Long-term protease inhibitor-containing therapy results in limited improvement in T cell function but not restoration of interleukin-12 production in pediatric patients with AIDS.

This study investigated whether immune restoration occurred in 26 human immunodeficiency virus (HIV) type 1-infected children treated first with indinavir for 16 weeks and then with combination antiretroviral therapy for >2 years. Compared with baseline, a significant, although modest, decrease in virus loads (maximum median, -0.86 log(10)) and increase in the number of CD4(+) lymphocytes, especially naive cells, were observed at several time points after 2 years. A maximum of 7% of treated children achieved undetectable viremia. There was a marked increase in the proliferative response and skin reactivity to recall antigens. However, responses to an HIV antigen remained depressed, and the production of interleukin-12 remained unchanged and abnormally low. The magnitude of virus suppression did not correlate with these measures of functional immune reconstitution. These findings suggest that long-term nonsuppressive antiretroviral therapy can induce limited improvement in immune function in pediatric AIDS patients and that the effect of suppressive treatments should be investigated.

Long-term virologic and immunologic responses in human immunodeficiency virus type 1-infected children treated with indinavir, zidovudine, and lamivudine.

Virologic and immunologic responses were examined for 33 human immunodeficiency virus (HIV)-infected children who participated for > or = 96 weeks in a phase 1/2 protocol of 16 weeks of indinavir monotherapy, followed by the addition of zidovudine and lamivudine. At week 96, a median increase of 199 CD4+ T cells/microL and a median decrease of 0.74 log(10) HIV RNA copies/mL were observed. The relationship between control of viral replication and CD4) T cell count was examined. Patients were categorized into 3 response groups on the basis of duration and extent of control of viral replication. Of 21 children with a transient decrease in virus load of > or = 0.7 log(10) HIV RNA copies/mL from baseline, 7 experienced sustained increases in CD4+, CD4+ CD45RA+, and CD4+ CD45RO+ T cell counts. CD4+ CD45RA+ (naive) T cells were the major contributor to CD4+ T cell expansion. Continued long-term immunologic benefit may be experienced by a subset of children, despite only transient virologic suppression.

Work-family issues and perceptions of stress among pediatric faculty and house staff.

OBJECTIVES: To examine work-family balance issues and predictors of stress related to work-family balance among pediatric house staff and faculty. METHODS: Data were obtained through an anonymous mail survey. Univariate analyses assessed associations between work-family issues (work-related factors that affect work-family balance, perceived support, work-family--related stress, and proposed solutions) and the following variables: gender, parental status, working status of spouse, and academic rank. Multiple linear regression examined independent predictors of perceived stress. RESULTS: Fifty percent of the 327 respondents cared for dependent children, and 20% expected to care for an elderly person in the next 5 years. Only 5% strongly agreed that their division or department was concerned about supporting members' work-family balance, and 4% strongly agreed that existing programs supported their needs. Eighty-three percent reported feeling stressed as a result of efforts to balance work and family. Independent predictors of stress included perceived need to choose between career and family, increasing age, dependent children, less support from colleagues and supervisors, and female gender. CONCLUSIONS: Work-family balance issues are responsible for substantial perceived stress. Academic departments should consider a commitment to supporting faculty who are struggling with these issues, including creation of work-family policies and programs, development of mentoring systems, and reexamination of existing expectations for work practices.

Esophageal candidiasis in pediatric acquired immunodeficiency syndrome: clinical manifestations and risk factors.

BACKGROUND: Little is known about the epidemiology and clinical features of esophageal candidiasis (EC) in pediatric AIDS. We therefore investigated the clinical presentation and risk factors of EC in a large prospectively monitored population of HIV-infected children at the National Cancer Institute. PATIENTS AND METHODS: We reviewed the records of all HIV-infected children (N = 448) followed between 1987 and 1995 for a history of esophageal candidiasis to characterize the epidemiology, clinical features, therapeutic interventions and outcome of esophageal candidiasis. To understand further the risk factors for EC in pediatric AIDS, we then performed a matched case-control analysis of 25 patients for whom control cases were available. RESULTS: There were 51 episodes of EC documented in 36 patients with 23 male and 13 female patients (0.2 to 17 years; median CD4, count 11/microl), representing a frequency of EC of 8.0%. Concurrent oropharyngeal candidiasis (OPC) was the most common clinical presentation of EC (94%); other signs and symptoms included odynophagia (80%), retrosternal pain (57%), fever (29%), nausea/vomiting (24%), drooling (12%), dehydration (12%), hoarseness (6%) and upper gastrointestinal bleeding (6%). The causative organism documented in 36 episodes (18 from OPC, 17 from endoscopic biopsy and 1 from autopsy) was Candida albicans in all cases. Patients received treatment for EC with amphotericin B (63%), fluconazole (29%), ketoconazole (4%) or itraconazole (1%). A clinical response was documented in all 45 evaluable episodes. In 6 other cases, EC was a final event without contributing to the cause of death. By a conditional logistic regression model for matched data, the best predictor of EC was the presence of prior OPC (P<0.0001), followed by CD4 count and CD4 percentage (P = 0.0002) and use of antibacterial antibiotics (P = 0.0013). The risks associated with low CD4 count were independent of that of prior OPC. CONCLUSION: EC in pediatric AIDS is a debilitating infection, which develops in the setting of prior OPC, low CD4 counts and previous antibiotics.

