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Biomedical subjects

Lawrence Corey

Publications and source records attributed to Lawrence Corey.

At least 91 records · Page 5Linked to original sources
PubMed2004

Prevention of herpes simplex virus type 2 transmission with antiviral therapy.

Worldwide, herpes simplex virus type 2 (HSV-2) infection is the biggest cause of genital ulcer disease, and is responsible for the majority of cases of genital herpes. The risk of transmitting genital herpes to a partner is one of the leading causes of psychological distress for those with the disease. Antiviral compounds available for the treatment of genital herpes are known to reduce clinical recurrence rates and HSV shedding. This understanding provided impetus for a randomized, placebo-controlled study to assess the ability to interrupt transmission of HSV using oral valaciclovir therapy (500 mg, once daily). The study enrolled 1484 immunocompetent, heterosexual, monogamous couples in stable relationships where both partners were aware of the source partner's infection and the source partner had symptomatic genital herpes. Valaciclovir reduced the risk of transmitting HSV-2 infection by 48%. Furthermore, valaciclovir reduced the risk of clinical disease in the susceptible partner by 75%. As a result, the International Herpes Management Forum (IHMF) now recommends that physicians offer suppressive valaciclovir therapy to immunocompetent individuals concerned about transmitting genital herpes to a heterosexual partner, and advises safer sex behaviour, including the use of condoms, to prevent genital herpes transmission.

Acyclovir↗
PubMed2003

Remission of HHV-8 and HIV-associated multicentric Castleman disease with ganciclovir treatment.

Multicentric Castleman disease (MCD) is a lymphoproliferative disorder associated with human herpesvirus 8 (HHV-8) infection among persons with human immunodeficiency virus (HIV) infection. Treatment often includes chemotherapy, and progression to non-Hodgkin lymphoma frequently occurs. MCD is characterized in part by active HHV-8 replication, and many of the symptoms of MCD may be attributable to viral gene products. We describe the effect of ganciclovir on the clinical and virologic course of MCD in a series of 3 case reports. Two patients experienced a reduction in the frequency of episodic flares of MCD and detectable HHV-8 DNA with intravenous or oral ganciclovir, whereas the third patient recovered from an acute episode of renal and respiratory failure with intravenous ganciclovir therapy. These data provide in vivo evidence for the utility of antiviral agents against HHV-8 in the management of MCD.

Administration, Oral↗
PubMed2003

Polymerase chain reaction for detection of herpes simplex virus (HSV) DNA on mucosal surfaces: comparison with HSV isolation in cell culture.

This study compared the rate of isolation of herpes simplex virus (HSV) from >36000 samples of mucosal secretions obtained from 296 HSV-infected persons versus the rate of detection of HSV DNA, by means of a real-time quantitative polymerase chain reaction (PCR) assay. Overall, HSV was isolated in 3.0% of samples, and HSV DNA was detected in 12.1% of samples. The mean number of HSV DNA copies was 10(4.9) in samples obtained on days when HSV lesions were present and 10(4.4) in samples from days when HSV lesions were absent. There was a linear relationship between the ability to isolate virus in culture and the log number of copies of HSV DNA in the sample; this relationship persisted in samples from men or women, in samples from human immunodeficiency virus-negative or -positive participants, and in samples obtained on days when lesions were present or absent. In home-collected specimens, the ratio of PCR positivity to viral-culture positivity rose from 3.8:1 in the winter to 8.8:1 in the summer months, reflecting the lability of viral-culture specimens transported during warm weather.

Adult↗
PubMed2003

Immunodominance among herpes simplex virus-specific CD8 T cells expressing a tissue-specific homing receptor.

