitions for intrathoracic tuberculosis in children to enable harmonized evaluation of new tuberculosis diagnostic technologies in pediatric populations. Draft definitions and statements were proposed and circulated widely for feedback. An expert panel then considered each of the proposed definitions and statements relating to clinical definitions. Formal group consensus rules were established and consensus was reached for each statement. The definitions presented in this article are intended for use in clinical research to evaluate diagnostic assays and not for individual patient diagnosis or treatment decisions. A complementary article addresses methodological issues to consider for research of diagnostics in children with suspected tuberculosis.

Latent Tuberculosis Diagnosis in Children by Using the QuantiFERON-TB Gold In-Tube Test

BACKGROUND. The QuantiFERON-TB Gold test was the first blood test to be approved for the diagnosis of latent tuberculosis infection. Although it has been shown to be sensitive and specific in adults, limited data on its performance in children are available. METHODS. This was a prospective study of children receiving health care in New York, New York. Each child was assessed for risk factors for Mycobacterium tuberculosis infection, underwent tuberculin skin testing, and had a QuantiFERON-TB Gold In-Tube test performed. The concordance between tuberculin skin test and QuantiFERON-TB Gold In-Tube test results was calculated, and the results were analyzed according to the likelihood of exposure to M tuberculosis. RESULTS. Data for 207 children with valid tuberculin skin test and QuantiFERON-TB Gold In-Tube test results were analyzed. There was excellent correlation between negative tuberculin skin test results and negative QuantiFERON-TB Gold In-Tube test results; however, only 23% of children with positive tuberculin skin test results had positive QuantiFERON-TB Gold In-Tube test results. Positive QuantiFERON-TB Gold In-Tube test results were associated with increased likelihood of M tuberculosis exposure, and interferon γ levels were higher in children with known recent exposure to M tuberculosis, compared with children with older exposure histories. Younger children produced lower interferon γ levels in response to the mitogen (phytohemagglutinin) control used in the QuantiFERON-TB Gold In-Tube test, but indeterminant results were low for children of all ages. Performance characteristics were similar across all age groups. CONCLUSION. The QuantiFERON-TB Gold In-Tube test is a specific test for M tuberculosis exposure in children, with performance characteristics similar to those for adults residing in regions with low levels of endemic disease. Concerns about test sensitivity, especially for children <2 years of age, will require additional prospective long-term evaluation.

Cell-mediated and humoral immune responses in children infected with human immunodeficiency virus during the first four years of life

OBJECTIVES To determine whether cell-mediated and humoral immune responses to recall antigens develop in children infected with the human immunodeficiency virus (HIV) and, if so, whether these responses are retained. METHODS Children infected with HIV and uninfected children born to mothers infected with HIV were compared with respect to lymphoproliferative responses to recall antigens and protective levels of antibody to bacterial toxoids during the first 4 years of life. RESULTS Children infected with HIV who were enrolled in a prospective study of the natural history of the infection were relatively normal (1) in their lymphoproliferative responses to diphtheria toxoid, tetanus toxoid, and Candida, and (2) in their ability to make protective diphtheria and tetanus antitoxins during the first 2 years of life. During the next 2 years, attrition was noted in both lymphoproliferative and humoral responses. Attrition in response was not necessarily correlated with declining numbers of helper T cells. CONCLUSIONS These results suggest that both cellular and humoral immune responses develop early in life in most children infected with HIV, while they remain relatively well both clinically and immunologically. Previously reported severe immune deficits in these children were probably attributable to advanced clinical disease when they were first studied.

The impact of early initiation of highly active antiretroviral therapy on the human immunodeficiency virus type 1-specific CD8 T cell response in children

This cross-sectional study investigated the effect of early highly active antiretroviral therapy (HAART) on human immunodeficiency virus (HIV) type 1-specific CD8 T cell responses in children. HIV-1-specific CD8 T cell responses were quantified using an enzyme-linked immunospot assay to measure interferon-gamma-secreting cells. HIV-1-infected children were classified by time of HAART initiation prior to age 1 year or after age 2 years as early (n=24) or late (n=28) treated. The magnitude and breadth of the HIV-1-specific CD8 T cell response was significantly lower in children receiving early compared with late HAART treatment (P=.0007 and.0001, respectively). However, total CD8 T cell responses in the early HAART treatment group did not differ significantly from those of age-matched non-HAART-treated controls (n=30). Thus, the reduced magnitude and breadth of the HIV-1-specific CD8 T cell response in early HAART-treated children is due to their younger age.

