Meei-Li Huang

Vaccine Prevention of Maternal Cytomegalovirus Infection

BACKGROUNDnCongenital infection with cytomegalovirus (CMV) is an important cause of hearing, cognitive, and motor impairments in newborns.nnnMETHODSnIn this phase 2, placebo-controlled, randomized, double-blind trial, we evaluated a vaccine consisting of recombinant CMV envelope glycoprotein B with MF59 adjuvant, as compared with placebo. Three doses of the CMV vaccine or placebo were given at 0, 1, and 6 months to CMV-seronegative women within 1 year after they had given birth. We tested for CMV infection in the women in quarterly tests during a 42-month period, using an assay for IgG antibodies against CMV proteins other than glycoprotein B. Infection was confirmed by virus culture or immunoblotting. The primary end point was the time until the detection of CMV infection.nnnRESULTSnWe randomly assigned 234 subjects to receive the CMV vaccine and 230 subjects to receive placebo. A scheduled interim analysis led to a stopping recommendation because of vaccine efficacy. After a minimum of 1 year of follow-up, there were 49 confirmed infections, 18 in the vaccine group and 31 in the placebo group. Kaplan-Meier analysis showed that the vaccine group was more likely to remain uninfected during a 42-month period than the placebo group (P=0.02). Vaccine efficacy was 50% (95% confidence interval, 7 to 73) on the basis of infection rates per 100 person-years. One congenital infection among infants of the subjects occurred in the vaccine group, and three infections occurred in the placebo group. There were more local reactions (pain, erythema, induration, and warmth) and systemic reactions (chills, arthralgias, and myalgias) in the vaccine group than in the placebo group.nnnCONCLUSIONSnCMV glycoprotein B vaccine has the potential to decrease incident cases of maternal and congenital CMV infection. (ClinicalTrials.gov number, NCT00125502.)

Virus-specific CD8+ T cells accumulate near sensory nerve endings in genital skin during subclinical HSV-2 reactivation

Cytotoxic CD8+ T cells play a critical role in controlling herpes simplex virus (HSV) infection and reactivation. However, little is known about the spatiotemporal dynamics of CD8+ T cells during HSV lesion evolution or about their involvement in immune surveillance after lesion resolution. Using quantum dot–conjugated peptide–major histocompatibility complex multimers, we investigated the in vivo localization of HSV-2–specific CD8+ T cells in sequential biopsies of human genital skin during acute, resolving, and healed stages of HSV-2 reactivation. Our studies revealed that functionally active CD8+ T cells selectively infiltrated to the site of viral reactivation. After lesion healing in concert with complete reepithelialization and loss of HSV DNA from skin biopsies, HSV-2–specific CD8+ T cells persisted for more than two months at the dermal–epidermal junction, adjacent to peripheral nerve endings. In two out of the six sequentially studied individuals, HSV-2 DNA reappeared in clinically and histologically normal–appearing skin. Detection of viral DNA was accompanied by increased numbers of both HSV-specific and total CD8+ T cells in the dermis. These findings indicate that the frequency and clinical course of HSV-2 reactivation in humans is influenced by virus-specific CD8+ T cells that persist in peripheral mucosa and genital skin after resolution of herpes lesions.

High Incidence of Ganciclovir-Resistant Cytomegalovirus Infection among Lung Transplant Recipients Receiving Preemptive Therapy

Preemptive antiviral therapy in transplant patients is thought to be less likely to lead to antiviral resistance than is routine prophylaxis. Cytomegalovirus (CMV)-seropositive lung transplant patients (R+) were assigned to receive pp65 antigen-guided ganciclovir therapy, and seronegative recipients of organs from seropositive donors (D+/R-) were assigned to receive initially preemptive and then routine ganciclovir prophylaxis. The incidence of infection with ganciclovir-resistant (ganR) CMV was assessed retrospectively. GanR CMV infection developed in 4 (9%) of 45 patients, at a median of 4.4 months (range, 3.1-6.6 months) after transplantation, and was more common among D+/R- patients than among R+ patients (3 of 11 vs. 1 of 34; P =.04). The incidence among patients who received preemptive therapy was similar to that among patients who received routine prophylaxis. All ganR isolates contained a UL97 mutation. GanR CMV infection occurs in nearly 10% of lung transplant recipients, despite preemptive antiviral therapy, and is more common among D+/R- patients.

Long-Term Entecavir Treatment Results in Sustained Antiviral Efficacy and Prolonged Life Span in the Woodchuck Model of Chronic Hepatitis Infection

Entecavir (ETV) is a guanosine nucleoside analogue with potent antiviral efficacy in woodchucks chronically infected with woodchuck hepatitis virus. To explore the consequences of prolonged virus suppression, woodchucks received ETV orally for 8 weeks and then weekly for 12 months. Of the 6 animals withdrawn from therapy and monitored for an additional 28 months, 3 had a sustained antiviral response and had no evidence of hepatocellular carcinoma (HCC). Of the 6 animals that continued on a weekly ETV regimen for an additional 22 months, 4 exhibited serum viral DNA levels near the lower limit of detection for >2 years and had no evidence of HCC. Viral antigens and covalently closed circular DNA levels in liver samples were significantly reduced in all animals. ETV was well tolerated, and there was no evidence of resistant variants. On the basis of historical data, long-term ETV treatment appeared to significantly prolong the life of treated animals and delay the emergence of HCC.