The study of immunodominance within microbe-specific CD8 T cell responses has been challenging. We used a previously undescribed approach to create unbiased panels of CD8 cytotoxic T lymphocyte clones specific for herpes simplex virus type 2, a pathogen with a complex genome encoding at least 85 polypeptides. Circulating herpes simplex virus type 2-specific cells were enriched and cloned after sorting for expression of the skin homing-associated receptor, cutaneous lymphocyte-associated antigen, bypassing restimulation with antigen. The specificity of the resultant cytotoxic clones was determined. Clonal frequencies were compared with each other and with the total number of cytotoxic clones. For each subject within the homing receptor-positive compartment, the CD8 cytotoxic response was dominated by T cells specific for only a few peptides. Previously undescribed antigens and epitopes in viral tegument, capsid, or scaffold proteins were immunodominant in some subjects. Clone enumeration analyses were confirmed in some subjects with dominance studies by using herpes simplex mutants, vaccinia recombinants, and/or enzyme-linked immune spots. We conclude that among circulating cells expressing a homing-associated receptor, during chronic herpes type 2 infection, the CD8 T cell response becomes quite focused despite the presence of many potential antigenic peptides.

Antigens, CD↗
PubMed2003

Itraconazole versus fluconazole for prevention of fungal infections in patients receiving allogeneic stem cell transplants.

Prophylactic fluconazole prevents candidiasis; however, this drug has no activity against molds. We performed a randomized trial to determine whether prophylactic itraconazole prevents invasive mold infections (IMIs). A total of 304 patients receiving allogeneic stem cell transplants (SCT) were randomized to receive fluconazole (400 mg/d) or itraconazole (oral solution 2.5 mg/kg 3 times daily, or intravenous 200 mg daily) for 180 days after SC transplantation, or until 4 weeks after discontinuation of graft-versus-host disease (GVHD) therapy. Proven or probable invasive fungal infections (IFI) were evaluated by intent-to-treat and "on-treatment" analyses. More patients in the itraconazole arm developed hepatotoxicities, and more patients were discontinued from itraconazole because of toxicities or gastrointestinal (GI) intolerance (36% versus 16%, P <.001). Intent-to-treat analysis demonstrated no difference in the incidence of IFI during the intended study period (fluconazole 16% versus itraconazole 13%, P =.46); however, fewer patients in the itraconazole arm developed IFI on treatment (fluconazole 15% versus itraconazole 7%, P =.03). Itraconazole provided better protection against IMI (fluconazole 12% versus itraconazole 5%, P =.03), but similar protection against candidiasis (3% versus 2%, P =.69). There was no difference in overall or fungal-free survival. Itraconazole appears to prevent IMI in the subset of patients who tolerate the drug; however, toxicities and poor tolerability limit its success as prophylactic therapy.

Adult↗
PubMed2003

Cyclophosphamide metabolism is affected by azole antifungals.

We performed a randomized trial to compare the safety and efficacy of itraconazole with fluconazole in preventing fungal infections in patients undergoing allogeneic stem cell transplantation (SCT). Itraconazole (intravenous 200 mg daily, or oral solution 2.5 mg/kg 3 times daily) and fluconazole (intravenous or oral, 400 mg daily) were administered with the start of conditioning therapy, until at least 120 days after SCT. After enrollment of the first 197 patients, a data and safety monitoring board reviewed potential drug-related toxicities. Patients who received itraconazole developed higher serum bilirubin and creatinine values in the first 20 days after SCT, with highest values in patients who received itraconazole concurrent with cyclophosphamide (CY) conditioning. Analysis of CY metabolism in a subset of patients demonstrated higher exposure to toxic metabolites among recipients of itraconazole compared with fluconazole. These data suggest that azole antifungals, through differential inhibition of hepatic cytochrome P-450 isoenzymes, affect CY metabolism and conditioning-related toxicities.

Adolescent↗
PubMed2003

Immune reconstitution to cytomegalovirus after allogeneic hematopoietic stem cell transplantation: impact of host factors, drug therapy, and subclinical reactivation.

