Sandra K. Burchett

Maternal levels of plasma human immunodeficiency virus type 1 RNA and the risk of perinatal transmission

BACKGROUND The importance of plasma levels of human immunodeficiency virus type 1 (HIV-1) RNA in pregnant women in relation to the other factors known to influence the risk of transmission of infection to their infants is incompletely defined. We studied the relation of maternal plasma HIV-1 RNA levels to the risk of perinatal transmission and the timing of transmission. METHODS We measured plasma HIV-1 RNA serially in 552 women with HIV-1 infection who had singleton pregnancies. The status of infection in their infants was assessed by culture of blood and further classified as early (if a culture of blood obtained within the first two days of life was positive) or late (if a culture of blood obtained in the first seven days of life was negative but subsequent cultures were positive). The rates of transmission at various levels of maternal plasma HIV-1 RNA were analyzed by tests for trend, with adjustment for covariates by stratification and logistic regression. RESULTS Increasing geometric mean levels of plasma HIV-1 RNA were associated with increasing rates of transmission: the rate was 0 percent among women with less than 1000 copies per milliliter (0 of 57), 16.6 percent among women with 1000 to 10,000 copies per milliliter (32 of 193), 21.3 percent among women with 10,001 to 50,000 copies per milliliter (39 of 183), 30.9 percent among women with 50,001 to 100,000 copies per milliliter (17 of 55), and 40.6 percent among women with more than 100,000 copies per milliliter (26 of 64) (P<0.001). The treatment status of one woman was unknown. The highest rate of transmission was among women whose plasma HIV-1 RNA levels exceeded 100,000 copies per milliliter and who had not received zidovudine (19 of 30 women, 63.3 percent). Neither higher HIV-1 RNA levels early in pregnancy nor higher levels late in pregnancy were associated with the timing of infection in the infants. CONCLUSIONS In pregnant women with HIV-1 infection the level of plasma HIV-1 RNA predicts the risk but not the timing of transmission of HIV-1 to their infants.

Evolution and transmission of stable CTL escape mutations in HIV infection

Increasing evidence indicates that potent anti-HIV-1 activity is mediated by cytotoxic T lymphocytes (CTLs); however, the effects of this immune pressure on viral transmission and evolution have not been determined. Here we investigate mother–child transmission in the setting of human leukocyte antigen (HLA)-B27 expression, selected for analysis because it is associated with prolonged immune containment in adult infection. In adults, mutations in a dominant and highly conserved B27-restricted Gag CTL epitope lead to loss of recognition and disease progression. In mothers expressing HLA-B27 who transmit HIV-1 perinatally, we document transmission of viruses encoding CTL escape variants in this dominant Gag epitope that no longer bind to B27. Their infected infants target an otherwise subdominant B27-restricted epitope and fail to contain HIV replication. These CTL escape variants remain stable without reversion in the absence of the evolutionary pressure that originally selected the mutation. These data suggest that CTL escape mutations in epitopes associated with suppression of viraemia will accumulate as the epidemic progresses, and therefore have important implications for vaccine design.

Neonatal herpes simplex virus infection in relation to asymptomatic maternal infection at the time of labor.

Abstract Background and Methods. To define the risk factors associated with neonatal acquisition of herpes simplex virus (HSV) infection, we prospectively obtained HSV cultures from the cervix and external genitalia of 15,923 pregnant women in early labor who were without symptoms or signs of genital HSV infection. Follow-up of the women with positive cultures for HSV and their HSV-exposed infants included serologic tests and serial cultures for HSV. Results. HSV was isolated from 56 of the women (0.35 percent), 18 of whom (35 percent) had serologic evidence of a recently acquired, subclinical first episode of genital HSV infection, and 34 of whom (65 percent) had reactivation of HSV. Neonatal HSV developed in 6 of 18 infants (33 percent) born to the women with a first episode of genital HSV, and in 1 of 34 infants (3 percent) born to the women with reactivation of HSV (P<0.01); neonatal HSV also occurred in three of the infants born to the 15,867 women with negative cultures. Neonatal HSV-2 occurred in 1...