Human Herpesvirus 6 Reactivation and Encephalitis in Allogeneic Bone Marrow Transplant Recipients

To determine whether receipt of an investigational anti-CD3 monoclonal antibody (BC3) increased the risk of human herpesvirus 6 (HHV-6) reactivation and development of encephalitis in bone marrow transplant (BMT) recipients, persons who had and had not received BC3 were compared. Odds of HHV-6 reactivation were higher among BC3 recipients than among control patients (odds ratio, 2.5; 95% confidence interval [CI], 1.3-4.7). In addition, BC3 recipients were more likely than control patients to develop encephalitis (risk ratio [RR], 3.5; 95% CI, 1.3-9.5), and this association followed a BC3 dose-dependent relationship (P=.03, by Mantel-Haenszel chi(2) test). In a multivariable model, HHV-6 reactivation and receipt of BC3 were associated with increased risk of encephalitis (RR, 5.4; 95% CI, 1.9-15.3, and RR, 3.3; 95% CI, 1.2-9.1, respectively). In conclusion, both HHV-6 reactivation and receipt of BC3 for prophylaxis of acute graft-versus-host disease independently increased the risk of encephalitis in allogeneic BMT recipients. Prospective studies to better define the relationship between HHV-6 reactivation and encephalitis in allogeneic BMT recipients are warranted.

Quantitative Real-Time Polymerase Chain Reaction for Detection of Adenovirus after T Cell–Replete Hematopoietic Cell Transplantation: Viral Load as a Marker for Invasive Disease

BACKGROUNDnThe value of adenovirus plasma DNA detection as an indicator for adenovirus disease is unknown in the context of T cell-replete hematopoietic cell transplantation, of which adenovirus disease is an uncommon but serious complication.nnnMETHODSnThree groups of 62 T cell-replete hematopoietic cell transplant recipients were selected and tested for adenovirus in plasma by polymerase chain reaction.nnnRESULTSnAdenovirus was detected in 21 (87.5%) of 24 patients with proven adenovirus disease (group 1), in 4 (21%) of 19 patients who shed adenovirus (group 2), and in 1 (10.5%) of 19 uninfected control patients. The maximum viral load was significantly higher in group 1 (median maximum viral load, 6.3x10(6) copies/mL; range, 0 to 1.0x10(9) copies/mL) than in group 2 (median maximum viral load, 0 copies/mL; range, 0 to 1.7x10(8) copies/mL; P<.001) and in group 3 (median maximum viral load, 0 copies/mL; range 0-40 copies/mL; P<.001). All patients in group 2 who developed adenoviremia had symptoms compatible with adenovirus disease (i.e., possible disease). A minimal plasma viral load of 10(3) copies/mL was detected in all patients with proven or possible disease. Adenoviremia was detectable at a median of 19.5 days (range, 8-48 days) and 24 days (range, 9-41 days) before death for patients with proven and possible adenovirus disease, respectively.nnnCONCLUSIONnSustained or high-level adenoviremia appears to be a specific and sensitive indicator of adenovirus disease after T cell-replete hematopoietic cell transplantation. In the context of low prevalence of adenovirus disease, the use of polymerase chain reaction of plasma specimens to detect virus might be a valuable tool to identify and treat patients at risk for viral invasive disease.

Reduced Mortality of Cytomegalovirus Pneumonia After Hematopoietic Cell Transplantation Due to Antiviral Therapy and Changes in Transplantation Practices

BACKGROUNDnDespite major advances in the prevention of cytomegalovirus (CMV) disease, the treatment of CMV pneumonia in recipients of hematopoietic cell transplant remains a significant challenge.nnnMETHODSnWe examined recipient, donor, transplant, viral, and treatment factors associated with overall and attributable mortality using Cox regression models.nnnRESULTSnFour hundred twenty-one cases were identified between 1986 and 2011. Overall survival at 6 months was 30% (95% confidence interval [CI], 25%-34%). Outcome improved after the year 2000 (all-cause mortality: adjusted hazard ratio [aHR], 0.7 [95% CI, .5-1.0]; P = .06; attributable mortality: aHR, 0.6 [95% CI, .4-.9]; P = .01). Factors independently associated with an increased risk of all-cause and attributable mortality included female sex, elevated bilirubin, lymphopenia, and mechanical ventilation; grade 3/4 acute graft-vs-host disease was associated with all-cause mortality only. An analysis of patients who received transplants in the current preemptive therapy era (n = 233) showed only lymphopenia and mechanical ventilation as significant risk factors for overall and attributable mortality. Antiviral treatment with ganciclovir or foscarnet was associated with improved outcome compared with no antiviral treatment. However, the addition of intravenous pooled or CMV-specific immunoglobulin to antiviral treatment did not seem to improve overall or attributable mortality.nnnCONCLUSIONSnOutcome of CMV pneumonia showed a modest improvement over the past 25 years. However, advances seem to be due to antiviral treatment and changes in transplant practices rather than immunoglobulin-based treatments. Novel treatment strategies for CMV pneumonia are needed.

