Adherence to assigned dosing regimen and sustained virological response among chronic hepatitis C genotype 1 patients treated with boceprevir plus peginterferon alfa-2b/ribavirin.

BACKGROUND: Adherence to therapeutic regimens affects the efficacy of peginterferon alfa (P) and ribavirin (R) therapy in patients with chronic hepatitis C virus genotype 1. AIM: To determine if medication adherence impacts efficacy [sustained virological response (SVR)] with triple therapy that includes boceprevir (BOC) plus P/R. METHODS: Adherence was determined in two Phase 3 clinical studies with BOC: SPRINT-2 (previously untreated patients) and RESPOND-2 (patients who failed previous therapy with P/R). Adherence to the assigned duration of the dosing regimen and adherence to the three times a day (t.d.s.) dosing interval of 7-9 h for BOC were assessed by the recording of data from patients' dosing diaries and by the amount of study drug dispensed and returned. RESULTS: Most patients (63-71%) adhered to ≥80% of their assigned treatment duration and achieved SVR rates of 86-90%. In contrast, patients who adhered to <80% of their assigned treatment duration achieved SVR rates of 8-32% (P < 0.0001), particularly low in patients who failed previous therapy (SVR = 8-15%). Different rates of adherence (<60% to >80%) to the t.d.s. dosing interval (7-9 h) with BOC did not influence the SVR rates (SVR = 60-83%) with the exception of patients who failed previous treatment and adhered to <60% of the t.d.s. dosing interval with BOC (SVR = 48-50%; P = 0.005). CONCLUSIONS: The achievement of an SVR is more dependent on adherence to the assigned duration of treatment than adherence to the t.d.s. dosing interval with boceprevir. Adherence to >60% of t.d.s. dosing with boceprevir is important in patients who failed previous therapy.

CMV-IVIG for prevention of Epstein Barr virus disease and posttransplant lymphoproliferative disease in pediatric liver transplant recipients.

A randomized controlled trial of CMV-IVIG (cytomegalovirus-intravenous immunoglobulin) for prevention of Epstein Barr virus (EBV) posttransplant lymphoproliferative disease (PTLD) in pediatric liver transplantation (PLTx) recipients was begun in Pittsburgh and subsequently expanded to four additional sites. Protocol EB viral loads were obtained in a blinded fashion; additional loads could be obtained for clinical indications. Patients were followed for 2 years post-LTx. Eighty-two evaluable patients (39 CMV-IVIG, 43 placebo) developed 18 episodes of EBV disease (7 CMV-IVIG, 11 placebo) including nine cases of PTLD (three CMV-IVIG, six placebo). No significant differences were seen in the adjusted 2-year EBV disease-free rate (CMV-IVIG 79%, placebo 71%) and PTLD-free rate (CMV-IVIG 91%, placebo 84%) between treatment and placebo groups at 2 years (p > 0.20). The absence of significant effect of CMV-IVIG may be explained by a lack of efficacy of the drug or limitations of sample size.

The role of quantitative Epstein-Barr virus polymerase chain reaction and preemptive immunosuppression reduction in pediatric liver transplantation: a preliminary experience.

BACKGROUND: Risk factors for the development of posttransplant lymphoproliferative disease (PTLD), a major cause of morbidity and mortality after pediatric liver transplantation, are primary Epstein-Barr virus (EBV) infection and intensity of immunosuppression. The authors assessed monitoring of EBV replication and preemptive immunosuppression reduction in pediatric liver transplant recipients. METHODS: The authors prospectively followed monthly EBV-quantitative competitive polymerase chain reaction to measure EBV replication in 23 patients who underwent liver transplant between July 1997 and November 1998. Preemptive immunosuppression reduction was instituted for significant EBV replication. Patients were followed up for at least 1 year and divided in two groups for analysis (group 1, pretransplant seronegative for EBV [13 patients]; group 2, seropositive for EBV [10 patients]). RESULTS: In group 1, 9 of 13 patients had positive polymerase chain reaction results at a mean time of 22.4 weeks after transplantation. All but one of these patients were asymptomatic. In seven of nine patients, preemptive immunosuppression reduction was undertaken without development of PTLD or rejection. In two of nine patients, immunosuppression could not be continuously reduced, and both patients experienced low-grade and medically responsive PTLD. In no patient in group 2 did an EBV-positive viral load or PTLD develop. CONCLUSIONS: Prospective longitudinal measurement of EBV by quantitative competitive polymerase chain reaction permits early detection of asymptomatic viral replication. Subsequent preemptive reduction of immunosuppression may prevent the progression to PTLD.