Preliminary evaluation of human immunodeficiency virus type 1 (HIV-1) immunogen in children with HIV-1 infection.

The safety and preliminary activity of human immunodeficiency virus type 1 (HIV-1) immunogen were evaluated in 10 HIV-1-infected children with disease stage N1,2 or A1,2. Multiple inoculations of 2. 5 or 10 units (U) of HIV-1 immunogen were safe and well tolerated without an acceleration of disease progression. When antiretroviral agents were coadministered, the 10 U dose appeared to be associated with more sustained reduction in plasma HIV-1 RNA than the 2.5 U dose (median log10 HIV-1 RNA at month 18, 3.07 vs. 4.01 copies/mL in 10 U [n=4] vs. 2.5 U [n=3], respectively; P=.034). Levels of regulated-on-activation, normal T cell-expressed and -secreted chemokine produced from HIV-1 immunogen-stimulated lymphocytes in vitro were increased in the children who had HIV-1 immunogen-specific antibody responses (P<.02) and appeared to be inversely correlated with levels of plasma HIV-1 RNA (P<.01). These preliminary data warrant larger studies to determine the effectiveness of adjunctive therapy with HIV-1 immunogen in children with HIV-1 infection.

Adherence of Candida albicans to bladder mucosa: development and application of a tissue explant assay.

In order to study the interactions between Candida species and uroepithelial tissue, a tissue explant assay was developed using bladder mucosa harvested from New Zealand white rabbits. Blastoconidia of Candida albicans, Candida tropicalis and Candida glabrata attached to the uroepithelial tissue in similar quantities. However, there was significantly more adherence to the uroepithelium by pre-germinated C. albicans compared with C. albicans blastoconidia. Furthermore, the amount of uroepithelial tissue injury was directly related to the length of exposure of the tissue to Candida. Thus, this tissue explant assay may provide a useful method for investigating properties related to fungal adherence to transitional uroepithelium and organism-mediated tissue injury.

A double-blind comparison of empirical oral and intravenous antibiotic therapy for low-risk febrile patients with neutropenia during cancer chemotherapy.

BACKGROUND: Among patients with fever and neutropenia during chemotherapy for cancer who have a low risk of complications, oral administration of empirical broad-spectrum antibiotics may be an acceptable alternative to intravenous treatment. METHODS: We conducted a randomized, double-blind, placebo-controlled study of patients (age, 5 to 74 years) who had fever and neutropenia during chemotherapy for cancer. Neutropenia was expected to be present for no more than 10 days in these patients, and they had to have no other underlying conditions. Patients were assigned to receive either oral ciprofloxacin plus amoxicillin-clavulanate or intravenous ceftazidime. They were hospitalized until fever and neutropenia resolved. RESULTS: A total of 116 episodes were included in each group (84 patients in the oral-therapy group and 79 patients in the intravenous-therapy group). The mean neutrophil counts at admission were 81 per cubic millimeter and 84 per cubic millimeter, respectively; the mean duration of neutropenia was 3.4 and 3.8 days, respectively. Treatment was successful without the need for modifications in 71 percent of episodes in the oral-therapy group and 67 percent of episodes in the intravenous-therapy group (difference between groups, 3 percent; 95 percent confidence interval, -8 percent to 15 percent; P=0.48). Treatment was considered to have failed because of the need for modifications in the regimen in 13 percent and 32 percent of episodes, respectively (P<0.001) and because of the patient's inability to tolerate the regimen in 16 percent and 1 percent of episodes, respectively (P<0.001). There were no deaths. The incidence of intolerance of the oral antibiotics was 16 percent, as compared with 8 percent for placebo (P=0.07). CONCLUSIONS: In hospitalized low-risk patients who have fever and neutropenia during cancer chemotherapy, empirical therapy with oral ciprofloxacin and amoxicillin-clavulanate is safe and effective.

