Mycoplasma pneumoniae Compared to Streptococcus pneumoniae Avoids Induction of Proinflammatory Epithelial Cell Responses despite Robustly Inducing TLR2 Signaling.

Mycoplasma pneumoniae and Streptococcus pneumoniae are the most common bacterial causes of pneumonia in children. The clinical characteristics of pneumonia differ significantly between the two bacteria. We aimed to elucidate the differences in pathogenesis between M. pneumoniae and S. pneumoniae by characterizing the respiratory epithelial cell immune response to both pathogens. Using primary human bronchial epithelial cells in air-liquid interface cultures, we observed lower production of the proinflammatory cytokines interleukin-6 (IL-6) and IL-8 in response to M. pneumoniae than to S. pneumoniae. In contrast to the differences in proinflammatory cytokine production, Toll-like receptor 2 (TLR2)-mediated signaling in response to M. pneumoniae was stronger than to S. pneumoniae. This difference largely depended on TLR1 and not TLR6. We found that M. pneumoniae, but not S. pneumoniae, also induced signaling of TLR10, a coreceptor of TLR2 that has inhibitory properties. M. pneumoniae-induced TLR10 signaling on airway epithelial cells was partially responsible for low IL-8 production, as blocking TLR10 by specific antibodies increased cytokine production. M. pneumoniae maintained Th2-associated cytokine production by epithelial cells, which concurs with the known association of M. pneumoniae infection with asthma. M. pneumoniae left IL-33 levels unchanged, whereas S. pneumoniae downregulated IL-33 production both under homeostatic and Th2-promoting conditions. By directly comparing M. pneumoniae and S. pneumoniae, we demonstrate that M. pneumoniae avoids induction of proinflammatory cytokine response despite its ability to induce robust TLR2 signaling. Our new findings suggest that this apparent paradox may be partially explained by M. pneumoniae-induced signaling of TLR2/TLR10.

Virological and Social Outcomes of HIV-Infected Adolescents and Young Adults in The Netherlands Before and After Transition to Adult Care.

BACKGROUND: As a result of effective combination antiretroviral therapy (cART) and advanced supportive healthcare, a growing number of human immunodeficiency virus (HIV)-infected children survive into adulthood. The period of transition to adult care is often associated with impaired adherence to treatment and discontinuity of care. We aimed to evaluate virological and social outcomes of HIV-infected adolescents and young adults (AYAs) before and after transition, and explore which factors are associated with virological failure. METHODS: We included 59 HIV-infected AYAs from the Netherlands who had entered into pediatric care and transitioned from pediatric to adult healthcare. We used HIV RNA load and cART data from the Dutch Stichting HIV Monitoring database (1996-2014), and collected social and treatment data from patients' medical records from all Dutch pediatric HIV treatment centers and 14 Dutch adult treatment centers involved. We evaluated risk factors for virological failure (VF) in a logistic regression model adjusted for repeated measurements. RESULTS: HIV VF occurred frequently during the study period (14%-36%). During the transition period (from 18 to 19 years of age) there was a significant increase in VF compared with the reference group of children aged 12-13 years (odds ratio, 4.26 [95% confidence interval, 1.12-16.28]; P = .03). Characteristics significantly associated with VF were low educational attainment and lack of autonomy regarding medication adherence at transition. CONCLUSIONS: HIV-infected AYAs are vulnerable to VF, especially during the transition period. Identification of HIV-infected adolescents at high risk for VF might help to improve treatment success in this group.

Human bocavirus infection as a cause of severe acute respiratory tract infection in children.

In 2005 human bocavirus (HBoV) was discovered in respiratory tract samples of children. The role of HBoV as the single causative agent for respiratory tract infections remains unclear. Detection of HBoV in children with respiratory disease is frequently in combination with other viruses or bacteria. We set up an algorithm to study whether HBoV alone can cause severe acute respiratory tract infection (SARI) in children. The algorithm was developed to exclude cases with no other likely cause than HBoV for the need for admission to the paediatric intensive care unit (PICU) with SARI. We searched for other viruses by next-generation sequencing (NGS) in these cases and studied their HBoV viral loads. To benchmark our algorithm, the same was applied to respiratory syncytial virus (RSV)-positive patients. From our total group of 990 patients who tested positive for a respiratory virus by means of RT-PCR, HBoV and RSV were detected in 178 and 366 children admitted to our hospital. Forty-nine HBoV-positive patients and 72 RSV-positive patients were admitted to the PICU. We found seven single HBoV-infected cases with SARI admitted to PICU (7/49, 14%). They had no other detectable virus by NGS. They had much higher HBoV loads than other patients positive for HBoV. We identified 14 RSV-infected SARI patients with a single RSV infection (14/72, 19%). We conclude that our study provides strong support that HBoV can cause SARI in children in the absence of viral and bacterial co-infections.