Predictors of Morbidity and Mortality in Neonates with Herpes Simplex Virus Infections

BACKGROUND In a controlled trial comparing acyclovir with vidarabine in the treatment of neonatal herpes simplex virus (HSV) infection, we found no significant difference between the treatments in adjusted mortality and morbidity. Hence, we sought to define for the entire cohort (n = 202) the clinical characteristics that best predicted the eventual outcome in these neonates. METHODS Data were gathered prospectively at 27 centers between 1981 and 1988 in infants less than one month of age who had virologically confirmed HSV infection. We examined the outcomes by multivariate analyses of 24 variables. Disease was classified in one of three categories based on the extent of the involvement at entry into the trial: infection confined to skin, eyes, or mouth; encephalitis; or disseminated infection. RESULTS AND CONCLUSIONS There were no deaths among the 85 infants with localized HSV infection. The mortality rate was significantly higher in the 46 neonates with disseminated infection (57 percent) than in the 71 with encephalitis (15 percent). In addition, the risk of death was increased in neonates who were in or near coma at entry (relative risk, 5.2), had disseminated intravascular coagulopathy (relative risk, 3.8), or were premature (relative risk, 3.7). In babies with disseminated disease, HSV pneumonitis was also associated with greater mortality (relative risk, 3.6). In the survivors, morbidity was most frequent in infants with encephalitis (relative risk, 4.4), disseminated infection (relative risk, 2.1), seizures (relative risk, 3.0), or infection with HSV type 2 (relative risk, 4.9). With HSV infection limited to the skin, eyes, or mouth, the presence of three or more recurrences of vesicles was associated with an increased risk of neurologic impairment as compared with two or fewer recurrences.

A CONTROLLED TRIAL COMPARING VIDARABINE WITH ACYCLOVIR IN NEONATAL HERPES SIMPLEX VIRUS INFECTION

BACKGROUND Despite the use of vidarabine, herpes simplex virus (HSV) infection in neonates continues to be a disease of high morbidity and mortality. We undertook a controlled trial comparing vidarabine with acyclovir for the treatment of neonatal HSV infection. METHODS Babies less than one month of age with virologically confirmed HSV infection were randomly and blindly assigned to receive either intravenous vidarabine (30 mg per kilogram of body weight per day; n = 95) or acyclovir (30 mg per kilogram per day; n = 107) for 10 days. Actuarial rates of mortality and morbidity among the survivors after one year were compared overall and according to the extent of the disease at entry into the study (infection confined to the skin, eyes, or mouth; encephalitis; or disseminated disease). RESULTS After adjustment for differences between groups in the extent of disease, there was no difference between vidarabine and acyclovir in either morbidity (P = 0.83) or mortality (P = 0.27). None of the 85 babies with disease confined to the skin, eyes, or mouth died. Of the 31 babies in this group who were treated with vidarabine and followed for a year, 88 percent (22 of 25) were judged to be developing normally after one year, as compared with 98 percent (45 of 46) of the 54 treated with acyclovir (95 percent confidence interval for the difference, -4 to 24). For the 71 babies with encephalitis, mortality was 14 percent with vidarabine (5 of 36) and with acyclovir (5 of 35); of the survivors, 43 percent (13 of 30) and 29 percent (8 of 28), respectively, were developing normally after one year (95 percent confidence interval for the difference, -11 to 39). For the 46 babies with disseminated disease, mortality was 50 percent (14 of 28) with vidarabine and 61 percent (11 of 18) with acyclovir (95 percent confidence interval for the difference, -20 to 40); of the survivors, 58 percent (7 of 12) and 60 percent (3 of 5), respectively, were judged to be developing normally after one year (95 percent confidence interval for the difference, -40 to 50). Both medications were without serious toxic effects. CONCLUSIONS In this multicenter, randomized, blinded study there were no differences in outcome between vidarabine and acyclovir in the treatment of neonatal HSV infection. The study lacked statistical power to determine whether there were sizable differences within the subgroups of those with localized HSV, encephalitis, or disseminated disease.