Immunoreconstitution after ritonavir therapy in children with human immunodeficiency virus infection involves multiple lymphocyte lineages.

OBJECTIVE: To evaluate lymphocyte reconstitution after protease inhibitor therapy in children with human immunodeficiency virus (HIV) infection. STUDY DESIGN: Forty-four HIV-infected children receiving ritonavir monotherapy followed by the addition of zidovudine and didanosine were evaluated during a phase I/II clinical trial. The cohort had a median age of 6.8 years and advanced disease (57% Centers for Disease Control and Prevention stage C, 73% immune stage 3) and was naive to protease inhibitor therapy. RESULTS: After 4 weeks of therapy, there was a significant increase in CD4(+) and CD8(+) T cells. CD4(+) T cells continued to increase, whereas CD8(+) T cells returned to baseline by 24 weeks. Unexpectedly, there was a significant increase in B cells. Changes in CD4(+) T-cell subsets revealed an initial increase in CD4(+) CD45RO T cells followed by a sustained increase in CD4(+) CD45RA T cells. Children <6 years of age had the highest increase in all lymphocyte populations. Significant improvement in CD4(+) T-cell counts was observed even in those children whose viral burden returned to pre-therapy levels. CONCLUSIONS: Early increases in lymphocytes after ritonavir therapy are a result of recirculation, as shown by increases in B cells and CD4(+) CD45RO and CD8(+) T cells. Children exhibited a high potential to reconstitute CD4(+) CD45RA T cells even with advanced disease and incomplete viral suppression.

Serum and cerebrospinal fluid pharmacokinetics of intravenous and oral lamivudine in human immunodeficiency virus-infected children.

We studied the pharmacokinetics of intravenously and orally administered lamivudine at six dose levels ranging from 0.5 to 10 mg/kg of body weight in 52 children with human immunodeficiency virus infection. A two-compartment model with first-order elimination from the central compartment was simultaneously fitted to the serum drug concentration-time data obtained after intravenous and oral administration. The maximal concentration at the end of the 1-h intravenous infusion and the area under the concentration-time curve after oral and intravenous administration increased proportionally with the dose. The mean clearance of lamivudine (+/- standard deviation) in the children was 0.53 +/- 0.19 liter/kg/h (229 +/- 77 ml/min/m2 of body surface area), and the mean half-lives at the distribution and elimination phases were 0.23 +/- 0.18 and 2.2 +/- 2.1 h, respectively. Clearance was age dependent when normalized to body weight but age independent when normalized to body surface area. Lamivudine was rapidly absorbed after oral administration, and 66% +/- 25% of the oral dose was absorbed. Serum lamivudine concentrations were maintained above 1 microM for >/=8 h of 24 h on the twice daily oral dosing schedule with doses of >/=2 mg/kg. The cerebrospinal fluid drug concentration measured 2 to 4 h after the dose was 12% (range, 0 to 46%) of the simultaneously measured serum drug concentration. A limited-sampling strategy was developed to estimate the area under the concentration-time curve for concentrations in serum at 2 and 6 h.

Individual prognoses of long-term responses to antiretroviral treatment based on virological, immunological and pharmacological parameters measured during the first week under therapy.

OBJECTIVE: To predict long-term (12 weeks or longer) virological responses to antiretroviral treatment from measurements made during the first few days on therapy. METHODS: Forty-one HIV-1-infected children were treated with ritonavir for 12 weeks followed by triple drug combination treatment, and the kinetics of virus decay in plasma, ritonavir concentration and CD4 cell counts were measured. A robust multivariate pattern recognition method was used for prediction of the longterm virological responses. RESULTS: The virus decay rate constants calculated from measurements of plasma viral RNA concentrations on the first, second, third, fourth and seventh day on therapy, the drug concentrations in the plasma on day seven, and the pretreatment levels of viral RNA and CD4 cell counts, correlated with long-term levels of plasma HIV-1 RNA. The combination of these parameters contained sufficient information for correct and robust prediction of the long-term response in 88% of the treated children. The predictions of individual responses were stable as demonstrated by a cross-validation analysis, which was highly statistically significant (r=0.87) and specific. CONCLUSION: These results demonstrate that multiple parameters determine the response to antiretroviral therapy and offer a very early measure of individual long-term responses, suggesting that treatment could be optimized after few days of therapy.

Pharmacokinetics of the protease inhibitor KNI-272 in plasma and cerebrospinal fluid in nonhuman primates after intravenous dosing and in human immunodeficiency virus-infected children after intravenous and oral dosing.

