Biomedical subjects

Lawrence Corey

Publications and source records attributed to Lawrence Corey.

At least 55 records · Page 3Linked to original sources

PubMed2005

Differentiation of herpes simplex virus types 1 and 2 in clinical samples by a real-time taqman PCR assay.

While the clinical manifestations of HSV-1 and -2 overlap, the site of CNS infection, complications, response to antivirals, frequency of antiviral resistance, and reactivation rate on mucosal surfaces varies between HSV-1 and -2. Detection of HSV DNA by PCR has been shown to be the most sensitive method for detecting HSV in clinical samples. As such, we developed a PCR-based assay to accurately distinguish HSV-1 from HSV-2. Our initial studies indicated the assay using type specific primers was slightly less efficient for detecting HSV-1 and -2 DNA than the high throughput quantitative PCR assay we utilize that employs type common primers to gB. We subsequently evaluated the type specific assay on 3,131 specimens that had HSV DNA detected in the type common PCR assay. The typing results of these specimens were compared with the monoclonal antibody staining results of culture isolates collected from the same patients at the same time, and the HSV serologic status of the patient. The typing assay accurately identified both HSV-1 and -2 with a specificity of >99.5% and was significantly more sensitive than typing by culture and subsequent monoclonal antibody assays. Complete concordance was seen between the typing assay and HSV serologic status of the patient. Dual (HSV-1 and -2) infection in clinical samples was recognized in 2.6% of clinical samples using the new typing assay. This assay, when used in combination with the type common assay, can now accurately type almost all mucosal and visceral HSV isolates by molecular techniques.

Antibodies, Monoclonal↗

PubMed2005

Risk factors for herpes simplex virus transmission to pregnant women: a couples study.

OBJECTIVE: This study was undertaken to determine risk factors for herpes simplex virus (HSV) acquisition among at risk pregnant women. STUDY DESIGN: Women in a prospective study of HSV acquisition in pregnancy invited their sexual partners for HSV type-specific serologic testing. Risk factors for HSV susceptibility, exposure, and acquisition were examined. RESULTS: A total of 3192 couples enrolled; 22% included women at risk for HSV-1 or HSV-2. Among 582 HSV-1 seronegative women with HSV-1 seropositive partners, 14 (3.5% adjusted for gestation length) acquired HSV-1. Having a partner with a history of oral herpes was associated with HSV-1 acquisition (odds ratio [OR] 8.1, 95% CI: 1.8-36.0) and accounted for 75% of incident infections. Among 125 HSV-2 seronegative women with HSV-2 seropositive partners, 17 (20% adjusted for gestation length) acquired HSV-2. Duration of partnership of 1 year or less was associated with HSV-2 acquisition (OR 7.8, 95% CI: 2.3-25.7) and accounted for 63% of incident infections. No combination of clinical characteristics could identify the majority of susceptible women with serologically discordant partners. CONCLUSION: HSV acquisition rates in pregnancy are high in discordant couples, especially for HSV-2. Interventions that address risk factors for HSV acquisition should be studied in pregnancy. Clinical profiles cannot replace serologic screening to identify susceptible women with serologically discordant partners.

Adult↗

PubMed2005

Cytomegalovirus disease before hematopoietic cell transplantation as a risk for complications after transplantation.

Cytomegalovirus (CMV) disease in candidates for hematopoietic cell transplantation (HCT) is increasingly observed. Among 22 patients with CMV disease before HCT, the incidence of CMV disease before HCT was significantly higher in patients with severe underlying immune deficiency syndromes compared with patients with hematologic malignancies (P < .001). The lung was the most commonly involved site of infection, followed by the gastrointestinal tract and the retina. Fourteen of 22 patients with CMV disease before HCT responded to treatment and proceeded to HCT; 8 of 22 did not receive an HCT because of fatal CMV disease (n = 2) or other complications (n = 6). Of 14 patients with CMV disease who subsequently underwent HCT, 6 (42%) had CMV disease diagnosed after transplantation despite antiviral prophylaxis or preemptive therapy, and 1 patient had evidence of persistent CMV disease before day 100 after HCT. This proportion was significantly higher than that in patients without CMV disease before HCT during the same time period (day 30, adjusted P = .003; day 100, adjusted P = .02). Thirteen of 14 patients with pretransplantation CMV disease died a median of 36 days after transplantation (range, 19-399 days; adjusted P = .005 compared with CMV-seropositive transplant recipients without a history of pretransplantation CMV disease). In summary, although CMV disease before HCT may be mild and responsive to treatment, it is associated with a high risk of early CMV disease and death after transplantation.