Immunization of pediatric solid organ transplant candidates and recipients.

Organ transplantation has evolved from an experimental procedure to an accepted treatment for otherwise irreversible or congenital disorders. The immunosuppression necessary to prevent rejection enhances the severity of many infectious diseases and may potentially attenuate the response to vaccines designed to prevent disease. In spite of the frequency and severity of infectious diseases in organ transplant recipients, many children are not fully vaccinated before transplantation. The safety and efficacy of many of the currently available vaccines for solid organ transplant recipients have not been evaluated. We review the currently available data on immunization safety and efficacy, discuss experimental vaccines, and outline strategies to avoid vaccine-preventable diseases in pediatric organ transplant recipients.

Clinical presentation of tuberculosis in culture-positive children. Pediatric Tuberculosis Consortium.

BACKGROUND: Because tuberculosis (TB) in children implies recent infection, children serve as sentinels for disease transmission within a community. Despite the significance of diagnosing tuberculosis in children, most cases are diagnosed on clinical evidence rather than laboratory findings. METHODS: We analyzed the demographic and clinical presentation of 156 children with culture proven tuberculosis using Epi-Info Version 6. RESULTS: Although the clinical characteristics of this population were generally consistent with those seen in previous studies, several unexpected results were observed. Boys were overrepresented in the group of very young children (72% < 1 year). Many of the children had coexisting diseases not known to predispose to TB (37%). Cavitation, usually observed in older children, was seen in four children < or = 1 year of age. Few children were homeless or HIV-infected, but many (42%) lived in female-headed households. Of the adult contacts at risk for TB, many (49%) were recent immigrants to the US. Overall 34% of the population was either foreign born or the children of recent immigrants. CONCLUSIONS: This series of 156 culture-positive children provides an understanding of the risk factors and clinical presentation of pediatric tuberculosis. The data emphasize the impact of the child's environment on the risk for tuberculosis.

Prospective longitudinal analysis of quantitative Epstein-Barr virus polymerase chain reaction in pediatric liver transplant recipients.

BACKGROUND: Posttransplant lymphoproliferative disease (PTLD) remains a significant cause of morbidity and mortality in pediatric liver transplant recipients. Epstein-Barr Virus (EBV) mismatch associated with more prevalent use of split-liver, reduced size, and living-related transplants has increased the risk of primary EBV infection and subsequent PTLD. Early identification of EBV viremia may reduce the risk of PTLD, because it allows for early adjustment of immunosuppression and antiviral therapy. METHODS: EBV viral load was measured monthly by quantitative competitive polymerase chain reactions in three pediatric liver transplant recipients. RESULTS: Onset of EBV viremia was documented in one recipient. Established EBV viremia was followed in the other two recipients (one with chronic rejection and one with PTLD) who were initially tested once monitoring was initiated in our program. CONCLUSIONS: EBV quantitative competitive polymerase chain reactions may represent a promising way to follow EBV viral load and potentially prevent the development of PTLD.

Policy guidelines for the utilization of formalin-fixed, paraffin-embedded tissue sections: the UNC SPORE experience. University of North Carolina Specialized Program of Research Excellence.

Paraffin blocks represent a valuable resource that has allowed investigators to apply today's technology to address scientific questions in a shorter period of time and in more diverse populations than would have been possible with fresh or frozen tissue. However, in addition to being an exhaustible resource, there is concern regarding the appropriate use of these tissues, both with respect to medical or legal considerations and quality control and quality assurance practices. We describe policy guidelines to address these concerns, including: safeguards to address medical/legal and patient confidentiality issues, quality control and quality assurance for tissue sectioning, processing and storage, database management for sample tracking, and scientific review for utilization of specimens. These policies and procedures have been developed and implemented by the University of North Carolina (UNC) Specialized Program of Research Excellence (SPORE) in the Breast Cancer Immunohistochemistry (IHC) Core laboratory, in collaboration with our study pathologists, participants, and research investigators. It is our hope that the information and experience described here may stimulate discussion that can ultimately lead to a uniform policy for handling formalin-fixed paraffin-embedded tissues in research.

Identification of genes differentially expressed in Mycobacterium tuberculosis by differential display PCR.