KNI-272 is a human immunodeficiency virus (HIV) protease inhibitor with potent activity in vitro. We studied the pharmacokinetics of KNI-272 in the plasma and cerebrospinal fluid (CSF) of a nonhuman primate model and after intravenous and oral administration to children with HIV infection. Plasma and CSF were sampled over 24 h after the administration of an intravenous dose of 50 mg of KNI-272 per kg of body weight (approximately 1,000 mg/m2) to three nonhuman primates. The pharmacokinetics of KNI-272 were also studied in 18 children (9 males and 9 females; median age, 9.4 years) enrolled in a phase I trial of four dose levels of KNI-272 (100, 200, 330, and 500 mg/m2 per dose given four times daily). The plasma concentration-time profile of KNI-272 in the nonhuman primate model was characterized by considerable interanimal variability and rapid elimination (clearance, 2.5 liters/h/kg; terminal half-life, 0.54 h). The level of drug exposure achieved in CSF, as measured by the area under the KNI-272 concentration-time curve, was only 1% of that achieved in plasma. The pharmacokinetics of KNI-272 in children were characterized by rapid elimination (clearance, 276 ml/min/m2; terminal half-life, 0.44 h), limited (12%) and apparently saturable bioavailability, and limited distribution (volume of distribution at steady state, 0.11 liter/kg). The concentrations in plasma were maintained above a concentration that is active in vitro for less than half of the 6-h dosing interval. There was no significant increase in CD4 cell counts or decrease in p24 antigen or HIV RNA levels. The pharmacokinetic profile of KNI-272 may limit the drug's efficacy in vivo. It appears that KNI-272 will play a limited role in the treatment of HIV-infected children.

A phase I/II study of the protease inhibitor indinavir in children with HIV infection.

BACKGROUND: Indinavir, an inhibitor of the human immunodeficiency virus type 1 (HIV-1) protease, is approved for the treatment of HIV infection in adults when antiretroviral therapy is indicated. We evaluated the safety and pharmacokinetic profile of the indinavir free-base liquid suspension and the sulfate salt dry-filled capsules in HIV-infected children, and studied its preliminary antiviral and clinical activity in this patient population. In addition, we evaluated the pharmacokinetic profile of a jet-milled suspension after a single dose. METHODS: Previously untreated children or patients with progressive HIV disease despite antiretroviral therapy or with treatment-associated toxicity were eligible for this phase I/II study. Three dose levels (250 mg/m2, 350 mg/m2, and 500 mg/m2 per dose given orally every 8 h) were evaluated in 2 age groups (<12 years and >/=12 years). Indinavir was initially administered as monotherapy and then in combination with zidovudine and lamivudine after 16 weeks. RESULTS: Fifty-four HIV-infected children (ages 3.1 to 18.9 years) were enrolled. The indinavir free-base suspension was less bioavailable than the dry-filled capsule formulation, and therapy was changed to capsules in all children. Hematuria was the most common side effect, occurring in 7 (13%) children, and associated with nephrolithiasis in 1 patient. The combination of indinavir, lamivudine, and zidovudine was well tolerated. The median CD4 cell count increased after 2 weeks of indinavir monotherapy by 64 cells/mm3, and this was sustained at all dose levels. Plasma ribonucleic acid levels decreased rapidly in a dose-dependent way, but increased toward baseline after a few weeks of indinavir monotherapy. CONCLUSIONS: Indinavir dry-filled capsules are relatively well tolerated by children with HIV infection, although hematuria occurs at higher doses. Future studies need to evaluate the efficacy of indinavir when combined de novo with zidovudine and lamivudine.

A phase I/II study of the protease inhibitor ritonavir in children with human immunodeficiency virus infection.