Acyclovir↗

PubMed2005

Toxicity and efficacy of daily dapsone as Pneumocystis jiroveci prophylaxis after hematopoietic stem cell transplantation: a case-control study.

The toxicity and efficacy of dapsone given daily as Pneumocystis jiroveci (PCP) prophylaxis in hematopoietic stem cell transplant (HSCT) recipients who cannot take trimethoprim-sulfamethoxazole (TMP-SMX) have not been fully evaluated. We compared 155 HSCT recipients who received daily dapsone as second-line PCP prophylaxis with 310 matched control patients who received TMP-SMX throughout the posttransplantation course. Among patients who started dapsone before transplantation because of TMP-SMX allergy, there was no difference in the transfusion requirement after HSCT when compared with controls. Among patients who started dapsone after transplantation, increased red blood cell ( P<.0001) and platelet transfusion ( P=.003) requirements were noted compared with controls. This effect was, however, limited to patients who were receiving dapsone for reasons (mostly neutropenia) other than TMP-SMX allergy. Two of 155 patients developed PCP, compared with 0 of 310 controls ( P=.11); both patients survived. In conclusion, the efficacy of daily dapsone in preventing PCP was similar to that observed in patients able to remain on TMP-SMX prophylaxis. Dapsone did not seem to cause hematologic toxicity among TMP-SMX--allergic patients. The observed higher transfusion need in patients who received dapsone for reasons other than TMP-SMX allergy seems mostly due to an underlying condition of poor marrow reserve. Further studies are required to establish whether the drug has an etiologic role in these situations.

Adolescent↗

PubMed2005

Detection and quantification of human metapneumovirus in pediatric specimens by real-time RT-PCR.

BACKGROUND: Human metapneumovirus (h MPV), a recently identified virus, causes respiratory illness in children. OBJECTIVES: A real-time reverse transcription-polymerase chain reaction (RT-PCR) assay was developed and used to detect and quantify h MPV in respiratory specimens. STUDY DESIGN: The quantitative RT-PCR assay amplified an approximately 70 base pair fragment from the h MPV fusion protein gene. The assay was validated and used to test respiratory specimens obtained from children seen at a hospital in Seattle, Washington, from December 2002 through May 2003. RESULTS: The assay detected 1000 h MPV copies/mL of specimen, did not detect 19 other respiratory viruses, and was able to detect and accurately quantify isolates from the four known h MPV genetic lineages in a proficiency panel of 20 previously tested samples. h MPV was detected in 52 (7.2%) of 719 pediatric respiratory specimens. The mean log10 copies/mL of h MPV in the 52 positive specimens was 7.67 (range=4.59-10.60). Children aged 7-12 months had a significantly higher h MPV prevalence (12.4%) than did children younger than 7 months (4.7%) (P<0.005). Children in this age group also had significantly higher levels of h MPV in their respiratory specimens (mean log 8.43 copies/mL) than did the younger children (mean log 6.93 copies/mL) (P=0.0025). CONCLUSIONS: The rapid real-time RT-PCR assay described here is a sensitive test for clarifying the epidemiology of and diseases associated with h MPV.

Adolescent↗

PubMed2005

Most DC-SIGNR transcripts at mucosal HIV transmission sites are alternatively spliced isoforms.