RNA arbitrarily-primed differential display PCR (RAP-PCR) was used to identify and isolate genes differentially expressed between attenuated (H37Ra) and virulent (H37Rv, Erdman) laboratory strains of Mycobacterium tuberculosis (Mtb). Using this method, cDNA fragments showing homology to three known mycobacterial genes and six putative novel genes in mycobacterial cosmid vectors were identified. Among the putative novel Mtb genes identified, we found: (1) gene MTV041.29, containing multiple tandem repetitive sequences and encoding a putative Gly-, Ala, Asn-rich protein (PPE family); (2) gene MTV004.03, containing the AT10S repetitive gene sequence; (3) gene MTV028.09, encoding a hypothetical protein of unknown function; (4) genes MTCY78.20,21, possibly encoding two hypothetical proteins of unknown function; (5) gene MTCY01A6.09, encoding a putative novel ferrodoxin dependent glutamate synthase; and (6) gene MTCY31.20, encoding a putative cyclohexanone monooxygenase. Using gene specific primers in a second differential display PCR and by RT-PCR amplification, novel genes 1, 2, 3 and 4 were shown to be differentially up-regulated in the attenuated Mtb strain H37Ra compared to H37Rv and Erdman strain. Overall, we demonstrated that RAP-PCR, as a first step, is a quick and sensitive method for the identification and isolation of novel genes expressed in Mtb. Because of limitations inherent to the lack of specificity of arbitrary primers in the RAP-PCR method, a second differential display PCR and RT-PCR amplification with gene-specific primers was necessary in order to confirm differential expression of the identified genes.

Adverse reactions to thalidomide in patients infected with human immunodeficiency virus.

Thalidomide is emerging as a useful agent in the management of several complications of disease due to human immunodeficiency virus (HIV). We conducted three prospective studies of 56 HIV-infected patients who were treated with thalidomide for 14-21 days; 24 (43%) of these patients discontinued therapy owing to adverse reactions. Cutaneous and/or febrile reactions were the most frequent toxicities, arising in 20 (36%) of the patients. These reactions occurred after a mean interval (+/-SD) of 10 +/- 3 days and were associated with significantly lower CD4 T lymphocyte counts in reactors than in nonreactors (median count, 52.5/mm3 vs. 242 cells/mm3, respectively; P = .009). Four of four rechallenged patients experienced accelerated hypersensitivity; hypotension occurred in one case. Although sedation was an almost universal side effect among the patients, it was moderate or severe in only seven (13%); constipation was moderate or severe in five (9%) of the patients. Severe neuropathic symptoms and mood changes were each noted in two (4%) of the 56 patients. We conclude that the increasing use of thalidomide to treat HIV-infected patients must be accompanied by recognition of the drug's increased potential for toxicity in this population.

Penetration of the blood-brain barrier: enhancement of drug delivery and imaging by bacterial glycopeptides.

The blood-brain barrier restricts the passage of many pharmacological agents into the brain parenchyma. Bacterial glycopeptides induce enhanced blood-brain barrier permeability when they are present in the subarachnoid space during meningitis. By presenting such glycopeptides intravenously, blood-brain barrier permeability in rabbits was enhanced in a reversible time- and dose-dependent manner to agents < or = 20 kD in size. Therapeutic application of this bioactivity was evident as enhanced penetration of the antibiotic penicillin and the magnetic resonance imaging contrast agent gadolinium-diethylene-triamine-pentaacetic acid into the brain parenchyma.

Effect of thalidomide on the inflammatory response in cerebrospinal fluid in experimental bacterial meningitis.

In experimental bacterial meningitis in rabbits, the inflammatory process is largely mediated by cytokines such as IL-1 and TNF-alpha. Since thalidomide has been shown to inhibit TNF-alpha production, experiments were carried out to determine whether the drug can modulate the inflammatory response to either lysates of H. influenzae (gram negative) or heat killed S. pneumoniae (gram positive) in rabbits. The introduction of a lysate of H. influenzae into the CSF of rabbits causes a very acute inflammatory response, as indicated by a rapid increase in TNF-alpha levels in the CSF and a concomitantly rapid leukocytosis. In contrast, the introduction of heat killed S. pneumoniae, induces a more indolent inflammatory response which also wanes more slowly. Thalidomide treatment reduces TNF-alpha production in both experimental systems, but has a greater effect on the more indolent gram positive inflammatory response in which peak TNF-alpha levels in the CSF are reduced by > 50%. Also, a sustained inhibition of leukocytosis is observed in the inflammatory response to heat-killed gram positive bacteria. In meningeal inflammation induced by the Gram negative lysate, treatment with thalidomide results in only a 29% inhibition of TNF-alpha release into the CSF. In contrast to the drug effect on TNF-alpha, thalidomide treatment does not significantly affect IL-1 levels in these models of rabbit bacterial meningitis.