Reduced lopinavir exposure during pregnancy.

Background:Optimal antiretroviral exposure during pregnancy is critical for prevention of mother-to-child HIV transmission and for maternal health. Pregnancy can alter antiretroviral pharmacokinetics. Our objective was to describe lopinavir/ritonavir (LPV/r) pharmacokinetics during pregnancy. Methods:We performed intensive steady-state 12-h pharmacokinetic profiles of lopinavir and ritonavir (three capsules: LPV 400 mg/r 100 mg) at 30–36 weeks gestation and 6–12 weeks postpartum. Maternal and umbilical cord blood samples were obtained at delivery. We measured LPV and ritonavir by reverse-phase high-performance liquid chromatography. Target LPV area under concentration versus time curve (AUC) was ≥ 52 μg h/ml, the estimated 10th percentile LPV AUC in non-pregnant historical controls (mean AUC = 83 μg h/ml). Results:Seventeen women completed antepartum evaluations; average gestational age was 35 weeks. Geometric mean antepartum LPV AUC was 44.4 μg h/ml [90% confidence interval (CI), 38.7–50.9] and 12-h post-dose concentration (C12h) was 1.6 μg/ml (90% CI, 1.1–2.5). Twelve women completed postpartum evaluations; geometric mean LPV AUC was 65.2 μg h/ml (90% CI, 49.7–85.4) and C12h was 4.6 μg/ml (90% CI, 3.7–5.7). The geometric mean ratio of antepartum/postpartum LPV AUC was 0.72 (90% CI, 0.54–0.96). Fourteen of 17 (82%) pregnant and three of 12 (25%) postpartum women did not meet our target LPV AUC. The ratio of cord blood/maternal LPV concentration in ten paired detectable samples was 0.2 ± 0.13. Conclusions:LPV/r exposure during late pregnancy was lower compared to postpartum and compared to non-pregnant historical controls. Small amounts of lopinavir cross the placenta. The pharmacokinetics, safety, and effectiveness of increased LPV/r dosing during the third trimester of pregnancy should be investigated.

Immune Response to Influenza Vaccine in Children With Inflammatory Bowel Disease

OBJECTIVES:Patients with inflammatory bowel disease (IBD) frequently receive immunosuppressive therapy. The immune response in these patients to vaccines has not been well studied. We conducted a prospective, open label study to evaluate the serologic response to influenza vaccine in children with IBD.METHODS:Serum was obtained from 146 children and young adults with IBD (96 Crohns disease, 47 ulcerative colitis, and 3 indeterminate colitis) for baseline influenza titer, immediately followed by immunization with trivalent (A/Solomon Islands/3/2006 (H1N1), A/Wisconsin/67/2005 (H3N2), and B/Malaysia/2506/2004 (B)) inactivated influenza vaccine. Patients returned for repeat titers 3–9 weeks later. Seroprotection against each influenza strain was defined as hemagglutination inhibition titer ≥40. Patients were categorized as nonimmunosuppressed (NIS; aminosalicylates only, antibiotics only, or no therapy) or immunosuppressed (IS; any immunosuppressive agent). IS patients were further subcategorized as: (i) tacrolimus, (ii) tumor necrosis factor-α (TNF-α) inhibitor, (3) immunomodulator, and (4) corticosteroids only.RESULTS:More patients were seroprotected against strains A/H1N1 and A/H3N2 than B strain (P<0.02), regardless of immunosuppression status. The proportion of seroprotected patients and geometric mean titers at post-vaccination were similar between NIS and IS groups for all three strains. Subanalysis of patients not seroprotected at baseline showed that those receiving anti-TNF therapy were less likely to be seroprotected against strain B (14%) compared to patients in the NIS group (39%, P=0.025). There were no serious vaccine-associated adverse events.CONCLUSIONS:Influenza vaccination produces a high prevalence of seroprotection in IBD patients, particularly against A strains. The vaccine is well tolerated. Routine influenza vaccination in IBD patients is recommended, irrespective of whether patients receive immunosuppressive medications.