Worldwide circulation of HSV-2 × HSV-1 recombinant strains

Homo sapiens harbor two distinct, medically significant species of simplexviruses, herpes simplex virus (HSV)-1 and HSV-2, with estimated divergence 6–8 million years ago (MYA). Unexpectedly, we found that circulating HSV-2 strains can contain HSV-1 DNA segments in three distinct genes. Using over 150 genital swabs from North and South America and Africa, we detected recombinants worldwide. Common, widely distributed gene UL39 genotypes are parsimoniously explained by an initialu2009>457 basepair (bp) HSV-1u2009×u2009HSV-2 crossover followed by back-recombination to HSV-2. Blocks ofu2009>244 andu2009>539u2009bp of HSV-1 DNA within genes UL29 and UL30, respectively, have reached near fixation, with a minority of strains retaining sequences we posit as ancestral HSV-2. Our data add to previous in vitro and animal work, implying that in vivo cellular co-infection with HSV-1 and HSV-2 yields viable interspecies recombinants in the natural human host.

Transient Oral Human Cytomegalovirus Infections Indicate Inefficient Viral Spread from Very Few Initially Infected Cells

ABSTRACT Cytomegalovirus (CMV) is acquired by the oral route in children, and primary infection is associated with abundant mucosal replication, as well as the establishment of latency in myeloid cells that results in lifelong infection. The efficiency of primary CMV infection in humans following oral exposure, however, is unknown. We consistently detected self-limited, low-level oral CMV shedding events, which we termed transient CMV infections, in a prospective birth cohort of 30 highly exposed CMV-uninfected infants. We estimated the likelihood of transient oral CMV infections by comparing their observed frequency to that of established primary infections, characterized by persistent high-level shedding, viremia, and seroconversion. We developed mathematical models of viral dynamics upon initial oral CMV infection and validated them using clinical shedding data. Transient infections comprised 76 to 88% of oral CMV shedding events. For this high percentage of transient infections to occur, we identified two mathematical prerequisites: a very small number of initially infected oral cells (1 to 4) and low viral infectivity (<1.5 new cells infected/cell). These observations indicate that oral CMV infection in infants typically begins with a single virus that spreads inefficiently to neighboring cells. Thus, although the incidence of CMV infection is high during infancy, our data provide a mechanistic framework to explain why multiple CMV exposures are typically required before infection is successfully established. These findings imply that a sufficiently primed immune response could prevent CMV from establishing latent infection in humans and support the achievability of a prophylactic CMV vaccine. IMPORTANCE CMV infects the majority of the worlds population and is a major cause of birth defects. Developing a vaccine to prevent CMV infection would be extremely valuable but would be facilitated by a better understanding of how natural human CMV infection is acquired. We studied CMV acquisition in infants and found that infections are usually brief and self-limited and are successfully established relatively rarely. Thus, although most people eventually acquire CMV infection, it usually requires numerous exposures. Our analyses indicate that this is because the virus is surprisingly inefficient, barely replicating well enough to spread to neighboring cells in the mouth. Greater knowledge of why CMV infection usually fails may provide insight into how to prevent it from succeeding.

Herpes Simplex Virus Type 1 Shedding in Tears and Nasal and Oral Mucosa of Healthy Adults

Background Herpes simplex virus type 1 (HSV-1) is prevalent worldwide and causes mucocutaneous infections of the oral area. We aimed to define the frequency and anatomic distribution of HSV-1 reactivation in the facial area in persons with a history of oral herpes. Methods Eight immunocompetent HSV-1 seropositive adults were evaluated for shedding of HSV-1 from 12 separate orofacial sites (8 from oral mucosa, 2 from nose, and 2 from conjunctiva) 5 days a week and from the oral cavity 7 days a week for approximately 5 consecutive weeks by a HSV DNA PCR assay. Symptoms and lesions were recorded by participants. Results Herpes simplex virus type 1 was detected at least from 1 site on 77 (26.5%) of 291 days. The most frequent site of shedding was the oral mucosa, with widespread shedding throughout the oral cavity. Lesional shedding rate was 36.4% (4 of 11 days with lesions), and the asymptomatic rate was 27.1% (65 of 240 nonlesional days). In individual participants, the median rate of HSV shedding by HSV PCR was 19.7% of days (range, 11%–63%). Conclusions Reactivation of HSV-1 on the oral mucosa is common and usually asymptomatic. However, HSV-1 is rarely found in tears and nasal mucosa. Frequent oral shedding of HSV-1 may increase the risk for transmitting the virus to both oral and genital mucosa of sexual partners.