Thalidomide treatment reduces tumor necrosis factor alpha production and enhances weight gain in patients with pulmonary tuberculosis.

BACKGROUND: The monocyte-derived cytokine, tumor necrosis factor alpha (TNF alpha), is essential for host immunity, but overproduction of this cytokine may have serious pathologic consequences. Excess TNF alpha produced in pulmonary tuberculosis may cause fevers, weakness, night sweats, necrosis, and progressive weight loss. Thalidomide (alpha-N-phthalimidoglutarimide) has recently been shown to suppress TNF alpha production by human monocytes in vitro and to reduce serum TNF alpha in leprosy patients. We have therefore conducted a two-part placebo-controlled pilot study of thalidomide in patients with active tuberculosis to determine its effects on clinical response, immune reactivity, TNF alpha levels, and weight. MATERIALS AND METHODS: 30 male patients with active tuberculosis, either human immunodeficiency virus type 1 positive (HIV-1+) or HIV-1-, received thalidomide or placebo for single or multiple 14 day cycles. Toxicity of the study drug, delayed type hypersensitivity (DTH), cytokine production, and weight gain were evaluated. RESULTS: Thalidomide treatment was well tolerated, without serious adverse events. The drug did not adversely affect the DTH response to purified protein derivative (PPD), total leukocyte, or differential cell counts. TNF alpha production was significantly reduced during thalidomide treatment while interferon-gamma (IFN gamma) production was enhanced. Daily administration of thalidomide resulted in a significant enhancement of weight gain. CONCLUSIONS: The results indicate that thalidomide is well tolerated by patients receiving anti-tuberculosis therapy. Thalidomide treatment reduces TNF alpha production both in vivo and in vitro and is associated with an accelerated weight gain during the study period.

Pharmacokinetics of fluconazole in cerebrospinal fluid and serum of rabbits: validation of an animal model used to measure drug concentrations in cerebrospinal fluid.

Complete concentration-time data describing the pharmacokinetics of fluconazole in the cerebrospinal fluid (CSF) following a single dose are not available for humans or animals. We studied the pharmacokinetics of fluconazole with an indwelling intracisternal needle as described by R.G. Dacey and M.A. Sande (Antimicrob. Agents Chemother. 6:437-441, 1974). To determine whether the presence of an intracisternal needle alters pharmacokinetics in the CSF, we validated this model with uninfected rabbits by measuring pharmacokinetic constants following direct intracisternal and intravenous administration of fluconazole. Following direct injection, there was no alteration of elimination rates in the CSF with increasing sample number or time. Following intravenous administration, the penetration and kinetic constants were the same in individual animals from which multiple CSF samples were obtained as in a composite subject constructed by pooling virgin samples from different animals. The presence of the intracisternal needle did not alter CSF chemistry or leukocyte counts, and erythrocyte contamination was < 0.001%. While drug concentrations were measured by a microbiological assay, we also compared the sensitivity and reproducibility of a high-performance liquid chromatography (HPLC) assay with those of the microbiological assay. Following a single intravenous dose, the maximum concentration of the drug in serum, the time to maximum concentration of the drug in serum, the terminal elimination half-life in the CSF, and the percent penetration by fluconazole were 6.12 micrograms/ml, 1 h, 9.0 h, and 84.3%, respectively. We conclude that the sampling of CSF via an indwelling needle does not alter fluconazole pharmacokinetics, cause inflammation, or alter chemical parameters; that the microbiological assay is at least equivalent in sensitivity and reproducibility to the HPLC assay; and that robust parameters describing the pharmacokinetics of fluconazole are possible with this model.

Characterization of virus-like particles produced by the expression of rotavirus capsid proteins in insect cells.