Towards early inclusion of children in tuberculosis drugs trials: a consensus statement.

Children represent a significant proportion of the global tuberculosis (TB) burden, and may be disproportionately more affected by its most severe clinical manifestations. Currently available treatments for pediatric drug-susceptible (DS) and drug-resistant (DR) TB, albeit generally effective, are hampered by high pill burden, long duration of treatment, coexistent toxicities, and an overall lack of suitable, child-friendly formulations. The complex and burdensome nature of administering the existing regimens to treat DS TB also contributes to the rise of DR TB strains. Despite the availability and use of these therapies for decades, a dearth of dosing evidence in children underscores the importance of sustained efforts for TB drug development to better meet the treatment needs of children with TB. Several new TB drugs and regimens with promising activity against both DS and DR TB strains have recently entered clinical development and are in various phases of clinical evaluation in adults or have received marketing authorization for adults. However, initiation of clinical trials to evaluate these drugs in children is often deferred, pending the availability of complete safety and efficacy data in adults or after drug approval. This document summarizes consensus statements from an international panel of childhood TB opinion leaders which support the initiation of evaluation of new TB drugs and regimens in children at earlier phases of the TB Drug development cycle.

Impaired Immunity to Recall Antigens and Neoantigens in Severely Immunocompromised Children and Adolescents during the First Year of Effective Highly Active Antiretroviral Therapy

BACKGROUND We studied whether severely immunocompromised, human immunodeficiency virus (HIV)-infected children who were beginning highly active antiretroviral therapy (HAART) or changing HAART regimens could spontaneously respond to a recall antigen (tetanus toxoid [TT] vaccine) or respond to a recall antigen and neoantigen (hepatitis A virus [HAV] vaccine) after 3 vaccinations. METHODS A total of 46 children who had CD4 cell percentages <15% and who demonstrated a >0.75-log reduction in plasma HIV RNA levels within 4 weeks of starting HAART were randomized to receive vaccinations with either TT or HAV vaccines during the first 6 months of HAART. Study subjects then received the alternate vaccine during the next 6 months of HAART. RESULTS Despite the early decline in viremia and the later increase in the percentage of CD4 T cells, spontaneous recovery of cell-mediated immunity (CMI) was not seen for TT. Serologic responses to TT required 3 vaccinations and were comparable in both groups. Serologic responses to HAV were infrequent and of low titer, although the group that received HAV vaccine after receiving TT vaccine performed somewhat better. CMI to HAV was virtually absent. CONCLUSIONS Severely immunocompromised children who are receiving HAART develop CMI and antibody to a recall antigen independent of the timing of vaccination, but they require a primary series of vaccinations. Antibodies to a neoantigen, HAV, developed when vaccination was delayed after initiation of HAART. CMI to a neoantigen was difficult to establish. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT00004735/PACTG P1006 .

Diagnosing Childhood Tuberculosis: Traditional and Innovative Modalities

uberculosis (TB) remains a leading cause ofmortality in children worldwide. The diagnosisof tuberculosis in children is traditionallybased on exposure history, symptoms, the tuberculinskin test, chest radiography, and mycobacterial stain-ing and culture. However, these investigations lack insensitivity and specificity and diagnosing childhoodtuberculosis remains a major global challenge. Recentadvances have improved our ability to diagnose tuber-culosis, but many of the new modalities either havenot been validated in the pediatric population or areinaccessible to tuberculosis endemic regions. More-over, diagnosing tuberculosis in human immunodefi-ciency virus-coinfected children, a growing popula-tion, remains a major challenge. This review providesan overview of traditional and novel approaches usedto diagnose

Streptococcus pneumoniae in human immunodeficiency virus type 1-infected children.