The repeat region of DC-SIGNR (CD209L) is polymorphic on the genomic level, and, in a separate study, we observed a correlation between the DC-SIGNR genotype and HIV-1 susceptibility during sexual contact. However, previous investigations using immunohistochemistry failed to detect membrane-bound DC-SIGNR on cells in the genital and rectal mucosa. We therefore explored the presence of DC-SIGNR in these compartments with a more sensitive limiting dilution RT-PCR, which also allowed for quantification of alternatively spliced mRNA isoforms. DC-SIGN (CD209) and DC-SIGNR mRNA transcript isoforms were found in all 12 vaginal and two rectal biopsies obtained from 14 healthy individuals. For DC-SIGNR, we detected significantly more isoform than full-length transcripts (mean copy numbers/mug RNA: 602 vs 26; P=0.0009). Four mucosal samples lacked full-length DC-SIGNR transcripts entirely. Cloning and sequencing of DC-SIGNR mRNA in three additional individuals revealed a diverse repertoire of DC-SIGNR isoforms, many of which encoded for proteins predicted to be soluble and secreted. Indeed, in one vaginal sample, we detected only soluble isoforms. In conjunction with our prior observation that the DC-SIGNR genotype has an effect on HIV-1 transmission in vivo, these findings emphasize that DC-SIGNR, in addition to DC-SIGN, should be considered as a cofactor in sexual HIV-1 transmission. Soluble isoforms, in particular, may modulate the efficiency of viral transmission and dissemination.

Amino Acid Sequence↗

PubMed2005

Poor correlation between genital lesions and detection of herpes simplex virus in women in labor.

OBJECTIVE: To estimate the accuracy of clinical diagnosis of genital herpes for herpes simplex virus (HSV) detection among women in labor. METHODS: Viral detection by culture and HSV DNA polymerase chain reaction (PCR) among women who underwent cesarean delivery for genital herpes was compared with women without HSV symptoms in labor who had genital swabs collected for HSV culture and to a subset of these women who had genital specimens available for PCR analysis, regardless of culture results. RESULTS: From 1989 to 1999, 126 of 19,568 (0.6%) women underwent cesarean delivery for HSV. Twenty-six percent of 110 of these women had HSV detected by culture from at least 1 genital specimen and 46% of 70 of these women had HSV detected by PCR. During the same period, 61 of 12,623 (0.5%) asymptomatic women had HSV detected by culture. Between 1995 and 1996, 57 of 2,109 (2.7%) asymptomatic women had HSV detected by PCR. Thus, the presence of genital lesions had a sensitivity for HSV detection of 37% by culture and 41% by PCR. The amount of HSV present in asymptomatic women with HSV detected in genital secretions by PCR was often as high as those with genital lesions, although the median amount of HSV DNA detected was greater in women with lesions. CONCLUSION: Clinical diagnosis of genital herpes at the time of labor correlates relatively poorly with HSV detection from genital sites or lesions by culture or PCR and fails to identify asymptomatic women who have HSV in their genital secretions at the time of labor.

Adolescent↗

PubMed2005

Genital herpes complicating pregnancy.

Approximately 22% of pregnant women are infected with herpes simplex virus (HSV)-2, and 2% of women will acquire HSV during pregnancy. Remarkably, up to 90% of these women are undiagnosed because they are asymptomatic or have subtle symptoms attributed to other vulvovaginal disorders. Diagnosis of genital herpes relies on laboratory confirmation with culture or polymerase chain reaction assay of genital lesions and type-specific glycoprotein G-based serologic testing. Neonatal herpes is the most severe complication of genital HSV infection and is caused by contact with infected genital secretions at the time of labor. Maternal acquisition of HSV in the third trimester of pregnancy carries the highest risk of neonatal transmission. Despite advances in the diagnosis and treatment of neonatal herpes, little change in the incidence or serious sequelae from this infection has occurred. As such, prevention of the initial neonatal infection is critically important. Obstetricians are in a unique position to prevent vertical HSV transmission by identifying women with genital lesions at the time of labor for cesarean delivery, prescribing antiviral suppressive therapy as appropriate, and avoiding unnecessary invasive intrapartum procedures in women with genital herpes. Enhanced prevention strategies include identification of women at risk for HSV acquisition during pregnancy by testing women and possibly their partners for HSV antibodies and providing counseling to prevent transmission to women in late pregnancy.

Antiviral Agents↗

PubMed2005

Neonatal herpes should be a reportable disease.