Rotaviruses are triple-layered particles that contain four major capsid proteins, VP2, VP4, VP6, and VP7, and two minor proteins, VP1 and VP3. We have cloned each of the rotavirus genes coding for a major capsid protein into the baculovirus expression system and expressed each protein in insect cells. Coexpression of different combinations of the rotavirus major structural proteins resulted in the formation of stable virus-like particles (VLPs). The coexpression of VP2 and VP6 alone or with VP4 resulted in the production of VP2/6 or VP2/4/6 VLPs, which were similar to double-layered rotavirus particles. Coexpression of VP2, VP6, and VP7, with or without VP4, produced triple-layered VP2/6/7 or VP2/4/6/7 VLPs, which were similar to native infectious rotavirus particles. The VLPs maintained the structural and functional characteristics of native particles, as determined by electron microscopic examination of the particles, the presence of nonneutralizing and neutralizing epitopes on VP4 and VP7, and hemagglutination activity of the VP2/4/6/7 VLPs. The production of VP2/4/6 particles indicated that VP4 interacts with VP6. Cell binding assays performed with each of the VLPs indicated that VP4 is the viral attachment protein. Chimeric particles containing VP7 from two different G serotypes also were obtained. The ability to express individual proteins or to coexpress different subsets of proteins provides a system with which to examine the interactions of the rotavirus structural proteins, the role of individual proteins in virus morphogenesis, and the feasibility of a subunit vaccine.

Antiinflammatory effects in experimental meningitis of prokaryotic peptides that mimic selectins.

The lectin domains of two subunits of pertussis toxin, S2 and S3, share amino acid sequence similarity with the lectin domains of the eukaryotic selectin family. During inflammation, selectins appear on endothelial cells and promote recruitment of leukocytes by reversibly binding carbohydrates. Synthetic peptides representing the carbohydrate recognition domains of S2 and S3 competitively inhibited adherence of neutrophils to endothelial cells in vitro. For some peptides, this antiinflammatory effect occurred without up-regulation of the function of the leukocyte integrin CD11b/CD18. Intravenous administration of peptides to animals with meningitis disrupted recruitment of leukocytes into the cerebrospinal fluid. These findings indicate that peptides derived from prokaryotic members of the selectin family have therapeutic antiinflammatory potential.

A structure-activity relationship for induction of meningeal inflammation by muramyl peptides.

Components of bacterial peptidoglycans have potent biological activities, including adjuvant effects, cytotoxicity, and induction of sleep. Mixtures of peptidoglycan components also induce inflammation in the lung, subarachnoid space, and joint, but the structural requirements for activity are unknown. Using a rabbit model for meningitis, we determined the biological activities of 14 individual muramyl peptides constituting > 90% of the peptidoglycan of the gram-negative pediatric pathogen Haemophilus influenzae. Upon intracisternal inoculation, most of the muropeptides induced leukocytosis in cerebrospinal fluid (CSF), influx of protein into CSF, or brain edema, alone or in combination. The disaccharide-tetrapeptide, the major component of all gram-negative peptidoglycans, induced CSF leukocytosis and protein influx at doses as low as 0.4 microgram (0.42 nM). Modification of the N-acetyl muramic acid or substitution of the alanine at position four in the peptide side chain decreased leukocytosis but enhanced brain edema. As the size of the muropeptide increased, the inflammatory activity decreased. Muropeptide carrying the diaminopimelyl-diaminopimelic acid cross-link specifically induced cytotoxic brain edema. These findings significantly expand the spectrum of biological activities of natural muramyl peptides and provide the basis for a structure-activity relationship for the inflammatory properties of bacterial muropeptides.

Composition of the peptidoglycan of Haemophilus influenzae.

The composition of the peptidoglycan of Haemophilus influenzae was determined by analyzing glycopeptides generated by M1 muramidase hydrolysis using high pressure liquid chromatography, fast atom bombardment mass spectrometry, and fast atom bombardment collisionally activated dissociation tandem mass spectrometry, and amino acid analysis. The structures of 17 glycopeptides, representing 96% of the total peptidoglycan, were ascertained. Fifteen glycopeptides resembled species described for Escherichia coli peptidoglycan (Glauner, B., and Schwarz, U. (1983) The Target of Penicillin (Hackenbeck, R., ed), Walter de Gruyter, Berlin pp. 29-34) as compared with 9 in common with Bordetella pertussis (Tuomanen, E., Schwartz, J., Sande, S., Light, K., and Gage, D. (1989) J. Biol. Chem. 264, 11093-11098). Substitutions for L-alanine in the fourth position of the stem peptide included glycine, aspartic acid, and serine. The peptidoglycan was 27% cross-linked, 2% of which formed between diaminopimelic acid residues. No species was identified containing lysyl-arginine residues characteristic of lipoprotein. The peptidoglycan of non-beta-lactamase-mediated antibiotic-resistant H. influenzae differed from that of sensitive strains by an increase in the amount of disaccharide tripeptides and a decrease in 1,6-anhydro dimers. Both changes were transformable properties that changed in a stepwise fashion in parallel with the degree of antibiotic resistance.