Indinavir/low-dose ritonavir containing HAART in HIV-1 infected children has potent antiretroviral activity, but is associated with side effects and frequent discontinuation of treatment.

We here present the study results of 21 HIV-1 infected children who were treated with indinavir plus low-dose ritonavir and two nucleoside reverse transcriptase inhibitors (NRTIs) for 48 weeks. Although this q12h HAART regimen had potent antiretroviral activity, it was frequently associated with side effects and discontinuation of therapy.

Procalcitonin as an early marker of infection in neonates and children.

A child or neonate presenting with fever is a common medical problem. To differentiate between those with a severe bacterial infection and those with a localised bacterial or a viral infection can be a challenge. This review provides an overview of neonatal and paediatric studies that assess the use of procalcitonin as an early marker of bacterial infection. Procalcitonin is an excellent marker for severe, invasive bacterial infection in children. However, the use of procalcitonin in the diagnosis of neonatal bacterial infection is complicated, but if correctly used procalcitonin results in a higher specificity than C-reactive protein. In addition, procalcitonin has been shown to correlate with severity of disease (urinary tract infections and sepsis), and can therefore be used as a prognostic marker. Procalcitonin is therefore a useful additional tool for the diagnosis of bacterial disease in neonates and children.

Pharmacokinetics of indinavir combined with low-dose ritonavir in human immunodeficiency virus type 1-infected children.

So far, no pediatric doses for indinavir combined with ritonavir have been defined. This study evaluated the pharmacokinetics of 400 mg of indinavir/m(2) combined with 125 mg of ritonavir/m(2) every 12 h (q12h) in 14 human immunodeficiency virus type 1-infected children. The area under the concentration-time curve from 0 to 24 h and the minimum concentration of drug in serum for indinavir were similar to those for 800 mg of indinavir-100 mg of ritonavir q12h in adults, while the maximum concentration of drug in serum was slightly decreased, with geometric mean ratios (90% confidence intervals in parentheses) of 1.1 (0.87 to 1.3), 0.96 (0.60 to 1.5), and 0.80 (0.68 to 0.94), respectively.

Changes in indinavir exposure over time: a case study in six HIV-1-infected children.

OBJECTIVE: To study changes in indinavir exposure over time in HIV-1-infected children. MATERIALS AND METHODS: Protease inhibitor (PI)-naive HIV-1-infected children were treated with indinavir, zidovudine and lamivudine. Steady-state plasma pharmacokinetic (PK) sampling was carried out as standard of care. The AUC(0-8) was targeted between 15 and 30 mg h/L. PK sampling was repeated after dosage adjustment until the AUC(0-8) reached target values. Patients were included when the time interval between PK samplings was > or =2 years and differences in dosage/m2 <10% between PK samplings 1 and 2. Corrections of dose for changes in body size were carried out. RESULTS: Six children were enrolled with a median age of 5.2 years (range 1.7-13.6 years). All had a viral load below 500 copies/mL. The geometric mean (GM) of the AUC(0-8) decreased from 25.3 mg h/L at the first PK-day to 19.1 mg h/L at the second PK-day [geometric mean ratio (GMR): 0.76 (95% C.I.: 0.48-1.20)]. The GM of Cmax decreased from 11.8 to 10.4 mg/L [GMR: 0.88 (95% C.I.: 0.59-1.32)]. The GM of Cmin decreased from 0.08 to 0.07 mg/L [GMR: 0.86 (95% C.I.: 0.62-1.18)]. All children had an AUC(0-8) above 15 mg h/L on the first PK-day; three had an AUC(0-8) below 15 mg h/L on the second PK-day. In two of these three children, the plasma viral load was >500 copies/mL. CONCLUSION: Changes in indinavir exposure were observed over time. In two patients, decreased indinavir exposure was associated with virological failure. Therapeutic drug monitoring should be carried out over time since this may prevent subtherapeutic dosing in children.