Neonatal herpes is a devastating disease, the most serious complication of genital herpes, one of the most common serious congenital or perinatal infections, and the most frequent complication of sexually transmitted infections among children. Nevertheless, neonatal herpes is not reportable to health authorities in most states. The potential for prevention has been enhanced by recent diagnostic and therapeutic advances, and the disease meets widely accepted criteria for reporting, including incidence rates that exceed those of comparable conditions, epidemiologic instability, disease severity, direct and indirect socioeconomic costs, concern by persons at risk, the potential for prevention by public health interventions, and the prospect that the resulting data would influence public health policy. The absence of national surveillance contributes to beliefs by healthcare providers and the public health community that genital and neonatal herpes are uncommon conditions that affect small segments of society, beliefs that directly interfere with prevention. Neonatal herpes should be a reportable condition.

Antiviral Agents↗

PubMed2005

How many human immunodeficiency virus type 1-infected target cells can a cytotoxic T-lymphocyte kill?

The antiviral role of CD8+ cytotoxic T lymphocytes (CTLs) in human immunodeficiency virus type 1 (HIV-1) infection is poorly understood. Specifically, the degree to which CTLs reduce viral replication by killing HIV-1-infected cells in vivo is not known. Here we employ mathematical models of the infection process and CTL action to estimate the rate that CTLs can kill HIV-1-infected cells from in vitro and in vivo data. Our estimates, which are surprisingly consistent considering the disparities between the two experimental systems, demonstrate that on average CTLs can kill from 0.7 to 3 infected target cells per day, with the variability in this figure due to epitope specificity or other factors. These results are compatible with the observed decline in viremia after primary infection being primarily a consequence of CTL activity and have interesting implications for vaccine design.

Cell Line↗

PubMed2005

Calibration curves for real-time PCR.

BACKGROUND: Despite the increasing use of real-time PCR in the diagnosis and management of viral infections, there are no published studies adequately addressing the optimum number of calibrators, the number of replicates of each calibrator, and the frequency with which calibration needs to be repeated. This study was designed to address these issues. METHODS: Cycle threshold data (ABI 7700) was collected from >50 consecutive real-time PCR runs for hepatitis B and Epstein-Barr viruses. Our routine calibration curve made from serial 10-fold dilutions run in duplicate was compared with alternative options, including duplicate 100-fold dilutions, inclusion of a low-copy calibrator, and omission of the duplicate determination. Control data were used to examine the use of an average calibration curve made from multiple runs. RESULTS: Use of duplicate serial 10-fold dilutions led to the least imprecision, duplicate 100-fold dilutions had slightly higher imprecision, and calibration curves obtained with singlet measurements showed the greatest imprecision. For patient data, the duplicate 100-fold dilution calibration curve produced results that best matched those from the routine calibration curve. Use of singlet dilutions or inclusion of a low-copy calibrator produced poorer agreement. Variability in controls was lower with a daily calibration curve than with an average calibration curve. CONCLUSIONS: Duplicate 100-fold dilution calibration curves produced equivalent results and the same imprecision as curves with more calibrators, and thus are a valid alternative. Laboratories should carefully evaluate the variability resulting from the use of average calibration curves before adopting this approach.

Calibration↗

PubMed2004

CD27 expression promotes long-term survival of functional effector-memory CD8+ cytotoxic T lymphocytes in HIV-infected patients.

Human immunodeficiency virus (HIV)-specific CD8(+) T cells persist in high frequencies in HIV-infected patients despite impaired CD4(+) T helper response to the virus, but, unlike other differentiated effector cytotoxic T lymphocytes, most continue to express the tumor necrosis factor receptor family member CD27. Because the ligand for CD27 (CD70) is also overexpressed in HIV-infected hosts, we examined the nature of expression and potential functional consequences of CD27 expression on HIV-specific CD8(+) T cells. Analysis of CD27(+) and CD27(-) T cells derived from the same HIV-specific clone revealed that retention of CD27 did not interfere with acquisition of effector functions, and that after T cell receptor stimulation, CD27(+) cells that concurrently were triggered via CD27 exhibited more resistance to apoptosis, interleukin 2 production, and proliferation than CD27(-) T cells. After transfer back into an HIV-infected patient, autologous HIV-specific CD27(-) T cells rapidly disappeared, but CD27(+) T cells derived from the same clone persisted at high frequency. Our findings suggest that the CD27-CD70 interaction in HIV infection may provide CD27(+) CD8(+) T cells with a survival advantage and compensate for limiting or absent CD4(+) T help to maintain the CD8 response.