Reconstitution of cellular immunity by 3 months after hematopoietic stem cell transplantation (HSCT) is a critical determinant of the long-term success of the transplantation. We analyzed the factors affecting recovery of cytomegalovirus (CMV)-specific CD4+ and CD8+ function at 3 months after HSCT by univariate and multivariable analyses including source of stem cells (bone marrow vs peripheral blood stem cells [PBSCs]), age, sex, graft-versus-host disease (GVHD), steroid use, conditioning regimens, ganciclovir use, HLA matching, circulating CMV antigenemia, absolute CD4+ and CD8+ counts, and donor CMV serology. High-dose steroids and CD4+ count less than 100 x 10(9)/L were significant predictors of impaired CD4+ functional recovery in the multivariable analysis. High-dose steroids, bone marrow as a source of stem cells, and CD8+ count less than 50 x 10(9)/L were associated with impaired CD8+ function in the multivariable analysis. Steroids were found to impair both CD4+ and CD8+ function in a dose-dependent manner. In the absence of high-dose steroids, low-level subclinical CMV antigenemia was found to stimulate both CD4+ and CD8+ functional recovery in recipients of ganciclovir prophylaxis. There was no difference in immune reconstitution between those who received prophylactic ganciclovir versus antigenemia-guided pre-emptive therapy. Thus, absolute CD4+ and CD8+ counts less than 100 x 10(9)/L and 50 x 10(9)/L, respectively; bone marrow as the source of stem cells; and high-dose steroid use all predict delayed recovery of functional T-cell immunity at 3 months after transplantation. Subclinical CMV reactivation while on ganciclovir appears to be a potent stimulator of T-cell function. These findings have implications for vaccination and adoptive-immunotherapy strategies in this population.

Adolescent↗
PubMed2003

What constitutes efficacy for a human immunodeficiency virus vaccine that ameliorates viremia: issues involving surrogate end points in phase 3 trials.

Initial human immunodeficiency virus (HIV) vaccines are unlikely to prevent acquisition of HIV in all recipients. Moreover, several HIV vaccines are under evaluation that are designed to reduce viremia after acquisition of infection. Such vaccines could provide important benefits to delay HIV progression and to reduce transmission. The decision to license a vaccine on the basis of observed effects on virus load and other postinfection surrogate end points in an efficacy trial is complicated by uncertainty about whether the vaccine effects will persist and reliably predict clinical effects, and by the challenge in interpreting the data posed by treatment of some seroconverters with antiretroviral drugs. Here, we evaluate how analyses of certain surrogate end points can be used for inferring clinically significant vaccine effects and propose end points that could be evaluated in efficacy trials to support licensure. The assessment suggests that a vaccine demonstrating moderately durable effects to delay therapy and to ameliorate viremia merits consideration for licensure.

AIDS Vaccines↗
PubMed2003

Medicine. The need for a global HIV vaccine enterprise.

A new collaborative model of research is needed to increase resources, to prioritize the R (ii) to increase the pace, reduce the overlap, and more systematically explore the elements of and delivery systems for vaccines; (iii) to use common standards for the prompt comparative testing of vaccine candidates; (iv) to expand resources for manufacturing vaccine candidates to speed their use in human trials; and (v) to increase the capacity for international clinical trials and to focus this effort toward quickly measuring the effectiveness of vaccine protection as prototype vaccine candidates are identified.

AIDS Vaccines↗
PubMed2003

Rhinovirus infections in hematopoietic stem cell transplant recipients with pneumonia.

Little is known about the impact of human rhinovirus (HRV) and coronavirus infections in hematopoietic stem cell transplant (HSCT) recipients. We tested bronchoalveolar lavage (BAL) samples obtained from HSCT recipients with acute pulmonary infiltrates for HRV (n=122) and coronavirus (n=46) by reverse-transcriptase polymerase chain reaction. HRV RNA was detected in 6 (8%) of 77 patients, and coronavirus RNA was detected in 0 of 46 of BAL samples from HSCT recipients. The fatality rate in HRV-infected patients was high (83%), but all patients had significant coinfections, and the overall mortality rate was not different from that of patients who were negative for HRV in BAL samples. These results suggest that HRV may be a cause of lower respiratory tract infections in HSCT recipients and that its detection in BAL samples is associated with frequent copathogens. Whether the poor prognosis is due to HRV or the copathogen is not clear.

Adolescent↗
PubMed2003

T cell immunity to herpes simplex viruses in seronegative subjects: silent infection or acquired immunity?