[Reduction of vertical transmission by means of perinatal prophylaxis in the case of children exposed to HIV-1 and born in the Netherlands during the period 1995-1999]. / Reductie van verticale transmissie door perinatale profylaxe bij aan HIV-1 geëxposeerde in Nederland geboren kinderen in de periode 1995-1999.

OBJECTIVE: Registration of the number of children born to HIV-infected mothers diagnosed prepartum and analysis of the efficacy of the policy for preventing mother-to-child transmission of HIV-1 in the period 1995 to 1999. DESIGN: Prospective. METHOD: On a monthly basis, Dutch paediatricians reported HIV-1 exposed children to the Dutch Paediatric Surveillance Unit. All reports were followed up with standard questionnaires. An additional retrospective study was performed because of incomplete registration. Paediatricians in centres for the care of HIV-infected patients were requested to retrospectively report HIV-exposed children. The standard questionnaires were submitted to these paediatricians. Data were collected during the period 1 January 1995-31 December 1999. RESULTS: The number of children known to be exposed to HIV-1 and for whom the mother was diagnosed prepartum, increased from 5 to 25 per year. The percentage of HIV-1 infected children decreased from 20% (1/5) to 4% (1/25). The number of pregnant HIV-1 infected women using highly active antiretroviral therapy increased during the study period from 0% (0/5) to 72% (18/25). Antiretroviral therapy was administered to 92% (23/25) of HIV-1 exposed children. In total 2% of the children received breastfeeding. CONCLUSION: Despite an increase in the number of children known to be exposed to HIV-1, a decrease in the percentage of HIV-1-infected children was observed. Of the children born in 1999 and known to be exposed to HIV-1, 4% were infected. Measures taken in the Netherlands to prevent mother-to-child transmission of HIV-1 infection are effective.

[Epidemiological characteristics of reported HIV-1 infection in children in the Netherlands, 1998-2000: vertical transmission via parents from countries with a generalised epidemic]. / Epidemiologische kenmerken van gemelde HIV-1-infectie bij kinderen in Nederland, 1998-2000: verticale transmissie door ouders uit gebieden met een gegeneraliseerde epidemie.

OBJECTIVE: To document the course and characteristics of the annual new diagnoses of HIV-1 infection in children in the Netherlands. DESIGN: Prospective registration from January 1, 1998 till December 31, 2000. METHODS: Dutch paediatricians reported HIV-positive children to the Dutch Paediatric Surveillance Unit on a monthly basis. All reports were followed up with standard questionnaires. RESULTS: During the period 1998-2000, 42 children were diagnosed with HIV-1 infection. This number was almost equal to the number of HIV-1 infected children diagnosed during the period 1995-1997 (n = 43). In 86% of the children one or both parents originated from a country with a generalised HIV epidemic. In the case of two children (5%), both parents were of Dutch origin. Most children (81%) were infected by mother-to-child transmission. Of these children, 48% (n = 20) were born in the Netherlands. Forty percent of the children born in the Netherlands and infected through vertical transmission lived in one of the four big cities of the Netherlands (Amsterdam, Rotterdam, The Hague and Utrecht). The remaining 60% were distributed across almost all the Dutch provinces. CONCLUSIONS: The increase in the number of newly-infected children in 1995-1997 appears to have reached a plateau in 1998-2000, possibly as a result of a more active detection and treatment policy amongst pregnant women in at-risk groups. However, the 20 newly infected children born in the Netherlands indicate that this policy aimed at preventing vertical transmission is not yet being fully implemented.

Therapeutic immune reconstitution in HIV-1-infected children is independent of their age and pretreatment immune status.