International perspectives, progress, and future challenges of paediatric HIV infection

Paediatric HIV infection is a growing health challenge worldwide, with an estimated 1500 new infections every day. In developed countries, well established prevention programmes keep mother-to-child transmission rates at less than 2%. However, in developing countries, where transmission rates are 25-40%, interventions are available to only 5-10% of women. Children with untreated natural infection progress rapidly to disease, especially in resource-poor settings where mortality is greater than 50% by 2 years of age. As in adult infection, antiretroviral therapy has the potential to rewrite the natural history of HIV, but is accessible only to a small number of children needing therapy. We focus on the clinical and immunological features of HIV that are specific to paediatric infection, and the formidable challenges ahead to ensure that all children worldwide have access to interventions that have proved successful in developed countries.

Administration of oral acyclovir suppressive therapy after neonatal herpes simplex virus disease limited to the skin, eyes and mouth: Results of a phase I/II trial

BACKGROUND Neonatal herpes simplex virus (HSV) infections limited to the skin, eyes and mouth (SEM) can result in neurologic impairment. A direct correlation exists between the development of neurologic deficits and the frequency of cutaneous HSV recurrences. Thus, the National Institutes of Allergy and Infectious Diseases Collaborative Antiviral Study Group conducted a Phase I/II trial of oral acyclovir therapy for the suppression of cutaneous recurrences after SEM disease in 26 neonates. METHODS Infants < or = 1 month of age with virologically confirmed HSV-2 SEM disease were eligible for enrollment. Suppressive oral acyclovir therapy (300 mg/m2/dose given either twice daily or three times per day) was administered for 6 months. RESULTS Twelve (46%) of the 26 infants developed neutropenia (< 1000 cells/mm3) while receiving acyclovir. Thirteen (81%) of the 16 infants who received drug 3 times per day experienced no recurrences of skin lesions while receiving therapy. In comparison, a previous Collaborative Antiviral Study Group study found that only 54% of infants have no cutaneous recurrences in the 6 months after resolution of neonatal HSV disease if oral acyclovir suppressive therapy is not initiated. In one infant, HSV DNA was detected in the cerebrospinal fluid during a cutaneous recurrence, and an acyclovir-resistant HSV mutant was isolated from another patient during the course of the study. CONCLUSIONS Administration of oral acyclovir can prevent cutaneous recurrences of HSV after neonatal SEM disease. The effect of such therapy on neurologic outcome must be assessed in a larger, Phase III study. As such, additional investigation is necessary before routine use of suppressive therapy in this population can be recommended.

HIV-1 Viral Escape in Infancy Followed by Emergence of a Variant-Specific CTL Response

Mutational escape from the CTL response represents a major driving force for viral diversification in HIV-1-infected adults, but escape during infancy has not been described previously. We studied the immune response of perinatally infected children to an epitope (B57-TW10) that is targeted early during acute HIV-1 infection in adults expressing HLA-B57 and rapidly mutates under this selection pressure. Viral sequencing revealed the universal presence of escape mutations within TW10 among B57- and B5801-positive children. Mutations in TW10 and other B57-restricted epitopes arose early following perinatal infection of B57-positive children born to B57-negative mothers. Surprisingly, the majority of B57/5801-positive children exhibited a robust response to the TW10 escape variant while recognizing the wild-type epitope weakly or not at all. These data demonstrate that children, even during the first years of life, are able to mount functional immune responses of sufficient potency to drive immune escape. Moreover, our data suggest that the consequences of immune escape may differ during infancy because most children mount a strong variant-specific immune response following escape, which is rarely seen in adults. Taken together, these findings indicate that the developing immune system of children may exhibit greater plasticity in responding to a continually evolving chronic viral infection.