BACKGROUND: Ritonavir, a potent antiretroviral protease inhibitor, has been approved for the treatment of adults and children with human immunodeficiency virus (HIV) infection. In a phase I/II study, we assessed the safety, tolerability, and pharmacokinetic profile of the oral solution of ritonavir in HIV-infected children and studied the preliminary antiviral and clinical effects. METHODS: HIV-infected children between 6 months and 18 years of age were eligible. Four dose levels of ritonavir oral solution (250, 300, 350, and 400 mg/m given every 12 hours) were evaluated in two age groups (2 years). Ritonavir was administered alone for the first 12 weeks and then in combination with zidovudine and/or didanosine. Clinical and laboratory parameters were monitored every 2 to 4 weeks. RESULTS: A total of 48 children (median age, 7.7 years; range, 0.5 to 14.4 years) were included in this analysis. Dose-related nausea, diarrhea, and abdominal pain were the most common toxicities and resulted in discontinuation of ritonavir in 7 children. Ritonavir was well absorbed at all dose levels, and plasma concentrations reached a peak 2 to 4 hours after a dose. CD4 cells counts increased by a median of 79 cells/mm3 after 4 weeks of monotherapy and were maintained throughout the study. Plasma HIV RNA decreased by 1 to 2 log10 copies/mL within 4 to 8 weeks of ritonavir monotherapy, and this level was sustained in patients enrolled at the highest dose level of 400 mg/m for the 24-week period. CONCLUSIONS: The oral solution of ritonavir has potent antiretroviral activity as a single agent and is relatively well tolerated by children when administered alone or in combination with zidovudine or didanosine.

Protease inhibitor and triple-drug therapy: cellular immune parameters are not restored in pediatric AIDS patients after 6 months of treatment.

OBJECTIVE: To assess whether treatment of HIV-positive children by antiretroviral drugs for a 6-month period would improve immune function significantly. DESIGN AND METHODS: Immunological assessment of 89 HIV-positive children who received protease inhibitor monotherapy for 12-16 weeks as part of phase I/II studies, followed by triple antiretroviral therapy for an additional 12 weeks, was conducted. Immunological parameters were assessed in vitro at four time points (at enrollment, at weeks 2-4, at weeks 12-16, and at weeks 24-28). Assessments included: cytokine production by monocytes, T-cell proliferation to mitogen or recall antigens (including an HIV antigen) and apoptotic cell death. Plasma levels of tumor necrosis factor (TNF)-alpha and soluble TNF receptor (sTNF-R) were also measured, in addition to CD4+ T-lymphocyte counts and viral load. In addition, limited analyses were performed on samples from 17 children after 120 weeks of therapy, including 104 weeks of triple therapy. RESULTS: At enrollment, the 89 children exhibited severe immune defects. Antiretroviral therapy raised CD4+ T-lymphocyte counts significantly and decreased viral loads. In contrast, the in vitro immune parameters studied were not improved, except for plasma levels of sTNF-RII which decreased in parallel with the decrease in viral load. In addition, there was a trend towards increased skin test reactivity for the ritonavir-treated children. No differences were seen in the immune parameters whether the patients were treated with mono- or triple therapy. Results obtained after 120 weeks of therapy demonstrated that defective interleukin-12 production was not restored by long-term therapy. CONCLUSIONS: After 6 months of therapy, with the exception of decreased sTNF-RII levels, and a trend towards increased skin test reactivity, restoration of several defective cellular immune responses did not occur despite significantly decreased viral loads and increased CD4+ T-lymphocyte counts.

Interleukin-4 suppresses antifungal activity of human mononuclear phagocytes against Candida albicans in association with decreased uptake of blastoconidia.

Pathogenesis of invasive candidiasis may involve regulatory activities of Th2 immunity on phagocytic host defenses. The effects of interleukin (IL)-4 on antifungal capacity of human mononuclear phagocytes against Candida albicans were studied. Incubation of adherent mononuclear leukocytes from healthy donors with IL-4 (1-5 ng ml(-1)) at 37 degrees C for 2-4 days suppressed uptake of C. albicans blastoconidia in the presence of human serum (P < or = 0.01), and anti-IL-4 inhibited its suppressive effect. The effect of IL-4 was protein synthesis-dependent. Interferon-gamma (0.25-25 ng ml(-1)), granulocyte-macrophage colony-stimulating factor (CSF, 20 ng ml(-1)), macrophage-CSF (15 ng ml(-1)) but not IL-10 (100 ng ml(-1)) somewhat counteracted the suppressive effect of IL-4. In contrast, mannose receptor-mediated uptake of blastoconidia in the absence of serum was increased by IL-4. Killing of conidia was decreased after incubation of morphonuclear leukocytes with IL-4 for 2 days (P < 0.05). While superoxide anion production in response to phorbol myristate acetate was decreased by IL-4 (P < 0.05), it was not altered in response to blastoconidia and pseudohyphae. Morphonuclear leukocyte-induced pseudohyphal damage also remained unaltered. These findings suggest that IL-4 plays its detrimental role in invasive candidiasis by predominantly suppressing uptake and killing of blastoconidia by morphonuclear leukocytes. Anti-IL-4, IFN-gamma, GM-CSF and M-CSF appear to counteract suppression of morphonuclear leukocyte phagocytic activity suggesting new approaches to the management of disseminated candidiasis.