OBJECTIVE: To evaluate long-term immune reconstitution of children treated with highly active antiretroviral therapy (HAART). METHODS: The long-term immunological response to HAART was studied in 71 HIV-1-infected children (aged 1 month to 18 years) in two prospective, open, uncontrolled national multicentre studies. Blood samples were taken before and after HAART was initiated, with a follow-up of 96 weeks, and peripheral CD4 and CD8 T cells plus naive and memory subsets were identified in whole blood samples. Relative cell counts were calculated in relation to the median of the age-specific reference. RESULTS: The absolute CD4 cell count and percentage and the CD4 cell count as a percentage of normal increased significantly (P < 0.001) to medians of 939 x 106 cells/l (range, 10-3520), 32% (range, 1-50) and 84% (range, 1-161), respectively, after 48 weeks. This increase was predominantly owing to naive CD4 T cells. There was a correlation between the increase of absolute naive CD4 T cell counts and age. However, when CD4 T cell restoration was studied as percentage of normal values, the inverse correlation between the increase of naive CD4 T cell count and age was not observed. In addition, no difference in immunological reconstitution was observed at any time point between virological responders and non-responders. CONCLUSIONS: Normalization of the CD4 cell counts in children treated with HAART is independent of age, indicating that children of all age groups can meet their CD4 T cell production demands. In general, it appears that children restore their CD4 T cell counts better and more rapidly than adults, even in a late stage of HIV-1 infection.

Pharmacokinetics of the protease inhibitor indinavir in human immunodeficiency virus type 1-infected children.

The objective of this study was to evaluate the pharmacokinetics of indinavir in human immunodeficiency virus-infected children as part of a prospective, open, uncontrolled, multicenter study in The Netherlands. Human immunodeficiency virus type 1-infected children were monitored over 6 months of treatment with zidovudine (120 mg/m(2) every 8 h [q8h]), lamivudine (4 mg/kg of body weight q12h), and indinavir (33mg/kg of metabolic weight [MW] q8h). Four weeks after the start of treatment, the steady-state pharmacokinetics of indinavir were determined by high-pressure liquid chromatography. If patients had an indinavir area under the concentration-time curve (AUC) of below 10 or above 30 mg/liter. h, a dose increase or a dose reduction was made and pharmacokinetic measurements were repeated 4 weeks later. Nineteen patients started with the dose of 33 mg/kg of MW q8h. The median AUC (range) was 10.5 (2.8 to 51.0) mg/liter. h. The median AUC (range) in 17 children treated with 50 mg/kg of MW q8h was 20.6 (4.1 to 38.7) mg/liter. h. Finally, five patients had a dose increase to 67 mg/kg of MW q8h, resulting in a median AUC (range) of 36.6 (27.2 to 80.0) mg/liter. h. After 6 months of treatment, there were 11 children with an AUC of below 20 mg/liter. h, of whom 5 (45%) had a detectable viral load, while this was the case in none of the 11 children with an AUC of higher than 20 mg/liter. h. We conclude that the optimal dose of indinavir in children to obtain drug exposure similar to that observed in adult patients is 50 mg/kg of MW q8h, which approximates 600 mg/m(2) q8h. It would even be better to adjust the indinavir dose based on an AUC of greater than 20 mg/liter. h.

Clinical and virologic response to combination treatment with indinavir, zidovudine, and lamivudine in children with human immunodeficiency virus-1 infection: a multicenter study in the Netherlands. On behalf of the Dutch Study Group for Children with HIV-1 infections.

OBJECTIVE: To evaluate the clinical, immunologic, and virologic response to indinavir, zidovudine, and lamivudine in children with human immunodeficiency virus-1 (HIV-1) infection. STUDY DESIGN: Twenty-eight HIV-1-infected children (3 months to 16 years of age) with or without prior treatment with reverse-transcriptase inhibitors and a HIV-1 RNA >5000 copies/mL and/or a CD4 cell count less than the lower limit of the age-specific reference value were treated with indinavir, zidovudine, and lamivudine. Pharmacokinetics of indinavir were determined in each child. RESULTS: The combination treatment was well tolerated in the majority of patients. Clinical improvement was seen in all patients. After 6 months of therapy, 70% of the patients had an HIV-1 RNA load below 500 copies/mL, whereas 48% of the children had a viral load below 40 copies/mL. Relative CD4 cell counts in relation to the lower limit of the age-specific reference value increased significantly from a median value of 79% at baseline to 106% after 6 months of therapy. The doses of indinavir necessary to achieve area under the curve values comparable to adult values varied from 1250 mg/m(2)/d to 2450 mg/m(2)/d. CONCLUSIONS: Highly active antiretroviral therapy consisting of indinavir, zidovudine, and lamivudine in children reduced HIV-1 RNA to less than 500 copies/mL in 70% of the children within 6 months. Improved CD4 cell counts were observed in most patients, as was a better clinical condition (no invasive or opportunistic infections, increased weight gain). Side effects of the triple therapy were mild. Highly active antiretroviral therapy can be used as successfully in children as in adults.