The purpose of this study was to characterize systemic Streptococcus pneumoniae disease in human immunodeficiency virus type 1 (HIV-1)-infected children. All cases of bacteremia and meningitis caused by S. pneumoniae among children less than 18 years old were collected by review of the Microbiology Laboratory records at the Bellevue Hospital Center during the period August 1, 1978, through July 31, 1993. There were 31 bouts of systemic S. pneumoniae disease in 19 of 235 HIV-1-infected children cared for by the Pediatric Infectious Disease staff and 116 bouts in 113 children not known to be HIV-1-infected. Four of the 19 HIV-1-infected children had multiple episodes of S. pneumoniae bacteremia as compared with 3 of 113 in the general population (P = 0.008). The frequency of serotypes and distribution of infections by season of the year did not differ between the 2 groups. The median ages at the time of the S. pneumoniae infection were 1.8 and 1.1 years for the HIV-1-infected children and the general population of children, respectively, when those children with multiple episodes were included for their initial episode only (P = 0.06). In the HIV-1-infected patients, 10 episodes were associated with pneumonia, 5 with pneumonia and otitis media, 5 with otitis media only, 1 with pneumonia and meningitis, 1 with meningitis only and 1 with periorbital cellulitis; 5 had no apparent focus of infection. One episode of pneumonia was complicated by lung abscess and there were 2 deaths. Most HIV-1-infected patients recovered without significant sequelae, and the clinical course of their systemic infections did not appear to be markedly different than that of healthy children.

Disseminated fungal infections in children infected with human immunodeficiency virus

&NA; A retrospective review of charts of 156 human immunodeficiency virus‐infected children cared for during a 7.5‐year period revealed 11 episodes of disseminateed candidiasis (DC) occurring in 11 patients (7%). All 11 patients developed the fungal infection in the context of advanced human immunodeficiency virus infection. All but one were hospital‐acquired, occurring at a mean of 2.3 months after admission. Ten patients had been febrile for more than 14 days before diagnosis. Previous oral thrush and central venous catheters (73 and 82% of patients) represented major predisposing factors for development of DC. Neutropenia (2 of 11 patients) did not represent a major risk factor for DC. Candida albicans was isolated in 9 patients, Rhodotorula minuta in 1 patient and 1 fungal isolate could not be identified. Sources of isolation were blood (8 of 11 patients), central venous catheters (3 of 11) and urine (2 of 11). Lungs (6 of 11 patients), esophagus (5 of 11) and brain, heart and kidneys (3 patients each) were the organs most often involved in DC. Antemortem diagnosis was achieved in only 7 (64%) patients; none of the 4 patients with DC diagnosed postmortem had been treated before death. Seven patients were treated with amphotericin B; 6 of them died but only 3 were treated for more than 7 days of therapy. The overall mortality was 90% (10 of 11 patients). In all 20% of the 50 human immunodeficiency virus‐infected children who died at our hospital during the study period had an episode of DC in close proximity to their death. DC was considered the direct cause of death in 4 of 10 children.

Immunoreconstitution in Children Receiving Highly Active Antiretroviral Therapy Depends on the CD4 Cell Percentage at Baseline

The effect of highly active antiretroviral therapy (HAART) in 85 children infected with human immunodeficiency virus type 1 (HIV-1) was compared retrospectively among Centers for Disease Control and Prevention (CDC) immunologic groups 1-3. The duration of HAART did not vary significantly among the immunologic groups (median, 39.07 months). The CD4 cell percentage increased in 39.1%, 58.3%, and 90% of patients in CDC groups 1-3, respectively (P <.001). HAART resulted in the suppression of HIV-1 below detectable levels in 34.8%, 25%, and 32% of patients in the 3 CDC groups, respectively, and in a frequent switch from syncytium-inducing to nonsyncytium-inducing virus. Thymic excision circles increased in a subset of patients with increases in CD4 cell percentage independently of HIV RNA level. The results support the option of delaying HAART in early asymptomatic HIV-1 disease in children and the use of other markers of disease progression, in addition to virus load.