Adoptive Transfer↗

PubMed2004

BK virus infection in hematopoietic stem cell transplant recipients: frequency, risk factors, and association with postengraftment hemorrhagic cystitis.

Blood samples from 132 consecutive hematopoietic stem cell transplant recipients were obtained and tested weekly for BK virus DNA by use of quantitative real-time PCR. Forty-four patients (33%) developed BK viremia at a median of 41 days (range, 9-91 days) after transplantation. Patients with hemorrhagic cystitis that occurred after platelet engraftment had higher levels of viremia than did patients without hemorrhagic cystitis (median, 9.7x10(3) vs. 0 copies/mL; P=.008) and patients with hemorrhagic cystitis that occurred before platelet engraftment (median, 9.7x10(3) vs. 0 copies/mL; P=.0006). BK viremia also was strongly associated with postengraftment hemorrhagic cystitis in a time-dependent analysis (P=.004).

BK Virus↗

PubMed2004

Demographic factors that influence the neutralizing antibody response in recipients of recombinant HIV-1 gp120 vaccines.

We compared neutralizing antibody responses in human immunodeficiency virus (HIV) type 1 gp120 vaccine recipients by age, sex, and race. Four phase 1 or 2 trials involving 505 vaccinated subjects were analyzed. Age and sex had no detectable effect on neutralizing antibody responses. However, race influenced the response to one vaccine, MN gp120, in alum. Four inoculations with this vaccine generated higher serum titers of neutralizing antibodies in African Americans than in whites. Despite potent neutralization of T cell line-adapted HIV-1, serum from these African Americans failed to neutralize primary HIV-1 isolates. Neutralizing antibody responses did not differ between races when SF2 gp120 in MF-59 was administered either alone or with recombinant canarypox vCP205; they also did not differ when vCP1452 was administered either alone or with AIDSVAX B/B in alum. These data indicate that race may affect the neutralizing antibody response to some gp120 immunogens. To fully evaluate immunogenicity, clinical trials of candidate vaccines should enroll diverse populations of subjects.

AIDS Vaccines↗

PubMed2004

Influenza infections after hematopoietic stem cell transplantation: risk factors, mortality, and the effect of antiviral therapy.

BACKGROUND: Community-acquired respiratory viruses, such as influenza virus, are thought to be major causes of morbidity and mortality in patients who had undergone hematopoietic stem cell transplantation (HSCT). Risk factors for acquisition, progression to pneumonia, and the effect of antiviral therapy are unknown. METHODS: We reviewed records from patients with documented influenza over 12 consecutive respiratory-virus infection seasons at a single transplantation center. RESULTS: From 1 September 1989 through 31 March 2002, influenza virus was isolated from 62 of 4797 persons undergoing HSCT (1.3%); 44 patients had upper respiratory tract infections (URIs) alone, and 18 developed pneumonia. Among patients with influenza virus infection, pneumonia developed more commonly among those infected earlier after transplantation (median, 36 vs. 61 days, P=.04) and those with concurrent lymphopenia. Of the 51 cases that were initially diagnosed as URIs, 17 were treated with antivirals, and 34 were not treated. Six untreated patients (18%) developed pneumonia, whereas 1 (13%) of 8 patients treated with rimantadine and 0 of 9 treated with oseltamivir developed pneumonia. The duration of influenza virus shedding was longer in patients treated with steroid doses of >1 mg/kg than among those treated with doses of <1 mg/kg (mean, 15 vs. 9 days); there was a trend towards decreased shedding with oseltamivir therapy (but not rimantadine therapy) after controlling for steroid use (P<.08). The 30-day mortality rate was highest among patients who had progression to pneumonia (5 [28%] of 18 patients); pulmonary copathogens (such as Aspergillus fumigatus) were commonly isolated. CONCLUSIONS: Influenza virus infection is an important cause of mortality early after HSCT. Our nonrandomized data suggest that early antiviral therapy with neuraminidase inhibitors may prevent progression to pneumonia and decrease viral shedding, which may prevent both influenza-related death in index patients and nosocomial transmission to others.

Adolescent↗

PubMed2004

Valacyclovir and acyclovir for suppression of shedding of herpes simplex virus in the genital tract.