During the course of investigating T cell responses to HSV among volunteers entering trials of investigational genital herpes vaccines, 6 of the 24 immunocompetent subjects with no prior history of oral/labial or genital herpes possessed HSV-specific T cell immunity but, by multiple determinants of even the most sensitive serological assays, remained seronegative to HSV-1 and -2. Of these six immune seronegative (IS; HSV-seronegative with HSV-specific T cell responses) subjects, two had transient HSV-specific T cell responses, while four had CD4(+) and CD8(+) T cell responses directed at HSV that persisted for up to 4 years. CD4(+) T cell clones were isolated that recognized and had high binding affinities to epitopes in HSV-2 tegument proteins. All six IS subjects had potential sexual exposure to an HSV-2-infected sexual partner. Oral and genital mucosal secretions were sampled and tested for the presence of infectious HSV and HSV DNA. No evidence of HSV was detected in >1500 samples obtained from these IS subjects. The identification of persistent T cell responses to HSV in seronegative subjects is a novel finding in the herpesvirus field and suggests either undetected infection or acquired immunity in the absence of infection. Understanding the basis of these acquired immune responses may be critical in developing effective vaccines for genital herpes.

Adult↗
PubMed2003

Innate immunity in human immunodeficiency virus infection: effect of viremia on natural killer cell function.

We examined the effect of viremia on cell contact and soluble factor-mediated suppression of endogenous human immunodeficiency virus (HIV) replication in CD4+ T cells from HIV-1-infected individuals by autologous natural killer (NK) and CD8+ T cells. NK cells suppressed HIV replication as effectively as did CD8+ T cells. Suppression of HIV replication by NK cell culture supernatant was predominantly mediated by CC-chemokine secretion and was considerably greater in patients without viremia than in patients with viremia. Furthermore, there was an inverse correlation between the level of viremia and the ability of NK cells and NK-derived supernatants to suppress virus replication. The ability of NK cells to control HIV replication was independent of levels of interferon-gamma expression and cytolytic activity. Our results demonstrate that NK-mediated suppression of HIV replication is as potent as that of CD8+ T cells; it is mediated predominantly by secretion of CC-chemokines, and the presence of viremia markedly impairs this NK-mediated inhibitory effect on HIV replication.

Adult↗
PubMed2003

Transferred herpes simplex virus immunity after stem-cell transplantation: clinical implications.

Herpes simplex virus (HSV) commonly reactivates after stem-cell transplantation (SCT), despite acyclovir prophylaxis. Whether HSV-seropositive recipients with HSV-seronegative or type-discordant donors had more frequent and severe HSV infections than those with HSV type-concordant donors was explored. Banked serum samples from HSV-positive SCT recipients and their donors were tested for the presence of HSV antibodies. HSV-1-positive SCT recipients from HSV-1-negative donors had more frequent and longer episodes than HSV-1-positive SCT recipients from HSV-1-positive donors; the proportion of patients receiving antiviral treatment for >10% of follow-up days was 27.4% versus 7.2% (P<.001). Both HSV-1 visceral infection (9.8% vs. 2.2%; P=.001) and acyclovir resistance (5.8% vs. 1.8%; P=.03) were more common in type-discordant than -concordant patients, respectively; these associations were confirmed in multivariable models. Serological testing of donors can identify patients who are at highest risk for HSV-related morbidity, for whom prolonged prophylaxis or donor vaccination (once available) could be considered.

Acyclovir↗
PubMed2003

Human herpesvirus 8: seroprevalence and correlates in prostitutes in Mombasa, Kenya.

Human herpesvirus 8 (HHV-8) infection is very prevalent in sub-Saharan Africa, but the role of sexual transmission has not been well characterized. HHV-8 seroprevalence and correlates were evaluated in a cohort of female prostitutes in Mombasa, Kenya. Between February 1993 and January 2000, stored plasma samples taken from 736 women were tested, by whole-virus ELISA assay, for the presence of HHV-8 antibodies; of these 736 women, 633 were included in the analysis of correlates of HHV-8 infection; and, of these 633, 44.1% were seropositive for HHV-8 antibodies. In univariate analysis, age, years of education, years of prostitution, workplace, hormonal contraception, intrauterine-device use, alcohol consumption, syphilis, and gonorrhea were all significantly associated with the presence of HHV-8 antibodies. In a multivariate model, older age, fewer years of education, and 2 markers of high-risk sexual behavior-namely, alcohol consumption and gonorrhea-were each independently associated with HHV-8 seropositivity. These results suggest that heterosexual transmission may contribute to acquisition of HHV-8 infections in this African population of prostitutes.

Adult↗