BACKGROUND: Valacyclovir exhibits better oral absorption and higher, more prolonged serum concentrations than oral acyclovir. The efficacy of valacyclovir and acyclovir on genital herpes simplex virus (HSV) shedding was assessed in a double-blind, 3-period crossover trial. METHODS: Sixty-nine immunocompetent participants with genital HSV-2 received oral valacyclovir, acyclovir, and matching placebo in random order for 7-week periods. Participants provided daily genital mucosal swabs for HSV detection by viral culture and polymerase chain reaction (PCR). RESULTS: HSV was detected at least once in 62 (90%) participants by culture and in 68 (98%) by PCR. During placebo, the total HSV shedding rate was 15.4% of days by culture (PCR, 40.2%); the subclinical shedding rate was 6.6% by culture (PCR, 27.1%). Both antivirals were associated with lower HSV shedding by culture (relative risk [RR], 0.03 [95% confidence interval [CI], 0.01-0.07] for valacyclovir and RR, 0.05 [95% CI, 0.03-0.10] for acyclovir) and PCR (RR, 0.18 [95% CI, 0.12-0.26] for valacyclovir and RR, 0.20 [95% CI, 0.15-0.28] for acyclovir), compared with placebo. No significant differences in frequency and quantity of HSV were detected by PCR between the valacyclovir and acyclovir arms. CONCLUSIONS: Although the suppression of viral replication is not complete, valacyclovir and acyclovir are highly effective in suppressing the frequency and quantity of genital HSV shedding.

Acyclovir↗

PubMed2004

Polyamides reveal a role for repression in latency within resting T cells of HIV-infected donors.

BACKGROUND: The persistence of human immunodeficiency virus (HIV) type 1 within resting CD4+ T cells poses a daunting therapeutic challenge. Histone deacetylase (HDAC)-1, a chromatin-remodeling enzyme that can mediate gene silencing, is recruited to the HIV-1 long terminal repeat by the host transcription factor LSF. Pyrrole-imidazole polyamides, small molecules that target specific DNA sequences, can access the nucleus of cells and specifically block transcription-factor binding. METHODS: We used polyamides to directly test the role of chromatin remodeling in HIV quiescence in primary resting CD4+ T cells obtained from HIV-infected patients. RESULTS: After exposure to any of 4 different polyamides that specifically block HDAC-1 recruitment by LSF to the HIV promoter, replication-competent HIV was recovered from cultures of resting CD4+ T cells in 6 of 8 HIV-infected patients whose viremia had been suppressed by therapy. In comparison, HIV was not recovered after exposure to control, mismatched polyamides but was recovered from 7 of 8 of these patients' samples after the activation of T cells. CONCLUSIONS: We identify histone deacetylation as a mechanism that can dampen viral expression in infected, activated CD4+ T cells and establish a persistent, quiescent reservoir of HIV infection.

Anti-HIV Agents↗

PubMed2004

Combination antifungal therapy for invasive aspergillosis.

BACKGROUND: Aspergillosis therapy with amphotericin, azoles, or echinocandins is associated with substantial mortality, ranging from 30% to 80%, depending on the stage of infection and the host's underlying disease. The results of in vitro studies and animal models suggest that combination therapy with azoles and echinocandins may have additive activity against Aspergillus species. METHODS: We evaluated the outcomes of patients with aspergillosis who experienced failure of initial therapy with amphotericin B formulations and received either voriconazole (n=31) or a combination of voriconazole and caspofungin (n=16) for salvage therapy. RESULTS: The combination of voriconazole and caspofungin was associated with improved 3-month survival rate, compared with voriconazole alone (hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.17-1.1; P=.048). In multivariable models, salvage therapy with the combination of voriconazole and caspofungin was associated with reduced mortality, compared with therapy with voriconazole (HR, 0.28; 95% CI, 0.28-0.92; P=.011), independent of other prognostic variables (e.g., receipt of transplant and type of conditioning therapy). The probability of death due to aspergillosis was lowest in patients who received the combination regimen. CONCLUSIONS: Randomized trials are warranted to determine whether this combination should be used as primary therapy for aspergillosis.

Adolescent↗